1 Privoxy 3.0.8 User Manual
3 [ Copyright 2001 - 2007 by Privoxy Developers ]
5 $Id: user-manual.sgml,v 2.53 2008/01/19 15:03:05 hal9 Exp $
7 The Privoxy User Manual gives users information on how to install, configure
10 Privoxy is a non-caching web proxy with advanced filtering capabilities for
11 enhancing privacy, modifying web page data, managing HTTP cookies, controlling
12 access, and removing ads, banners, pop-ups and other obnoxious Internet junk.
13 Privoxy has a flexible configuration and can be customized to suit individual
14 needs and tastes. Privoxy has application for both stand-alone systems and
17 Privoxy is based on Internet Junkbuster (tm).
19 You can find the latest version of the Privoxy User Manual at http://
20 www.privoxy.org/user-manual/. Please see the Contact section on how to contact
23 -------------------------------------------------------------------------------
34 2.1.1. Red Hat and Fedora RPMs
35 2.1.2. Debian and Ubuntu
44 2.2. Building from Source
45 2.3. Keeping your Installation Up-to-Date
47 3. What's New in this Release
49 3.1. Note to Upgraders
51 4. Quickstart to Using Privoxy
53 4.1. Quickstart to Ad Blocking
57 5.1. Red Hat and Fedora
60 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
65 5.9. Command Line Options
67 6. Privoxy Configuration
69 6.1. Controlling Privoxy with Your Web Browser
70 6.2. Configuration Files Overview
72 7. The Main Configuration File
74 7.1. Local Set-up Documentation
81 7.2. Configuration and Log File Locations
95 7.3.2. single-threaded
97 7.4. Access Control and Security
101 7.4.3. enable-remote-toggle
102 7.4.4. enable-remote-http-toggle
103 7.4.5. enable-edit-actions
104 7.4.6. enforce-blocks
105 7.4.7. ACLs: permit-access and deny-access
111 7.5.2. forward-socks4 and forward-socks4a
112 7.5.3. Advanced Forwarding Examples
113 7.5.4. forwarded-connect-retries
114 7.5.5. accept-intercepted-requests
115 7.5.6. allow-cgi-request-crunching
116 7.5.7. split-large-forms
118 7.6. Windows GUI Options
122 8.1. Finding the Right Mix
124 8.3. How Actions are Applied to Requests
127 8.4.1. The Domain Pattern
128 8.4.2. The Path Pattern
129 8.4.3. The Tag Pattern
135 8.5.3. client-header-filter
136 8.5.4. client-header-tagger
137 8.5.5. content-type-overwrite
138 8.5.6. crunch-client-header
139 8.5.7. crunch-if-none-match
140 8.5.8. crunch-incoming-cookies
141 8.5.9. crunch-server-header
142 8.5.10. crunch-outgoing-cookies
143 8.5.11. deanimate-gifs
144 8.5.12. downgrade-http-version
145 8.5.13. fast-redirects
147 8.5.15. force-text-mode
148 8.5.16. forward-override
149 8.5.17. handle-as-empty-document
150 8.5.18. handle-as-image
151 8.5.19. hide-accept-language
152 8.5.20. hide-content-disposition
153 8.5.21. hide-if-modified-since
154 8.5.22. hide-forwarded-for-headers
155 8.5.23. hide-from-header
156 8.5.24. hide-referrer
157 8.5.25. hide-user-agent
158 8.5.26. inspect-jpegs
160 8.5.28. limit-connect
161 8.5.29. prevent-compression
162 8.5.30. overwrite-last-modified
164 8.5.32. send-vanilla-wafer
166 8.5.34. server-header-filter
167 8.5.35. server-header-tagger
168 8.5.36. session-cookies-only
169 8.5.37. set-image-blocker
170 8.5.38. treat-forbidden-connects-like-blocks
174 8.7. Actions Files Tutorial
176 8.7.1. default.action
181 9.1. Filter File Tutorial
182 9.2. The Pre-defined Filters
184 10. Privoxy's Template Files
185 11. Contacting the Developers, Bug Reporting and Feature Requests
188 11.2. Reporting Problems
190 11.2.1. Reporting Ads or Other Configuration Problems
191 11.2.2. Reporting Bugs
193 11.3. Request New Features
196 12. Privoxy Copyright, License and History
205 14.1. Regular Expressions
206 14.2. Privoxy's Internal Pages
210 14.3. Chain of Events
211 14.4. Troubleshooting: Anatomy of an Action
215 This documentation is included with the current stable version of Privoxy,
218 -------------------------------------------------------------------------------
222 In addition to the core features of ad blocking and cookie management, Privoxy
223 provides many supplemental features, that give the end-user more control, more
224 privacy and more freedom:
226 * Can be run as an "intercepting" proxy, which obviates the need to configure
227 browsers individually.
229 * Sophisticated actions and filters for manipulating both server and client
232 * Can be chained with other proxies.
234 * Integrated browser based configuration and control utility at http://
235 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
236 and filter effects. Remote toggling.
238 * Web page filtering (text replacements, removes banners based on size,
239 invisible "web-bugs", JavaScript and HTML annoyances, pop-up windows, etc.)
241 * Modularized configuration that allows for standard settings and user
242 settings to reside in separate files, so that installing updated actions
243 files won't overwrite individual user settings.
245 * Support for Perl Compatible Regular Expressions in the configuration files,
246 and a more sophisticated and flexible configuration syntax.
248 * Improved cookie management features (e.g. session based cookies).
252 * Bypass many click-tracking scripts (avoids script redirection).
254 * Multi-threaded (POSIX and native threads).
256 * User-customizable HTML templates for all proxy-generated pages (e.g.
259 * Auto-detection and re-reading of config file changes.
261 * Improved signal handling, and a true daemon mode (Unix).
263 * Every feature now controllable on a per-site or per-location basis,
264 configuration more powerful and versatile over-all.
266 * Many smaller new features added, limitations and bugs removed, and security
269 -------------------------------------------------------------------------------
273 Privoxy is available both in convenient pre-compiled packages for a wide range
274 of operating systems, and as raw source code. For most users, we recommend
275 using the packages, which can be downloaded from our Privoxy Project Page.
277 Note: On some platforms, the installer may remove previously installed
278 versions, if found. (See below for your platform). In any case be sure to
279 backup your old configuration if it is valuable to you. See the note to
280 upgraders section below.
282 -------------------------------------------------------------------------------
286 How to install the binary packages depends on your operating system:
288 -------------------------------------------------------------------------------
290 2.1.1. Red Hat and Fedora RPMs
292 RPMs can be installed with rpm -Uvh privoxy-3.0.8-1.rpm, and will use /etc/
293 privoxy for the location of configuration files.
295 Note that on Red Hat, Privoxy will not be automatically started on system boot.
296 You will need to enable that using chkconfig, ntsysv, or similar methods.
298 If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm
299 --rebuild privoxy-3.0.8-1.src.rpm. This will use your locally installed
300 libraries and RPM version.
302 Also note that if you have a Junkbuster RPM installed on your system, you need
303 to remove it first, because the packages conflict. Otherwise, RPM will try to
304 remove Junkbuster automatically if found, before installing Privoxy.
306 -------------------------------------------------------------------------------
308 2.1.2. Debian and Ubuntu
310 DEBs can be installed with apt-get install privoxy, and will use /etc/privoxy
311 for the location of configuration files.
313 -------------------------------------------------------------------------------
317 Just double-click the installer, which will guide you through the installation
318 process. You will find the configuration files in the same directory as you
319 installed Privoxy in.
321 Version 3.0.5 beta introduced full Windows service functionality. On Windows
322 only, the Privoxy program has two new command line arguments to install and
323 uninstall Privoxy as a service.
327 --install[:service_name]
329 --uninstall[:service_name]
331 After invoking Privoxy with --install, you will need to bring up the Windows
332 service console to assign the user you want Privoxy to run under, and whether
333 or not you want it to run whenever the system starts. You can start the Windows
334 services console with the following command: services.msc. If you do not take
335 the manual step of modifying Privoxy's service settings, it will not start.
336 Note too that you will need to give Privoxy a user account that actually
337 exists, or it will not be permitted to write to its log and configuration
340 -------------------------------------------------------------------------------
344 Create a new directory, cd to it, then unzip and untar the archive. For the
345 most part, you'll have to figure out where things go.
347 -------------------------------------------------------------------------------
351 First, make sure that no previous installations of Junkbuster and / or Privoxy
352 are left on your system. Check that no Junkbuster or Privoxy objects are in
355 Then, just double-click the WarpIN self-installing archive, which will guide
356 you through the installation process. A shadow of the Privoxy executable will
357 be placed in your startup folder so it will start automatically whenever OS/2
360 The directory you choose to install Privoxy into will contain all of the
363 -------------------------------------------------------------------------------
367 Unzip the downloaded file (you can either double-click on the file from the
368 finder, or from the desktop if you downloaded it there). Then, double-click on
369 the package installer icon named Privoxy.pkg and follow the installation
370 process. Privoxy will be installed in the folder /Library/Privoxy. It will
371 start automatically whenever you start up. To prevent it from starting
372 automatically, remove or rename the folder /Library/StartupItems/Privoxy.
374 To start Privoxy by hand, double-click on StartPrivoxy.command in the /Library/
375 Privoxy folder. Or, type this command in the Terminal:
377 /Library/Privoxy/StartPrivoxy.command
381 You will be prompted for the administrator password.
383 -------------------------------------------------------------------------------
387 Copy and then unpack the lha archive to a suitable location. All necessary
388 files will be installed into Privoxy directory, including all configuration and
389 log files. To uninstall, just remove this directory.
391 -------------------------------------------------------------------------------
395 Privoxy is part of FreeBSD's Ports Collection, you can build and install it
396 with cd /usr/ports/www/privoxy; make install clean.
398 If you don't use the ports, you can fetch and install the package with pkg_add
401 The port skeleton and the package can also be downloaded from the File Release
402 Page, but there's no reason to use them unless you're interested in the beta
403 releases which are only available there.
405 -------------------------------------------------------------------------------
409 Gentoo source packages (Ebuilds) for Privoxy are contained in the Gentoo
410 Portage Tree (they are not on the download page, but there is a Gentoo section,
411 where you can see when a new Privoxy Version is added to the Portage Tree).
413 Before installing Privoxy under Gentoo just do first emerge rsync to get the
414 latest changes from the Portage tree. With emerge privoxy you install the
417 Configuration files are in /etc/privoxy, the documentation is in /usr/share/doc
418 /privoxy-3.0.8 and the Log directory is in /var/log/privoxy.
420 -------------------------------------------------------------------------------
422 2.2. Building from Source
424 The most convenient way to obtain the Privoxy sources is to download the source
425 tarball from our project download page.
427 If you like to live on the bleeding edge and are not afraid of using possibly
428 unstable development versions, you can check out the up-to-the-minute version
429 directly from the CVS repository.
431 To build Privoxy from source, autoconf, GNU make (gmake), and, of course, a C
432 compiler like gcc are required.
434 When building from a source tarball, first unpack the source:
436 tar xzvf privoxy-3.0.8-src* [.tgz or .tar.gz]
440 For retrieving the current CVS sources, you'll need a CVS client installed.
441 Note that sources from CVS are typically development quality, and may not be
442 stable, or well tested. To download CVS source, check the Sourceforge
443 documentation, which might give commands like:
445 cvs -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa login
446 cvs -z3 -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa co current
450 This will create a directory named current/, which will contain the source
453 You can also check out any Privoxy "branch", just exchange the current name
454 with the wanted branch name (Example: v_3_0_branch for the 3.0 cvs tree).
456 It is also strongly recommended to not run Privoxy as root. You should
457 configure/install/run Privoxy as an unprivileged user, preferably by creating a
458 "privoxy" user and group just for this purpose. See your local documentation
459 for the correct command line to do add new users and groups (something like
460 adduser, but the command syntax may vary from platform to platform).
462 /etc/passwd might then look like:
464 privoxy:*:7777:7777:privoxy proxy:/no/home:/no/shell
467 And then /etc/group, like:
472 Some binary packages may do this for you.
474 Then, to build from either unpacked tarball or CVS source:
478 ./configure # (--help to see options)
479 make # (the make from GNU, sometimes called gmake)
480 su # Possibly required
481 make -n install # (to see where all the files will go)
482 make -s install # (to really install, -s to silence output)
485 Using GNU make, you can have the first four steps automatically done for you by
491 in the freshly downloaded or unpacked source directory.
493 To build an executable with security enhanced features so that users cannot
494 easily bypass the proxy (e.g. "Go There Anyway"), or alter their own
495 configurations, configure like this:
497 ./configure --disable-toggle --disable-editor --disable-force
500 Then build as above. In Privoxy 3.0.7 and later, all of these options can also
501 be disabled through the configuration file.
503 WARNING: If installing as root, the install will fail unless a non-root user or
504 group is specified, or a privoxy user and group already exist on the system. If
505 a non-root user is specified, and no group, then the installation will try to
506 also use a group of the same name as "user". If a group is specified (and no
507 user), then the support files will be installed as writable by that group, and
508 owned by the user running the installation.
510 configure accepts --with-user and --with-group options for setting user and
511 group ownership of the configuration files (which need to be writable by the
512 daemon). The specified user must already exist. When starting Privoxy, it must
513 be run as this same user to insure write access to configuration and log files!
515 Alternately, you can specify user and group on the make command line, but be
516 sure both already exist:
518 make -s install USER=privoxy GROUP=privoxy
521 The default installation path for make install is /usr/local. This may of
522 course be customized with the various ./configure path options. If you are
523 doing an install to anywhere besides /usr/local, be sure to set the appropriate
524 paths with the correct configure options (./configure --help). Non-privileged
525 users must of course have write access permissions to wherever the target
526 installation is going.
528 If you do install to /usr/local, the install will use sysconfdir=$prefix/etc/
529 privoxy by default. All other destinations, and the direct usage of
530 --sysconfdir flag behave like normal, i.e. will not add the extra privoxy
531 directory. This is for a safer install, as there may already exist another
532 program that uses a file with the "config" name, and thus makes /usr/local/etc
535 If installing to /usr/local, the documentation will go by default to $prefix/
536 share/doc. But if this directory doesn't exist, it will then try $prefix/doc
537 and install there before creating a new $prefix/share/doc just for Privoxy.
539 Again, if the installs goes to /usr/local, the localstatedir (ie: var/) will
540 default to /var instead of $prefix/var so the logs will go to /var/log/privoxy
541 /, and the pid file will be created in /var/run/privoxy.pid.
543 make install will attempt to set the correct values in config (main
544 configuration file). You should check this to make sure all values are correct.
545 If appropriate, an init script will be installed, but it is up to the user to
546 determine how and where to start Privoxy. The init script should be checked for
547 correct paths and values, if anything other than a default install is done.
549 If install finds previous versions of local configuration files, most of these
550 will not be overwritten, and the new ones will be installed with a "new"
551 extension. default.action, default.filter, and standard.action will be
552 overwritten. You will then need to manually update the other installed
553 configuration files as needed. The default template files will be overwritten.
554 If you have customized, local templates, these should be stored safely in a
555 separate directory and defined in config by the "templdir" directive. It is of
556 course wise to always back-up any important configuration files "just in case".
557 If a previous version of Privoxy is already running, you will have to restart
560 For more detailed instructions on how to build Redhat RPMs, Windows
561 self-extracting installers, building on platforms with special requirements
562 etc, please consult the developer manual.
564 -------------------------------------------------------------------------------
566 2.3. Keeping your Installation Up-to-Date
568 As user feedback comes in and development continues, we will make updated
569 versions of both the main actions file (as a separate package) and the software
570 itself (including the actions file) available for download.
572 If you wish to receive an email notification whenever we release updates of
573 Privoxy or the actions file, subscribe to our announce mailing list,
574 ijbswa-announce@lists.sourceforge.net.
576 In order not to lose your personal changes and adjustments when updating to the
577 latest default.action file we strongly recommend that you use user.action and
578 user.filter for your local customizations of Privoxy. See the Chapter on
579 actions files for details.
581 -------------------------------------------------------------------------------
583 3. What's New in this Release
585 There are many improvements and new features since Privoxy 3.0.6, the last
588 * Two new actions server-header-tagger and client-header-tagger that can be
589 used to create arbitrary "tags" based on client and server headers. These
590 "tags" can then subsequently be used to control the other actions used for
591 the current request, greatly increasing Privoxy's flexibility and
592 selectivity. See tag patterns for more information on tags.
594 * Header filtering is done with dedicated header filters now. As a result the
595 actions "filter-client-headers" and "filter-server-headers" that were
596 introduced with Privoxy 3.0.5 to apply content filters to the headers have
597 been removed. See the new actions server-header-filter and
598 client-header-filter for details.
600 * There are four new options for the main config file:
602 + allow-cgi-request-crunching which allows requests for Privoxy's
603 internal CGI pages to be blocked, redirected or (un)trusted like
606 + split-large-forms that will work around a browser bug that caused IE6
607 and IE7 to ignore the Submit button on the Privoxy's
608 edit-actions-for-url CGI page.
610 + accept-intercepted-requests which allows to combine Privoxy with any
611 packet filter to create an intercepting proxy for HTTP/1.1 requests
612 (and for HTTP/1.0 requests with Host header set). This means clients
613 can be forced to use Privoxy even if their proxy settings are
614 configured differently.
616 + templdir to designate an alternate location for Privoxy's locally
617 customized CGI templates so that these are not overwritten during
620 * A new command line option --pre-chroot-nslookup hostname to initialize the
621 resolver library before chroot'ing. On some systems this reduces the number
622 of files that must be copied into the chroot tree. (Patch provided by
625 * The forward-override action allows changing of the forwarding settings
626 through the actions files. Combined with tags, this allows to choose the
627 forwarder based on client headers like the User-Agent, or the request
630 * The redirect action can now use regular expression substitutions against
633 * zlib support is now available as a compile time option to filter compressed
634 content. Patch provided by Wil Mahan.
636 * Improve various filters, and add new ones.
638 * Include support for RFC 3253 so that Subversion works with Privoxy. Patch
639 provided by Petr Kadlec.
641 * Logging can be completely turned off by not specifying a logfile directive.
643 * A number of improvements to Privoxy's internal CGI pages, including the use
644 of favicons for error and control pages.
646 * Many bugfixes, memory leaks addressed, code improvements, and logging
649 For a more detailed list of changes please have a look at the ChangeLog.
651 -------------------------------------------------------------------------------
653 3.1. Note to Upgraders
655 A quick list of things to be aware of before upgrading from earlier versions of
658 * The recommended way to upgrade Privoxy is to backup your old configuration
659 files, install the new ones, verify that Privoxy is working correctly and
660 finally merge back your changes using diff and maybe patch.
662 There are a number of new features in each Privoxy release and most of them
663 have to be explicitly enabled in the configuration files. Old configuration
664 files obviously don't do that and due to syntax changes using old
665 configuration files with a new Privoxy isn't always possible anyway.
667 * Note that some installers remove earlier versions completely, including
668 configuration files, therefore you should really save any important
671 * On the other hand, other installers don't overwrite existing configuration
672 files, thinking you will want to do that yourself.
674 * standard.action now only includes the enabled actions. Not all actions as
677 * In the default configuration only fatal errors are logged now. You can
678 change that in the debug section of the configuration file. You may also
679 want to enable more verbose logging until you verified that the new Privoxy
680 version is working as expected.
682 * Three other config file settings are now off by default:
683 enable-remote-toggle, enable-remote-http-toggle, and enable-edit-actions.
684 If you use or want these, you will need to explicitly enable them, and be
685 aware of the security issues involved.
687 * The "filter-client-headers" and "filter-server-headers" actions that were
688 introduced with Privoxy 3.0.5 to apply content filters to the headers have
689 been removed and replaced with new actions. See the What's New section
692 -------------------------------------------------------------------------------
694 4. Quickstart to Using Privoxy
696 * Install Privoxy. See the Installation Section below for platform specific
699 * Advanced users and those who want to offer Privoxy service to more than
700 just their local machine should check the main config file, especially the
701 security-relevant options. These are off by default.
703 * Start Privoxy, if the installation program has not done this already (may
704 vary according to platform). See the section Starting Privoxy.
706 * Set your browser to use Privoxy as HTTP and HTTPS (SSL) proxy by setting
707 the proxy configuration for address of 127.0.0.1 and port 8118. DO NOT
708 activate proxying for FTP or any protocols besides HTTP and HTTPS (SSL)
709 unless you intend to prevent your browser from using these protocols.
711 * Flush your browser's disk and memory caches, to remove any cached ad
712 images. If using Privoxy to manage cookies, you should remove any currently
715 * A default installation should provide a reasonable starting point for most.
716 There will undoubtedly be occasions where you will want to adjust the
717 configuration, but that can be dealt with as the need arises. Little to no
718 initial configuration is required in most cases, you may want to enable the
719 web-based action editor though. Be sure to read the warnings first.
721 See the Configuration section for more configuration options, and how to
722 customize your installation. You might also want to look at the next
723 section for a quick introduction to how Privoxy blocks ads and banners.
725 * If you experience ads that slip through, innocent images that are blocked,
726 or otherwise feel the need to fine-tune Privoxy's behavior, take a look at
727 the actions files. As a quick start, you might find the richly commented
728 examples helpful. You can also view and edit the actions files through the
729 web-based user interface. The Appendix "Troubleshooting: Anatomy of an
730 Action" has hints on how to understand and debug actions that "misbehave".
732 * Please see the section Contacting the Developers on how to report bugs,
733 problems with websites or to get help.
735 * Now enjoy surfing with enhanced control, comfort and privacy!
737 -------------------------------------------------------------------------------
739 4.1. Quickstart to Ad Blocking
741 Ad blocking is but one of Privoxy's array of features. Many of these features
742 are for the technically minded advanced user. But, ad and banner blocking is
743 surely common ground for everybody.
745 This section will provide a quick summary of ad blocking so you can get up to
746 speed quickly without having to read the more extensive information provided
747 below, though this is highly recommended.
749 First a bit of a warning ... blocking ads is much like blocking SPAM: the more
750 aggressive you are about it, the more likely you are to block things that were
751 not intended. And the more likely that some things may not work as intended. So
752 there is a trade off here. If you want extreme ad free browsing, be prepared to
753 deal with more "problem" sites, and to spend more time adjusting the
754 configuration to solve these unintended consequences. In short, there is not an
755 easy way to eliminate all ads. Either take the easy way and settle for most ads
756 blocked with the default configuration, or jump in and tweak it for your
757 personal surfing habits and preferences.
759 Secondly, a brief explanation of Privoxy's "actions". "Actions" in this
760 context, are the directives we use to tell Privoxy to perform some task
761 relating to HTTP transactions (i.e. web browsing). We tell Privoxy to take some
762 "action". Each action has a unique name and function. While there are many
763 potential actions in Privoxy's arsenal, only a few are used for ad blocking.
764 Actions, and action configuration files, are explained in depth below.
766 Actions are specified in Privoxy's configuration, followed by one or more URLs
767 to which the action should apply. URLs can actually be URL type patterns that
768 use wildcards so they can apply potentially to a range of similar URLs. The
769 actions, together with the URL patterns are called a section.
771 When you connect to a website, the full URL will either match one or more of
772 the sections as defined in Privoxy's configuration, or not. If so, then Privoxy
773 will perform the respective actions. If not, then nothing special happens.
774 Furthermore, web pages may contain embedded, secondary URLs that your web
775 browser will use to load additional components of the page, as it parses the
776 original page's HTML content. An ad image for instance, is just an URL embedded
777 in the page somewhere. The image itself may be on the same server, or a server
778 somewhere else on the Internet. Complex web pages will have many such embedded
779 URLs. Privoxy can deal with each URL individually, so, for instance, the main
780 page text is not touched, but images from such-and-such server are blocked.
782 The most important actions for basic ad blocking are: block, handle-as-image,
783 handle-as-empty-document,and set-image-blocker:
785 * block - this is perhaps the single most used action, and is particularly
786 important for ad blocking. This action stops any contact between your
787 browser and any URL patterns that match this action's configuration. It can
788 be used for blocking ads, but also anything that is determined to be
789 unwanted. By itself, it simply stops any communication with the remote
790 server and sends Privoxy's own built-in BLOCKED page instead to let you now
791 what has happened (with some exceptions, see below).
793 * handle-as-image - tells Privoxy to treat this URL as an image. Privoxy's
794 default configuration already does this for all common image types (e.g.
795 GIF), but there are many situations where this is not so easy to determine.
796 So we'll force it in these cases. This is particularly important for ad
797 blocking, since only if we know that it's an image of some kind, can we
798 replace it with an image of our choosing, instead of the Privoxy BLOCKED
799 page (which would only result in a "broken image" icon). There are some
800 limitations to this though. For instance, you can't just brute-force an
801 image substitution for an entire HTML page in most situations.
803 * handle-as-empty-document - sends an empty document instead of Privoxy's
804 normal BLOCKED HTML page. This is useful for file types that are neither
805 HTML nor images, such as blocking JavaScript files.
807 * set-image-blocker - tells Privoxy what to display in place of an ad image
808 that has hit a block rule. For this to come into play, the URL must match a
809 block action somewhere in the configuration, and, it must also match an
810 handle-as-image action.
812 The configuration options on what to display instead of the ad are:
814 pattern - a checkerboard pattern, so that an ad replacement is obvious.
817 blank - A very small empty GIF image is displayed. This is the so-called
818 "invisible" configuration option.
820 http://<URL> - A redirect to any image anywhere of the user's choosing
823 Advanced users will eventually want to explore Privoxy filters as well. Filters
824 are very different from blocks. A "block" blocks a site, page, or unwanted
825 contented. Filters are a way of filtering or modifying what is actually on the
826 page. An example filter usage: a text replacement of "no-no" for "nasty-word".
827 That is a very simple example. This process can be used for ad blocking, but it
828 is more in the realm of advanced usage and has some pitfalls to be wary off.
830 The quickest way to adjust any of these settings is with your browser through
831 the special Privoxy editor at http://config.privoxy.org/show-status (shortcut:
832 http://p.p/show-status). This is an internal page, and does not require
835 Note that as of Privoxy 3.0.7 beta the action editor is disabled by default.
836 Check the enable-edit-actions section in the configuration file to learn why
837 and in which cases it's safe to enable again.
839 If you decided to enable the action editor, select the appropriate "actions"
840 file, and click "Edit". It is best to put personal or local preferences in
841 user.action since this is not meant to be overwritten during upgrades, and will
842 over-ride the settings in other files. Here you can insert new "actions", and
843 URLs for ad blocking or other purposes, and make other adjustments to the
844 configuration. Privoxy will detect these changes automatically.
846 A quick and simple step by step example:
848 * Right click on the ad image to be blocked, then select "Copy Link Location"
849 from the pop-up menu.
851 * Set your browser to http://config.privoxy.org/show-status
853 * Find user.action in the top section, and click on "Edit":
855 Figure 1. Actions Files in Use
859 * You should have a section with only block listed under "Actions:". If not,
860 click a "Insert new section below" button, and in the new section that just
861 appeared, click the Edit button right under the word "Actions:". This will
862 bring up a list of all actions. Find block near the top, and click in the
863 "Enabled" column, then "Submit" just below the list.
865 * Now, in the block actions section, click the "Add" button, and paste the
866 URL the browser got from "Copy Link Location". Remove the http:// at the
867 beginning of the URL. Then, click "Submit" (or "OK" if in a pop-up window).
869 * Now go back to the original page, and press SHIFT-Reload (or flush all
870 browser caches). The image should be gone now.
872 This is a very crude and simple example. There might be good reasons to use a
873 wildcard pattern match to include potentially similar images from the same
874 site. For a more extensive explanation of "patterns", and the entire actions
875 concept, see the Actions section.
877 For advanced users who want to hand edit their config files, you might want to
878 now go to the Actions Files Tutorial. The ideas explained therein also apply to
879 the web-based editor.
881 There are also various filters that can be used for ad blocking (filters are a
882 special subset of actions). These fall into the "advanced" usage category, and
883 are explained in depth in later sections.
885 -------------------------------------------------------------------------------
889 Before launching Privoxy for the first time, you will want to configure your
890 browser(s) to use Privoxy as a HTTP and HTTPS (SSL) proxy. The default is
891 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
892 used port 8000). This is the one configuration step that must be done!
894 Please note that Privoxy can only proxy HTTP and HTTPS traffic. It will not
895 work with FTP or other protocols.
897 Figure 2. Proxy Configuration Showing Mozilla/Netscape HTTP and HTTPS (SSL)
902 With Firefox, this is typically set under:
904 Tools -> Options -> General -> Connection Settings -> Manual Proxy
908 Or optionally on some platforms:
910 Edit -> Preferences -> General -> Connection Settings -> Manual Proxy
914 With Netscape (and Mozilla), this can be set under:
916 Edit -> Preferences -> Advanced -> Proxies -> HTTP Proxy
919 For Internet Explorer v.5-6:
921 Tools -> Internet Options -> Connections -> LAN Settings
923 Then, check "Use Proxy" and fill in the appropriate info (Address: 127.0.0.1,
924 Port: 8118). Include HTTPS (SSL), if you want HTTPS proxy support too
925 (sometimes labeled "Secure"). Make sure any checkboxes like "Use the same proxy
926 server for all protocols" is UNCHECKED. You want only HTTP and HTTPS (SSL)!
928 Figure 3. Proxy Configuration Showing Internet Explorer HTTP and HTTPS (Secure)
933 After doing this, flush your browser's disk and memory caches to force a
934 re-reading of all pages and to get rid of any ads that may be cached. Remove
935 any cookies, if you want Privoxy to manage that. You are now ready to start
936 enjoying the benefits of using Privoxy!
938 Privoxy itself is typically started by specifying the main configuration file
939 to be used on the command line. If no configuration file is specified on the
940 command line, Privoxy will look for a file named config in the current
941 directory. Except on Win32 where it will try config.txt.
943 -------------------------------------------------------------------------------
945 5.1. Red Hat and Fedora
947 A default Red Hat installation may not start Privoxy upon boot. It will use the
948 file /etc/privoxy/config as its main configuration file.
950 # /etc/rc.d/init.d/privoxy start
955 # service privoxy start
958 -------------------------------------------------------------------------------
962 We use a script. Note that Debian typically starts Privoxy upon booting per
963 default. It will use the file /etc/privoxy/config as its main configuration
966 # /etc/init.d/privoxy start
969 -------------------------------------------------------------------------------
973 Click on the Privoxy Icon to start Privoxy. If no configuration file is
974 specified on the command line, Privoxy will look for a file named config.txt.
975 Note that Windows will automatically start Privoxy when the system starts if
976 you chose that option when installing.
978 Privoxy can run with full Windows service functionality. On Windows only, the
979 Privoxy program has two new command line arguments to install and uninstall
980 Privoxy as a service. See the Windows Installation instructions for details.
982 -------------------------------------------------------------------------------
984 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
986 Example Unix startup command:
988 # /usr/sbin/privoxy /etc/privoxy/config
991 -------------------------------------------------------------------------------
995 During installation, Privoxy is configured to start automatically when the
996 system restarts. You can start it manually by double-clicking on the Privoxy
997 icon in the Privoxy folder.
999 -------------------------------------------------------------------------------
1003 During installation, Privoxy is configured to start automatically when the
1004 system restarts. To start Privoxy manually, double-click on the
1005 StartPrivoxy.command icon in the /Library/Privoxy folder. Or, type this command
1008 /Library/Privoxy/StartPrivoxy.command
1012 You will be prompted for the administrator password.
1014 -------------------------------------------------------------------------------
1018 Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in
1019 s:user-startup (RoadShow), as startup program in your startup script (Genesis),
1020 or as startup action (Miami and MiamiDx). Privoxy will automatically quit when
1021 you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack
1022 may display that Privoxy is still running).
1024 -------------------------------------------------------------------------------
1028 A script is again used. It will use the file /etc/privoxy/config as its main
1031 /etc/init.d/privoxy start
1035 Note that Privoxy is not automatically started at boot time by default. You can
1036 change this with the rc-update command.
1038 rc-update add privoxy default
1042 -------------------------------------------------------------------------------
1044 5.9. Command Line Options
1046 Privoxy may be invoked with the following command-line options:
1050 Print version info and exit. Unix only.
1054 Print short usage info and exit. Unix only.
1058 Don't become a daemon, i.e. don't fork and become process group leader, and
1059 don't detach from controlling tty. Unix only.
1063 On startup, write the process ID to FILE. Delete the FILE on exit. Failure
1064 to create or delete the FILE is non-fatal. If no FILE option is given, no
1065 PID file will be used. Unix only.
1067 * --user USER[.GROUP]
1069 After (optionally) writing the PID file, assume the user ID of USER, and if
1070 included the GID of GROUP. Exit if the privileges are not sufficient to do
1075 Before changing to the user ID given in the --user option, chroot to that
1076 user's home directory, i.e. make the kernel pretend to the Privoxy process
1077 that the directory tree starts there. If set up carefully, this can limit
1078 the impact of possible vulnerabilities in Privoxy to the files contained in
1079 that hierarchy. Unix only.
1081 * --pre-chroot-nslookup hostname
1083 Specifies a hostname to look up before doing a chroot. On some systems,
1084 initializing the resolver library involves reading config files from /etc
1085 and/or loading additional shared libraries from /lib. On these systems,
1086 doing a hostname lookup before the chroot reduces the number of files that
1087 must be copied into the chroot tree.
1089 For fastest startup speed, a good value is a hostname that is not in /etc/
1090 hosts but that your local name server (listed in /etc/resolv.conf) can
1091 resolve without recursion (that is, without having to ask any other name
1092 servers). The hostname need not exist, but if it doesn't, an error message
1093 (which can be ignored) will be output.
1097 If no configfile is included on the command line, Privoxy will look for a
1098 file named "config" in the current directory (except on Win32 where it will
1099 look for "config.txt" instead). Specify full path to avoid confusion. If no
1100 config file is found, Privoxy will fail to start.
1102 On MS Windows only there are two additional command-line options to allow
1103 Privoxy to install and run as a service. See the Window Installation section
1106 -------------------------------------------------------------------------------
1108 6. Privoxy Configuration
1110 All Privoxy configuration is stored in text files. These files can be edited
1111 with a text editor. Many important aspects of Privoxy can also be controlled
1112 easily with a web browser.
1114 -------------------------------------------------------------------------------
1116 6.1. Controlling Privoxy with Your Web Browser
1118 Privoxy's user interface can be reached through the special URL http://
1119 config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works
1120 without Internet access. You will see the following section:
1123 ? View & change the current configuration
1124 ? View the source code version numbers
1125 ? View the request headers.
1126 ? Look up which actions apply to a URL and why
1127 ? Toggle Privoxy on or off
1131 This should be self-explanatory. Note the first item leads to an editor for the
1132 actions files, which is where the ad, banner, cookie, and URL blocking magic is
1133 configured as well as other advanced features of Privoxy. This is an easy way
1134 to adjust various aspects of Privoxy configuration. The actions file, and other
1135 configuration files, are explained in detail below.
1137 "Toggle Privoxy On or Off" is handy for sites that might have problems with
1138 your current actions and filters. You can in fact use it as a test to see
1139 whether it is Privoxy causing the problem or not. Privoxy continues to run as a
1140 proxy in this case, but all manipulation is disabled, i.e. Privoxy acts like a
1141 normal forwarding proxy. There is even a toggle Bookmarklet offered, so that
1142 you can toggle Privoxy with one click from your browser.
1144 Note that several of the features described above are disabled by default in
1145 Privoxy 3.0.7 beta and later. Check the configuration file to learn why and in
1146 which cases it's safe to enable them again.
1148 -------------------------------------------------------------------------------
1150 6.2. Configuration Files Overview
1152 For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/
1153 by default. For MS Windows, OS/2, and AmigaOS these are all in the same
1154 directory as the Privoxy executable.
1156 The installed defaults provide a reasonable starting point, though some
1157 settings may be aggressive by some standards. For the time being, the principle
1158 configuration files are:
1160 * The main configuration file is named config on Linux, Unix, BSD, OS/2, and
1161 AmigaOS and config.txt on Windows. This is a required file.
1163 * default.action (the main actions file) is used to define which "actions"
1164 relating to banner-blocking, images, pop-ups, content modification, cookie
1165 handling etc should be applied by default. It also defines many exceptions
1166 (both positive and negative) from this default set of actions that enable
1167 Privoxy to selectively eliminate the junk, and only the junk, on as many
1168 websites as possible.
1170 Multiple actions files may be defined in config. These are processed in the
1171 order they are defined. Local customizations and locally preferred
1172 exceptions to the default policies as defined in default.action (which you
1173 will most probably want to define sooner or later) are probably best
1174 applied in user.action, where you can preserve them across upgrades.
1175 standard.action is only for Privoxy's internal use.
1177 There is also a web based editor that can be accessed from http://
1178 config.privoxy.org/show-status (Shortcut: http://p.p/show-status) for the
1179 various actions files.
1181 * "Filter files" (the filter file) can be used to re-write the raw page
1182 content, including viewable text as well as embedded HTML and JavaScript,
1183 and whatever else lurks on any given web page. The filtering jobs are only
1184 pre-defined here; whether to apply them or not is up to the actions files.
1185 default.filter includes various filters made available for use by the
1186 developers. Some are much more intrusive than others, and all should be
1187 used with caution. You may define additional filter files in config as you
1188 can with actions files. We suggest user.filter for any locally defined
1189 filters or customizations.
1191 The syntax of the configuration and filter files may change between different
1192 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1194 All files use the "#" character to denote a comment (the rest of the line will
1195 be ignored) and understand line continuation through placing a backslash ("\")
1196 as the very last character in a line. If the # is preceded by a backslash, it
1197 looses its special function. Placing a # in front of an otherwise valid
1198 configuration line to prevent it from being interpreted is called "commenting
1199 out" that line. Blank lines are ignored.
1201 The actions files and filter files can use Perl style regular expressions for
1202 maximum flexibility.
1204 After making any changes, there is no need to restart Privoxy in order for the
1205 changes to take effect. Privoxy detects such changes automatically. Note,
1206 however, that it may take one or two additional requests for the change to take
1207 effect. When changing the listening address of Privoxy, these "wake up"
1208 requests must obviously be sent to the old listening address.
1210 -------------------------------------------------------------------------------
1212 7. The Main Configuration File
1214 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
1215 and config.txt on Windows. Configuration lines consist of an initial keyword
1216 followed by a list of values, all separated by whitespace (any number of spaces
1217 or tabs). For example:
1219 confdir /etc/privoxy
1221 Assigns the value /etc/privoxy to the option confdir and thus indicates that
1222 the configuration directory is named "/etc/privoxy/".
1224 All options in the config file except for confdir and logdir are optional.
1225 Watch out in the below description for what happens if you leave them unset.
1227 The main config file controls all aspects of Privoxy's operation that are not
1228 location dependent (i.e. they apply universally, no matter where you may be
1231 -------------------------------------------------------------------------------
1233 7.1. Local Set-up Documentation
1235 If you intend to operate Privoxy for more users than just yourself, it might be
1236 a good idea to let them know how to reach you, what you block and why you do
1237 that, your policies, etc.
1239 -------------------------------------------------------------------------------
1245 Location of the Privoxy User Manual.
1249 A fully qualified URI
1257 http://www.privoxy.org/version/user-manual/ will be used, where version is
1258 the Privoxy version.
1262 The User Manual URI is the single best source of information on Privoxy,
1263 and is used for help links from some of the internal CGI pages. The manual
1264 itself is normally packaged with the binary distributions, so you probably
1265 want to set this to a locally installed copy.
1269 The best all purpose solution is simply to put the full local PATH to where
1270 the User Manual is located:
1272 user-manual /usr/share/doc/privoxy/user-manual
1275 The User Manual is then available to anyone with access to Privoxy, by
1276 following the built-in URL: http://config.privoxy.org/user-manual/ (or the
1277 shortcut: http://p.p/user-manual/).
1279 If the documentation is not on the local system, it can be accessed from a
1282 user-manual http://example.com/privoxy/user-manual/
1285 +-----------------------------------------------------------------+
1287 |-----------------------------------------------------------------|
1288 |If set, this option should be the first option in the config |
1289 |file, because it is used while the config file is being read on |
1291 +-----------------------------------------------------------------+
1293 -------------------------------------------------------------------------------
1295 7.1.2. trust-info-url
1299 A URL to be displayed in the error page that users will see if access to an
1300 untrusted page is denied.
1308 Two example URLs are provided
1312 No links are displayed on the "untrusted" error page.
1316 The value of this option only matters if the experimental trust mechanism
1317 has been activated. (See trustfile below.)
1319 If you use the trust mechanism, it is a good idea to write up some on-line
1320 documentation about your trust policy and to specify the URL(s) here. Use
1321 multiple times for multiple URLs.
1323 The URL(s) should be added to the trustfile as well, so users don't end up
1324 locked out from the information on why they were locked out in the first
1327 -------------------------------------------------------------------------------
1329 7.1.3. admin-address
1333 An email address to reach the Privoxy administrator.
1345 No email address is displayed on error pages and the CGI user interface.
1349 If both admin-address and proxy-info-url are unset, the whole "Local
1350 Privoxy Support" box on all generated pages will not be shown.
1352 -------------------------------------------------------------------------------
1354 7.1.4. proxy-info-url
1358 A URL to documentation about the local Privoxy setup, configuration or
1371 No link to local documentation is displayed on error pages and the CGI user
1376 If both admin-address and proxy-info-url are unset, the whole "Local
1377 Privoxy Support" box on all generated pages will not be shown.
1379 This URL shouldn't be blocked ;-)
1381 -------------------------------------------------------------------------------
1383 7.2. Configuration and Log File Locations
1385 Privoxy can (and normally does) use a number of other files for additional
1386 configuration, help and logging. This section of the configuration file tells
1387 Privoxy where to find those other files.
1389 The user running Privoxy, must have read permission for all configuration
1390 files, and write permission to any files that would be modified, such as log
1391 files and actions files.
1393 -------------------------------------------------------------------------------
1399 The directory where the other configuration files are located.
1407 /etc/privoxy (Unix) or Privoxy installation dir (Windows)
1415 No trailing "/", please.
1417 -------------------------------------------------------------------------------
1423 An alternative directory where the templates are loaded from.
1435 The templates are assumed to be located in confdir/template.
1439 Privoxy's original templates are usually overwritten with each update. Use
1440 this option to relocate customized templates that should be kept. As
1441 template variables might change between updates, you shouldn't expect
1442 templates to work with Privoxy releases other than the one they were part
1445 -------------------------------------------------------------------------------
1451 The directory where all logging takes place (i.e. where logfile and jarfile
1460 /var/log/privoxy (Unix) or Privoxy installation dir (Windows)
1468 No trailing "/", please.
1470 -------------------------------------------------------------------------------
1476 The actions file(s) to use
1480 Complete file name, relative to confdir
1484 standard.action # Internal purposes, no editing recommended
1486 default.action # Main actions file
1488 user.action # User customizations
1492 No actions are taken at all. More or less neutral proxying.
1496 Multiple actionsfile lines are permitted, and are in fact recommended!
1498 The default values include standard.action, which is used for internal
1499 purposes and should be loaded, default.action, which is the "main" actions
1500 file maintained by the developers, and user.action, where you can make your
1503 Actions files contain all the per site and per URL configuration for ad
1504 blocking, cookie management, privacy considerations, etc. There is no point
1505 in using Privoxy without at least one actions file.
1507 Note that since Privoxy 3.0.7, the complete filename, including the
1508 ".action" extension has to be specified. The syntax change was necessary to
1509 be consistent with the other file options and to allow previously forbidden
1512 -------------------------------------------------------------------------------
1518 The filter file(s) to use
1522 File name, relative to confdir
1526 default.filter (Unix) or default.filter.txt (Windows)
1530 No textual content filtering takes place, i.e. all +filter{name} actions in
1531 the actions files are turned neutral.
1535 Multiple filterfile lines are permitted.
1537 The filter files contain content modification rules that use regular
1538 expressions. These rules permit powerful changes on the content of Web
1539 pages, and optionally the headers as well, e.g., you could try to disable
1540 your favorite JavaScript annoyances, re-write the actual displayed text, or
1541 just have some fun playing buzzword bingo with web pages.
1543 The +filter{name} actions rely on the relevant filter (name) to be defined
1546 A pre-defined filter file called default.filter that contains a number of
1547 useful filters for common problems is included in the distribution. See the
1548 section on the filter action for a list.
1550 It is recommended to place any locally adapted filters into a separate
1551 file, such as user.filter.
1553 -------------------------------------------------------------------------------
1563 File name, relative to logdir
1567 Unset (commented out). When activated: logfile (Unix) or privoxy.log
1572 No logfile is written.
1576 The logfile is where all logging and error messages are written. The level
1577 of detail and number of messages are set with the debug option (see below).
1578 The logfile can be useful for tracking down a problem with Privoxy (e.g.,
1579 it's not blocking an ad you think it should block) and it can help you to
1580 monitor what your browser is doing.
1582 Depending on the debug options below, the logfile may be a privacy risk if
1583 third parties can get access to it. As most users will never look at it,
1584 Privoxy 3.0.7 and later only log fatal errors by default.
1586 For most troubleshooting purposes, you will have to change that, please
1587 refer to the debugging section for details.
1589 Your logfile will grow indefinitely, and you will probably want to
1590 periodically remove it. On Unix systems, you can do this with a cron job
1591 (see "man cron"). For Red Hat based Linux distributions, a logrotate script
1594 Any log files must be writable by whatever user Privoxy is being run as (on
1595 Unix, default user id is "privoxy").
1597 -------------------------------------------------------------------------------
1603 The file to store intercepted cookies in
1607 File name, relative to logdir
1611 Unset (commented out). When activated: jarfile (Unix) or privoxy.jar
1616 Intercepted cookies are not stored in a dedicated log file.
1620 The jarfile may grow to ridiculous sizes over time.
1622 If debug 8 (show header parsing) is enabled, cookies are also written to
1623 the logfile with the rest of the headers. Therefore this option isn't very
1624 useful and may be removed in future releases. Please report to the
1625 developers if you are still using it.
1627 -------------------------------------------------------------------------------
1633 The name of the trust file to use
1637 File name, relative to confdir
1641 Unset (commented out). When activated: trust (Unix) or trust.txt (Windows)
1645 The entire trust mechanism is disabled.
1649 The trust mechanism is an experimental feature for building white-lists and
1650 should be used with care. It is NOT recommended for the casual user.
1652 If you specify a trust file, Privoxy will only allow access to sites that
1653 are specified in the trustfile. Sites can be listed in one of two ways:
1655 Prepending a ~ character limits access to this site only (and any sub-paths
1656 within this site), e.g. ~www.example.com allows access to ~www.example.com/
1657 features/news.html, etc.
1659 Or, you can designate sites as trusted referrers, by prepending the name
1660 with a + character. The effect is that access to untrusted sites will be
1661 granted -- but only if a link from this trusted referrer was used to get
1662 there. The link target will then be added to the "trustfile" so that
1663 future, direct accesses will be granted. Sites added via this mechanism do
1664 not become trusted referrers themselves (i.e. they are added with a ~
1665 designation). There is a limit of 512 such entries, after which new entries
1668 If you use the + operator in the trust file, it may grow considerably over
1671 It is recommended that Privoxy be compiled with the --disable-force,
1672 --disable-toggle and --disable-editor options, if this feature is to be
1675 Possible applications include limiting Internet access for children.
1677 -------------------------------------------------------------------------------
1681 These options are mainly useful when tracing a problem. Note that you might
1682 also want to invoke Privoxy with the --no-daemon command line option when
1685 -------------------------------------------------------------------------------
1691 Key values that determine what information gets logged.
1699 0 (i.e.: only fatal errors (that cause Privoxy to exit) are logged)
1703 Default value is used (see above).
1707 The available debug levels are:
1709 debug 1 # log each request destination (and the crunch reason if Privoxy intercepted the request)
1710 debug 2 # show each connection status
1711 debug 4 # show I/O status
1712 debug 8 # show header parsing
1713 debug 16 # log all data written to the network into the logfile
1714 debug 32 # debug force feature
1715 debug 64 # debug regular expression filters
1716 debug 128 # debug redirects
1717 debug 256 # debug GIF de-animation
1718 debug 512 # Common Log Format
1719 debug 1024 # debug kill pop-ups
1720 debug 2048 # CGI user interface
1721 debug 4096 # Startup banner and warnings.
1722 debug 8192 # Non-fatal errors
1725 To select multiple debug levels, you can either add them or use multiple
1728 A debug level of 1 is informative because it will show you each request as
1729 it happens. 1, 4096 and 8192 are recommended so that you will notice when
1730 things go wrong. The other levels are probably only of interest if you are
1731 hunting down a specific problem. They can produce a hell of an output
1734 Privoxy used to ship with the debug levels recommended above enabled by
1735 default, but due to privacy concerns 3.0.7 and later are configured to only
1738 If you are used to the more verbose settings, simply enable the debug lines
1741 If you want to use pure CLF (Common Log Format), you should set "debug 512"
1742 ONLY and not enable anything else.
1744 Privoxy has a hard-coded limit for the length of log messages. If it's
1745 reached, messages are logged truncated and marked with "... [too long,
1748 Please don't file any support requests without trying to reproduce the
1749 problem with increased debug level first. Once you read the log messages,
1750 you may even be able to solve the problem on your own.
1752 -------------------------------------------------------------------------------
1754 7.3.2. single-threaded
1758 Whether to run only one server thread.
1770 Multi-threaded (or, where unavailable: forked) operation, i.e. the ability
1771 to serve multiple requests simultaneously.
1775 This option is only there for debugging purposes. It will drastically
1778 -------------------------------------------------------------------------------
1780 7.4. Access Control and Security
1782 This section of the config file controls the security-relevant aspects of
1783 Privoxy's configuration.
1785 -------------------------------------------------------------------------------
1787 7.4.1. listen-address
1791 The IP address and TCP port on which Privoxy will listen for client
1804 Bind to 127.0.0.1 (localhost), port 8118. This is suitable and recommended
1805 for home users who run Privoxy on the same machine as their browser.
1809 You will need to configure your browser(s) to this proxy address and port.
1811 If you already have another service running on port 8118, or if you want to
1812 serve requests from other machines (e.g. on your local network) as well,
1813 you will need to override the default.
1815 If you leave out the IP address, Privoxy will bind to all interfaces
1816 (addresses) on your machine and may become reachable from the Internet. In
1817 that case, consider using access control lists (ACL's, see below), and/or a
1820 If you open Privoxy to untrusted users, you will also want to make sure
1821 that the following actions are disabled: enable-edit-actions and
1822 enable-remote-toggle
1826 Suppose you are running Privoxy on a machine which has the address
1827 192.168.0.1 on your local private network (192.168.0.0) and has another
1828 outside connection with a different address. You want it to serve requests
1831 listen-address 192.168.0.1:8118
1834 -------------------------------------------------------------------------------
1840 Initial state of "toggle" status
1852 Act as if toggled on
1856 If set to 0, Privoxy will start in "toggled off" mode, i.e. mostly behave
1857 like a normal, content-neutral proxy with both ad blocking and content
1858 filtering disabled. See enable-remote-toggle below.
1860 The windows version will only display the toggle icon in the system tray if
1861 this option is present.
1863 -------------------------------------------------------------------------------
1865 7.4.3. enable-remote-toggle
1869 Whether or not the web-based toggle feature may be used
1881 The web-based toggle feature is disabled.
1885 When toggled off, Privoxy mostly acts like a normal, content-neutral proxy,
1886 i.e. doesn't block ads or filter content.
1888 Access to the toggle feature can not be controlled separately by "ACLs" or
1889 HTTP authentication, so that everybody who can access Privoxy (see "ACLs"
1890 and listen-address above) can toggle it for all users. So this option is
1891 not recommended for multi-user environments with untrusted users.
1893 Note that malicious client side code (e.g Java) is also capable of using
1896 As a lot of Privoxy users don't read documentation, this feature is
1897 disabled by default.
1899 Note that you must have compiled Privoxy with support for this feature,
1900 otherwise this option has no effect.
1902 -------------------------------------------------------------------------------
1904 7.4.4. enable-remote-http-toggle
1908 Whether or not Privoxy recognizes special HTTP headers to change its
1921 Privoxy ignores special HTTP headers.
1925 When toggled on, the client can change Privoxy's behaviour by setting
1926 special HTTP headers. Currently the only supported special header is
1927 "X-Filter: No", to disable filtering for the ongoing request, even if it is
1928 enabled in one of the action files.
1930 This feature is disabled by default. If you are using Privoxy in a
1931 environment with trusted clients, you may enable this feature at your
1932 discretion. Note that malicious client side code (e.g Java) is also capable
1933 of using this feature.
1935 This option will be removed in future releases as it has been obsoleted by
1936 the more general header taggers.
1938 -------------------------------------------------------------------------------
1940 7.4.5. enable-edit-actions
1944 Whether or not the web-based actions file editor may be used
1956 The web-based actions file editor is disabled.
1960 Access to the editor can not be controlled separately by "ACLs" or HTTP
1961 authentication, so that everybody who can access Privoxy (see "ACLs" and
1962 listen-address above) can modify its configuration for all users.
1964 This option is not recommended for environments with untrusted users and as
1965 a lot of Privoxy users don't read documentation, this feature is disabled
1968 Note that malicious client side code (e.g Java) is also capable of using
1969 the actions editor and you shouldn't enable this options unless you
1970 understand the consequences and are sure your browser is configured
1973 Note that you must have compiled Privoxy with support for this feature,
1974 otherwise this option has no effect.
1976 -------------------------------------------------------------------------------
1978 7.4.6. enforce-blocks
1982 Whether the user is allowed to ignore blocks and can "go there anyway".
1994 Blocks are not enforced.
1998 Privoxy is mainly used to block and filter requests as a service to the
1999 user, for example to block ads and other junk that clogs the pipes.
2000 Privoxy's configuration isn't perfect and sometimes innocent pages are
2001 blocked. In this situation it makes sense to allow the user to enforce the
2002 request and have Privoxy ignore the block.
2004 In the default configuration Privoxy's "Blocked" page contains a "go there
2005 anyway" link to adds a special string (the force prefix) to the request
2006 URL. If that link is used, Privoxy will detect the force prefix, remove it
2007 again and let the request pass.
2009 Of course Privoxy can also be used to enforce a network policy. In that
2010 case the user obviously should not be able to bypass any blocks, and that's
2011 what the "enforce-blocks" option is for. If it's enabled, Privoxy hides the
2012 "go there anyway" link. If the user adds the force prefix by hand, it will
2013 not be accepted and the circumvention attempt is logged.
2019 -------------------------------------------------------------------------------
2021 7.4.7. ACLs: permit-access and deny-access
2025 Who can access what.
2029 src_addr[/src_masklen] [dst_addr[/dst_masklen]]
2031 Where src_addr and dst_addr are IP addresses in dotted decimal notation or
2032 valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
2033 notation, i.e. integer values from 2 to 30 representing the length (in
2034 bits) of the network address. The masks and the whole destination part are
2043 Don't restrict access further than implied by listen-address
2047 Access controls are included at the request of ISPs and systems
2048 administrators, and are not usually needed by individual users. For a
2049 typical home user, it will normally suffice to ensure that Privoxy only
2050 listens on the localhost (127.0.0.1) or internal (home) network address by
2051 means of the listen-address option.
2053 Please see the warnings in the FAQ that Privoxy is not intended to be a
2054 substitute for a firewall or to encourage anyone to defer addressing basic
2055 security weaknesses.
2057 Multiple ACL lines are OK. If any ACLs are specified, Privoxy only talks to
2058 IP addresses that match at least one permit-access line and don't match any
2059 subsequent deny-access line. In other words, the last match wins, with the
2060 default being deny-access.
2062 If Privoxy is using a forwarder (see forward below) for a particular
2063 destination URL, the dst_addr that is examined is the address of the
2064 forwarder and NOT the address of the ultimate target. This is necessary
2065 because it may be impossible for the local Privoxy to determine the IP
2066 address of the ultimate target (that's often what gateways are used for).
2068 You should prefer using IP addresses over DNS names, because the address
2069 lookups take time. All DNS names must resolve! You can not use domain
2070 patterns like "*.org" or partial domain names. If a DNS name resolves to
2071 multiple IP addresses, only the first one is used.
2073 Denying access to particular sites by ACL may have undesired side effects
2074 if the site in question is hosted on a machine which also hosts other sites
2079 Explicitly define the default behavior if no ACL and listen-address are
2080 set: "localhost" is OK. The absence of a dst_addr implies that all
2081 destination addresses are OK:
2083 permit-access localhost
2086 Allow any host on the same class C subnet as www.privoxy.org access to
2087 nothing but www.example.com (or other domains hosted on the same system):
2089 permit-access www.privoxy.org/24 www.example.com/32
2092 Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
2093 with the exception that 192.168.45.73 may not access the IP address behind
2094 www.dirty-stuff.example.com:
2096 permit-access 192.168.45.64/26
2097 deny-access 192.168.45.73 www.dirty-stuff.example.com
2100 -------------------------------------------------------------------------------
2106 Maximum size of the buffer for content filtering.
2118 Use a 4MB (4096 KB) limit.
2122 For content filtering, i.e. the +filter and +deanimate-gif actions, it is
2123 necessary that Privoxy buffers the entire document body. This can be
2124 potentially dangerous, since a server could just keep sending data
2125 indefinitely and wait for your RAM to exhaust -- with nasty consequences.
2128 When a document buffer size reaches the buffer-limit, it is flushed to the
2129 client unfiltered and no further attempt to filter the rest of the document
2130 is made. Remember that there may be multiple threads running, which might
2131 require up to buffer-limit Kbytes each, unless you have enabled
2132 "single-threaded" above.
2134 -------------------------------------------------------------------------------
2138 This feature allows routing of HTTP requests through a chain of multiple
2141 Forwarding can be used to chain Privoxy with a caching proxy to speed up
2142 browsing. Using a parent proxy may also be necessary if the machine that
2143 Privoxy runs on has no direct Internet access.
2145 Note that parent proxies can severely decrease your privacy level. For example
2146 a parent proxy could add your IP address to the request headers and if it's a
2147 caching proxy it may add the "Etag" header to revalidation requests again, even
2148 though you configured Privoxy to remove it. It may also ignore Privoxy's header
2149 time randomization and use the original values which could be used by the
2150 server as cookie replacement to track your steps between visits.
2152 Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
2155 -------------------------------------------------------------------------------
2161 To which parent HTTP proxy specific requests should be routed.
2165 target_pattern http_parent[:port]
2167 where target_pattern is a URL pattern that specifies to which requests
2168 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
2169 http_parent[:port] is the DNS name or IP address of the parent HTTP proxy
2170 through which the requests should be forwarded, optionally followed by its
2171 listening port (default: 8080). Use a single dot (.) to denote "no
2180 Don't use parent HTTP proxies.
2184 If http_parent is ".", then requests are not forwarded to another HTTP
2185 proxy but are made directly to the web servers.
2187 Multiple lines are OK, they are checked in sequence, and the last match
2192 Everything goes to an example parent proxy, except SSL on port 443 (which
2195 forward / parent-proxy.example.org:8080
2199 Everything goes to our example ISP's caching proxy, except for requests to
2202 forward / caching-proxy.isp.example.net:8000
2203 forward .isp.example.net .
2206 -------------------------------------------------------------------------------
2208 7.5.2. forward-socks4 and forward-socks4a
2212 Through which SOCKS proxy (and optionally to which parent HTTP proxy)
2213 specific requests should be routed.
2217 target_pattern socks_proxy[:port] http_parent[:port]
2219 where target_pattern is a URL pattern that specifies to which requests
2220 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
2221 http_parent and socks_proxy are IP addresses in dotted decimal notation or
2222 valid DNS names (http_parent may be "." to denote "no HTTP forwarding"),
2223 and the optional port parameters are TCP ports, i.e. integer values from 1
2232 Don't use SOCKS proxies.
2236 Multiple lines are OK, they are checked in sequence, and the last match
2239 The difference between forward-socks4 and forward-socks4a is that in the
2240 SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
2241 SOCKS server, while in SOCKS 4 it happens locally.
2243 If http_parent is ".", then requests are not forwarded to another HTTP
2244 proxy but are made (HTTP-wise) directly to the web servers, albeit through
2249 From the company example.com, direct connections are made to all "internal"
2250 domains, but everything outbound goes through their ISP's proxy by way of
2251 example.com's corporate SOCKS 4A gateway to the Internet.
2253 forward-socks4a / socks-gw.example.com:1080 www-cache.isp.example.net:8080
2254 forward .example.com .
2257 A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
2260 forward-socks4 / socks-gw.example.com:1080 .
2263 To chain Privoxy and Tor, both running on the same system, you would use
2266 forward-socks4a / 127.0.0.1:9050 .
2269 The public Tor network can't be used to reach your local network, if you
2270 need to access local servers you therefore might want to make some
2273 forward 192.168.*.*/ .
2275 forward 127.*.*.*/ .
2278 Unencrypted connections to systems in these address ranges will be as (un)
2279 secure as the local network is, but the alternative is that you can't reach
2280 the local network through Privoxy at all. Of course this may actually be
2281 desired and there is no reason to make these exceptions if you aren't sure
2284 If you also want to be able to reach servers in your local network by using
2285 their names, you will need additional exceptions that look like this:
2287 forward localhost/ .
2290 -------------------------------------------------------------------------------
2292 7.5.3. Advanced Forwarding Examples
2294 If you have links to multiple ISPs that provide various special content only to
2295 their subscribers, you can configure multiple Privoxies which have connections
2296 to the respective ISPs to act as forwarders to each other, so that your users
2297 can see the internal content of all ISPs.
2299 Assume that host-a has a PPP connection to isp-a.example.net. And host-b has a
2300 PPP connection to isp-b.example.org. Both run Privoxy. Their forwarding
2301 configuration can look like this:
2306 forward .isp-b.example.net host-b:8118
2312 forward .isp-a.example.org host-a:8118
2315 Now, your users can set their browser's proxy to use either host-a or host-b
2316 and be able to browse the internal content of both isp-a and isp-b.
2318 If you intend to chain Privoxy and squid locally, then chaining as browser ->
2319 squid -> privoxy is the recommended way.
2321 Assuming that Privoxy and squid run on the same box, your squid configuration
2322 could then look like this:
2324 # Define Privoxy as parent proxy (without ICP)
2325 cache_peer 127.0.0.1 parent 8118 7 no-query
2327 # Define ACL for protocol FTP
2330 # Do not forward FTP requests to Privoxy
2331 always_direct allow ftp
2333 # Forward all the rest to Privoxy
2334 never_direct allow all
2337 You would then need to change your browser's proxy settings to squid's address
2338 and port. Squid normally uses port 3128. If unsure consult http_port in
2341 You could just as well decide to only forward requests you suspect of leading
2342 to Windows executables through a virus-scanning parent proxy, say, on
2343 antivir.example.com, port 8010:
2346 forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010
2349 -------------------------------------------------------------------------------
2351 7.5.4. forwarded-connect-retries
2355 How often Privoxy retries if a forwarded connection request fails.
2367 Connections forwarded through other proxies are treated like direct
2368 connections and no retry attempts are made.
2372 forwarded-connect-retries is mainly interesting for socks4a connections,
2373 where Privoxy can't detect why the connections failed. The connection might
2374 have failed because of a DNS timeout in which case a retry makes sense, but
2375 it might also have failed because the server doesn't exist or isn't
2376 reachable. In this case the retry will just delay the appearance of
2377 Privoxy's error message.
2379 Note that in the context of this option, "forwarded connections" includes
2380 all connections that Privoxy forwards through other proxies. This option is
2381 not limited to the HTTP CONNECT method.
2383 Only use this option, if you are getting lots of forwarding-related error
2384 messages that go away when you try again manually. Start with a small value
2385 and check Privoxy's logfile from time to time, to see how many retries are
2390 forwarded-connect-retries 1
2392 -------------------------------------------------------------------------------
2394 7.5.5. accept-intercepted-requests
2398 Whether intercepted requests should be treated as valid.
2410 Only proxy requests are accepted, intercepted requests are treated as
2415 If you don't trust your clients and want to force them to use Privoxy,
2416 enable this option and configure your packet filter to redirect outgoing
2417 HTTP connections into Privoxy.
2419 Make sure that Privoxy's own requests aren't redirected as well.
2420 Additionally take care that Privoxy can't intentionally connect to itself,
2421 otherwise you could run into redirection loops if Privoxy's listening port
2422 is reachable by the outside or an attacker has access to the pages you
2427 accept-intercepted-requests 1
2429 -------------------------------------------------------------------------------
2431 7.5.6. allow-cgi-request-crunching
2435 Whether requests to Privoxy's CGI pages can be blocked or redirected.
2447 Privoxy ignores block and redirect actions for its CGI pages.
2451 By default Privoxy ignores block or redirect actions for its CGI pages.
2452 Intercepting these requests can be useful in multi-user setups to implement
2453 fine-grained access control, but it can also render the complete web
2454 interface useless and make debugging problems painful if done without care.
2456 Don't enable this option unless you're sure that you really need it.
2460 allow-cgi-request-crunching 1
2462 -------------------------------------------------------------------------------
2464 7.5.7. split-large-forms
2468 Whether the CGI interface should stay compatible with broken HTTP clients.
2480 The CGI form generate long GET URLs.
2484 Privoxy's CGI forms can lead to rather long URLs. This isn't a problem as
2485 far as the HTTP standard is concerned, but it can confuse clients with
2486 arbitrary URL length limitations.
2488 Enabling split-large-forms causes Privoxy to divide big forms into smaller
2489 ones to keep the URL length down. It makes editing a lot less convenient
2490 and you can no longer submit all changes at once, but at least it works
2491 around this browser bug.
2493 If you don't notice any editing problems, there is no reason to enable this
2494 option, but if one of the submit buttons appears to be broken, you should
2501 -------------------------------------------------------------------------------
2503 7.6. Windows GUI Options
2505 Privoxy has a number of options specific to the Windows GUI interface:
2507 If "activity-animation" is set to 1, the Privoxy icon will animate when
2508 "Privoxy" is active. To turn off, set to 0.
2510 activity-animation 1
2513 If "log-messages" is set to 1, Privoxy will log messages to the console window:
2518 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
2519 of memory used for the log messages displayed in the console window, will be
2520 limited to "log-max-lines" (see below).
2522 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
2528 log-max-lines is the maximum number of lines held in the log buffer. See above.
2533 If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
2534 log messages with a bold-faced font:
2536 log-highlight-messages 1
2539 The font used in the console window:
2541 log-font-name Comic Sans MS
2544 Font size used in the console window:
2549 "show-on-task-bar" controls whether or not Privoxy will appear as a button on
2550 the Task bar when minimized:
2555 If "close-button-minimizes" is set to 1, the Windows close button will minimize
2556 Privoxy instead of closing the program (close with the exit option on the File
2559 close-button-minimizes 1
2562 The "hide-console" option is specific to the MS-Win console version of Privoxy.
2563 If this option is used, Privoxy will disconnect from and hide the command
2569 -------------------------------------------------------------------------------
2573 The actions files are used to define what actions Privoxy takes for which URLs,
2574 and thus determines how ad images, cookies and various other aspects of HTTP
2575 content and transactions are handled, and on which sites (or even parts
2576 thereof). There are a number of such actions, with a wide range of
2577 functionality. Each action does something a little different. These actions
2578 give us a veritable arsenal of tools with which to exert our control,
2579 preferences and independence. Actions can be combined so that their effects are
2580 aggregated when applied against a given set of URLs.
2582 There are three action files included with Privoxy with differing purposes:
2584 * default.action - is the primary action file that sets the initial values
2585 for all actions. It is intended to provide a base level of functionality
2586 for Privoxy's array of features. So it is a set of broad rules that should
2587 work reasonably well as-is for most users. This is the file that the
2588 developers are keeping updated, and making available to users. The user's
2589 preferences as set in standard.action, e.g. either Cautious (the default),
2590 Medium, or Advanced (see below).
2592 * user.action - is intended to be for local site preferences and exceptions.
2593 As an example, if your ISP or your bank has specific requirements, and need
2594 special handling, this kind of thing should go here. This file will not be
2597 * standard.action - is used only by the web based editor at http://
2598 config.privoxy.org/edit-actions-list?f=default, to set various pre-defined
2599 sets of rules for the default actions section in default.action.
2601 Edit Set to Cautious Set to Medium Set to Advanced
2603 These have increasing levels of aggressiveness and have no influence on
2604 your browsing unless you select them explicitly in the editor. A default
2605 installation should be pre-set to Cautious (versions prior to 3.0.5 were
2606 set to Medium). New users should try this for a while before adjusting the
2607 settings to more aggressive levels. The more aggressive the settings, then
2608 the more likelihood there is of problems such as sites not working as they
2611 The Edit button allows you to turn each action on/off individually for
2612 fine-tuning. The Cautious button changes the actions list to low/safe
2613 settings which will activate ad blocking and a minimal set of Privoxy's
2614 features, and subsequently there will be less of a chance for accidental
2615 problems. The Medium button sets the list to a medium level of other
2616 features and a low level set of privacy features. The Advanced button sets
2617 the list to a high level of ad blocking and medium level of privacy. See
2618 the chart below. The latter three buttons over-ride any changes via with
2619 the Edit button. More fine-tuning can be done in the lower sections of this
2622 It is not recommend to edit the standard.action file itself.
2624 The default profiles, and their associated actions, as pre-defined in
2625 standard.action are:
2627 Table 1. Default Configurations
2629 +---------------------------------------------------------------+
2630 | Feature | Cautious | Medium | Advanced |
2631 |--------------------------+-----------+------------+-----------|
2632 |Ad-blocking Aggressiveness|medium |high |high |
2633 |--------------------------+-----------+------------+-----------|
2634 |Ad-filtering by size |no |yes |yes |
2635 |--------------------------+-----------+------------+-----------|
2636 |Ad-filtering by link |no |no |yes |
2637 |--------------------------+-----------+------------+-----------|
2638 |Pop-up killing |blocks only|blocks only |blocks only|
2639 |--------------------------+-----------+------------+-----------|
2640 |Privacy Features |low |medium |medium/high|
2641 |--------------------------+-----------+------------+-----------|
2642 |Cookie handling |none |session-only|kill |
2643 |--------------------------+-----------+------------+-----------|
2644 |Referer forging |no |yes |yes |
2645 |--------------------------+-----------+------------+-----------|
2646 |GIF de-animation |no |yes |yes |
2647 |--------------------------+-----------+------------+-----------|
2648 |Fast redirects |no |no |yes |
2649 |--------------------------+-----------+------------+-----------|
2650 |HTML taming |no |no |yes |
2651 |--------------------------+-----------+------------+-----------|
2652 |JavaScript taming |no |no |yes |
2653 |--------------------------+-----------+------------+-----------|
2654 |Web-bug killing |no |yes |yes |
2655 |--------------------------+-----------+------------+-----------|
2656 |Image tag reordering |no |no |yes |
2657 +---------------------------------------------------------------+
2659 The list of actions files to be used are defined in the main configuration
2660 file, and are processed in the order they are defined (e.g. default.action is
2661 typically processed before user.action). The content of these can all be viewed
2662 and edited from http://config.privoxy.org/show-status. The over-riding
2663 principle when applying actions, is that the last action that matches a given
2664 URL wins. The broadest, most general rules go first (defined in
2665 default.action), followed by any exceptions (typically also in default.action),
2666 which are then followed lastly by any local preferences (typically in
2667 user.action). Generally, user.action has the last word.
2669 An actions file typically has multiple sections. If you want to use "aliases"
2670 in an actions file, you have to place the (optional) alias section at the top
2671 of that file. Then comes the default set of rules which will apply universally
2672 to all sites and pages (be very careful with using such a universal set in
2673 user.action or any other actions file after default.action, because it will
2674 override the result from consulting any previous file). And then below that,
2675 exceptions to the defined universal policies. You can regard user.action as an
2676 appendix to default.action, with the advantage that it is a separate file,
2677 which makes preserving your personal settings across Privoxy upgrades easier.
2679 Actions can be used to block anything you want, including ads, banners, or just
2680 some obnoxious URL whose content you would rather not see. Cookies can be
2681 accepted or rejected, or accepted only during the current browser session (i.e.
2682 not written to disk), content can be modified, some JavaScripts tamed,
2683 user-tracking fooled, and much more. See below for a complete list of actions.
2685 -------------------------------------------------------------------------------
2687 8.1. Finding the Right Mix
2689 Note that some actions, like cookie suppression or script disabling, may render
2690 some sites unusable that rely on these techniques to work properly. Finding the
2691 right mix of actions is not always easy and certainly a matter of personal
2692 taste. And, things can always change, requiring refinements in the
2693 configuration. In general, it can be said that the more "aggressive" your
2694 default settings (in the top section of the actions file) are, the more
2695 exceptions for "trusted" sites you will have to make later. If, for example,
2696 you want to crunch all cookies per default, you'll have to make exceptions from
2697 that rule for sites that you regularly use and that require cookies for
2698 actually useful purposes, like maybe your bank, favorite shop, or newspaper.
2700 We have tried to provide you with reasonable rules to start from in the
2701 distribution actions files. But there is no general rule of thumb on these
2702 things. There just are too many variables, and sites are constantly changing.
2703 Sooner or later you will want to change the rules (and read this chapter again
2706 -------------------------------------------------------------------------------
2710 The easiest way to edit the actions files is with a browser by using our
2711 browser-based editor, which can be reached from http://config.privoxy.org/
2712 show-status. Note: the config file option enable-edit-actions must be enabled
2713 for this to work. The editor allows both fine-grained control over every single
2714 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2715 like "Cautious", "Medium" or "Advanced". Warning: the "Advanced" setting is
2716 more aggressive, and will be more likely to cause problems for some sites.
2717 Experienced users only!
2719 If you prefer plain text editing to GUIs, you can of course also directly edit
2720 the the actions files with your favorite text editor. Look at default.action
2721 which is richly commented with many good examples.
2723 -------------------------------------------------------------------------------
2725 8.3. How Actions are Applied to Requests
2727 Actions files are divided into sections. There are special sections, like the "
2728 alias" sections which will be discussed later. For now let's concentrate on
2729 regular sections: They have a heading line (often split up to multiple lines
2730 for readability) which consist of a list of actions, separated by whitespace
2731 and enclosed in curly braces. Below that, there is a list of URL and tag
2732 patterns, each on a separate line.
2734 To determine which actions apply to a request, the URL of the request is
2735 compared to all URL patterns in each "action file". Every time it matches, the
2736 list of applicable actions for the request is incrementally updated, using the
2737 heading of the section in which the pattern is located. The same is done again
2738 for tags and tag patterns later on.
2740 If multiple applying sections set the same action differently, the last match
2741 wins. If not, the effects are aggregated. E.g. a URL might match a regular
2742 section with a heading line of { +handle-as-image }, then later another one
2743 with just { +block }, resulting in both actions to apply. And there may well be
2744 cases where you will want to combine actions together. Such a section then
2747 { +handle-as-image +block }
2748 # Block these as if they were images. Send no block page.
2750 media.example.com/.*banners
2751 .example.com/images/ads/
2754 You can trace this process for URL patterns and any given URL by visiting http:
2755 //config.privoxy.org/show-url-info.
2757 Examples and more detail on this is provided in the Appendix, Troubleshooting:
2758 Anatomy of an Action section.
2760 -------------------------------------------------------------------------------
2764 As mentioned, Privoxy uses "patterns" to determine what actions might apply to
2765 which sites and pages your browser attempts to access. These "patterns" use
2766 wild card type pattern matching to achieve a high degree of flexibility. This
2767 allows one expression to be expanded and potentially match against many similar
2770 Generally, an URL pattern has the form <domain>/<path>, where both the <domain>
2771 and <path> are optional. (This is why the special / pattern matches all URLs).
2772 Note that the protocol portion of the URL pattern (e.g. http://) should not be
2773 included in the pattern. This is assumed already!
2775 The pattern matching syntax is different for the domain and path parts of the
2776 URL. The domain part uses a simple globbing type matching technique, while the
2777 path part uses a more flexible "Regular Expressions (PCRE)" based syntax.
2781 is a domain-only pattern and will match any request to www.example.com,
2782 regardless of which document on that server is requested. So ALL pages in
2783 this domain would be covered by the scope of this action. Note that a
2784 simple example.com is different and would NOT match.
2788 means exactly the same. For domain-only patterns, the trailing / may be
2791 www.example.com/index.html$
2793 matches all the documents on www.example.com whose name starts with /
2796 www.example.com/index.html$
2798 matches only the single document /index.html on www.example.com.
2802 matches the document /index.html, regardless of the domain, i.e. on any web
2807 matches nothing, since it would be interpreted as a domain name and there
2808 is no top-level domain called .html. So its a mistake.
2810 -------------------------------------------------------------------------------
2812 8.4.1. The Domain Pattern
2814 The matching of the domain part offers some flexible options: if the domain
2815 starts or ends with a dot, it becomes unanchored at that end. For example:
2819 matches any domain with first-level domain com and second-level domain
2820 example. For example www.example.com, example.com and
2821 foo.bar.baz.example.com. Note that it wouldn't match if the second-level
2822 domain was another-example.
2826 matches any domain that STARTS with www. (It also matches the domain www
2827 but most of the time that doesn't matter.)
2831 matches any domain that CONTAINS .example.. And, by the way, also included
2832 would be any files or documents that exist within that domain since no path
2833 limitations are specified. (Correctly speaking: It matches any FQDN that
2834 contains example as a domain.) This might be www.example.com,
2835 news.example.de, or www.example.net/cgi/testing.pl for instance. All these
2838 Additionally, there are wild-cards that you can use in the domain names
2839 themselves. These work similarly to shell globbing type wild-cards: "*"
2840 represents zero or more arbitrary characters (this is equivalent to the
2841 "Regular Expression" based syntax of ".*"), "?" represents any single character
2842 (this is equivalent to the regular expression syntax of a simple "."), and you
2843 can define "character classes" in square brackets which is similar to the same
2844 regular expression technique. All of this can be freely mixed:
2848 matches "adserver.example.com", "ads.example.com", etc but not
2853 matches all of the above, and then some.
2857 matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
2859 www[1-9a-ez].example.c*
2861 matches www1.example.com, www4.example.cc, wwwd.example.cy,
2862 wwwz.example.com etc., but not wwww.example.com.
2864 While flexible, this is not the sophistication of full regular expression based
2867 -------------------------------------------------------------------------------
2869 8.4.2. The Path Pattern
2871 Privoxy uses Perl compatible (PCRE) "Regular Expression" based syntax (through
2872 the PCRE library) for matching the path portion (after the slash), and is thus
2875 There is an Appendix with a brief quick-start into regular expressions, and
2876 full (very technical) documentation on PCRE regex syntax is available on-line
2877 at http://www.pcre.org/man.txt. You might also find the Perl man page on
2878 regular expressions (man perlre) useful, which is available on-line at http://
2879 perldoc.perl.org/perlre.html.
2881 Note that the path pattern is automatically left-anchored at the "/", i.e. it
2882 matches as if it would start with a "^" (regular expression speak for the
2883 beginning of a line).
2885 Please also note that matching in the path is CASE INSENSITIVE by default, but
2886 you can switch to case sensitive at any point in the pattern by using the "(?
2887 -i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
2888 path starts with PaTtErN in exactly this capitalization.
2892 Is equivalent to just ".example.com", since any documents within that
2893 domain are matched with or without the ".*" regular expression. This is
2896 .example.com/.*/index.html$
2898 Will match any page in the domain of "example.com" that is named
2899 "index.html", and that is part of some path. For example, it matches
2900 "www.example.com/testing/index.html" but NOT "www.example.com/index.html"
2901 because the regular expression called for at least two "/'s", thus the path
2902 requirement. It also would match "www.example.com/testing/index_html",
2903 because of the special meta-character ".".
2905 .example.com/(.*/)?index\.html$
2907 This regular expression is conditional so it will match any page named
2908 "index.html" regardless of path which in this case can have one or more "/
2909 's". And this one must contain exactly ".html" (but does not have to end
2912 .example.com/(.*/)(ads|banners?|junk)
2914 This regular expression will match any path of "example.com" that contains
2915 any of the words "ads", "banner", "banners" (because of the "?") or "junk".
2916 The path does not have to end in these words, just contain them.
2918 .example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$
2920 This is very much the same as above, except now it must end in either
2921 ".jpg", ".jpeg", ".gif" or ".png". So this one is limited to common image
2924 There are many, many good examples to be found in default.action, and more
2925 tutorials below in Appendix on regular expressions.
2927 -------------------------------------------------------------------------------
2929 8.4.3. The Tag Pattern
2931 Tag patterns are used to change the applying actions based on the request's
2932 tags. Tags can be created with either the client-header-tagger or the
2933 server-header-tagger action.
2935 Tag patterns have to start with "TAG:", so Privoxy can tell them apart from URL
2936 patterns. Everything after the colon including white space, is interpreted as a
2937 regular expression with path pattern syntax, except that tag patterns aren't
2938 left-anchored automatically (Privoxy doesn't silently add a "^", you have to do
2939 it yourself if you need it).
2941 To match all requests that are tagged with "foo" your pattern line should be
2942 "TAG:^foo$", "TAG:foo" would work as well, but it would also match requests
2943 whose tags contain "foo" somewhere. "TAG: foo" wouldn't work as it requires
2946 Sections can contain URL and tag patterns at the same time, but tag patterns
2947 are checked after the URL patterns and thus always overrule them, even if they
2948 are located before the URL patterns.
2950 Once a new tag is added, Privoxy checks right away if it's matched by one of
2951 the tag patterns and updates the action settings accordingly. As a result tags
2952 can be used to activate other tagger actions, as long as these other taggers
2953 look for headers that haven't already be parsed.
2955 For example you could tag client requests which use the POST method, then use
2956 this tag to activate another tagger that adds a tag if cookies are sent, and
2957 then use a block action based on the cookie tag. This allows the outcome of one
2958 action, to be input into a subsequent action. However if you'd reverse the
2959 position of the described taggers, and activated the method tagger based on the
2960 cookie tagger, no method tags would be created. The method tagger would look
2961 for the request line, but at the time the cookie tag is created, the request
2962 line has already been parsed.
2964 While this is a limitation you should be aware of, this kind of indirection is
2965 seldom needed anyway and even the example doesn't make too much sense.
2967 -------------------------------------------------------------------------------
2971 All actions are disabled by default, until they are explicitly enabled
2972 somewhere in an actions file. Actions are turned on if preceded with a "+", and
2973 turned off if preceded with a "-". So a +action means "do that action", e.g.
2974 +block means "please block URLs that match the following patterns", and -block
2975 means "don't block URLs that match the following patterns, even if +block
2976 previously applied."
2978 Again, actions are invoked by placing them on a line, enclosed in curly braces
2979 and separated by whitespace, like in {+some-action -some-other-action
2980 {some-parameter}}, followed by a list of URL patterns, one per line, to which
2981 they apply. Together, the actions line and the following pattern lines make up
2982 a section of the actions file.
2984 Actions fall into three categories:
2986 * Boolean, i.e the action can only be "enabled" or "disabled". Syntax:
2988 +name # enable action name
2989 -name # disable action name
2994 * Parameterized, where some value is required in order to enable this type of
2997 +name{param} # enable action and set parameter to param,
2998 # overwriting parameter from previous match if necessary
2999 -name # disable action. The parameter can be omitted
3002 Note that if the URL matches multiple positive forms of a parameterized
3003 action, the last match wins, i.e. the params from earlier matches are
3006 Example: +hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US;
3007 rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}
3009 * Multi-value. These look exactly like parameterized actions, but they behave
3010 differently: If the action applies multiple times to the same URL, but with
3011 different parameters, all the parameters from all matches are remembered.
3012 This is used for actions that can be executed for the same request
3013 repeatedly, like adding multiple headers, or filtering through multiple
3016 +name{param} # enable action and add param to the list of parameters
3017 -name{param} # remove the parameter param from the list of parameters
3018 # If it was the last one left, disable the action.
3019 -name # disable this action completely and remove all parameters from the list
3022 Examples: +add-header{X-Fun-Header: Some text} and +filter{html-annoyances}
3024 If nothing is specified in any actions file, no "actions" are taken. So in this
3025 case Privoxy would just be a normal, non-blocking, non-filtering proxy. You
3026 must specifically enable the privacy and blocking features you need (although
3027 the provided default actions files will give a good starting point).
3029 Later defined action sections always over-ride earlier ones of the same type.
3030 So exceptions to any rules you make, should come in the latter part of the file
3031 (or in a file that is processed later when using multiple actions files such as
3032 user.action). For multi-valued actions, the actions are applied in the order
3033 they are specified. Actions files are processed in the order they are defined
3034 in config (the default installation has three actions files). It also quite
3035 possible for any given URL to match more than one "pattern" (because of
3036 wildcards and regular expressions), and thus to trigger more than one set of
3037 actions! Last match wins.
3039 The list of valid Privoxy actions are:
3041 -------------------------------------------------------------------------------
3047 Confuse log analysis, custom applications
3051 Sends a user defined HTTP header to the web server.
3059 Any string value is possible. Validity of the defined HTTP headers is not
3060 checked. It is recommended that you use the "X-" prefix for custom headers.
3064 This action may be specified multiple times, in order to define multiple
3065 headers. This is rarely needed for the typical user. If you don't know what
3066 "HTTP headers" are, you definitely don't need to worry about this one.
3070 +add-header{X-User-Tracking: sucks}
3073 -------------------------------------------------------------------------------
3079 Block ads or other unwanted content
3083 Requests for URLs to which this action applies are blocked, i.e. the
3084 requests are trapped by Privoxy and the requested URL is never retrieved,
3085 but is answered locally with a substitute page or image, as determined by
3086 the handle-as-image, set-image-blocker, and handle-as-empty-document
3099 Privoxy sends a special "BLOCKED" page for requests to blocked pages. This
3100 page contains links to find out why the request was blocked, and a
3101 click-through to the blocked content (the latter only if compiled with the
3102 force feature enabled). The "BLOCKED" page adapts to the available screen
3103 space -- it displays full-blown if space allows, or miniaturized and
3104 text-only if loaded into a small frame or window. If you are using Privoxy
3105 right now, you can take a look at the "BLOCKED" page.
3107 A very important exception occurs if both block and handle-as-image, apply
3108 to the same request: it will then be replaced by an image. If
3109 set-image-blocker (see below) also applies, the type of image will be
3110 determined by its parameter, if not, the standard checkerboard pattern is
3113 It is important to understand this process, in order to understand how
3114 Privoxy deals with ads and other unwanted content. Blocking is a core
3115 feature, and one upon which various other features depend.
3117 The filter action can perform a very similar task, by "blocking" banner
3118 images and other content through rewriting the relevant URLs in the
3119 document's HTML source, so they don't get requested in the first place.
3120 Note that this is a totally different technique, and it's easy to confuse
3123 Example usage (section):
3126 # Block and replace with "blocked" page
3127 .nasty-stuff.example.com
3129 {+block +handle-as-image}
3130 # Block and replace with image
3134 {+block +handle-as-empty-document}
3135 # Block and then ignore
3136 adserver.exampleclick.net/.*\.js$
3139 -------------------------------------------------------------------------------
3141 8.5.3. client-header-filter
3145 Rewrite or remove single client headers.
3149 All client headers to which this action applies are filtered on-the-fly
3150 through the specified regular expression based substitutions.
3158 The name of a client-header filter, as defined in one of the filter files.
3162 Client-header filters are applied to each header on its own, not to all at
3163 once. This makes it easier to diagnose problems, but on the downside you
3164 can't write filters that only change header x if header y's value is z. You
3165 can do that by using tags though.
3167 Client-header filters are executed after the other header actions have
3168 finished and use their output as input.
3170 If the request URL gets changed, Privoxy will detect that and use the new
3171 one. This can be used to rewrite the request destination behind the
3172 client's back, for example to specify a Tor exit relay for certain
3175 Please refer to the filter file chapter to learn which client-header
3176 filters are available by default, and how to create your own.
3178 Example usage (section):
3180 {+client-header-filter{hide-tor-exit-notation}}
3185 -------------------------------------------------------------------------------
3187 8.5.4. client-header-tagger
3191 Block requests based on their headers.
3195 Client headers to which this action applies are filtered on-the-fly through
3196 the specified regular expression based substitutions, the result is used as
3205 The name of a client-header tagger, as defined in one of the filter files.
3209 Client-header taggers are applied to each header on its own, and as the
3210 header isn't modified, each tagger "sees" the original.
3212 Client-header taggers are the first actions that are executed and their
3213 tags can be used to control every other action.
3215 Example usage (section):
3217 # Tag every request with the User-Agent header
3218 {+client-header-tagger{user-agent}}
3223 -------------------------------------------------------------------------------
3225 8.5.5. content-type-overwrite
3229 Stop useless download menus from popping up, or change the browser's
3234 Replaces the "Content-Type:" HTTP server header.
3246 The "Content-Type:" HTTP server header is used by the browser to decide
3247 what to do with the document. The value of this header can cause the
3248 browser to open a download menu instead of displaying the document by
3249 itself, even if the document's format is supported by the browser.
3251 The declared content type can also affect which rendering mode the browser
3252 chooses. If XHTML is delivered as "text/html", many browsers treat it as
3253 yet another broken HTML document. If it is send as "application/xml",
3254 browsers with XHTML support will only display it, if the syntax is correct.
3256 If you see a web site that proudly uses XHTML buttons, but sets
3257 "Content-Type: text/html", you can use Privoxy to overwrite it with
3258 "application/xml" and validate the web master's claim inside your
3259 XHTML-supporting browser. If the syntax is incorrect, the browser will
3262 You can also go the opposite direction: if your browser prints error
3263 messages instead of rendering a document falsely declared as XHTML, you can
3264 overwrite the content type with "text/html" and have it rendered as broken
3267 By default content-type-overwrite only replaces "Content-Type:" headers
3268 that look like some kind of text. If you want to overwrite it
3269 unconditionally, you have to combine it with force-text-mode. This
3270 limitation exists for a reason, think twice before circumventing it.
3272 Most of the time it's easier to replace this action with a custom
3273 server-header filter. It allows you to activate it for every document of a
3274 certain site and it will still only replace the content types you aimed at.
3276 Of course you can apply content-type-overwrite to a whole site and then
3277 make URL based exceptions, but it's a lot more work to get the same
3280 Example usage (sections):
3282 # Check if www.example.net/ really uses valid XHTML
3283 { +content-type-overwrite{application/xml} }
3286 # but leave the content type unmodified if the URL looks like a style sheet
3287 {-content-type-overwrite}
3288 www.example.net/.*\.css$
3289 www.example.net/.*style
3292 -------------------------------------------------------------------------------
3294 8.5.6. crunch-client-header
3298 Remove a client header Privoxy has no dedicated action for.
3302 Deletes every header sent by the client that contains the string the user
3303 supplied as parameter.
3315 This action allows you to block client headers for which no dedicated
3316 Privoxy action exists. Privoxy will remove every client header that
3317 contains the string you supplied as parameter.
3319 Regular expressions are not supported and you can't use this action to
3320 block different headers in the same request, unless they contain the same
3323 crunch-client-header is only meant for quick tests. If you have to block
3324 several different headers, or only want to modify parts of them, you should
3325 use a client-header filter.
3327 +-----------------------------------------------------------------+
3329 |-----------------------------------------------------------------|
3330 |Don't block any header without understanding the consequences. |
3331 +-----------------------------------------------------------------+
3332 Example usage (section):
3334 # Block the non-existent "Privacy-Violation:" client header
3335 { +crunch-client-header{Privacy-Violation:} }
3340 -------------------------------------------------------------------------------
3342 8.5.7. crunch-if-none-match
3346 Prevent yet another way to track the user's steps between sessions.
3350 Deletes the "If-None-Match:" HTTP client header.
3362 Removing the "If-None-Match:" HTTP client header is useful for filter
3363 testing, where you want to force a real reload instead of getting status
3364 code "304" which would cause the browser to use a cached copy of the page.
3366 It is also useful to make sure the header isn't used as a cookie
3367 replacement (unlikely but possible).
3369 Blocking the "If-None-Match:" header shouldn't cause any caching problems,
3370 as long as the "If-Modified-Since:" header isn't blocked or missing as
3373 It is recommended to use this action together with hide-if-modified-since
3374 and overwrite-last-modified.
3376 Example usage (section):
3378 # Let the browser revalidate cached documents but don't
3379 # allow the server to use the revalidation headers for user tracking.
3380 {+hide-if-modified-since{-60} \
3381 +overwrite-last-modified{randomize} \
3382 +crunch-if-none-match}
3386 -------------------------------------------------------------------------------
3388 8.5.8. crunch-incoming-cookies
3392 Prevent the web server from setting HTTP cookies on your system
3396 Deletes any "Set-Cookie:" HTTP headers from server replies.
3408 This action is only concerned with incoming HTTP cookies. For outgoing HTTP
3409 cookies, use crunch-outgoing-cookies. Use both to disable HTTP cookies
3412 It makes no sense at all to use this action in conjunction with the
3413 session-cookies-only action, since it would prevent the session cookies
3414 from being set. See also filter-content-cookies.
3418 +crunch-incoming-cookies
3421 -------------------------------------------------------------------------------
3423 8.5.9. crunch-server-header
3427 Remove a server header Privoxy has no dedicated action for.
3431 Deletes every header sent by the server that contains the string the user
3432 supplied as parameter.
3444 This action allows you to block server headers for which no dedicated
3445 Privoxy action exists. Privoxy will remove every server header that
3446 contains the string you supplied as parameter.
3448 Regular expressions are not supported and you can't use this action to
3449 block different headers in the same request, unless they contain the same
3452 crunch-server-header is only meant for quick tests. If you have to block
3453 several different headers, or only want to modify parts of them, you should
3454 use a custom server-header filter.
3456 +-----------------------------------------------------------------+
3458 |-----------------------------------------------------------------|
3459 |Don't block any header without understanding the consequences. |
3460 +-----------------------------------------------------------------+
3461 Example usage (section):
3463 # Crunch server headers that try to prevent caching
3464 { +crunch-server-header{no-cache} }
3468 -------------------------------------------------------------------------------
3470 8.5.10. crunch-outgoing-cookies
3474 Prevent the web server from reading any HTTP cookies from your system
3478 Deletes any "Cookie:" HTTP headers from client requests.
3490 This action is only concerned with outgoing HTTP cookies. For incoming HTTP
3491 cookies, use crunch-incoming-cookies. Use both to disable HTTP cookies
3494 It makes no sense at all to use this action in conjunction with the
3495 session-cookies-only action, since it would prevent the session cookies
3500 +crunch-outgoing-cookies
3503 -------------------------------------------------------------------------------
3505 8.5.11. deanimate-gifs
3509 Stop those annoying, distracting animated GIF images.
3513 De-animate GIF animations, i.e. reduce them to their first or last image.
3525 This will also shrink the images considerably (in bytes, not pixels!). If
3526 the option "first" is given, the first frame of the animation is used as
3527 the replacement. If "last" is given, the last frame of the animation is
3528 used instead, which probably makes more sense for most banner animations,
3529 but also has the risk of not showing the entire last frame (if it is only a
3530 delta to an earlier frame).
3532 You can safely use this action with patterns that will also match non-GIF
3533 objects, because no attempt will be made at anything that doesn't look like
3538 +deanimate-gifs{last}
3541 -------------------------------------------------------------------------------
3543 8.5.12. downgrade-http-version
3547 Work around (very rare) problems with HTTP/1.1
3551 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3563 This is a left-over from the time when Privoxy didn't support important
3564 HTTP/1.1 features well. It is left here for the unlikely case that you
3565 experience HTTP/1.1 related problems with some server out there. Not all
3566 HTTP/1.1 features and requirements are supported yet, so there is a chance
3567 you might need this action.
3569 Example usage (section):
3571 {+downgrade-http-version}
3572 problem-host.example.com
3575 -------------------------------------------------------------------------------
3577 8.5.13. fast-redirects
3581 Fool some click-tracking scripts and speed up indirect links.
3585 Detects redirection URLs and redirects the browser without contacting the
3586 redirection server first.
3594 + "simple-check" to just search for the string "http://" to detect
3597 + "check-decoded-url" to decode URLs (if necessary) before searching for
3602 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3603 will link to some script on their own servers, giving the destination as a
3604 parameter, which will then redirect you to the final target. URLs resulting
3605 from this scheme typically look like: "http://www.example.org/
3606 click-tracker.cgi?target=http%3a//www.example.net/".
3608 Sometimes, there are even multiple consecutive redirects encoded in the
3609 URL. These redirections via scripts make your web browsing more traceable,
3610 since the server from which you follow such a link can see where you go to.
3611 Apart from that, valuable bandwidth and time is wasted, while your browser
3612 asks the server for one redirect after the other. Plus, it feeds the
3615 This feature is currently not very smart and is scheduled for improvement.
3616 If it is enabled by default, you will have to create some exceptions to
3617 this action. It can lead to failures in several ways:
3619 Not every URLs with other URLs as parameters is evil. Some sites offer a
3620 real service that requires this information to work. For example a
3621 validation service needs to know, which document to validate.
3622 fast-redirects assumes that every URL parameter that looks like another URL
3623 is a redirection target, and will always redirect to the last one. Most of
3624 the time the assumption is correct, but if it isn't, the user gets
3627 Another failure occurs if the URL contains other parameters after the URL
3628 parameter. The URL: "http://www.example.org/?redirect=http%3a//
3629 www.example.net/&foo=bar". contains the redirection URL "http://
3630 www.example.net/", followed by another parameter. fast-redirects doesn't
3631 know that and will cause a redirect to "http://www.example.net/&foo=bar".
3632 Depending on the target server configuration, the parameter will be
3633 silently ignored or lead to a "page not found" error. You can prevent this
3634 problem by first using the redirect action to remove the last part of the
3635 URL, but it requires a little effort.
3637 To detect a redirection URL, fast-redirects only looks for the string
3638 "http://", either in plain text (invalid but often used) or encoded as
3639 "http%3a//". Some sites use their own URL encoding scheme, encrypt the
3640 address of the target server or replace it with a database id. In theses
3641 cases fast-redirects is fooled and the request reaches the redirection
3642 server where it probably gets logged.
3646 { +fast-redirects{simple-check} }
3649 { +fast-redirects{check-decoded-url} }
3650 another.example.com/testing
3653 -------------------------------------------------------------------------------
3659 Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3660 do fun text replacements, add personalized effects, etc.
3664 All instances of text-based type, most notably HTML and JavaScript, to
3665 which this action applies, can be filtered on-the-fly through the specified
3666 regular expression based substitutions. (Note: as of version 3.0.3 plain
3667 text documents are exempted from filtering, because web servers often use
3668 the text/plain MIME type for all files whose type they don't know.)
3676 The name of a content filter, as defined in the filter file. Filters can be
3677 defined in one or more files as defined by the filterfile option in the
3678 config file. default.filter is the collection of filters supplied by the
3679 developers. Locally defined filters should go in their own file, such as
3682 When used in its negative form, and without parameters, all filtering is
3683 completely disabled.
3687 For your convenience, there are a number of pre-defined filters available
3688 in the distribution filter file that you can use. See the examples below
3691 Filtering requires buffering the page content, which may appear to slow
3692 down page rendering since nothing is displayed until all content has passed
3693 the filters. (It does not really take longer, but seems that way since the
3694 page is not incrementally displayed.) This effect will be more noticeable
3695 on slower connections.
3697 "Rolling your own" filters requires a knowledge of "Regular Expressions"
3698 and "HTML". This is very powerful feature, and potentially very intrusive.
3699 Filters should be used with caution, and where an equivalent "action" is
3702 The amount of data that can be filtered is limited to the buffer-limit
3703 option in the main config file. The default is 4096 KB (4 Megs). Once this
3704 limit is exceeded, the buffered data, and all pending data, is passed
3707 Inappropriate MIME types, such as zipped files, are not filtered at all.
3708 (Again, only text-based types except plain text). Encrypted SSL data (from
3709 HTTPS servers) cannot be filtered either, since this would violate the
3710 integrity of the secure transaction. In some situations it might be
3711 necessary to protect certain text, like source code, from filtering by
3712 defining appropriate -filter exceptions.
3714 Compressed content can't be filtered either, unless Privoxy is compiled
3715 with zlib support (requires at least Privoxy 3.0.7), in which case Privoxy
3716 will decompress the content before filtering it.
3718 If you use a Privoxy version without zlib support, but want filtering to
3719 work on as much documents as possible, even those that would normally be
3720 sent compressed, you must use the prevent-compression action in conjunction
3723 Content filtering can achieve some of the same effects as the block action,
3724 i.e. it can be used to block ads and banners. But the mechanism works quite
3725 differently. One effective use, is to block ad banners based on their size
3726 (see below), since many of these seem to be somewhat standardized.
3728 Feedback with suggestions for new or improved filters is particularly
3731 The below list has only the names and a one-line description of each
3732 predefined filter. There are more verbose explanations of what these
3733 filters do in the filter file chapter.
3735 Example usage (with filters from the distribution default.filter file). See the
3736 Predefined Filters section for more explanation on each:
3738 +filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse
3741 +filter{js-events} # Kill all JS event bindings (Radically destructive! Only for extra nasty sites)
3744 +filter{html-annoyances} # Get rid of particularly annoying HTML abuse
3747 +filter{content-cookies} # Kill cookies that come in the HTML or JS content
3750 +filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups)
3753 +filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.
3756 +filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.
3759 +filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective
3762 +filter{banners-by-size} # Kill banners by size
3765 +filter{banners-by-link} # Kill banners by their links to known clicktrackers
3768 +filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking)
3771 +filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap
3774 +filter{jumping-windows} # Prevent windows from resizing and moving themselves
3777 +filter{frameset-borders} # Give frames a border and make them resizeable
3780 +filter{demoronizer} # Fix MS's non-standard use of standard charsets
3783 +filter{shockwave-flash} # Kill embedded Shockwave Flash objects
3786 +filter{quicktime-kioskmode} # Make Quicktime movies savable
3789 +filter{fun} # Text replacements for subversive browsing fun!
3792 +filter{crude-parental} # Crude parental filtering (demo only)
3795 +filter{ie-exploits} # Disable a known Internet Explorer bug exploits
3798 +filter{site-specifics} # Custom filters for specific site related problems
3801 +filter{google} # Removes text ads and other Google specific improvements
3804 +filter{yahoo} # Removes text ads and other Yahoo specific improvements
3807 +filter{msn} # Removes text ads and other MSN specific improvements
3810 +filter{blogspot} # Cleans up Blogspot blogs
3813 +filter{no-ping} # Removes non-standard ping attributes from anchor and area tags
3816 -------------------------------------------------------------------------------
3818 8.5.15. force-text-mode
3822 Force Privoxy to treat a document as if it was in some kind of text format.
3826 Declares a document as text, even if the "Content-Type:" isn't detected as
3839 As explained above, Privoxy tries to only filter files that are in some
3840 kind of text format. The same restrictions apply to content-type-overwrite.
3841 force-text-mode declares a document as text, without looking at the
3842 "Content-Type:" first.
3844 +-----------------------------------------------------------------+
3846 |-----------------------------------------------------------------|
3847 |Think twice before activating this action. Filtering binary data |
3848 |with regular expressions can cause file damage. |
3849 +-----------------------------------------------------------------+
3856 -------------------------------------------------------------------------------
3858 8.5.16. forward-override
3862 Change the forwarding settings based on User-Agent or request origin
3866 Overrules the forward directives in the configuration file.
3874 + "forward ." to use a direct connection without any additional proxies.
3876 + "forward 127.0.0.1:8123" to use the HTTP proxy listening at 127.0.0.1
3879 + "forward-socks4a 127.0.0.1:9050 ." to use the socks4a proxy listening
3880 at 127.0.0.1 port 9050. Replace "forward-socks4a" with "forward-socks4"
3881 to use a socks4 connection (with local DNS resolution) instead.
3883 + "forward-socks4a 127.0.0.1:9050 proxy.example.org:8000" to use the
3884 socks4a proxy listening at 127.0.0.1 port 9050 to reach the HTTP proxy
3885 listening at proxy.example.org port 8000. Replace "forward-socks4a"
3886 with "forward-socks4" to use a socks4 connection (with local DNS
3887 resolution) instead.
3891 This action takes parameters similar to the forward directives in the
3892 configuration file, but without the URL pattern. It can be used as
3893 replacement, but normally it's only used in cases where matching based on
3894 the request URL isn't sufficient.
3896 +-----------------------------------------------------------------+
3898 |-----------------------------------------------------------------|
3899 |Please read the description for the forward directives before |
3900 |using this action. Forwarding to the wrong people will reduce |
3901 |your privacy and increase the chances of man-in-the-middle |
3904 |If the ports are missing or invalid, default values will be used.|
3905 |This might change in the future and you shouldn't rely on it. |
3906 |Otherwise incorrect syntax causes Privoxy to exit. |
3908 |Use the show-url-info CGI page to verify that your forward |
3909 |settings do what you thought the do. |
3910 +-----------------------------------------------------------------+
3913 # Always use direct connections for requests previously tagged as
3914 # "User-Agent: fetch libfetch/2.0" and make sure
3915 # resuming downloads continues to work.
3916 # This way you can continue to use Tor for your normal browsing,
3917 # without overloading the Tor network with your FreeBSD ports updates
3918 # or downloads of bigger files like ISOs.
3919 # Note that HTTP headers are easy to fake and therefore their
3920 # values are as (un)trustworthy as your clients and users.
3921 {+forward-override{forward .} \
3922 -hide-if-modified-since \
3923 -overwrite-last-modified \
3925 TAG:^User-Agent: fetch libfetch/2\.0$
3929 -------------------------------------------------------------------------------
3931 8.5.17. handle-as-empty-document
3935 Mark URLs that should be replaced by empty documents if they get blocked
3939 This action alone doesn't do anything noticeable. It just marks URLs. If
3940 the block action also applies, the presence or absence of this mark decides
3941 whether an HTML "BLOCKED" page, or an empty document will be sent to the
3942 client as a substitute for the blocked content. The empty document isn't
3943 literally empty, but actually contains a single space.
3955 Some browsers complain about syntax errors if JavaScript documents are
3956 blocked with Privoxy's default HTML page; this option can be used to
3957 silence them. And of course this action can also be used to eliminate the
3958 Privoxy BLOCKED message in frames.
3960 The content type for the empty document can be specified with
3961 content-type-overwrite{}, but usually this isn't necessary.
3965 # Block all documents on example.org that end with ".js",
3966 # but send an empty document instead of the usual HTML message.
3967 {+block +handle-as-empty-document}
3972 -------------------------------------------------------------------------------
3974 8.5.18. handle-as-image
3978 Mark URLs as belonging to images (so they'll be replaced by images if they
3979 do get blocked, rather than HTML pages)
3983 This action alone doesn't do anything noticeable. It just marks URLs as
3984 images. If the block action also applies, the presence or absence of this
3985 mark decides whether an HTML "blocked" page, or a replacement image (as
3986 determined by the set-image-blocker action) will be sent to the client as a
3987 substitute for the blocked content.
3999 The below generic example section is actually part of default.action. It
4000 marks all URLs with well-known image file name extensions as images and
4001 should be left intact.
4003 Users will probably only want to use the handle-as-image action in
4004 conjunction with block, to block sources of banners, whose URLs don't
4005 reflect the file type, like in the second example section.
4007 Note that you cannot treat HTML pages as images in most cases. For
4008 instance, (in-line) ad frames require an HTML page to be sent, or they
4009 won't display properly. Forcing handle-as-image in this situation will not
4010 replace the ad frame with an image, but lead to error messages.
4012 Example usage (sections):
4014 # Generic image extensions:
4017 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4019 # These don't look like images, but they're banners and should be
4020 # blocked as images:
4022 {+block +handle-as-image}
4023 some.nasty-banner-server.com/junk.cgi\?output=trash
4025 # Banner source! Who cares if they also have non-image content?
4029 -------------------------------------------------------------------------------
4031 8.5.19. hide-accept-language
4035 Pretend to use different language settings.
4039 Deletes or replaces the "Accept-Language:" HTTP header in client requests.
4047 Keyword: "block", or any user defined value.
4051 Faking the browser's language settings can be useful to make a foreign
4052 User-Agent set with hide-user-agent more believable.
4054 However some sites with content in different languages check the
4055 "Accept-Language:" to decide which one to take by default. Sometimes it
4056 isn't possible to later switch to another language without changing the
4057 "Accept-Language:" header first.
4059 Therefore it's a good idea to either only change the "Accept-Language:"
4060 header to languages you understand, or to languages that aren't wide
4063 Before setting the "Accept-Language:" header to a rare language, you should
4064 consider that it helps to make your requests unique and thus easier to
4065 trace. If you don't plan to change this header frequently, you should stick
4066 to a common language.
4068 Example usage (section):
4070 # Pretend to use Canadian language settings.
4071 {+hide-accept-language{en-ca} \
4072 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4077 -------------------------------------------------------------------------------
4079 8.5.20. hide-content-disposition
4083 Prevent download menus for content you prefer to view inside the browser.
4087 Deletes or replaces the "Content-Disposition:" HTTP header set by some
4096 Keyword: "block", or any user defined value.
4100 Some servers set the "Content-Disposition:" HTTP header for documents they
4101 assume you want to save locally before viewing them. The
4102 "Content-Disposition:" header contains the file name the browser is
4103 supposed to use by default.
4105 In most browsers that understand this header, it makes it impossible to
4106 just view the document, without downloading it first, even if it's just a
4107 simple text file or an image.
4109 Removing the "Content-Disposition:" header helps to prevent this annoyance,
4110 but some browsers additionally check the "Content-Type:" header, before
4111 they decide if they can display a document without saving it first. In
4112 these cases, you have to change this header as well, before the browser
4113 stops displaying download menus.
4115 It is also possible to change the server's file name suggestion to another
4116 one, but in most cases it isn't worth the time to set it up.
4118 This action will probably be removed in the future, use server-header
4123 # Disarm the download link in Sourceforge's patch tracker
4125 +content-type-overwrite{text/plain}\
4126 +hide-content-disposition{block} }
4127 .sourceforge.net/tracker/download\.php
4130 -------------------------------------------------------------------------------
4132 8.5.21. hide-if-modified-since
4136 Prevent yet another way to track the user's steps between sessions.
4140 Deletes the "If-Modified-Since:" HTTP client header or modifies its value.
4148 Keyword: "block", or a user defined value that specifies a range of hours.
4152 Removing this header is useful for filter testing, where you want to force
4153 a real reload instead of getting status code "304", which would cause the
4154 browser to use a cached copy of the page.
4156 Instead of removing the header, hide-if-modified-since can also add or
4157 subtract a random amount of time to/from the header's value. You specify a
4158 range of minutes where the random factor should be chosen from and Privoxy
4159 does the rest. A negative value means subtracting, a positive value adding.
4161 Randomizing the value of the "If-Modified-Since:" makes it less likely that
4162 the server can use the time as a cookie replacement, but you will run into
4163 caching problems if the random range is too high.
4165 It is a good idea to only use a small negative value and let
4166 overwrite-last-modified handle the greater changes.
4168 It is also recommended to use this action together with
4169 crunch-if-none-match, otherwise it's more or less pointless.
4171 Example usage (section):
4173 # Let the browser revalidate but make tracking based on the time less likely.
4174 {+hide-if-modified-since{-60} \
4175 +overwrite-last-modified{randomize} \
4176 +crunch-if-none-match}
4180 -------------------------------------------------------------------------------
4182 8.5.22. hide-forwarded-for-headers
4186 Improve privacy by not forwarding the source of the request in the HTTP
4191 Deletes any existing "X-Forwarded-for:" HTTP header from client requests.
4203 It is safe and recommended to leave this on.
4207 +hide-forwarded-for-headers
4210 -------------------------------------------------------------------------------
4212 8.5.23. hide-from-header
4216 Keep your (old and ill) browser from telling web servers your email address
4220 Deletes any existing "From:" HTTP header, or replaces it with the specified
4229 Keyword: "block", or any user defined value.
4233 The keyword "block" will completely remove the header (not to be confused
4234 with the block action).
4236 Alternately, you can specify any value you prefer to be sent to the web
4237 server. If you do, it is a matter of fairness not to use any address that
4238 is actually used by a real person.
4240 This action is rarely needed, as modern web browsers don't send "From:"
4245 +hide-from-header{block}
4250 +hide-from-header{spam-me-senseless@sittingduck.example.com}
4253 -------------------------------------------------------------------------------
4255 8.5.24. hide-referrer
4259 Conceal which link you followed to get to a particular site
4263 Deletes the "Referer:" (sic) HTTP header from the client request, or
4264 replaces it with a forged one.
4272 + "conditional-block" to delete the header completely if the host has
4275 + "conditional-forge" to forge the header if the host has changed.
4277 + "block" to delete the header unconditionally.
4279 + "forge" to pretend to be coming from the homepage of the server we are
4282 + Any other string to set a user defined referrer.
4286 conditional-block is the only parameter, that isn't easily detected in the
4287 server's log file. If it blocks the referrer, the request will look like
4288 the visitor used a bookmark or typed in the address directly.
4290 Leaving the referrer unmodified for requests on the same host allows the
4291 server owner to see the visitor's "click path", but in most cases she could
4292 also get that information by comparing other parts of the log file: for
4293 example the User-Agent if it isn't a very common one, or the user's IP
4294 address if it doesn't change between different requests.
4296 Always blocking the referrer, or using a custom one, can lead to failures
4297 on servers that check the referrer before they answer any requests, in an
4298 attempt to prevent their content from being embedded or linked to
4301 Both conditional-block and forge will work with referrer checks, as long as
4302 content and valid referring page are on the same host. Most of the time
4305 hide-referer is an alternate spelling of hide-referrer and the two can be
4306 can be freely substituted with each other. ("referrer" is the correct
4307 English spelling, however the HTTP specification has a bug - it requires it
4308 to be spelled as "referer".)
4312 +hide-referrer{forge}
4317 +hide-referrer{http://www.yahoo.com/}
4320 -------------------------------------------------------------------------------
4322 8.5.25. hide-user-agent
4326 Try to conceal your type of browser and client operating system
4330 Replaces the value of the "User-Agent:" HTTP header in client requests with
4331 the specified value.
4339 Any user-defined string.
4343 +-----------------------------------------------------------------+
4345 |-----------------------------------------------------------------|
4346 |This can lead to problems on web sites that depend on looking at |
4347 |this header in order to customize their content for different |
4348 |browsers (which, by the way, is NOT the right thing to do: good |
4349 |web sites work browser-independently). |
4350 +-----------------------------------------------------------------+
4352 Using this action in multi-user setups or wherever different types of
4353 browsers will access the same Privoxy is not recommended. In single-user,
4354 single-browser setups, you might use it to delete your OS version
4355 information from the headers, because it is an invitation to exploit known
4356 bugs for your OS. It is also occasionally useful to forge this in order to
4357 access sites that won't let you in otherwise (though there may be a good
4358 reason in some cases). Example of this: some MSN sites will not let Mozilla
4359 enter, yet forging to a Netscape 6.1 user-agent works just fine. (Must be
4360 just a silly MS goof, I'm sure :-).
4362 More information on known user-agent strings can be found at http://
4363 www.user-agents.org/ and http://en.wikipedia.org/wiki/User_agent.
4367 +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
4370 -------------------------------------------------------------------------------
4372 8.5.26. inspect-jpegs
4376 Try to protect against a MS buffer over-run in JPEG processing
4380 Protect against a known exploit
4392 See Microsoft Security Bulletin MS04-028. JPEG images are one of the most
4393 common image types found across the Internet. The exploit as described can
4394 allow execution of code on the target system, giving an attacker access to
4395 the system in question by merely planting an altered JPEG image, which
4396 would have no obvious indications of what lurks inside. This action tries
4397 to prevent this exploit if delivered through unencrypted HTTP.
4399 Note that the exploit mentioned is several years old and it's unlikely that
4400 your client is still vulnerable against it. This action may be removed in
4401 one of the next releases.
4408 -------------------------------------------------------------------------------
4414 Eliminate those annoying pop-up windows (deprecated)
4418 While loading the document, replace JavaScript code that opens pop-up
4419 windows with (syntactically neutral) dummy code on the fly.
4431 This action is basically a built-in, hardwired special-purpose filter
4432 action, but there are important differences: For kill-popups, the document
4433 need not be buffered, so it can be incrementally rendered while
4434 downloading. But kill-popups doesn't catch as many pop-ups as filter
4435 {all-popups} does and is not as smart as filter{unsolicited-popups} is.
4437 Think of it as a fast and efficient replacement for a filter that you can
4438 use if you don't want any filtering at all. Note that it doesn't make sense
4439 to combine it with any filter action, since as soon as one filter applies,
4440 the whole document needs to be buffered anyway, which destroys the
4441 advantage of the kill-popups action over its filter equivalent.
4443 Killing all pop-ups unconditionally is problematic. Many shops and banks
4444 rely on pop-ups to display forms, shopping carts etc, and the filter
4445 {unsolicited-popups} does a better job of catching only the unwanted ones.
4447 If the only kind of pop-ups that you want to kill are exit consoles (those
4448 really nasty windows that appear when you close an other one), you might
4449 want to use filter{js-annoyances} instead.
4451 This action is most appropriate for browsers that don't have any controls
4452 for unwanted pop-ups. Not recommended for general usage.
4454 This action doesn't work very reliable and may be removed in future
4462 -------------------------------------------------------------------------------
4464 8.5.28. limit-connect
4468 Prevent abuse of Privoxy as a TCP proxy relay or disable SSL for untrusted
4473 Specifies to which ports HTTP CONNECT requests are allowable.
4481 A comma-separated list of ports or port ranges (the latter using dashes,
4482 with the minimum defaulting to 0 and the maximum to 65K).
4486 By default, i.e. if no limit-connect action applies, Privoxy only allows
4487 HTTP CONNECT requests to port 443 (the standard, secure HTTPS port). Use
4488 limit-connect if more fine-grained control is desired for some or all
4491 The CONNECT methods exists in HTTP to allow access to secure websites
4492 ("https://" URLs) through proxies. It works very simply: the proxy connects
4493 to the server on the specified port, and then short-circuits its
4494 connections to the client and to the remote server. This means
4495 CONNECT-enabled proxies can be used as TCP relays very easily.
4497 Privoxy relays HTTPS traffic without seeing the decoded content. Websites
4498 can leverage this limitation to circumvent Privoxy's filters. By specifying
4499 an invalid port range you can disable HTTPS entirely. If you plan to
4500 disable SSL by default, consider enabling
4501 treat-forbidden-connects-like-blocks as well, to be able to quickly create
4506 +limit-connect{443} # This is the default and need not be specified.
4507 +limit-connect{80,443} # Ports 80 and 443 are OK.
4508 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4509 +limit-connect{-} # All ports are OK
4510 +limit-connect{,} # No HTTPS/SSL traffic is allowed
4513 -------------------------------------------------------------------------------
4515 8.5.29. prevent-compression
4519 Ensure that servers send the content uncompressed, so it can be passed
4524 Removes the Accept-Encoding header which can be used to ask for compressed
4537 More and more websites send their content compressed by default, which is
4538 generally a good idea and saves bandwidth. But the filter, deanimate-gifs
4539 and kill-popups actions need access to the uncompressed data.
4541 When compiled with zlib support (available since Privoxy 3.0.7), content
4542 that should be filtered is decompressed on-the-fly and you don't have to
4543 worry about this action. If you are using an older Privoxy version, or one
4544 that hasn't been compiled with zlib support, this action can be used to
4545 convince the server to send the content uncompressed.
4547 Most text-based instances compress very well, the size is seldom decreased
4548 by less than 50%, for markup-heavy instances like news feeds saving more
4549 than 90% of the original size isn't unusual.
4551 Not using compression will therefore slow down the transfer, and you should
4552 only enable this action if you really need it. As of Privoxy 3.0.7 it's
4553 disabled in all predefined action settings.
4555 Note that some (rare) ill-configured sites don't handle requests for
4556 uncompressed documents correctly. Broken PHP applications tend to send an
4557 empty document body, some IIS versions only send the beginning of the
4558 content. If you enable prevent-compression per default, you might want to
4559 add exceptions for those sites. See the example for how to do that.
4561 Example usage (sections):
4563 # Selectively turn off compression, and enable a filter
4565 { +filter{tiny-textforms} +prevent-compression }
4566 # Match only these sites
4571 # Or instead, we could set a universal default:
4573 { +prevent-compression }
4576 # Then maybe make exceptions for broken sites:
4578 { -prevent-compression }
4582 -------------------------------------------------------------------------------
4584 8.5.30. overwrite-last-modified
4588 Prevent yet another way to track the user's steps between sessions.
4592 Deletes the "Last-Modified:" HTTP server header or modifies its value.
4600 One of the keywords: "block", "reset-to-request-time" and "randomize"
4604 Removing the "Last-Modified:" header is useful for filter testing, where
4605 you want to force a real reload instead of getting status code "304", which
4606 would cause the browser to reuse the old version of the page.
4608 The "randomize" option overwrites the value of the "Last-Modified:" header
4609 with a randomly chosen time between the original value and the current
4610 time. In theory the server could send each document with a different
4611 "Last-Modified:" header to track visits without using cookies. "Randomize"
4612 makes it impossible and the browser can still revalidate cached documents.
4614 "reset-to-request-time" overwrites the value of the "Last-Modified:" header
4615 with the current time. You could use this option together with
4616 hided-if-modified-since to further customize your random range.
4618 The preferred parameter here is "randomize". It is safe to use, as long as
4619 the time settings are more or less correct. If the server sets the
4620 "Last-Modified:" header to the time of the request, the random range
4621 becomes zero and the value stays the same. Therefore you should later
4622 randomize it a second time with hided-if-modified-since, just to be sure.
4624 It is also recommended to use this action together with
4625 crunch-if-none-match.
4629 # Let the browser revalidate without being tracked across sessions
4630 { +hide-if-modified-since{-60} \
4631 +overwrite-last-modified{randomize} \
4632 +crunch-if-none-match}
4636 -------------------------------------------------------------------------------
4642 Redirect requests to other sites.
4646 Convinces the browser that the requested document has been moved to another
4647 location and the browser should get it from there.
4655 An absolute URL or a single pcrs command.
4659 Requests to which this action applies are answered with a HTTP redirect to
4660 URLs of your choosing. The new URL is either provided as parameter, or
4661 derived by applying a single pcrs command to the original URL.
4663 This action will be ignored if you use it together with block. It can be
4664 combined with fast-redirects{check-decoded-url} to redirect to a decoded
4665 version of a rewritten URL.
4667 Use this action carefully, make sure not to create redirection loops and be
4668 aware that using your own redirects might make it possible to fingerprint
4673 # Replace example.com's style sheet with another one
4674 { +redirect{http://localhost/css-replacements/example.com.css} }
4675 example.com/stylesheet\.css
4677 # Create a short, easy to remember nickname for a favorite site
4678 # (relies on the browser accept and forward invalid URLs to Privoxy)
4679 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
4682 # Always use the expanded view for Undeadly.org articles
4683 # (Note the $ at the end of the URL pattern to make sure
4684 # the request for the rewritten URL isn't redirected as well)
4685 {+redirect{s@$@&mode=expanded@}}
4686 undeadly.org/cgi\?action=article&sid=\d*$
4689 -------------------------------------------------------------------------------
4691 8.5.32. send-vanilla-wafer
4695 Feed log analysis scripts with useless data.
4699 Sends a cookie with each request stating that you do not accept any
4700 copyright on cookies sent to you, and asking the site operator not to track
4713 The vanilla wafer is a (relatively) unique header and could conceivably be
4716 This action is rarely used and not enabled in the default configuration.
4723 -------------------------------------------------------------------------------
4729 Send custom cookies or feed log analysis scripts with even more useless
4734 Sends a custom, user-defined cookie with each request.
4742 A string of the form "name=value".
4746 Being multi-valued, multiple instances of this action can apply to the same
4747 request, resulting in multiple cookies being sent.
4749 This action is rarely used and not enabled in the default configuration.
4751 Example usage (section):
4753 {+send-wafer{UsingPrivoxy=true}}
4754 my-internal-testing-server.void
4757 -------------------------------------------------------------------------------
4759 8.5.34. server-header-filter
4763 Rewrite or remove single server headers.
4767 All server headers to which this action applies are filtered on-the-fly
4768 through the specified regular expression based substitutions.
4776 The name of a server-header filter, as defined in one of the filter files.
4780 Server-header filters are applied to each header on its own, not to all at
4781 once. This makes it easier to diagnose problems, but on the downside you
4782 can't write filters that only change header x if header y's value is z. You
4783 can do that by using tags though.
4785 Server-header filters are executed after the other header actions have
4786 finished and use their output as input.
4788 Please refer to the filter file chapter to learn which server-header
4789 filters are available by default, and how to create your own.
4791 Example usage (section):
4793 {+server-header-filter{html-to-xml}}
4794 example.org/xml-instance-that-is-delivered-as-html
4796 {+server-header-filter{xml-to-html}}
4797 example.org/instance-that-is-delivered-as-xml-but-is-not
4801 -------------------------------------------------------------------------------
4803 8.5.35. server-header-tagger
4807 Enable or disable filters based on the Content-Type header.
4811 Server headers to which this action applies are filtered on-the-fly through
4812 the specified regular expression based substitutions, the result is used as
4821 The name of a server-header tagger, as defined in one of the filter files.
4825 Server-header taggers are applied to each header on its own, and as the
4826 header isn't modified, each tagger "sees" the original.
4828 Server-header taggers are executed before all other header actions that
4829 modify server headers. Their tags can be used to control all of the other
4830 server-header actions, the content filters and the crunch actions (redirect
4833 Obviously crunching based on tags created by server-header taggers doesn't
4834 prevent the request from showing up in the server's log file.
4836 Example usage (section):
4838 # Tag every request with the content type declared by the server
4839 {+server-header-tagger{content-type}}
4844 -------------------------------------------------------------------------------
4846 8.5.36. session-cookies-only
4850 Allow only temporary "session" cookies (for the current browser session
4855 Deletes the "expires" field from "Set-Cookie:" server headers. Most
4856 browsers will not store such cookies permanently and forget them in between
4869 This is less strict than crunch-incoming-cookies / crunch-outgoing-cookies
4870 and allows you to browse websites that insist or rely on setting cookies,
4871 without compromising your privacy too badly.
4873 Most browsers will not permanently store cookies that have been processed
4874 by session-cookies-only and will forget about them between sessions. This
4875 makes profiling cookies useless, but won't break sites which require
4876 cookies so that you can log in for transactions. This is generally turned
4877 on for all sites, and is the recommended setting.
4879 It makes no sense at all to use session-cookies-only together with
4880 crunch-incoming-cookies or crunch-outgoing-cookies. If you do, cookies will
4883 Note that it is up to the browser how it handles such cookies without an
4884 "expires" field. If you use an exotic browser, you might want to try it out
4887 This setting also has no effect on cookies that may have been stored
4888 previously by the browser before starting Privoxy. These would have to be
4891 Privoxy also uses the content-cookies filter to block some types of
4892 cookies. Content cookies are not effected by session-cookies-only.
4896 +session-cookies-only
4899 -------------------------------------------------------------------------------
4901 8.5.37. set-image-blocker
4905 Choose the replacement for blocked images
4909 This action alone doesn't do anything noticeable. If both block and
4910 handle-as-image also apply, i.e. if the request is to be blocked as an
4911 image, then the parameter of this action decides what will be sent as a
4920 + "pattern" to send a built-in checkerboard pattern image. The image is
4921 visually decent, scales very well, and makes it obvious where banners
4924 + "blank" to send a built-in transparent image. This makes banners
4925 disappear completely, but makes it hard to detect where Privoxy has
4926 blocked images on a given page and complicates troubleshooting if
4927 Privoxy has blocked innocent images, like navigation icons.
4929 + "target-url" to send a redirect to target-url. You can redirect to any
4930 image anywhere, even in your local filesystem via "file:///" URL. (But
4931 note that not all browsers support redirecting to a local file system).
4933 A good application of redirects is to use special Privoxy-built-in
4934 URLs, which send the built-in images, as target-url. This has the same
4935 visual effect as specifying "blank" or "pattern" in the first place,
4936 but enables your browser to cache the replacement image, instead of
4937 requesting it over and over again.
4941 The URLs for the built-in images are "http://config.privoxy.org/
4942 send-banner?type=type", where type is either "blank" or "pattern".
4944 There is a third (advanced) type, called "auto". It is NOT to be used in
4945 set-image-blocker, but meant for use from filters. Auto will select the
4946 type of image that would have applied to the referring page, had it been an
4953 +set-image-blocker{pattern}
4956 Redirect to the BSD daemon:
4958 +set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}
4961 Redirect to the built-in pattern for better caching:
4963 +set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}
4966 -------------------------------------------------------------------------------
4968 8.5.38. treat-forbidden-connects-like-blocks
4972 Block forbidden connects with an easy to find error message.
4976 If this action is enabled, Privoxy no longer makes a difference between
4977 forbidden connects and ordinary blocks.
4989 By default Privoxy answers forbidden "Connect" requests with a short error
4990 message inside the headers. If the browser doesn't display headers (most
4991 don't), you just see an empty page.
4993 With this action enabled, Privoxy displays the message that is used for
4994 ordinary blocks instead. If you decide to make an exception for the page in
4995 question, you can do so by following the "See why" link.
4997 For "Connect" requests the clients tell Privoxy which host they are
4998 interested in, but not which document they plan to get later. As a result,
4999 the "Go there anyway" wouldn't work and is therefore suppressed.
5003 +treat-forbidden-connects-like-blocks
5006 -------------------------------------------------------------------------------
5010 Note that many of these actions have the potential to cause a page to
5011 misbehave, possibly even not to display at all. There are many ways a site
5012 designer may choose to design his site, and what HTTP header content, and other
5013 criteria, he may depend on. There is no way to have hard and fast rules for all
5014 sites. See the Appendix for a brief example on troubleshooting actions.
5016 -------------------------------------------------------------------------------
5020 Custom "actions", known to Privoxy as "aliases", can be defined by combining
5021 other actions. These can in turn be invoked just like the built-in actions.
5022 Currently, an alias name can contain any character except space, tab, "=", "{"
5023 and "}", but we strongly recommend that you only use "a" to "z", "0" to "9",
5024 "+", and "-". Alias names are not case sensitive, and are not required to start
5025 with a "+" or "-" sign, since they are merely textually expanded.
5027 Aliases can be used throughout the actions file, but they must be defined in a
5028 special section at the top of the file! And there can only be one such section
5029 per actions file. Each actions file may have its own alias section, and the
5030 aliases defined in it are only visible within that file.
5032 There are two main reasons to use aliases: One is to save typing for frequently
5033 used combinations of actions, the other one is a gain in flexibility: If you
5034 decide once how you want to handle shops by defining an alias called "shop",
5035 you can later change your policy on shops in one place, and your changes will
5036 take effect everywhere in the actions file where the "shop" alias is used.
5037 Calling aliases by their purpose also makes your actions files more readable.
5039 Currently, there is one big drawback to using aliases, though: Privoxy's
5040 built-in web-based action file editor honors aliases when reading the actions
5041 files, but it expands them before writing. So the effects of your aliases are
5042 of course preserved, but the aliases themselves are lost when you edit sections
5043 that use aliases with it.
5045 Now let's define some aliases...
5047 # Useful custom aliases we can use later.
5049 # Note the (required!) section header line and that this section
5050 # must be at the top of the actions file!
5054 # These aliases just save typing later:
5055 # (Note that some already use other aliases!)
5057 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5058 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5059 +block-as-image = +block +handle-as-image
5060 allow-all-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
5062 # These aliases define combinations of actions
5063 # that are useful for certain types of sites:
5065 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups -prevent-compression
5067 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
5069 # Short names for other aliases, for really lazy people ;-)
5071 c0 = +crunch-all-cookies
5072 c1 = -crunch-all-cookies
5075 ...and put them to use. These sections would appear in the lower part of an
5076 actions file and define exceptions to the default actions (as specified further
5077 up for the "/" pattern):
5079 # These sites are either very complex or very keen on
5080 # user data and require minimal interference to work:
5083 .office.microsoft.com
5084 .windowsupdate.microsoft.com
5085 # Gmail is really mail.google.com, not gmail.com
5089 # Allow cookies (for setting and retrieving your customer data)
5093 .worldpay.com # for quietpc.com
5096 # These shops require pop-ups:
5098 {-kill-popups -filter{all-popups} -filter{unsolicited-popups}}
5103 Aliases like "shop" and "fragile" are typically used for "problem" sites that
5104 require more than one action to be disabled in order to function properly.
5106 -------------------------------------------------------------------------------
5108 8.7. Actions Files Tutorial
5110 The above chapters have shown which actions files there are and how they are
5111 organized, how actions are specified and applied to URLs, how patterns work,
5112 and how to define and use aliases. Now, let's look at an example default.action
5113 and user.action file and see how all these pieces come together:
5115 -------------------------------------------------------------------------------
5117 8.7.1. default.action
5119 Every config file should start with a short comment stating its purpose:
5121 # Sample default.action file <ijbswa-developers@lists.sourceforge.net>
5124 Then, since this is the default.action file, the first section is a special
5125 section for internal use that you needn't change or worry about:
5127 ##########################################################################
5128 # Settings -- Don't change! For internal Privoxy use ONLY.
5129 ##########################################################################
5132 for-privoxy-version=3.0
5135 After that comes the (optional) alias section. We'll use the example section
5136 from the above chapter on aliases, that also explains why and how aliases are
5139 ##########################################################################
5141 ##########################################################################
5144 # These aliases just save typing later:
5145 # (Note that some already use other aliases!)
5147 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5148 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5149 +block-as-image = +block +handle-as-image
5150 mercy-for-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
5152 # These aliases define combinations of actions
5153 # that are useful for certain types of sites:
5155 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups
5156 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
5159 Now come the regular sections, i.e. sets of actions, accompanied by URL
5160 patterns to which they apply. Remember all actions are disabled when matching
5161 starts, so we have to explicitly enable the ones we want.
5163 The first regular section is probably the most important. It has only one
5164 pattern, "/", but this pattern matches all URLs. Therefore, the set of actions
5165 used in this "default" section will be applied to all requests as a start. It
5166 can be partly or wholly overridden by later matches further down this file, or
5167 in user.action, but it will still be largely responsible for your overall
5168 browsing experience.
5170 Again, at the start of matching, all actions are disabled, so there is no need
5171 to disable any actions here. (Remember: a "+" preceding the action name enables
5172 the action, a "-" disables!). Also note how this long line has been made more
5173 readable by splitting it into multiple lines with line continuation.
5175 ##########################################################################
5176 # "Defaults" section:
5177 ##########################################################################
5180 +filter{html-annoyances} \
5181 +filter{refresh-tags} \
5183 +filter{ie-exploits} \
5184 +hide-forwarded-for-headers \
5185 +hide-from-header{block} \
5186 +hide-referrer{forge} \
5187 +prevent-compression \
5188 +session-cookies-only \
5189 +set-image-blocker{pattern} \
5191 / # forward slash will match *all* potential URL patterns.
5194 The default behavior is now set.
5196 The first of our specialized sections is concerned with "fragile" sites, i.e.
5197 sites that require minimum interference, because they are either very complex
5198 or very keen on tracking you (and have mechanisms in place that make them
5199 unusable for people who avoid being tracked). We will simply use our
5200 pre-defined fragile alias instead of stating the list of actions explicitly:
5202 ##########################################################################
5203 # Exceptions for sites that'll break under the default action set:
5204 ##########################################################################
5206 # "Fragile" Use a minimum set of actions for these sites (see alias above):
5209 .office.microsoft.com # surprise, surprise!
5210 .windowsupdate.microsoft.com
5214 Shopping sites are not as fragile, but they typically require cookies to log
5215 in, and pop-up windows for shopping carts or item details. Again, we'll use a
5222 .worldpay.com # for quietpc.com
5227 The fast-redirects action, which we enabled per default above, breaks some
5228 sites. So disable it for popular sites where we know it misbehaves:
5234 .altavista.com/.*(like|url|link):http
5235 .altavista.com/trans.*urltext=http
5239 It is important that Privoxy knows which URLs belong to images, so that if they
5240 are to be blocked, a substitute image can be sent, rather than an HTML page.
5241 Contacting the remote site to find out is not an option, since it would destroy
5242 the loading time advantage of banner blocking, and it would feed the
5243 advertisers (in terms of money and information). We can mark any URL as an
5244 image with the handle-as-image action, and marking all URLs that end in a known
5245 image file extension is a good start:
5247 ##########################################################################
5249 ##########################################################################
5251 # Define which file types will be treated as images, in case they get
5252 # blocked further down this file:
5254 { +handle-as-image }
5255 /.*\.(gif|jpe?g|png|bmp|ico)$
5258 And then there are known banner sources. They often use scripts to generate the
5259 banners, so it won't be visible from the URL that the request is for an image.
5260 Hence we block them and mark them as images in one go, with the help of our
5261 +block-as-image alias defined above. (We could of course just as well use +
5262 block +handle-as-image here.) Remember that the type of the replacement image
5263 is chosen by the set-image-blocker action. Since all URLs have matched the
5264 default section with its +set-image-blocker{pattern} action before, it still
5265 applies and needn't be repeated:
5267 # Known ad generators:
5272 .ad.*.doubleclick.net
5273 .a.yimg.com/(?:(?!/i/).)*$
5274 .a[0-9].yimg.com/(?:(?!/i/).)*$
5279 One of the most important jobs of Privoxy is to block banners. Many of these
5280 can be "blocked" by the filter{banners-by-size} action, which we enabled above,
5281 and which deletes the references to banner images from the pages while they are
5282 loaded, so the browser doesn't request them anymore, and hence they don't need
5283 to be blocked here. But this naturally doesn't catch all banners, and some
5284 people choose not to use filters, so we need a comprehensive list of patterns
5285 for banner URLs here, and apply the block action to them.
5287 First comes many generic patterns, which do most of the work, by matching
5288 typical domain and path name components of banners. Then comes a list of
5289 individual patterns for specific sites, which is omitted here to keep the
5292 ##########################################################################
5293 # Block these fine banners:
5294 ##########################################################################
5303 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
5304 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
5306 # Site-specific patterns (abbreviated):
5311 It's quite remarkable how many advertisers actually call their banner servers
5312 ads.company.com, or call the directory in which the banners are stored simply
5313 "banners". So the above generic patterns are surprisingly effective.
5315 But being very generic, they necessarily also catch URLs that we don't want to
5316 block. The pattern .*ads. e.g. catches "nasty-ads.nasty-corp.com" as intended,
5317 but also "downloads.sourcefroge.net" or "adsl.some-provider.net." So here come
5318 some well-known exceptions to the +block section above.
5320 Note that these are exceptions to exceptions from the default! Consider the URL
5321 "downloads.sourcefroge.net": Initially, all actions are deactivated, so it
5322 wouldn't get blocked. Then comes the defaults section, which matches the URL,
5323 but just deactivates the block action once again. Then it matches .*ads., an
5324 exception to the general non-blocking policy, and suddenly +block applies. And
5325 now, it'll match .*loads., where -block applies, so (unless it matches again
5326 further down) it ends up with no block action applying.
5328 ##########################################################################
5329 # Save some innocent victims of the above generic block patterns:
5330 ##########################################################################
5335 adv[io]*. # (for advogato.org and advice.*)
5336 adsl. # (has nothing to do with ads)
5337 adobe. # (has nothing to do with ads either)
5338 ad[ud]*. # (adult.* and add.*)
5339 .edu # (universities don't host banners (yet!))
5340 .*loads. # (downloads, uploads etc)
5348 www.globalintersec.com/adv # (adv = advanced)
5349 www.ugu.com/sui/ugu/adv
5352 Filtering source code can have nasty side effects, so make an exception for our
5353 friends at sourceforge.net, and all paths with "cvs" in them. Note that -filter
5354 disables all filters in one fell swoop!
5356 # Don't filter code!
5366 The actual default.action is of course much more comprehensive, but we hope
5367 this example made clear how it works.
5369 -------------------------------------------------------------------------------
5373 So far we are painting with a broad brush by setting general policies, which
5374 would be a reasonable starting point for many people. Now, you might want to be
5375 more specific and have customized rules that are more suitable to your personal
5376 habits and preferences. These would be for narrowly defined situations like
5377 your ISP or your bank, and should be placed in user.action, which is parsed
5378 after all other actions files and hence has the last word, over-riding any
5379 previously defined actions. user.action is also a safe place for your personal
5380 settings, since default.action is actively maintained by the Privoxy developers
5381 and you'll probably want to install updated versions from time to time.
5383 So let's look at a few examples of things that one might typically do in
5386 # My user.action file. <fred@example.com>
5389 As aliases are local to the actions file that they are defined in, you can't
5390 use the ones from default.action, unless you repeat them here:
5392 # Aliases are local to the file they are defined in.
5393 # (Re-)define aliases for this file:
5397 # These aliases just save typing later, and the alias names should
5398 # be self explanatory.
5400 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5401 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5402 allow-all-cookies = -crunch-all-cookies -session-cookies-only
5403 allow-popups = -filter{all-popups} -kill-popups
5404 +block-as-image = +block +handle-as-image
5405 -block-as-image = -block
5407 # These aliases define combinations of actions that are useful for
5408 # certain types of sites:
5410 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer -kill-popups
5411 shop = -crunch-all-cookies allow-popups
5413 # Allow ads for selected useful free sites:
5415 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
5417 # Alias for specific file types that are text, but might have conflicting
5418 # MIME types. We want the browser to force these to be text documents.
5419 handle-as-text = -filter +-content-type-overwrite{text/plain} +-force-text-mode -hide-content-disposition
5424 Say you have accounts on some sites that you visit regularly, and you don't
5425 want to have to log in manually each time. So you'd like to allow persistent
5426 cookies for these sites. The allow-all-cookies alias defined above does exactly
5427 that, i.e. it disables crunching of cookies in any direction, and the
5428 processing of cookies to make them only temporary.
5430 { allow-all-cookies }
5437 Your bank is allergic to some filter, but you don't know which, so you disable
5441 .your-home-banking-site.com
5444 Some file types you may not want to filter for various reasons:
5446 # Technical documentation is likely to contain strings that might
5447 # erroneously get altered by the JavaScript-oriented filters:
5452 # And this stupid host sends streaming video with a wrong MIME type,
5453 # so that Privoxy thinks it is getting HTML and starts filtering:
5455 stupid-server.example.com/
5458 Example of a simple block action. Say you've seen an ad on your favourite page
5459 on example.com that you want to get rid of. You have right-clicked the image,
5460 selected "copy image location" and pasted the URL below while removing the
5461 leading http://, into a { +block } section. Note that { +handle-as-image } need
5462 not be specified, since all URLs ending in .gif will be tagged as images by the
5463 general rules as set in default.action anyway:
5466 www.example.com/nasty-ads/sponsor\.gif
5467 another.example.net/more/junk/here/
5470 The URLs of dynamically generated banners, especially from large banner farms,
5471 often don't use the well-known image file name extensions, which makes it
5472 impossible for Privoxy to guess the file type just by looking at the URL. You
5473 can use the +block-as-image alias defined above for these cases. Note that
5474 objects which match this rule but then turn out NOT to be an image are
5475 typically rendered as a "broken image" icon by the browser. Use cautiously.
5484 Now you noticed that the default configuration breaks Forbes Magazine, but you
5485 were too lazy to find out which action is the culprit, and you were again too
5486 lazy to give feedback, so you just used the fragile alias on the site, and --
5487 whoa! -- it worked. The fragile aliases disables those actions that are most
5488 likely to break a site. Also, good for testing purposes to see if it is Privoxy
5489 that is causing the problem or not. We later find other regular sites that
5490 misbehave, and add those to our personalized list of troublemakers:
5498 You like the "fun" text replacements in default.filter, but it is disabled in
5499 the distributed actions file. So you'd like to turn it on in your private,
5500 update-safe config, once and for all:
5506 Note that the above is not really a good idea: There are exceptions to the
5507 filters in default.action for things that really shouldn't be filtered, like
5508 code on CVS->Web interfaces. Since user.action has the last word, these
5509 exceptions won't be valid for the "fun" filtering specified here.
5511 You might also worry about how your favourite free websites are funded, and
5512 find that they rely on displaying banner advertisements to survive. So you
5513 might want to specifically allow banners for those sites that you feel provide
5522 Note that allow-ads has been aliased to -block, -filter{banners-by-size}, and -
5523 filter{banners-by-link} above.
5525 Invoke another alias here to force an over-ride of the MIME type application/
5526 x-sh which typically would open a download type dialog. In my case, I want to
5527 look at the shell script, and then I can save it should I choose to.
5533 user.action is generally the best place to define exceptions and additions to
5534 the default policies of default.action. Some actions are safe to have their
5535 default policies set here though. So let's set a default policy to have a
5536 "blank" image as opposed to the checkerboard pattern for ALL sites. "/" of
5537 course matches all URL paths and patterns:
5539 { +set-image-blocker{blank} }
5543 -------------------------------------------------------------------------------
5547 On-the-fly text substitutions need to be defined in a "filter file". Once
5548 defined, they can then be invoked as an "action".
5550 Privoxy supports three different filter actions: filter to rewrite the content
5551 that is send to the client, client-header-filter to rewrite headers that are
5552 send by the client, and server-header-filter to rewrite headers that are send
5555 Privoxy also supports two tagger actions: client-header-tagger and
5556 server-header-tagger. Taggers and filters use the same syntax in the filter
5557 files, the difference is that taggers don't modify the text they are filtering,
5558 but use a rewritten version of the filtered text as tag. The tags can then be
5559 used to change the applying actions through sections with tag-patterns.
5561 Multiple filter files can be defined through the filterfile config directive.
5562 The filters as supplied by the developers are located in default.filter. It is
5563 recommended that any locally defined or modified filters go in a separately
5564 defined file such as user.filter.
5566 Common tasks for content filters are to eliminate common annoyances in HTML and
5567 JavaScript, such as pop-up windows, exit consoles, crippled windows without
5568 navigation tools, the infamous <BLINK> tag etc, to suppress images with certain
5569 width and height attributes (standard banner sizes or web-bugs), or just to
5572 Enabled content filters are applied to any content whose "Content Type" header
5573 is recognised as a sign of text-based content, with the exception of text/
5574 plain. Use the force-text-mode action to also filter other content.
5576 Substitutions are made at the source level, so if you want to "roll your own"
5577 filters, you should first be familiar with HTML syntax, and, of course, regular
5580 Just like the actions files, the filter file is organized in sections, which
5581 are called filters here. Each filter consists of a heading line, that starts
5582 with one of the keywords FILTER:, CLIENT-HEADER-FILTER: or
5583 SERVER-HEADER-FILTER: followed by the filter's name, and a short (one line)
5584 description of what it does. Below that line come the jobs, i.e. lines that
5585 define the actual text substitutions. By convention, the name of a filter
5586 should describe what the filter eliminates. The comment is used in the
5587 web-based user interface.
5589 Once a filter called name has been defined in the filter file, it can be
5590 invoked by using an action of the form +filter{name} in any actions file.
5592 Filter definitions start with a header line that contains the filter type, the
5593 filter name and the filter description. A content filter header line for a
5594 filter called "foo" could look like this:
5596 FILTER: foo Replace all "foo" with "bar"
5599 Below that line, and up to the next header line, come the jobs that define what
5600 text replacements the filter executes. They are specified in a syntax that
5601 imitates Perl's s/// operator. If you are familiar with Perl, you will find
5602 this to be quite intuitive, and may want to look at the PCRS documentation for
5603 the subtle differences to Perl behaviour. Most notably, the non-standard option
5604 letter U is supported, which turns the default to ungreedy matching.
5606 If you are new to "Regular Expressions", you might want to take a look at the
5607 Appendix on regular expressions, and see the Perl manual for the s///
5608 operator's syntax and Perl-style regular expressions in general. The below
5609 examples might also help to get you started.
5611 -------------------------------------------------------------------------------
5613 9.1. Filter File Tutorial
5615 Now, let's complete our "foo" content filter. We have already defined the
5616 heading, but the jobs are still missing. Since all it does is to replace "foo"
5617 with "bar", there is only one (trivial) job needed:
5622 But wait! Didn't the comment say that all occurrences of "foo" should be
5623 replaced? Our current job will only take care of the first "foo" on each page.
5624 For global substitution, we'll need to add the g option:
5629 Our complete filter now looks like this:
5631 FILTER: foo Replace all "foo" with "bar"
5635 Let's look at some real filters for more interesting examples. Here you see a
5636 filter that protects against some common annoyances that arise from JavaScript
5637 abuse. Let's look at its jobs one after the other:
5639 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
5641 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
5643 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg
5646 Following the header line and a comment, you see the job. Note that it uses |
5647 as the delimiter instead of /, because the pattern contains a forward slash,
5648 which would otherwise have to be escaped by a backslash (\).
5650 Now, let's examine the pattern: it starts with the text <script.* enclosed in
5651 parentheses. Since the dot matches any character, and * means: "Match an
5652 arbitrary number of the element left of myself", this matches "<script",
5653 followed by any text, i.e. it matches the whole page, from the start of the
5656 That's more than we want, but the pattern continues: document\.referrer matches
5657 only the exact string "document.referrer". The dot needed to be escaped, i.e.
5658 preceded by a backslash, to take away its special meaning as a joker, and make
5659 it just a regular dot. So far, the meaning is: Match from the start of the
5660 first <script> tag in a the page, up to, and including, the text
5661 "document.referrer", if both are present in the page (and appear in that
5664 But there's still more pattern to go. The next element, again enclosed in
5665 parentheses, is .*</script>. You already know what .* means, so the whole
5666 pattern translates to: Match from the start of the first <script> tag in a page
5667 to the end of the last <script> tag, provided that the text "document.referrer"
5668 appears somewhere in between.
5670 This is still not the whole story, since we have ignored the options and the
5671 parentheses: The portions of the page matched by sub-patterns that are enclosed
5672 in parentheses, will be remembered and be available through the variables $1,
5673 $2, ... in the substitute. The U option switches to ungreedy matching, which
5674 means that the first .* in the pattern will only "eat up" all text in between "
5675 <script" and the first occurrence of "document.referrer", and that the second
5676 .* will only span the text up to the first "</script>" tag. Furthermore, the s
5677 option says that the match may span multiple lines in the page, and the g
5678 option again means that the substitution is global.
5680 So, to summarize, the pattern means: Match all scripts that contain the text
5681 "document.referrer". Remember the parts of the script from (and including) the
5682 start tag up to (and excluding) the string "document.referrer" as $1, and the
5683 part following that string, up to and including the closing tag, as $2.
5685 Now the pattern is deciphered, but wasn't this about substituting things? So
5686 lets look at the substitute: $1"Not Your Business!"$2 is easy to read: The text
5687 remembered as $1, followed by "Not Your Business!" (including the quotation
5688 marks!), followed by the text remembered as $2. This produces an exact copy of
5689 the original string, with the middle part (the "document.referrer") replaced by
5690 "Not Your Business!".
5692 The whole job now reads: Replace "document.referrer" by "Not Your Business!"
5693 wherever it appears inside a <script> tag. Note that this job won't break
5694 JavaScript syntax, since both the original and the replacement are
5695 syntactically valid string objects. The script just won't have access to the
5696 referrer information anymore.
5698 We'll show you two other jobs from the JavaScript taming department, but this
5699 time only point out the constructs of special interest:
5701 # The status bar is for displaying link targets, not pointless blahblah
5703 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig
5706 \s stands for whitespace characters (space, tab, newline, carriage return, form
5707 feed), so that \s* means: "zero or more whitespace". The ? in .*? makes this
5708 matching of arbitrary text ungreedy. (Note that the U option is not set). The
5709 ['"] construct means: "a single or a double quote". Finally, \1 is a
5710 back-reference to the first parenthesis just like $1 above, with the difference
5711 that in the pattern, a backslash indicates a back-reference, whereas in the
5712 substitute, it's the dollar.
5714 So what does this job do? It replaces assignments of single- or double-quoted
5715 strings to the "window.status" object with a dummy assignment (using a variable
5716 name that is hopefully odd enough not to conflict with real variables in
5717 scripts). Thus, it catches many cases where e.g. pointless descriptions are
5718 displayed in the status bar instead of the link target when you move your mouse
5721 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
5723 s/(<body [^>]*)onunload(.*>)/$1never$2/iU
5726 Including the OnUnload event binding in the HTML DOM was a CRIME. When I close
5727 a browser window, I want it to close and die. Basta. This job replaces the
5728 "onunload" attribute in "<body>" tags with the dummy word never. Note that the
5729 i option makes the pattern matching case-insensitive. Also note that ungreedy
5730 matching alone doesn't always guarantee a minimal match: In the first
5731 parenthesis, we had to use [^>]* instead of .* to prevent the match from
5732 exceeding the <body> tag if it doesn't contain "OnUnload", but the page's
5735 The last example is from the fun department:
5737 FILTER: fun Fun text replacements
5739 # Spice the daily news:
5741 s/microsoft(?!\.com)/MicroSuck/ig
5744 Note the (?!\.com) part (a so-called negative lookahead) in the job's pattern,
5745 which means: Don't match, if the string ".com" appears directly following
5746 "microsoft" in the page. This prevents links to microsoft.com from being
5747 trashed, while still replacing the word everywhere else.
5749 # Buzzword Bingo (example for extended regex syntax)
5751 s* industry[ -]leading \
5753 | customer[ -]focused \
5754 | market[ -]driven \
5755 | award[ -]winning # Comments are OK, too! \
5756 | high[ -]performance \
5757 | solutions[ -]based \
5761 *<font color="red"><b>BINGO!</b></font> \
5765 The x option in this job turns on extended syntax, and allows for e.g. the
5766 liberal use of (non-interpreted!) whitespace for nicer formatting.
5770 -------------------------------------------------------------------------------
5772 9.2. The Pre-defined Filters
5774 The distribution default.filter file contains a selection of pre-defined
5775 filters for your convenience:
5779 The purpose of this filter is to get rid of particularly annoying
5780 JavaScript abuse. To that end, it
5782 + replaces JavaScript references to the browser's referrer information
5783 with the string "Not Your Business!". This compliments the
5784 hide-referrer action on the content level.
5786 + removes the bindings to the DOM's unload event which we feel has no
5787 right to exist and is responsible for most "exit consoles", i.e. nasty
5788 windows that pop up when you close another one.
5790 + removes code that causes new windows to be opened with undesired
5791 properties, such as being full-screen, non-resizeable, without
5792 location, status or menu bar etc.
5794 Use with caution. This is an aggressive filter, and can break sites that
5795 rely heavily on JavaScript.
5799 This is a very radical measure. It removes virtually all JavaScript event
5800 bindings, which means that scripts can not react to user actions such as
5801 mouse movements or clicks, window resizing etc, anymore. Use with caution!
5803 We strongly discourage using this filter as a default since it breaks many
5804 legitimate scripts. It is meant for use only on extra-nasty sites (should
5805 you really need to go there).
5809 This filter will undo many common instances of HTML based abuse.
5811 The BLINK and MARQUEE tags are neutralized (yeah baby!), and browser
5812 windows will be created as resizeable (as of course they should be!), and
5813 will have location, scroll and menu bars -- even if specified otherwise.
5817 Most cookies are set in the HTTP dialog, where they can be intercepted by
5818 the crunch-incoming-cookies and crunch-outgoing-cookies actions. But web
5819 sites increasingly make use of HTML meta tags and JavaScript to sneak
5820 cookies to the browser on the content level.
5822 This filter disables most HTML and JavaScript code that reads or sets
5823 cookies. It cannot detect all clever uses of these types of code, so it
5824 should not be relied on as an absolute fix. Use it wherever you would also
5825 use the cookie crunch actions.
5829 Disable any refresh tags if the interval is greater than nine seconds (so
5830 that redirections done via refresh tags are not destroyed). This is useful
5831 for dial-on-demand setups, or for those who find this HTML feature
5836 This filter attempts to prevent only "unsolicited" pop-up windows from
5837 opening, yet still allow pop-up windows that the user has explicitly chosen
5838 to open. It was added in version 3.0.1, as an improvement over earlier such
5841 Technical note: The filter works by redefining the window.open JavaScript
5842 function to a dummy function, PrivoxyWindowOpen(), during the loading and
5843 rendering phase of each HTML page access, and restoring the function
5846 This is recommended only for browsers that cannot perform this function
5847 reliably themselves. And be aware that some sites require such windows in
5848 order to function normally. Use with caution.
5852 Attempt to prevent all pop-up windows from opening. Note this should be
5853 used with even more discretion than the above, since it is more likely to
5854 break some sites that require pop-ups for normal usage. Use with caution.
5858 This is a helper filter that has no value if used alone. It makes the
5859 banners-by-size and banners-by-link (see below) filters more effective and
5860 should be enabled together with them.
5864 This filter removes image tags purely based on what size they are.
5865 Fortunately for us, many ads and banner images tend to conform to certain
5866 standardized sizes, which makes this filter quite effective for ad
5869 Occasionally this filter will cause false positives on images that are not
5870 ads, but just happen to be of one of the standard banner sizes.
5872 Recommended only for those who require extreme ad blocking. The default
5873 block rules should catch 95+% of all ads without this filter enabled.
5877 This is an experimental filter that attempts to kill any banners if their
5878 URLs seem to point to known or suspected click trackers. It is currently
5879 not of much value and is not recommended for use by default.
5883 Webbugs are small, invisible images (technically 1X1 GIF images), that are
5884 used to track users across websites, and collect information on them. As an
5885 HTML page is loaded by the browser, an embedded image tag causes the
5886 browser to contact a third-party site, disclosing the tracking information
5887 through the requested URL and/or cookies for that third-party domain,
5888 without the user ever becoming aware of the interaction with the
5889 third-party site. HTML-ized spam also uses a similar technique to verify
5892 This filter removes the HTML code that loads such "webbugs".
5896 A rather special-purpose filter that can be used to enlarge textareas
5897 (those multi-line text boxes in web forms) and turn off hard word wrap in
5898 them. It was written for the sourceforge.net tracker system where such
5899 boxes are a nuisance, but it can be handy on other sites, too.
5901 It is not recommended to use this filter as a default.
5905 Many consider windows that move, or resize themselves to be abusive. This
5906 filter neutralizes the related JavaScript code. Note that some sites might
5907 not display or behave as intended when using this filter. Use with caution.
5911 Some web designers seem to assume that everyone in the world will view
5912 their web sites using the same browser brand and version, screen resolution
5913 etc, because only that assumption could explain why they'd use static frame
5914 sizes, yet prevent their frames from being resized by the user, should they
5915 be too small to show their whole content.
5917 This filter removes the related HTML code. It should only be applied to
5918 sites which need it.
5922 Many Microsoft products that generate HTML use non-standard extensions
5923 (read: violations) of the ISO 8859-1 aka Latin-1 character set. This can
5924 cause those HTML documents to display with errors on standard-compliant
5927 This filter translates the MS-only characters into Latin-1 equivalents. It
5928 is not necessary when using MS products, and will cause corruption of all
5929 documents that use 8-bit character sets other than Latin-1. It's mostly
5930 worthwhile for Europeans on non-MS platforms, if weird garbage characters
5931 sometimes appear on some pages, or user agents that don't correct for this
5936 A filter for shockwave haters. As the name suggests, this filter strips
5937 code out of web pages that is used to embed shockwave flash objects.
5941 Change HTML code that embeds Quicktime objects so that kioskmode, which
5942 prevents saving, is disabled.
5946 Text replacements for subversive browsing fun. Make fun of your favorite
5947 Monopolist or play buzzword bingo.
5951 A demonstration-only filter that shows how Privoxy can be used to delete
5952 web content on a keyword basis.
5956 An experimental collection of text replacements to disable malicious HTML
5957 and JavaScript code that exploits known security holes in Internet
5960 Presently, it only protects against Nimda and a cross-site scripting bug,
5961 and would need active maintenance to provide more substantial protection.
5965 Some web sites have very specific problems, the cure for which doesn't
5966 apply anywhere else, or could even cause damage on other sites.
5968 This is a collection of such site-specific cures which should only be
5969 applied to the sites they were intended for, which is what the supplied
5970 default.action file does. Users shouldn't need to change anything regarding
5975 A CSS based block for Google text ads. Also removes a width limitation and
5976 the toolbar advertisement.
5980 Another CSS based block, this time for Yahoo text ads. And removes a width
5985 Another CSS based block, this time for MSN text ads. And removes tracking
5986 URLs, as well as a width limitation.
5990 Cleans up some Blogspot blogs. Read the fine print before using this one!
5992 This filter also intentionally removes some navigation stuff and sets the
5993 page width to 100%. As a result, some rounded "corners" would appear to
5994 early or not at all and as fixing this would require a browser that
5995 understands background-size (CSS3), they are removed instead.
5999 Server-header filter to change the Content-Type from xml to html.
6003 Server-header filter to change the Content-Type from html to xml.
6007 Removes the non-standard ping attribute from anchor and area HTML tags.
6009 hide-tor-exit-notation
6011 Client-header filter to remove the Tor exit node notation found in Host and
6014 If Privoxy and Tor are chained and Privoxy is configured to use socks4a,
6015 one can use "http://www.example.org.foobar.exit/" to access the host
6016 "www.example.org" through the Tor exit node "foobar".
6018 As the HTTP client isn't aware of this notation, it treats the whole string
6019 "www.example.org.foobar.exit" as host and uses it for the "Host" and
6020 "Referer" headers. From the server's point of view the resulting headers
6021 are invalid and can cause problems.
6023 An invalid "Referer" header can trigger "hot-linking" protections, an
6024 invalid "Host" header will make it impossible for the server to find the
6025 right vhost (several domains hosted on the same IP address).
6027 This client-header filter removes the "foo.exit" part in those headers to
6028 prevent the mentioned problems. Note that it only modifies the HTTP
6029 headers, it doesn't make it impossible for the server to detect your Tor
6030 exit node based on the IP address the request is coming from.
6032 -------------------------------------------------------------------------------
6034 10. Privoxy's Template Files
6036 All Privoxy built-in pages, i.e. error pages such as the "404 - No Such Domain"
6037 error page, the "BLOCKED" page and all pages of its web-based user interface,
6038 are generated from templates. (Privoxy must be running for the above links to
6041 These templates are stored in a subdirectory of the configuration directory
6042 called templates. On Unixish platforms, this is typically /etc/privoxy/
6045 The templates are basically normal HTML files, but with place-holders (called
6046 symbols or exports), which Privoxy fills at run time. It is possible to edit
6047 the templates with a normal text editor, should you want to customize them.
6048 (Not recommended for the casual user). Should you create your own custom
6049 templates, you should use the config setting templdir to specify an alternate
6050 location, so your templates do not get overwritten during upgrades.
6052 Note that just like in configuration files, lines starting with # are ignored
6053 when the templates are filled in.
6055 The place-holders are of the form @name@, and you will find a list of available
6056 symbols, which vary from template to template, in the comments at the start of
6057 each file. Note that these comments are not always accurate, and that it's
6058 probably best to look at the existing HTML code to find out which symbols are
6059 supported and what they are filled in with.
6061 A special application of this substitution mechanism is to make whole blocks of
6062 HTML code disappear when a specific symbol is set. We use this for many
6063 purposes, one of them being to include the beta warning in all our user
6064 interface (CGI) pages when Privoxy is in an alpha or beta development stage:
6066 <!-- @if-unstable-start -->
6068 ... beta warning HTML code goes here ...
6070 <!-- if-unstable-end@ -->
6073 If the "unstable" symbol is set, everything in between and including
6074 @if-unstable-start and if-unstable-end@ will disappear, leaving nothing but an
6080 There's also an if-then-else construct and an #include mechanism, but you'll
6081 sure find out if you are inclined to edit the templates ;-)
6083 All templates refer to a style located at http://config.privoxy.org/
6084 send-stylesheet. This is, of course, locally served by Privoxy and the source
6085 for it can be found and edited in the cgi-style.css template.
6087 -------------------------------------------------------------------------------
6089 11. Contacting the Developers, Bug Reporting and Feature Requests
6091 We value your feedback. In fact, we rely on it to improve Privoxy and its
6092 configuration. However, please note the following hints, so we can provide you
6093 with the best support:
6095 -------------------------------------------------------------------------------
6099 For casual users, our support forum at SourceForge is probably best suited:
6100 http://sourceforge.net/tracker/?group_id=11118&atid=211118
6102 All users are of course welcome to discuss their issues on the users mailing
6103 list, where the developers also hang around.
6105 Note that the Privoxy mailing lists are moderated. Posts from unsubscribed
6106 addresses have to be accepted manually by a moderator. This may cause a delay
6107 of several days and if you use a subject that doesn't clearly mention Privoxy
6108 or one of its features, your message may be accidentally discarded as spam.
6110 If you aren't subscribed, you should therefore spend a few seconds to come up
6111 with a proper subject. Additionally you should make it clear that you want to
6112 get CC'd. Otherwise some responses will be directed to the mailing list only,
6113 and you won't see them.
6115 -------------------------------------------------------------------------------
6117 11.2. Reporting Problems
6119 "Problems" for our purposes, come in two forms:
6121 * Configuration issues, such as ads that slip through, or sites that don't
6122 function properly due to one Privoxy "action" or another being turned "on".
6124 * "Bugs" in the programming code that makes up Privoxy, such as that might
6127 -------------------------------------------------------------------------------
6129 11.2.1. Reporting Ads or Other Configuration Problems
6131 Please send feedback on ads that slipped through, innocent images that were
6132 blocked, sites that don't work properly, and other configuration related
6133 problem of default.action file, to http://sourceforge.net/tracker/?group_id=
6134 11118&atid=460288, the Actions File Tracker.
6136 New, improved default.action files may occasionally be made available based on
6137 your feedback. These will be announced on the ijbswa-announce list and
6138 available from our the files section of our project page.
6140 -------------------------------------------------------------------------------
6142 11.2.2. Reporting Bugs
6144 Please report all bugs through our bug tracker: http://sourceforge.net/tracker
6145 /?group_id=11118&atid=111118.
6147 Before doing so, please make sure that the bug has not already been submitted
6148 and observe the additional hints at the top of the submit form. If already
6149 submitted, please feel free to add any info to the original report that might
6150 help to solve the issue.
6152 Please try to verify that it is a Privoxy bug, and not a browser or site bug or
6153 documented behaviour that just happens to be different than what you expected.
6154 If unsure, try toggling off Privoxy, and see if the problem persists.
6156 If you are using your own custom configuration, please try the stock configs to
6157 see if the problem is configuration related. If you're having problems with a
6158 feature that is disabled by default, please ask around on the mailing list if
6159 others can reproduce the problem.
6161 If you aren't using the latest Privoxy version, the bug may have been found and
6162 fixed in the meantime. We would appreciate if you could take the time to
6163 upgrade to the latest version (or even the latest CVS snapshot) and verify that
6164 your bug still exists.
6166 Please be sure to provide the following information:
6168 * The exact Privoxy version you are using (if you got the source from CVS,
6169 please also provide the source code revisions as shown in http://
6170 config.privoxy.org/show-version).
6172 * The operating system and versions you run Privoxy on, (e.g. Windows XP
6173 SP2), if you are using a Unix flavor, sending the output of "uname -a"
6174 should do, in case of GNU/Linux, please also name the distribution.
6176 * The name, platform, and version of the browser you were using (e.g.
6177 Internet Explorer v5.5 for Mac).
6179 * The URL where the problem occurred, or some way for us to duplicate the
6180 problem (e.g. http://somesite.example.com/?somethingelse=123).
6182 * Whether your version of Privoxy is one supplied by the Privoxy developers
6183 via SourceForge, or if you got your copy somewhere else.
6185 * Whether you are using Privoxy in tandem with another proxy such as Tor. If
6186 so, please temporary disable the other proxy to see if the symptoms change.
6188 * Whether you are using a personal firewall product. If so, does Privoxy work
6191 * Any other pertinent information to help identify the problem such as config
6192 or log file excerpts (yes, you should have log file entries for each action
6195 You don't have to tell us your actual name when filing a problem report, but
6196 please use a nickname so we can differentiate between your messages and the
6197 ones entered by other "anonymous" users that may respond to your request if
6198 they have the same problem or already found a solution.
6200 Please also check the status of your request a few days after submitting it, as
6201 we may request additional information. If you use a SF id, you should
6202 automatically get a mail when someone responds to your request.
6204 The appendix of the Privoxy User Manual also has helpful information on
6205 understanding actions, and action debugging.
6207 -------------------------------------------------------------------------------
6209 11.3. Request New Features
6211 You are welcome to submit ideas on new features or other proposals for
6212 improvement through our feature request tracker at http://sourceforge.net/
6213 tracker/?atid=361118&group_id=11118.
6215 -------------------------------------------------------------------------------
6219 For any other issues, feel free to use the mailing lists. Technically
6220 interested users and people who wish to contribute to the project are also
6221 welcome on the developers list! You can find an overview of all Privoxy-related
6222 mailing lists, including list archives, at: http://sourceforge.net/mail/?
6225 -------------------------------------------------------------------------------
6227 12. Privoxy Copyright, License and History
6229 Copyright 2001-2007 by Privoxy Developers <
6230 ijbswa-developers@lists.sourceforge.net>
6232 Some source code is based on code Copyright 1997 by Anonymous Coders and
6233 Junkbusters, Inc. and licensed under the GNU General Public License.
6235 -------------------------------------------------------------------------------
6239 Privoxy is free software; you can redistribute it and/or modify it under the
6240 terms of the GNU General Public License, version 2, as published by the Free
6241 Software Foundation.
6243 This program is distributed in the hope that it will be useful, but WITHOUT ANY
6244 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
6245 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
6246 is available from the Free Software Foundation, Inc, 51 Franklin Street, Fifth
6247 Floor, Boston, MA 02110-1301, USA
6249 You should have received a copy of the GNU General Public License along with
6250 this program; if not, write to the
6253 Foundation, Inc. 51 Franklin Street, Fifth Floor
6254 Boston, MA 02110-1301
6257 -------------------------------------------------------------------------------
6261 A long time ago, there was the Internet Junkbuster, by Anonymous Coders and
6262 Junkbusters Corporation. This saved many users a lot of pain in the early days
6263 of web advertising and user tracking.
6265 But the web, its protocols and standards, and with it, the techniques for
6266 forcing ads on users, give up autonomy over their browsing, and for tracking
6267 them, keeps evolving. Unfortunately, the Internet Junkbuster did not. Version
6268 2.0.2, published in 1998, was (and is) the last official release available from
6269 Junkbusters Corporation. Fortunately, it had been released under the GNU GPL,
6270 which allowed further development by others.
6272 So Stefan Waldherr started maintaining an improved version of the software, to
6273 which eventually a number of people contributed patches. It could already
6274 replace banners with a transparent image, and had a first version of pop-up
6275 killing, but it was still very closely based on the original, with all its
6276 limitations, such as the lack of HTTP/1.1 support, flexible per-site
6277 configuration, or content modification. The last release from this effort was
6278 version 2.0.2-10, published in 2000.
6280 Then, some developers picked up the thread, and started turning the software
6281 inside out, upside down, and then reassembled it, adding many new features
6284 The result of this is Privoxy, whose first stable version, 3.0, was released
6287 -------------------------------------------------------------------------------
6291 Current Privoxy Team:
6293 Fabian Keil, lead developer
6294 David Schmidt, developer
6301 Former Privoxy Team Members:
6326 Thanks to the many people who have tested Privoxy, reported bugs, provided
6327 patches, made suggestions or contributed in some way. These include (in
6328 alphabetical order):
6384 Privoxy is based in part on code originally developed by Junkbusters Corp. and
6387 Privoxy heavily relies on Philip Hazel's PCRE.
6389 The code to filter compressed content makes use of zlib which is written by
6390 Jean-loup Gailly and Mark Adler.
6392 On systems that lack snprintf(), Privoxy is using a version written by Mark
6393 Martinec. On systems that lack strptime(), Privoxy is using the one from the
6394 GNU C Library written by Ulrich Drepper.
6396 -------------------------------------------------------------------------------
6400 Other references and sites of interest to Privoxy users:
6402 http://www.privoxy.org/, the Privoxy Home page.
6404 http://www.privoxy.org/faq/, the Privoxy FAQ.
6406 http://sourceforge.net/projects/ijbswa/, the Project Page for Privoxy on
6409 http://config.privoxy.org/, the web-based user interface. Privoxy must be
6410 running for this to work. Shortcut: http://p.p/
6412 http://sourceforge.net/tracker/?group_id=11118&atid=460288, to submit "misses"
6413 and other configuration related suggestions to the developers.
6415 http://www.junkbusters.com/ht/en/cookies.html, an explanation how cookies are
6416 used to track web users.
6418 http://www.junkbusters.com/ijb.html, the original Internet Junkbuster.
6420 http://privacy.net/, a useful site to check what information about you is
6421 leaked while you browse the web.
6423 http://www.squid-cache.org/, a popular caching proxy, which is often used
6424 together with Privoxy.
6426 http://www.pps.jussieu.fr/~jch/software/polipo/, Polipo is a caching proxy with
6427 advanced features like pipelining, multiplexing and caching of partial
6428 instances. In many setups it can be used as Squid replacement.
6430 http://tor.eff.org/, Tor can help anonymize web browsing, web publishing,
6431 instant messaging, IRC, SSH, and other applications.
6433 http://www.privoxy.org/developer-manual/, the Privoxy developer manual.
6435 -------------------------------------------------------------------------------
6439 14.1. Regular Expressions
6441 Privoxy uses Perl-style "regular expressions" in its actions files and filter
6442 file, through the PCRE and PCRS libraries.
6444 If you are reading this, you probably don't understand what "regular
6445 expressions" are, or what they can do. So this will be a very brief
6446 introduction only. A full explanation would require a book ;-)
6448 Regular expressions provide a language to describe patterns that can be run
6449 against strings of characters (letter, numbers, etc), to see if they match the
6450 string or not. The patterns are themselves (sometimes complex) strings of
6451 literal characters, combined with wild-cards, and other special characters,
6452 called meta-characters. The "meta-characters" have special meanings and are
6453 used to build complex patterns to be matched against. Perl Compatible Regular
6454 Expressions are an especially convenient "dialect" of the regular expression
6457 To make a simple analogy, we do something similar when we use wild-card
6458 characters when listing files with the dir command in DOS. *.* matches all
6459 filenames. The "special" character here is the asterisk which matches any and
6460 all characters. We can be more specific and use ? to match just individual
6461 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
6462 are pattern matching, using a similar technique to "regular expressions"!
6464 Regular expressions do essentially the same thing, but are much, much more
6465 powerful. There are many more "special characters" and ways of building complex
6466 patterns however. Let's look at a few of the common ones, and then some
6469 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
6471 ? - The preceding character or expression is matched ZERO or ONE times. Either/
6474 + - The preceding character or expression is matched ONE or MORE times.
6476 * - The preceding character or expression is matched ZERO or MORE times.
6478 \ - The "escape" character denotes that the following character should be taken
6479 literally. This is used where one of the special characters (e.g. ".") needs to
6480 be taken literally and not as a special meta-character. Example: "example
6481 \.com", makes sure the period is recognized only as a period (and not expanded
6482 to its meta-character meaning of any single character).
6484 [ ] - Characters enclosed in brackets will be matched if any of the enclosed
6485 characters are encountered. For instance, "[0-9]" matches any numeric digit
6486 (zero through nine). As an example, we can combine this with "+" to match any
6487 digit one of more times: "[0-9]+".
6489 ( ) - parentheses are used to group a sub-expression, or multiple
6492 | - The "bar" character works like an "or" conditional statement. A match is
6493 successful if the sub-expression on either side of "|" matches. As an example:
6494 "/(this|that) example/" uses grouping and the bar character and would match
6495 either "this example" or "that example", and nothing else.
6497 These are just some of the ones you are likely to use when matching URLs with
6498 Privoxy, and is a long way from a definitive list. This is enough to get us
6499 started with a few simple examples which may be more illuminating:
6501 /.*/banners/.* - A simple example that uses the common combination of "." and
6502 "*" to denote any character, zero or more times. In other words, any string at
6503 all. So we start with a literal forward slash, then our regular expression
6504 pattern (".*") another literal forward slash, the string "banners", another
6505 forward slash, and lastly another ".*". We are building a directory path here.
6506 This will match any file with the path that has a directory named "banners" in
6507 it. The ".*" matches any characters, and this could conceivably be more forward
6508 slashes, so it might expand into a much longer looking path. For example, this
6509 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
6510 banners/annoying.html", or almost an infinite number of other possible
6511 combinations, just so it has "banners" in the path somewhere.
6513 And now something a little more complex:
6515 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
6516 slashes again ("/"), so we are building another expression that is a file path
6517 statement. We have another ".*", so we are matching against any conceivable
6518 sub-path, just so it matches our expression. The only true literal that must
6519 match our pattern is adv, together with the forward slashes. What comes after
6520 the "adv" string is the interesting part.
6522 Remember the "?" means the preceding expression (either a literal character or
6523 anything grouped with "(...)" in this case) can exist or not, since this means
6524 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
6525 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
6526 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
6527 to match either "ing" OR "ements?". What is being done here, is an attempt at
6528 matching as many variations of "advertisement", and similar, as possible. So
6529 this would expand to match just "adv", or "advert", or "adverts", or
6530 "advertising", or "advertisement", or "advertisements". You get the idea. But
6531 it would not match "advertizements" (with a "z"). We could fix that by changing
6532 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
6533 would then match either spelling.
6535 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
6536 slashes. Anything in the square brackets "[ ]" can be matched. This is using
6537 "0-9" as a shorthand expression to mean any digit one through nine. It is the
6538 same as saying "0123456789". So any digit matches. The "+" means one or more of
6539 the preceding expression must be included. The preceding expression here is
6540 what is in the square brackets -- in this case, any digit one through nine.
6541 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
6542 this needs to match the expression on either side of that bar character also. A
6543 simple "gif" on one side, and the other side will in turn match either "jpeg"
6544 or "jpg", since the "?" means the letter "e" is optional and can be matched
6545 once or not at all. So we are building an expression here to match image GIF or
6546 JPEG type image file. It must include the literal string "advert", then one or
6547 more digits, and a "." (which is now a literal, and not a special character,
6548 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
6549 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
6550 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
6551 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
6552 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
6554 We are barely scratching the surface of regular expressions here so that you
6555 can understand the default Privoxy configuration files, and maybe use this
6556 knowledge to customize your own installation. There is much, much more that can
6557 be done with regular expressions. Now that you know enough to get started, you
6558 can learn more on your own :/
6560 More reading on Perl Compatible Regular expressions: http://perldoc.perl.org/
6563 For information on regular expression based substitutions and their
6564 applications in filters, please see the filter file tutorial in this manual.
6566 -------------------------------------------------------------------------------
6568 14.2. Privoxy's Internal Pages
6570 Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
6571 certain special URLs. In this way, we can talk directly to Privoxy, and see how
6572 it is configured, see how our rules are being applied, change these rules and
6573 other configuration options, and even turn Privoxy's filtering off, all with a
6576 The URLs listed below are the special ones that allow direct access to Privoxy.
6577 Of course, Privoxy must be running to access these. If not, you will get a
6578 friendly error message. Internet access is not necessary either.
6580 * Privoxy main page:
6582 http://config.privoxy.org/
6584 There is a shortcut: http://p.p/ (But it doesn't provide a fall-back to a
6585 real page, in case the request is not sent through Privoxy)
6587 * Show information about the current configuration, including viewing and
6588 editing of actions files:
6590 http://config.privoxy.org/show-status
6592 * Show the source code version numbers:
6594 http://config.privoxy.org/show-version
6596 * Show the browser's request headers:
6598 http://config.privoxy.org/show-request
6600 * Show which actions apply to a URL and why:
6602 http://config.privoxy.org/show-url-info
6604 * Toggle Privoxy on or off. This feature can be turned off/on in the main
6605 config file. When toggled "off", "Privoxy" continues to run, but only as a
6606 pass-through proxy, with no actions taking place:
6608 http://config.privoxy.org/toggle
6610 Short cuts. Turn off, then on:
6612 http://config.privoxy.org/toggle?set=disable
6614 http://config.privoxy.org/toggle?set=enable
6616 These may be bookmarked for quick reference. See next.
6618 -------------------------------------------------------------------------------
6620 14.2.1. Bookmarklets
6622 Below are some "bookmarklets" to allow you to easily access a "mini" version of
6623 some of Privoxy's special pages. They are designed for MS Internet Explorer,
6624 but should work equally well in Netscape, Mozilla, and other browsers which
6625 support JavaScript. They are designed to run directly from your bookmarks - not
6626 by clicking the links below (although that should work for testing).
6628 To save them, right-click the link and choose "Add to Favorites" (IE) or "Add
6629 Bookmark" (Netscape). You will get a warning that the bookmark "may not be
6630 safe" - just click OK. Then you can run the Bookmarklet directly from your
6631 favorites/bookmarks. For even faster access, you can put them on the "Links"
6632 bar (IE) or the "Personal Toolbar" (Netscape), and run them with a single
6639 * Privoxy - Toggle Privoxy (Toggles between enabled and disabled)
6641 * Privoxy- View Status
6645 Credit: The site which gave us the general idea for these bookmarklets is
6646 www.bookmarklets.com. They have more information about bookmarklets.
6648 -------------------------------------------------------------------------------
6650 14.3. Chain of Events
6652 Let's take a quick look at how some of Privoxy's core features are triggered,
6653 and the ensuing sequence of events when a web page is requested by your
6656 * First, your web browser requests a web page. The browser knows to send the
6657 request to Privoxy, which will in turn, relay the request to the remote web
6658 server after passing the following tests:
6660 * Privoxy traps any request for its own internal CGI pages (e.g http://p.p/)
6661 and sends the CGI page back to the browser.
6663 * Next, Privoxy checks to see if the URL matches any "+block" patterns. If
6664 so, the URL is then blocked, and the remote web server will not be
6665 contacted. "+handle-as-image" and "+handle-as-empty-document" are then
6666 checked, and if there is no match, an HTML "BLOCKED" page is sent back to
6667 the browser. Otherwise, if it does match, an image is returned for the
6668 former, and an empty text document for the latter. The type of image would
6669 depend on the setting of "+set-image-blocker" (blank, checkerboard pattern,
6670 or an HTTP redirect to an image elsewhere).
6672 * Untrusted URLs are blocked. If URLs are being added to the trust file, then
6675 * If the URL pattern matches the "+fast-redirects" action, it is then
6676 processed. Unwanted parts of the requested URL are stripped.
6678 * Now the rest of the client browser's request headers are processed. If any
6679 of these match any of the relevant actions (e.g. "+hide-user-agent", etc.),
6680 headers are suppressed or forged as determined by these actions and their
6683 * Now the web server starts sending its response back (i.e. typically a web
6686 * First, the server headers are read and processed to determine, among other
6687 things, the MIME type (document type) and encoding. The headers are then
6688 filtered as determined by the "+crunch-incoming-cookies",
6689 "+session-cookies-only", and "+downgrade-http-version" actions.
6691 * If the "+kill-popups" action applies, and it is an HTML or JavaScript
6692 document, the popup-code in the response is filtered on-the-fly as it is
6695 * If any "+filter" action or "+deanimate-gifs" action applies (and the
6696 document type fits the action), the rest of the page is read into memory
6697 (up to a configurable limit). Then the filter rules (from default.filter
6698 and any other filter files) are processed against the buffered content.
6699 Filters are applied in the order they are specified in one of the filter
6700 files. Animated GIFs, if present, are reduced to either the first or last
6701 frame, depending on the action setting.The entire page, which is now
6702 filtered, is then sent by Privoxy back to your browser.
6704 If neither a "+filter" action or "+deanimate-gifs" matches, then Privoxy
6705 passes the raw data through to the client browser as it becomes available.
6707 * As the browser receives the now (possibly filtered) page content, it reads
6708 and then requests any URLs that may be embedded within the page source,
6709 e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
6710 frames), sounds, etc. For each of these objects, the browser issues a
6711 separate request (this is easily viewable in Privoxy's logs). And each such
6712 request is in turn processed just as above. Note that a complex web page
6713 will have many, many such embedded URLs. If these secondary requests are to
6714 a different server, then quite possibly a very differing set of actions is
6717 NOTE: This is somewhat of a simplistic overview of what happens with each URL
6718 request. For the sake of brevity and simplicity, we have focused on Privoxy's
6721 -------------------------------------------------------------------------------
6723 14.4. Troubleshooting: Anatomy of an Action
6725 The way Privoxy applies actions and filters to any given URL can be complex,
6726 and not always so easy to understand what is happening. And sometimes we need
6727 to be able to see just what Privoxy is doing. Especially, if something Privoxy
6728 is doing is causing us a problem inadvertently. It can be a little daunting to
6729 look at the actions and filters files themselves, since they tend to be filled
6730 with regular expressions whose consequences are not always so obvious.
6732 One quick test to see if Privoxy is causing a problem or not, is to disable it
6733 temporarily. This should be the first troubleshooting step. See the
6734 Bookmarklets section on a quick and easy way to do this (be sure to flush
6735 caches afterward!). Looking at the logs is a good idea too. (Note that both the
6736 toggle feature and logging are enabled via config file settings, and may need
6739 Another easy troubleshooting step to try is if you have done any customization
6740 of your installation, revert back to the installed defaults and see if that
6741 helps. There are times the developers get complaints about one thing or
6742 another, and the problem is more related to a customized configuration issue.
6744 Privoxy also provides the http://config.privoxy.org/show-url-info page that can
6745 show us very specifically how actions are being applied to any given URL. This
6746 is a big help for troubleshooting.
6748 First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell
6749 us how the current configuration will handle it. This will not help with
6750 filtering effects (i.e. the "+filter" action) from one of the filter files
6751 since this is handled very differently and not so easy to trap! It also will
6752 not tell you about any other URLs that may be embedded within the URL you are
6753 testing. For instance, images such as ads are expressed as URLs within the raw
6754 page source of HTML pages. So you will only get info for the actual URL that is
6755 pasted into the prompt area -- not any sub-URLs. If you want to know about
6756 embedded URLs like ads, you will have to dig those out of the HTML source. Use
6757 your browser's "View Page Source" option for this. Or right click on the ad,
6760 Let's try an example, google.com, and look at it one section at a time in a
6761 sample configuration (your real configuration may vary):
6763 Matches for http://www.google.com:
6765 In file: default.action [ View ] [ Edit ]
6767 {+deanimate-gifs {last}
6768 +fast-redirects {check-decoded-url}
6769 +filter {refresh-tags}
6770 +filter {img-reorder}
6771 +filter {banners-by-size}
6773 +filter {jumping-windows}
6774 +filter {ie-exploits}
6775 +hide-forwarded-for-headers
6776 +hide-from-header {block}
6777 +hide-referrer {forge}
6778 +session-cookies-only
6779 +set-image-blocker {pattern}
6782 { -session-cookies-only }
6788 In file: user.action [ View ] [ Edit ]
6789 (no matches in this file)
6792 This is telling us how we have defined our "actions", and which ones match for
6793 our test case, "google.com". Displayed is all the actions that are available to
6794 us. Remember, the + sign denotes "on". - denotes "off". So some are "on" here,
6795 but many are "off". Each example we try may provide a slightly different end
6796 result, depending on our configuration directives.
6798 The first listing is for our default.action file. The large, multi-line
6799 listing, is how the actions are set to match for all URLs, i.e. our default
6800 settings. If you look at your "actions" file, this would be the section just
6801 below the "aliases" section near the top. This will apply to all URLs as
6802 signified by the single forward slash at the end of the listing -- " / ".
6804 But we have defined additional actions that would be exceptions to these
6805 general rules, and then we list specific URLs (or patterns) that these
6806 exceptions would apply to. Last match wins. Just below this then are two
6807 explicit matches for ".google.com". The first is negating our previous cookie
6808 setting, which was for "+session-cookies-only" (i.e. not persistent). So we
6809 will allow persistent cookies for google, at least that is how it is in this
6810 example. The second turns off any "+fast-redirects" action, allowing this to
6811 take place unmolested. Note that there is a leading dot here -- ".google.com".
6812 This will match any hosts and sub-domains, in the google.com domain also, such
6813 as "www.google.com" or "mail.google.com". But it would not match
6814 "www.google.de"! So, apparently, we have these two actions defined as
6815 exceptions to the general rules at the top somewhere in the lower part of our
6816 default.action file, and "google.com" is referenced somewhere in these latter
6819 Then, for our user.action file, we again have no hits. So there is nothing
6820 google-specific that we might have added to our own, local configuration. If
6821 there was, those actions would over-rule any actions from previously processed
6822 files, such as default.action. user.action typically has the last word. This is
6823 the best place to put hard and fast exceptions,
6825 And finally we pull it all together in the bottom section and summarize how
6826 Privoxy is applying all its "actions" to "google.com":
6832 -client-header-filter{hide-tor-exit-notation}
6833 -content-type-overwrite
6834 -crunch-client-header
6835 -crunch-if-none-match
6836 -crunch-incoming-cookies
6837 -crunch-outgoing-cookies
6838 -crunch-server-header
6839 +deanimate-gifs {last}
6840 -downgrade-http-version
6843 -filter {content-cookies}
6844 -filter {all-popups}
6845 -filter {banners-by-link}
6846 -filter {tiny-textforms}
6847 -filter {frameset-borders}
6848 -filter {demoronizer}
6849 -filter {shockwave-flash}
6850 -filter {quicktime-kioskmode}
6852 -filter {crude-parental}
6853 -filter {site-specifics}
6854 -filter {js-annoyances}
6855 -filter {html-annoyances}
6856 +filter {refresh-tags}
6857 -filter {unsolicited-popups}
6858 +filter {img-reorder}
6859 +filter {banners-by-size}
6861 +filter {jumping-windows}
6862 +filter {ie-exploits}
6869 -handle-as-empty-document
6871 -hide-accept-language
6872 -hide-content-disposition
6873 +hide-forwarded-for-headers
6874 +hide-from-header {block}
6875 -hide-if-modified-since
6876 +hide-referrer {forge}
6881 -overwrite-last-modified
6882 -prevent-compression
6886 -server-header-filter{xml-to-html}
6887 -server-header-filter{html-to-xml}
6888 -session-cookies-only
6889 +set-image-blocker {pattern}
6890 -treat-forbidden-connects-like-blocks
6893 Notice the only difference here to the previous listing, is to "fast-redirects"
6894 and "session-cookies-only", which are activated specifically for this site in
6895 our configuration, and thus show in the "Final Results".
6897 Now another example, "ad.doubleclick.net":
6905 { +block +handle-as-image }
6906 .[a-vx-z]*.doubleclick.net
6909 We'll just show the interesting part here - the explicit matches. It is matched
6910 three different times. Two "+block" sections, and a "+block +handle-as-image",
6911 which is the expanded form of one of our aliases that had been defined as:
6912 "+block-as-image". ("Aliases" are defined in the first section of the actions
6913 file and typically used to combine more than one action.)
6915 Any one of these would have done the trick and blocked this as an unwanted
6916 image. This is unnecessarily redundant since the last case effectively would
6917 also cover the first. No point in taking chances with these guys though ;-)
6918 Note that if you want an ad or obnoxious URL to be invisible, it should be
6919 defined as "ad.doubleclick.net" is done here -- as both a "+block" and an
6920 "+handle-as-image". The custom alias "+block-as-image" just simplifies the
6921 process and make it more readable.
6923 One last example. Let's try "http://www.example.net/adsl/HOWTO/". This one is
6924 giving us problems. We are getting a blank page. Hmmm ...
6926 Matches for http://www.example.net/adsl/HOWTO/:
6928 In file: default.action [ View ] [ Edit ]
6932 -client-header-filter{hide-tor-exit-notation}
6933 -content-type-overwrite
6934 -crunch-client-header
6935 -crunch-if-none-match
6936 -crunch-incoming-cookies
6937 -crunch-outgoing-cookies
6938 -crunch-server-header
6940 -downgrade-http-version
6941 +fast-redirects {check-decoded-url}
6943 -filter {content-cookies}
6944 -filter {all-popups}
6945 -filter {banners-by-link}
6946 -filter {tiny-textforms}
6947 -filter {frameset-borders}
6948 -filter {demoronizer}
6949 -filter {shockwave-flash}
6950 -filter {quicktime-kioskmode}
6952 -filter {crude-parental}
6953 -filter {site-specifics}
6954 -filter {js-annoyances}
6955 -filter {html-annoyances}
6956 +filter {refresh-tags}
6957 -filter {unsolicited-popups}
6958 +filter {img-reorder}
6959 +filter {banners-by-size}
6961 +filter {jumping-windows}
6962 +filter {ie-exploits}
6969 -handle-as-empty-document
6971 -hide-accept-language
6972 -hide-content-disposition
6973 +hide-forwarded-for-headers
6974 +hide-from-header{block}
6975 +hide-referer{forge}
6979 -overwrite-last-modified
6980 +prevent-compression
6984 -server-header-filter{xml-to-html}
6985 -server-header-filter{html-to-xml}
6986 +session-cookies-only
6987 +set-image-blocker{blank}
6988 -treat-forbidden-connects-like-blocks }
6991 { +block +handle-as-image }
6995 Ooops, the "/adsl/" is matching "/ads" in our configuration! But we did not
6996 want this at all! Now we see why we get the blank page. It is actually
6997 triggering two different actions here, and the effects are aggregated so that
6998 the URL is blocked, and Privoxy is told to treat the block as if it were an
6999 image. But this is, of course, all wrong. We could now add a new action below
7000 this (or better in our own user.action file) that explicitly un blocks ( "
7001 {-block}") paths with "adsl" in them (remember, last match in the configuration
7002 wins). There are various ways to handle such exceptions. Example:
7008 Now the page displays ;-) Remember to flush your browser's caches when making
7009 these kinds of changes to your configuration to insure that you get a freshly
7010 delivered page! Or, try using Shift+Reload.
7012 But now what about a situation where we get no explicit matches like we did
7015 { +block +handle-as-image }
7019 That actually was very helpful and pointed us quickly to where the problem was.
7020 If you don't get this kind of match, then it means one of the default rules in
7021 the first section of default.action is causing the problem. This would require
7022 some guesswork, and maybe a little trial and error to isolate the offending
7023 rule. One likely cause would be one of the "+filter" actions. These tend to be
7024 harder to troubleshoot. Try adding the URL for the site to one of aliases that
7029 .worldpay.com # for quietpc.com
7035 "{ shop }" is an "alias" that expands to "{ -filter -session-cookies-only }".
7036 Or you could do your own exception to negate filtering:
7039 # Disable ALL filter actions for sites in this section
7045 This would turn off all filtering for these sites. This is best put in
7046 user.action, for local site exceptions. Note that when a simple domain pattern
7047 is used by itself (without the subsequent path portion), all sub-pages within
7048 that domain are included automatically in the scope of the action.
7050 Images that are inexplicably being blocked, may well be hitting the "+filter
7051 {banners-by-size}" rule, which assumes that images of certain sizes are ad
7052 banners (works well most of the time since these tend to be standardized).
7054 "{ fragile }" is an alias that disables most actions that are the most likely
7055 to cause trouble. This can be used as a last resort for problem sites.
7058 # Handle with care: easy to break
7063 Remember to flush caches! Note that the mail.google reference lacks the TLD
7064 portion (e.g. ".com"). This will effectively match any TLD with google in it,
7065 such as mail.google.de., just as an example.
7067 If this still does not work, you will have to go through the remaining actions
7068 one by one to find which one(s) is causing the problem.
projects / privoxy.git / blob