1 Privoxy 3.0.6 User Manual
3 Copyright © 2001 - 2006 by Privoxy Developers
5 $Id: user-manual.sgml,v 2.26 2006/10/24 11:16:44 hal9 Exp $
7 The Privoxy User Manual gives users information on how to install, configure
10 Privoxy is a web proxy with advanced filtering capabilities for protecting
11 privacy, modifying web page data, managing cookies, controlling access, and
12 removing ads, banners, pop-ups and other obnoxious Internet junk. Privoxy has a
13 very flexible configuration and can be customized to suit individual needs and
14 tastes. Privoxy has application for both stand-alone systems and multi-user
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
37 2.1.4. Solaris, NetBSD, FreeBSD, HP-UX
43 2.2. Building from Source
44 2.3. Keeping your Installation Up-to-Date
46 3. What's New in this Release
48 3.1. Note to Upgraders
50 4. Quickstart to Using Privoxy
52 4.1. Quickstart to Ad Blocking
56 5.1. Red Hat and Fedora
59 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
64 5.9. Command Line Options
66 6. Privoxy Configuration
68 6.1. Controlling Privoxy with Your Web Browser
69 6.2. Configuration Files Overview
71 7. The Main Configuration File
73 7.1. Local Set-up Documentation
80 7.2. Configuration and Log File Locations
93 7.3.2. single-threaded
95 7.4. Access Control and Security
99 7.4.3. enable-remote-toggle
100 7.4.4. enable-remote-http-toggle
101 7.4.5. enable-edit-actions
102 7.4.6. ACLs: permit-access and deny-access
108 7.5.2. forward-socks4 and forward-socks4a
109 7.5.3. Advanced Forwarding Examples
110 7.5.4. forwarded-connect-retries
112 7.6. Windows GUI Options
116 8.1. Finding the Right Mix
118 8.3. How Actions are Applied to URLs
121 8.4.1. The Domain Pattern
122 8.4.2. The Path Pattern
128 8.5.3. content-type-overwrite
129 8.5.4. crunch-client-header
130 8.5.5. crunch-if-none-match
131 8.5.6. crunch-incoming-cookies
132 8.5.7. crunch-server-header
133 8.5.8. crunch-outgoing-cookies
134 8.5.9. deanimate-gifs
135 8.5.10. downgrade-http-version
136 8.5.11. fast-redirects
138 8.5.13. filter-client-headers
139 8.5.14. filter-server-headers
140 8.5.15. force-text-mode
141 8.5.16. handle-as-empty-document
142 8.5.17. handle-as-image
143 8.5.18. hide-accept-language
144 8.5.19. hide-content-disposition
145 8.5.20. hide-if-modified-since
146 8.5.21. hide-forwarded-for-headers
147 8.5.22. hide-from-header
148 8.5.23. hide-referrer
149 8.5.24. hide-user-agent
150 8.5.25. inspect-jpegs
152 8.5.27. limit-connect
153 8.5.28. prevent-compression
154 8.5.29. overwrite-last-modified
156 8.5.31. send-vanilla-wafer
158 8.5.33. session-cookies-only
159 8.5.34. set-image-blocker
160 8.5.35. treat-forbidden-connects-like-blocks
164 8.7. Actions Files Tutorial
166 8.7.1. default.action
171 9.1. Filter File Tutorial
172 9.2. The Pre-defined Filters
174 10. Privoxy's Template Files
175 11. Contacting the Developers, Bug Reporting and Feature Requests
178 11.2. Reporting Problems
180 11.2.1. Reporting Ads or Other Configuration Problems
181 11.2.2. Reporting Bugs
183 11.3. Request New Features
186 12. Privoxy Copyright, License and History
195 14.1. Regular Expressions
196 14.2. Privoxy's Internal Pages
200 14.3. Chain of Events
201 14.4. Troubleshooting: Anatomy of an Action
205 This documentation is included with the current stable version of Privoxy,
208 -------------------------------------------------------------------------------
212 In addition to the core features of ad blocking and cookie management, Privoxy
213 provides many supplemental features, that give the end-user more control, more
214 privacy and more freedom:
216 * Integrated browser based configuration and control utility at http://
217 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
218 and filter effects. Remote toggling.
220 * Web page filtering (text replacements, removes banners based on size,
221 invisible "web-bugs", JavaScript and HTML annoyances, pop-up windows,
222 header manipulation, etc.)
224 * Modularized configuration that allows for standard settings and user
225 settings to reside in separate files, so that installing updated actions
226 files won't overwrite individual user settings.
228 * HTTP/1.1 compliant (but not all optional 1.1 features are supported).
230 * Support for Perl Compatible Regular Expressions in the configuration files,
231 and generally a more sophisticated and flexible configuration syntax over
234 * Improved cookie management features (e.g. session based cookies).
238 * Bypass many click-tracking scripts (avoids script redirection).
240 * Multi-threaded (POSIX and native threads).
242 * User-customizable HTML templates for all proxy-generated pages (e.g.
245 * Auto-detection and re-reading of config file changes.
247 * Improved signal handling, and a true daemon mode (Unix).
249 * Every feature now controllable on a per-site or per-location basis,
250 configuration more powerful and versatile over-all.
252 * Many smaller new features added, limitations and bugs removed, and security
255 -------------------------------------------------------------------------------
259 Privoxy is available both in convenient pre-compiled packages for a wide range
260 of operating systems, and as raw source code. For most users, we recommend
261 using the packages, which can be downloaded from our Privoxy Project Page.
263 Note: On some platforms, the installer may remove previously installed
264 versions, if found. (See below for your platform). In any case be sure to
265 backup your old configuration if it is valuable to you. See the note to
266 upgraders section below.
268 -------------------------------------------------------------------------------
272 How to install the binary packages depends on your operating system:
274 -------------------------------------------------------------------------------
276 2.1.1. Red Hat and Fedora RPMs
278 RPMs can be installed with rpm -Uvh privoxy-3.0.6-1.rpm, and will use /etc/
279 privoxy for the location of configuration files.
281 Note that on Red Hat, Privoxy will not be automatically started on system boot.
282 You will need to enable that using chkconfig, ntsysv, or similar methods.
284 If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm
285 --rebuild privoxy-3.0.6-1.src.rpm. This will use your locally installed
286 libraries and RPM version.
288 Also note that if you have a Junkbuster RPM installed on your system, you need
289 to remove it first, because the packages conflict. Otherwise, RPM will try to
290 remove Junkbuster automatically if found, before installing Privoxy.
292 -------------------------------------------------------------------------------
296 DEBs can be installed with apt-get install privoxy, and will use /etc/privoxy
297 for the location of configuration files.
299 -------------------------------------------------------------------------------
303 Just double-click the installer, which will guide you through the installation
304 process. You will find the configuration files in the same directory as you
305 installed Privoxy in.
307 Version 3.0.4 introduced full Windows service functionality. On Windows only,
308 the Privoxy program has two new command line arguments to install and uninstall
309 Privoxy as a service.
313 --install[:service_name]
315 --uninstall[:service_name]
317 After invoking Privoxy with --install, you will need to bring up the Windows
318 service console to assign the user you want Privoxy to run under, and whether
319 or not you want it to run whenever the system starts. You can start the Windows
320 services console with the following command: services.msc. If you do not take
321 the manual step of modifying Privoxy's service settings, it will not start.
322 Note too that you will need to give Privoxy a user account that actually
323 exists, or it will not be permitted to write to its log and configuration
326 -------------------------------------------------------------------------------
328 2.1.4. Solaris, NetBSD, FreeBSD, HP-UX
330 Create a new directory, cd to it, then unzip and untar the archive. For the
331 most part, you'll have to figure out where things go.
333 -------------------------------------------------------------------------------
337 First, make sure that no previous installations of Junkbuster and / or Privoxy
338 are left on your system. Check that no Junkbuster or Privoxy objects are in
341 Then, just double-click the WarpIN self-installing archive, which will guide
342 you through the installation process. A shadow of the Privoxy executable will
343 be placed in your startup folder so it will start automatically whenever OS/2
346 The directory you choose to install Privoxy into will contain all of the
349 -------------------------------------------------------------------------------
353 Unzip the downloaded file (you can either double-click on the file from the
354 finder, or from the desktop if you downloaded it there). Then, double-click on
355 the package installer icon named Privoxy.pkg and follow the installation
356 process. Privoxy will be installed in the folder /Library/Privoxy. It will
357 start automatically whenever you start up. To prevent it from starting
358 automatically, remove or rename the folder /Library/StartupItems/Privoxy.
360 To start Privoxy by hand, double-click on StartPrivoxy.command in the /Library/
361 Privoxy folder. Or, type this command in the Terminal:
363 /Library/Privoxy/StartPrivoxy.command
366 You will be prompted for the administrator password.
368 -------------------------------------------------------------------------------
372 Copy and then unpack the lha archive to a suitable location. All necessary
373 files will be installed into Privoxy directory, including all configuration and
374 log files. To uninstall, just remove this directory.
376 -------------------------------------------------------------------------------
380 Gentoo source packages (Ebuilds) for Privoxy are contained in the Gentoo
381 Portage Tree (they are not on the download page, but there is a Gentoo section,
382 where you can see when a new Privoxy Version is added to the Portage Tree).
384 Before installing Privoxy under Gentoo just do first emerge rsync to get the
385 latest changes from the Portage tree. With emerge privoxy you install the
388 Configuration files are in /etc/privoxy, the documentation is in /usr/share/doc
389 /privoxy-3.0.6 and the Log directory is in /var/log/privoxy.
391 -------------------------------------------------------------------------------
393 2.2. Building from Source
395 The most convenient way to obtain the Privoxy sources is to download the source
396 tarball from our project download page.
398 If you like to live on the bleeding edge and are not afraid of using possibly
399 unstable development versions, you can check out the up-to-the-minute version
400 directly from the CVS repository.
402 To build Privoxy from source, autoconf, GNU make (gmake), and, of course, a C
403 compiler like gcc are required.
405 When building from a source tarball, first unpack the source:
407 tar xzvf privoxy-3.0.6-src* [.tgz or .tar.gz]
410 For retrieving the current CVS sources, you'll need a CVS client installed.
411 Note that sources from CVS are typically development quality, and may not be
412 stable, or well tested. To download CVS source, check the Sourceforge
413 documentation, which might give commands like:
415 cvs -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa login
416 cvs -z3 -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa co current
419 This will create a directory named current/, which will contain the source
422 You can also check out any Privoxy "branch", just exchange the current name
423 with the wanted branch name (Example: v_3_0_branch for the 3.0 cvs tree).
425 It is also strongly recommended to not run Privoxy as root. You should
426 configure/install/run Privoxy as an unprivileged user, preferably by creating a
427 "privoxy" user and group just for this purpose. See your local documentation
428 for the correct command line to do add new users and groups (something like
429 adduser, but the command syntax may vary from platform to platform).
431 /etc/passwd might then look like:
433 privoxy:*:7777:7777:privoxy proxy:/no/home:/no/shell
435 And then /etc/group, like:
439 Some binary packages may do this for you.
441 Then, to build from either unpacked tarball or CVS source:
445 ./configure # (--help to see options)
446 make # (the make from GNU, sometimes called gmake)
447 su # Possibly required
448 make -n install # (to see where all the files will go)
449 make -s install # (to really install, -s to silence output)
451 Using GNU make, you can have the first four steps automatically done for you by
456 in the freshly downloaded or unpacked source directory.
458 To build an executable with security enhanced features so that users cannot
459 easily bypass the proxy (e.g. "Go There Anyway"), or alter their own
460 configurations, configure like this:
462 ./configure --disable-toggle --disable-editor --disable-force
466 WARNING: If installing as root, the install will fail unless a non-root user or
467 group is specified, or a privoxy user and group already exist on the system. If
468 a non-root user is specified, and no group, then the installation will try to
469 also use a group of the same name as "user". If a group is specified (and no
470 user), then the support files will be installed as writable by that group, and
471 owned by the user running the installation.
473 configure accepts --with-user and --with-group options for setting user and
474 group ownership of the configuration files (which need to be writable by the
475 daemon). The specified user must already exist. When starting Privoxy, it must
476 be run as this same user to insure write access to configuration and log files!
478 Alternately, you can specify user and group on the make command line, but be
479 sure both already exist:
481 make -s install USER=privoxy GROUP=privoxy
483 The default installation path for make install is /usr/local. This may of
484 course be customized with the various ./configure path options. If you are
485 doing an install to anywhere besides /usr/local, be sure to set the appropriate
486 paths with the correct configure options (./configure --help). Non-privileged
487 users must of course have write access permissions to wherever the target
488 installation is going.
490 If you do install to /usr/local, the install will use sysconfdir=$prefix/etc/
491 privoxy by default. All other destinations, and the direct usage of
492 --sysconfdir flag behave like normal, i.e. will not add the extra privoxy
493 directory. This is for a safer install, as there may already exist another
494 program that uses a file with the "config" name, and thus makes /usr/local/etc
497 If installing to /usr/local, the documentation will go by default to $prefix/
498 share/doc. But if this directory doesn't exist, it will then try $prefix/doc
499 and install there before creating a new $prefix/share/doc just for Privoxy.
501 Again, if the installs goes to /usr/local, the localstatedir (ie: var/) will
502 default to /var instead of $prefix/var so the logs will go to /var/log/privoxy
503 /, and the pid file will be created in /var/run/privoxy.pid.
505 make install will attempt to set the correct values in config (main
506 configuration file). You should check this to make sure all values are correct.
507 If appropriate, an init script will be installed, but it is up to the user to
508 determine how and where to start Privoxy. The init script should be checked for
509 correct paths and values, if anything other than a default install is done.
511 If install finds previous versions of local configuration files, most of these
512 will not be overwritten, and the new ones will be installed with a "new"
513 extension. default.action, default.filter, and standard.action will be
514 overwritten. You will then need to manually update the other installed
515 configuration files as needed. All template files will be overwritten. If you
516 have customized, local templates, you should save these first, and in fact it
517 is wise to always save any important configuration files "just in case". If a
518 previous version of Privoxy is already running, you will have to restart it
521 For more detailed instructions on how to build Redhat RPMs, Windows
522 self-extracting installers, building on platforms with special requirements
523 etc, please consult the developer manual.
525 -------------------------------------------------------------------------------
527 2.3. Keeping your Installation Up-to-Date
529 As user feedback comes in and development continues, we will make updated
530 versions of both the main actions file (as a separate package) and the software
531 itself (including the actions file) available for download.
533 If you wish to receive an email notification whenever we release updates of
534 Privoxy or the actions file, subscribe to our announce mailing list,
535 ijbswa-announce@lists.sourceforge.net.
537 In order not to lose your personal changes and adjustments when updating to the
538 latest default.action file we strongly recommend that you use user.action and
539 user.filter for your local customizations of Privoxy. See the Chapter on
540 actions files for details.
542 -------------------------------------------------------------------------------
544 3. What's New in this Release
546 There are many improvements and new features since Privoxy 3.0.3, the last
549 * Multiple filter files can now be specified in config. This allows for
550 locally defined filters that can be maintained separately from the filters
551 as supplied by the developers, i.e. default.filter.
553 * There are a number of new actions:
555 + content-type-overwrite
557 + crunch-client-header
559 + crunch-if-none-match
561 + crunch-server-header
563 + filter-client-headers
565 + filter-server-headers
569 + handle-as-empty-document
571 + hide-accept-language
573 + hide-content-disposition
575 + hide-if-modified-since
579 + overwrite-last-modified
583 + treat-forbidden-connects-like-blocks
585 In addition, fast-redirects has been significantly improved with enhanced
588 And hide-referrer has a new option, conditional block.
590 * MS-Windows versions can now be installed and started as a Windows service.
592 * config has two new options: enable-remote-http-toggle, and
593 forwarded-connect-retries.
595 And there is improved handling of the user-manual option, for placing
596 documentation and help files on the local system.
598 * There are six new filters.
600 * Actions files problems and suggestions are now being directed to: http://
601 sourceforge.net/tracker/?group_id=11118&atid=460288. Please use this to
602 report such configuration related problems as missed ads, sites that don't
603 function properly due to one action or another, innocent images being
606 * In addition, there are numerous bug fixes and significant enhancements,
607 including error pages should no longer be cached if the problem is fixed,
608 much better DNS error handling, various logging improvements, and
609 configuration updates for better ad blocking and junk elimination.
611 -------------------------------------------------------------------------------
613 3.1. Note to Upgraders
615 A quick list of things to be aware of before upgrading from earlier versions of
618 * Some installers may remove earlier versions completely, including
619 configuration files. Save any important configuration files!
621 * On the other hand, other installers may not overwrite any existing
622 configuration files, thinking you will want to do that. You may want to
623 manually check your saved files against the newer versions to see if the
624 improvements have merit, or whether there are new options that you may want
625 to consider. There are a number of new features, but most won't be
626 available unless these features are incorporated into your configuration
629 * See the full documentation on fast-redirects which has changed syntax, and
630 will require adjustments to local configs, such as user.action. You must
631 reference the new syntax:
633 { +fast-redirects{check-decoded-url} }
638 * The jarfile, cookie logger, is off by default now.
640 * What constitutes a "default" configuration has changed, and you may want to
641 review which actions are "on" by default. This is primarily a matter of
642 emphasis, but some features you may have been used to, may now be "off" by
643 default. There are also a number of new actions and filters you may want to
644 consider, most of which are not fully incorporated into the default
645 settings as yet (see above).
647 * The default actions setting is now Cautious. Previous releases had a
648 default setting of Medium. Experienced users may want to adjust this, as it
649 is fairly conservative by Privoxy standards and past practices. See http://
650 config.privoxy.org/edit-actions-list?f=default. New users should try the
651 default settings for a while before turning up the volume.
653 * The default setting has filtering turned off, which subsequently means that
654 compression is on. Remember that filtering does not work on compressed
655 pages, so if you use, or want to use, filtering, you will need to force
656 compression off. Example:
658 { +filter{google} +prevent-compression }
661 Or if you use a number of filters, or filter many sites, you may just want
662 to turn off compression for all sites in default.action (or user.action).
664 * Also, session-cookies-only is off by default now. If you've liked this
665 feature in the past, you may want to turn it back on in user.action now.
667 * Some installers may not automatically start Privoxy after installation.
669 -------------------------------------------------------------------------------
671 4. Quickstart to Using Privoxy
673 * Install Privoxy. See the Installation Section below for platform specific
676 * Advanced users and those who want to offer Privoxy service to more than
677 just their local machine should check the main config file, especially the
678 security-relevant options. These are off by default.
680 * Start Privoxy, if the installation program has not done this already (may
681 vary according to platform). See the section Starting Privoxy.
683 * Set your browser to use Privoxy as HTTP and HTTPS (SSL) proxy by setting
684 the proxy configuration for address of 127.0.0.1 and port 8118. DO NOT
685 activate proxying for FTP or any protocols besides HTTP and HTTPS (SSL)! It
688 * Flush your browser's disk and memory caches, to remove any cached ad
689 images. If using Privoxy to manage cookies, you should remove any currently
692 * A default installation should provide a reasonable starting point for most.
693 There will undoubtedly be occasions where you will want to adjust the
694 configuration, but that can be dealt with as the need arises. Little to no
695 initial configuration is required in most cases.
697 See the Configuration section for more configuration options, and how to
698 customize your installation. You might also want to look at the next
699 section for a quick introduction to how Privoxy blocks ads and banners.
701 * If you experience ads that slip through, innocent images that are blocked,
702 or otherwise feel the need to fine-tune Privoxy's behavior, take a look at
703 the actions files. As a quick start, you might find the richly commented
704 examples helpful. You can also view and edit the actions files through the
705 web-based user interface. The Appendix "Troubleshooting: Anatomy of an
706 Action" has hints on how to understand and debug actions that "misbehave".
708 * For easy access to Privoxy's most important controls, drag the provided
709 Bookmarklets into your browser's personal toolbar.
711 * Please see the section Contacting the Developers on how to report bugs,
712 problems with websites or to get help.
714 * Now enjoy surfing with enhanced control, comfort and privacy!
716 -------------------------------------------------------------------------------
718 4.1. Quickstart to Ad Blocking
720 Ad blocking is but one of Privoxy's array of features. Many of these features
721 are for the technically minded advanced user. But, ad and banner blocking is
722 surely common ground for everybody.
724 This section will provide a quick summary of ad blocking so you can get up to
725 speed quickly without having to read the more extensive information provided
726 below, though this is highly recommended.
728 First a bit of a warning ... blocking ads is much like blocking SPAM: the more
729 aggressive you are about it, the more likely you are to block things that were
730 not intended. And the more likely that some things may not work as intended. So
731 there is a trade off here. If you want extreme ad free browsing, be prepared to
732 deal with more "problem" sites, and to spend more time adjusting the
733 configuration to solve these unintended consequences. In short, there is not an
734 easy way to eliminate all ads. Either take the easy way and settle for most ads
735 blocked with the default configuration, or jump in and tweak it for your
736 personal surfing habits and preferences.
738 Secondly, a brief explanation of Privoxy's "actions". "Actions" in this
739 context, are the directives we use to tell Privoxy to perform some task
740 relating to WWW transactions (i.e. web browsing). We tell Privoxy to take some
741 "action". Each action has a unique name and function. While there are many
742 potential actions in Privoxy's arsenal, only a few are used for ad blocking.
743 Actions, and action configuration files, are explained in depth below.
745 Actions are specified in Privoxy's configuration, followed by one or more URLs
746 to which the action should apply. URLs can actually be URL type patterns that
747 use wildcards so they can apply potentially to a range of similar URLs. The
748 actions, together with the URL patterns are called a section.
750 When you connect to a website, the full URL will either match one or more of
751 the sections as defined in Privoxy's configuration, or not. If so, then Privoxy
752 will perform the respective actions. If not, then nothing special happens.
753 Furthermore, web pages may contain embedded, secondary URLs that your web
754 browser will use to load additional components of the page, as it parses the
755 original page's HTML content. An ad image for instance, is just an URL embedded
756 in the page somewhere. The image itself may be on the same server, or a server
757 somewhere else on the Internet. Complex web pages will have many such embedded
758 URLs. Privoxy can deal with each URL individually, so, for instance, the main
759 page text is not touched, but images from such-and-such server are blocked.
761 The most important actions for basic ad blocking are: block, handle-as-image,
762 handle-as-empty-document,and set-image-blocker:
764 * block - this is perhaps the single most used action, and is particularly
765 important for ad blocking. This action stops any contact between your
766 browser and any URL patterns that match this action's configuration. It can
767 be used for blocking ads, but also anything that is determined to be
768 unwanted. By itself, it simply stops any communication with the remote
769 server and sends Privoxy's own built-in BLOCKED page instead to let you now
770 what has happened (with some exceptions, see below).
772 * handle-as-image - tells Privoxy to treat this URL as an image. Privoxy's
773 default configuration already does this for all common image types (e.g.
774 GIF), but there are many situations where this is not so easy to determine.
775 So we'll force it in these cases. This is particularly important for ad
776 blocking, since only if we know that it's an image of some kind, can we
777 replace it with an image of our choosing, instead of the Privoxy BLOCKED
778 page (which would only result in a "broken image" icon). There are some
779 limitations to this though. For instance, you can't just brute-force an
780 image substitution for an entire HTML page in most situations.
782 * handle-as-empty-document - sends an empty document instead of Privoxy's
783 normal BLOCKED HTML page. This is useful for file types that are neither
784 HTML nor images, such as blocking JavaScript files.
786 * set-image-blocker - tells Privoxy what to display in place of an ad image
787 that has hit a block rule. For this to come into play, the URL must match a
788 block action somewhere in the configuration, and, it must also match an
789 handle-as-image action.
791 The configuration options on what to display instead of the ad are:
793 pattern - a checkerboard pattern, so that an ad replacement is obvious.
796 blank - A very small empty GIF image is displayed. This is the so-called
797 "invisible" configuration option.
799 http://<URL> - A redirect to any image anywhere of the user's choosing
802 The quickest way to adjust any of these settings is with your browser through
803 the special Privoxy editor at http://config.privoxy.org/show-status (shortcut:
804 http://p.p/show-status). This is an internal page, and does not require
805 Internet access. Select the appropriate "actions" file, and click "Edit". It is
806 best to put personal or local preferences in user.action since this is not
807 meant to be overwritten during upgrades, and will over-ride the settings in
808 other files. Here you can insert new "actions", and URLs for ad blocking or
809 other purposes, and make other adjustments to the configuration. Privoxy will
810 detect these changes automatically.
812 A quick and simple step by step example:
814 * Right click on the ad image to be blocked, then select "Copy Link Location"
815 from the pop-up menu.
817 * Set your browser to http://config.privoxy.org/show-status
819 * Find user.action in the top section, and click on "Edit":
821 Figure 1. Actions Files in Use
825 * You should have a section with only block listed under "Actions:". If not,
826 click a "Insert new section below" button, and in the new section that just
827 appeared, click the Edit button right under the word "Actions:". This will
828 bring up a list of all actions. Find block near the top, and click in the
829 "Enabled" column, then "Submit" just below the list.
831 * Now, in the block actions section, click the "Add" button, and paste the
832 URL the browser got from "Copy Link Location". Remove the http:// at the
833 beginning of the URL. Then, click "Submit" (or "OK" if in a pop-up window).
835 * Now go back to the original page, and press SHIFT-Reload (or flush all
836 browser caches). The image should be gone now.
838 This is a very crude and simple example. There might be good reasons to use a
839 wildcard pattern match to include potentially similar images from the same
840 site. For a more extensive explanation of "patterns", and the entire actions
841 concept, see the Actions section.
843 For advanced users who want to hand edit their config files, you might want to
844 now go to the Actions Files Tutorial. The ideas explained therein also apply to
845 the web-based editor.
847 There are also various filters that can be used for ad blocking (filters are a
848 special subset of actions). These fall into the "advanced" usage category, and
849 are explained in depth in later sections.
851 -------------------------------------------------------------------------------
855 Before launching Privoxy for the first time, you will want to configure your
856 browser(s) to use Privoxy as a HTTP and HTTPS (SSL) proxy. The default is
857 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
858 used port 8000). This is the one configuration step that must be done!
860 Please note that Privoxy can only proxy HTTP and HTTPS traffic. It will not
861 work with FTP or other protocols.
863 Figure 2. Proxy Configuration Showing Mozilla/Netscape HTTP and HTTPS (SSL)
868 With Firefox, this is typically set under:
870 Tools -> Options -> General -> Connection Settings -> Manual Proxy
874 Or optionally on some platforms:
876 Edit -> Preferences -> General -> Connection Settings -> Manual Proxy
880 With Netscape (and Mozilla), this can be set under:
882 Edit -> Preferences -> Advanced -> Proxies -> HTTP Proxy
885 For Internet Explorer v.5-6:
887 Tools -> Internet Options -> Connections -> LAN Settings
889 Then, check "Use Proxy" and fill in the appropriate info (Address: 127.0.0.1,
890 Port: 8118). Include HTTPS (SSL), if you want HTTPS proxy support too
891 (sometimes labeled "Secure"). Make sure any checkboxes like "Use the same proxy
892 server for all protocols" is UNCHECKED. You want only HTTP and HTTPS (SSL)!
894 Figure 3. Proxy Configuration Showing Internet Explorer HTTP and HTTPS (Secure)
899 After doing this, flush your browser's disk and memory caches to force a
900 re-reading of all pages and to get rid of any ads that may be cached. Remove
901 any cookies, if you want Privoxy to manage that. You are now ready to start
902 enjoying the benefits of using Privoxy!
904 Privoxy itself is typically started by specifying the main configuration file
905 to be used on the command line. If no configuration file is specified on the
906 command line, Privoxy will look for a file named config in the current
907 directory. Except on Win32 where it will try config.txt.
909 -------------------------------------------------------------------------------
911 5.1. Red Hat and Fedora
913 A default Red Hat installation may not start Privoxy upon boot. It will use the
914 file /etc/privoxy/config as its main configuration file.
916 # /etc/rc.d/init.d/privoxy start
920 # service privoxy start
922 -------------------------------------------------------------------------------
926 We use a script. Note that Debian typically starts Privoxy upon booting per
927 default. It will use the file /etc/privoxy/config as its main configuration
930 # /etc/init.d/privoxy start
932 -------------------------------------------------------------------------------
936 Click on the Privoxy Icon to start Privoxy. If no configuration file is
937 specified on the command line, Privoxy will look for a file named config.txt.
938 Note that Windows will automatically start Privoxy when the system starts if
939 you chose that option when installing.
941 Privoxy can run with full Windows service functionality. On Windows only, the
942 Privoxy program has two new command line arguments to install and uninstall
943 Privoxy as a service. See the Windows Installation instructions for details.
945 -------------------------------------------------------------------------------
947 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
949 Example Unix startup command:
951 # /usr/sbin/privoxy /etc/privoxy/config
953 -------------------------------------------------------------------------------
957 During installation, Privoxy is configured to start automatically when the
958 system restarts. You can start it manually by double-clicking on the Privoxy
959 icon in the Privoxy folder.
961 -------------------------------------------------------------------------------
965 During installation, Privoxy is configured to start automatically when the
966 system restarts. To start Privoxy manually, double-click on the
967 StartPrivoxy.command icon in the /Library/Privoxy folder. Or, type this command
970 /Library/Privoxy/StartPrivoxy.command
973 You will be prompted for the administrator password.
975 -------------------------------------------------------------------------------
979 Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in s:
980 user-startup (RoadShow), as startup program in your startup script (Genesis),
981 or as startup action (Miami and MiamiDx). Privoxy will automatically quit when
982 you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack
983 may display that Privoxy is still running).
985 -------------------------------------------------------------------------------
989 A script is again used. It will use the file /etc/privoxy/config as its main
992 /etc/init.d/privoxy start
995 Note that Privoxy is not automatically started at boot time by default. You can
996 change this with the rc-update command.
998 rc-update add privoxy default
1001 -------------------------------------------------------------------------------
1003 5.9. Command Line Options
1005 Privoxy may be invoked with the following command-line options:
1009 Print version info and exit. Unix only.
1013 Print short usage info and exit. Unix only.
1017 Don't become a daemon, i.e. don't fork and become process group leader, and
1018 don't detach from controlling tty. Unix only.
1022 On startup, write the process ID to FILE. Delete the FILE on exit. Failure
1023 to create or delete the FILE is non-fatal. If no FILE option is given, no
1024 PID file will be used. Unix only.
1026 * --user USER[.GROUP]
1028 After (optionally) writing the PID file, assume the user ID of USER, and if
1029 included the GID of GROUP. Exit if the privileges are not sufficient to do
1034 Before changing to the user ID given in the --user option, chroot to that
1035 user's home directory, i.e. make the kernel pretend to the Privoxy process
1036 that the directory tree starts there. If set up carefully, this can limit
1037 the impact of possible vulnerabilities in Privoxy to the files contained in
1038 that hierarchy. Unix only.
1042 If no configfile is included on the command line, Privoxy will look for a
1043 file named "config" in the current directory (except on Win32 where it will
1044 look for "config.txt" instead). Specify full path to avoid confusion. If no
1045 config file is found, Privoxy will fail to start.
1047 On MS Windows only there are two additional command-line options to allow
1048 Privoxy to install and run as a service. See the Window Installation section
1051 -------------------------------------------------------------------------------
1053 6. Privoxy Configuration
1055 All Privoxy configuration is stored in text files. These files can be edited
1056 with a text editor. Many important aspects of Privoxy can also be controlled
1057 easily with a web browser.
1059 -------------------------------------------------------------------------------
1061 6.1. Controlling Privoxy with Your Web Browser
1063 Privoxy's user interface can be reached through the special URL http://
1064 config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works
1065 without Internet access. You will see the following section:
1068 ? View & change the current configuration
1069 ? View the source code version numbers
1070 ? View the request headers.
1071 ? Look up which actions apply to a URL and why
1072 ? Toggle Privoxy on or off
1076 This should be self-explanatory. Note the first item leads to an editor for the
1077 actions files, which is where the ad, banner, cookie, and URL blocking magic is
1078 configured as well as other advanced features of Privoxy. This is an easy way
1079 to adjust various aspects of Privoxy configuration. The actions file, and other
1080 configuration files, are explained in detail below.
1082 "Toggle Privoxy On or Off" is handy for sites that might have problems with
1083 your current actions and filters. You can in fact use it as a test to see
1084 whether it is Privoxy causing the problem or not. Privoxy continues to run as a
1085 proxy in this case, but all manipulation is disabled, i.e. Privoxy acts like a
1086 normal forwarding proxy. There is even a toggle Bookmarklet offered, so that
1087 you can toggle Privoxy with one click from your browser.
1089 -------------------------------------------------------------------------------
1091 6.2. Configuration Files Overview
1093 For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/
1094 by default. For MS Windows, OS/2, and AmigaOS these are all in the same
1095 directory as the Privoxy executable.
1097 The installed defaults provide a reasonable starting point, though some
1098 settings may be aggressive by some standards. For the time being, the principle
1099 configuration files are:
1101 * The main configuration file is named config on Linux, Unix, BSD, OS/2, and
1102 AmigaOS and config.txt on Windows. This is a required file.
1104 * default.action (the main actions file) is used to define which "actions"
1105 relating to banner-blocking, images, pop-ups, content modification, cookie
1106 handling etc should be applied by default. It also defines many exceptions
1107 (both positive and negative) from this default set of actions that enable
1108 Privoxy to selectively eliminate the junk, and only the junk, on as many
1109 websites as possible.
1111 Multiple actions files may be defined in config. These are processed in the
1112 order they are defined. Local customizations and locally preferred
1113 exceptions to the default policies as defined in default.action (which you
1114 will most probably want to define sooner or later) are probably best
1115 applied in user.action, where you can preserve them across upgrades.
1116 standard.action is only for Privoxy's internal use.
1118 There is also a web based editor that can be accessed from http://
1119 config.privoxy.org/show-status (Shortcut: http://p.p/show-status) for the
1120 various actions files.
1122 * "Filter files" (the filter file) can be used to re-write the raw page
1123 content, including viewable text as well as embedded HTML and JavaScript,
1124 and whatever else lurks on any given web page. The filtering jobs are only
1125 pre-defined here; whether to apply them or not is up to the actions files.
1126 default.filter includes various filters made available for use by the
1127 developers. Some are much more intrusive than others, and all should be
1128 used with caution. You may define additional filter files in config as you
1129 can with actions files. We suggest user.filter for any locally defined
1130 filters or customizations.
1132 The syntax of all configuration files has remained the same throughout the 3.x
1133 series. There have been enhancements, but no changes that would preclude the
1134 use of any configuration file from one version to the next. (There is one
1135 exception: +fast-redirects which has enhanced syntax and will require updating
1136 any local configs from earlier versions.)
1138 All files use the "#" character to denote a comment (the rest of the line will
1139 be ignored) and understand line continuation through placing a backslash ("\")
1140 as the very last character in a line. If the # is preceded by a backslash, it
1141 looses its special function. Placing a # in front of an otherwise valid
1142 configuration line to prevent it from being interpreted is called "commenting
1143 out" that line. Blank lines are ignored.
1145 The actions files and filter files can use Perl style regular expressions for
1146 maximum flexibility.
1148 After making any changes, there is no need to restart Privoxy in order for the
1149 changes to take effect. Privoxy detects such changes automatically. Note,
1150 however, that it may take one or two additional requests for the change to take
1151 effect. When changing the listening address of Privoxy, these "wake up"
1152 requests must obviously be sent to the old listening address.
1154 -------------------------------------------------------------------------------
1156 7. The Main Configuration File
1158 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
1159 and config.txt on Windows. Configuration lines consist of an initial keyword
1160 followed by a list of values, all separated by whitespace (any number of spaces
1161 or tabs). For example:
1163 confdir /etc/privoxy
1165 Assigns the value /etc/privoxy to the option confdir and thus indicates that
1166 the configuration directory is named "/etc/privoxy/".
1168 All options in the config file except for confdir and logdir are optional.
1169 Watch out in the below description for what happens if you leave them unset.
1171 The main config file controls all aspects of Privoxy's operation that are not
1172 location dependent (i.e. they apply universally, no matter where you may be
1175 -------------------------------------------------------------------------------
1177 7.1. Local Set-up Documentation
1179 If you intend to operate Privoxy for more users than just yourself, it might be
1180 a good idea to let them know how to reach you, what you block and why you do
1181 that, your policies, etc.
1183 -------------------------------------------------------------------------------
1189 Location of the Privoxy User Manual.
1193 A fully qualified URI
1201 http://www.privoxy.org/version/user-manual/ will be used, where version is
1202 the Privoxy version.
1206 The User Manual URI is the single best source of information on Privoxy,
1207 and is used for help links from some of the internal CGI pages. The manual
1208 itself is normally packaged with the binary distributions, so you probably
1209 want to set this to a locally installed copy.
1213 The best all purpose solution is simply to put the full local PATH to where
1214 the User Manual is located:
1216 user-manual /usr/share/doc/privoxy/user-manual
1218 The User Manual is then available to anyone with access to the proxy, by
1219 following the built-in URL: http://config.privoxy.org/user-manual/ (or the
1220 shortcut: http://p.p/user-manual/).
1222 If the documentation is not on the local system, it can be accessed from a
1225 user-manual http://example.com/privoxy/user-manual/
1227 +-----------------------------------------------------------------+
1229 |-----------------------------------------------------------------|
1230 |If set, this option should be the first option in the config |
1231 |file, because it is used while the config file is being read on |
1233 +-----------------------------------------------------------------+
1235 -------------------------------------------------------------------------------
1237 7.1.2. trust-info-url
1241 A URL to be displayed in the error page that users will see if access to an
1242 untrusted page is denied.
1250 Two example URL are provided
1254 No links are displayed on the "untrusted" error page.
1258 The value of this option only matters if the experimental trust mechanism
1259 has been activated. (See trustfile above.)
1261 If you use the trust mechanism, it is a good idea to write up some on-line
1262 documentation about your trust policy and to specify the URL(s) here. Use
1263 multiple times for multiple URLs.
1265 The URL(s) should be added to the trustfile as well, so users don't end up
1266 locked out from the information on why they were locked out in the first
1269 -------------------------------------------------------------------------------
1271 7.1.3. admin-address
1275 An email address to reach the proxy administrator.
1287 No email address is displayed on error pages and the CGI user interface.
1291 If both admin-address and proxy-info-url are unset, the whole "Local
1292 Privoxy Support" box on all generated pages will not be shown.
1294 -------------------------------------------------------------------------------
1296 7.1.4. proxy-info-url
1300 A URL to documentation about the local Privoxy setup, configuration or
1313 No link to local documentation is displayed on error pages and the CGI user
1318 If both admin-address and proxy-info-url are unset, the whole "Local
1319 Privoxy Support" box on all generated pages will not be shown.
1321 This URL shouldn't be blocked ;-)
1323 -------------------------------------------------------------------------------
1325 7.2. Configuration and Log File Locations
1327 Privoxy can (and normally does) use a number of other files for additional
1328 configuration, help and logging. This section of the configuration file tells
1329 Privoxy where to find those other files.
1331 The user running Privoxy, must have read permission for all configuration
1332 files, and write permission to any files that would be modified, such as log
1333 files and actions files.
1335 -------------------------------------------------------------------------------
1341 The directory where the other configuration files are located
1349 /etc/privoxy (Unix) or Privoxy installation dir (Windows)
1357 No trailing "/", please
1359 -------------------------------------------------------------------------------
1365 The directory where all logging takes place (i.e. where logfile and jarfile
1374 /var/log/privoxy (Unix) or Privoxy installation dir (Windows)
1382 No trailing "/", please
1384 -------------------------------------------------------------------------------
1390 The actions file(s) to use
1394 File name, relative to confdir, without the .action suffix
1398 standard # Internal purposes, no editing recommended
1400 default # Main actions file
1402 user # User customizations
1406 No actions are taken at all. Simple neutral proxying.
1410 Multiple actionsfile lines are permitted, and are in fact recommended!
1412 The default values include standard.action, which is used for internal
1413 purposes and should be loaded, default.action, which is the "main" actions
1414 file maintained by the developers, and user.action, where you can make your
1417 Actions files are where all the per site and per URL configuration is done
1418 for ad blocking, cookie management, privacy considerations, etc. There is
1419 no point in using Privoxy without at least one actions file.
1421 -------------------------------------------------------------------------------
1427 The filter file(s) to use
1431 File name, relative to confdir
1435 default.filter (Unix) or default.filter.txt (Windows)
1439 No textual content filtering takes place, i.e. all +filter{name} actions in
1440 the actions files are turned neutral.
1444 Multiple filterfile lines are permitted.
1446 The filter files contain content modification rules that use regular
1447 expressions. These rules permit powerful changes on the content of Web
1448 pages, and optionally the headers as well, e.g., you could disable your
1449 favorite JavaScript annoyances, re-write the actual displayed text, or just
1450 have some fun playing buzzword bingo with web pages.
1452 The +filter{name} actions rely on the relevant filter (name) to be defined
1455 A pre-defined filter file called default.filter that contains a number of
1456 useful filters for common problems is included in the distribution. See the
1457 section on the filter action for a list.
1459 It is recommended to place any locally adapted filters into a separate
1460 file, such as user.filter.
1462 -------------------------------------------------------------------------------
1472 File name, relative to logdir
1476 logfile (Unix) or privoxy.log (Windows)
1480 No log file is used, all log messages go to the console (STDERR).
1484 The logfile is where all logging and error messages are written. The level
1485 of detail and number of messages are set with the debug option (see below).
1486 The logfile can be useful for tracking down a problem with Privoxy (e.g.,
1487 it's not blocking an ad you think it should block) but in most cases you
1488 probably will never look at it.
1490 Your logfile will grow indefinitely, and you will probably want to
1491 periodically remove it. On Unix systems, you can do this with a cron job
1492 (see "man cron"). For Red Hat, a logrotate script has been included.
1494 On SuSE Linux systems, you can place a line like "/var/log/privoxy.* +1024k
1495 644 nobody.nogroup" in /etc/logfiles, with the effect that cron.daily will
1496 automatically archive, gzip, and empty the log, when it exceeds 1M size.
1498 Any log files must be writable by whatever user Privoxy is being run as
1499 (default on UNIX, user id is "privoxy").
1501 -------------------------------------------------------------------------------
1507 The file to store intercepted cookies in
1511 File name, relative to logdir
1515 Unset (commented out). When activated: jarfile (Unix) or privoxy.jar
1520 Intercepted cookies are not stored in a dedicated log file.
1524 The jarfile may grow to ridiculous sizes over time.
1526 If debug 8 (show header parsing) is enabled, cookies are written to the
1527 logfile with the rest of the headers.
1529 -------------------------------------------------------------------------------
1535 The name of the trust file to use
1539 File name, relative to confdir
1543 Unset (commented out). When activated: trust (Unix) or trust.txt (Windows)
1547 The entire trust mechanism is disabled.
1551 The trust mechanism is an experimental feature for building white-lists and
1552 should be used with care. It is NOT recommended for the casual user.
1554 If you specify a trust file, Privoxy will only allow access to sites that
1555 are specified in the trustfile. Sites can be listed in one of two ways:
1557 Prepending a ~ character limits access to this site only (and any sub-paths
1558 within this site), e.g. ~www.example.com allows access to ~www.example.com/
1559 features/news.html, etc.
1561 Or, you can designate sites as trusted referrers, by prepending the name
1562 with a + character. The effect is that access to untrusted sites will be
1563 granted -- but only if a link from this trusted referrer was used to get
1564 there. The link target will then be added to the "trustfile" so that
1565 future, direct accesses will be granted. Sites added via this mechanism do
1566 not become trusted referrers themselves (i.e. they are added with a ~
1567 designation). There is a limit of 512 such entries, after which new entries
1570 If you use the + operator in the trust file, it may grow considerably over
1573 It is recommended that Privoxy be compiled with the --disable-force,
1574 --disable-toggle and --disable-editor options, if this feature is to be
1577 Possible applications include limiting Internet access for children.
1579 -------------------------------------------------------------------------------
1583 These options are mainly useful when tracing a problem. Note that you might
1584 also want to invoke Privoxy with the --no-daemon command line option when
1587 -------------------------------------------------------------------------------
1593 Key values that determine what information gets logged to the logfile.
1601 12289 (i.e.: URLs plus informational and warning messages)
1605 Nothing gets logged.
1609 The available debug levels are:
1611 debug 1 # show each GET/POST/CONNECT request
1612 debug 2 # show each connection status
1613 debug 4 # show I/O status
1614 debug 8 # show header parsing
1615 debug 16 # log all data into the logfile
1616 debug 32 # debug force feature
1617 debug 64 # debug regular expression filter
1618 debug 128 # debug fast redirects
1619 debug 256 # debug GIF de-animation
1620 debug 512 # Common Log Format
1621 debug 1024 # debug kill pop-ups
1622 debug 2048 # CGI user interface
1623 debug 4096 # Startup banner and warnings.
1624 debug 8192 # Non-fatal errors
1626 To select multiple debug levels, you can either add them or use multiple
1629 A debug level of 1 is informative because it will show you each request as
1630 it happens. 1, 4096 and 8192 are highly recommended so that you will notice
1631 when things go wrong. The other levels are probably only of interest if you
1632 are hunting down a specific problem. They can produce a hell of an output
1635 The reporting of fatal errors (i.e. ones which crash Privoxy) is always on
1636 and cannot be disabled.
1638 If you want to use CLF (Common Log Format), you should set "debug 512" ONLY
1639 and not enable anything else.
1641 -------------------------------------------------------------------------------
1643 7.3.2. single-threaded
1647 Whether to run only one server thread
1659 Multi-threaded (or, where unavailable: forked) operation, i.e. the ability
1660 to serve multiple requests simultaneously.
1664 This option is only there for debug purposes and you should never need to
1665 use it. It will drastically reduce performance.
1667 -------------------------------------------------------------------------------
1669 7.4. Access Control and Security
1671 This section of the config file controls the security-relevant aspects of
1672 Privoxy's configuration.
1674 -------------------------------------------------------------------------------
1676 7.4.1. listen-address
1680 The IP address and TCP port on which Privoxy will listen for client
1693 Bind to 127.0.0.1 (localhost), port 8118. This is suitable and recommended
1694 for home users who run Privoxy on the same machine as their browser.
1698 You will need to configure your browser(s) to this proxy address and port.
1700 If you already have another service running on port 8118, or if you want to
1701 serve requests from other machines (e.g. on your local network) as well,
1702 you will need to override the default.
1704 If you leave out the IP address, Privoxy will bind to all interfaces
1705 (addresses) on your machine and may become reachable from the Internet. In
1706 that case, consider using access control lists (ACL's, see below), and/or a
1709 If you open Privoxy to untrusted users, you will also want to turn off the
1710 enable-edit-actions and enable-remote-toggle options!
1714 Suppose you are running Privoxy on a machine which has the address
1715 192.168.0.1 on your local private network (192.168.0.0) and has another
1716 outside connection with a different address. You want it to serve requests
1719 listen-address 192.168.0.1:8118
1721 -------------------------------------------------------------------------------
1727 Initial state of "toggle" status
1739 Act as if toggled on
1743 If set to 0, Privoxy will start in "toggled off" mode, i.e. behave like a
1744 normal, content-neutral proxy where all ad blocking, filtering, etc are
1745 disabled. See enable-remote-toggle below. This is not really useful
1746 anymore, since toggling is much easier via the web interface than via
1747 editing the conf file.
1749 The windows version will only display the toggle icon in the system tray if
1750 this option is present.
1752 -------------------------------------------------------------------------------
1754 7.4.3. enable-remote-toggle
1758 Whether or not the web-based toggle feature may be used
1770 The web-based toggle feature is disabled.
1774 When toggled off, Privoxy acts like a normal, content-neutral proxy, i.e.
1775 it acts as if none of the actions applied to any URL.
1777 For the time being, access to the toggle feature can not be controlled
1778 separately by "ACLs" or HTTP authentication, so that everybody who can
1779 access Privoxy (see "ACLs" and listen-address above) can toggle it for all
1780 users. So this option is not recommended for multi-user environments with
1783 Note that you must have compiled Privoxy with support for this feature,
1784 otherwise this option has no effect.
1786 -------------------------------------------------------------------------------
1788 7.4.4. enable-remote-http-toggle
1792 Whether or not Privoxy recognizes special HTTP headers to change its
1805 Privoxy ignores special HTTP headers.
1809 When toggled on, the client can change Privoxy's behaviour by setting
1810 special HTTP headers. Currently the only supported special header is
1811 "X-Filter: No", to disable filtering for the ongoing request, even if it is
1812 enabled in one of the action files.
1814 If you are using Privoxy in a multi-user environment or with untrustworthy
1815 clients and want to enforce filtering, you will have to disable this
1816 option, otherwise you can ignore it.
1818 -------------------------------------------------------------------------------
1820 7.4.5. enable-edit-actions
1824 Whether or not the web-based actions file editor may be used
1836 The web-based actions file editor is disabled.
1840 For the time being, access to the editor can not be controlled separately
1841 by "ACLs" or HTTP authentication, so that everybody who can access Privoxy
1842 (see "ACLs" and listen-address above) can modify its configuration for all
1843 users. So this option is not recommended for multi-user environments with
1846 Note that you must have compiled Privoxy with support for this feature,
1847 otherwise this option has no effect.
1849 -------------------------------------------------------------------------------
1851 7.4.6. ACLs: permit-access and deny-access
1855 Who can access what.
1859 src_addr[/src_masklen] [dst_addr[/dst_masklen]]
1861 Where src_addr and dst_addr are IP addresses in dotted decimal notation or
1862 valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
1863 notation, i.e. integer values from 2 to 30 representing the length (in
1864 bits) of the network address. The masks and the whole destination part are
1873 Don't restrict access further than implied by listen-address
1877 Access controls are included at the request of ISPs and systems
1878 administrators, and are not usually needed by individual users. For a
1879 typical home user, it will normally suffice to ensure that Privoxy only
1880 listens on the localhost (127.0.0.1) or internal (home) network address by
1881 means of the listen-address option.
1883 Please see the warnings in the FAQ that this proxy is not intended to be a
1884 substitute for a firewall or to encourage anyone to defer addressing basic
1885 security weaknesses.
1887 Multiple ACL lines are OK. If any ACLs are specified, then the Privoxy
1888 talks only to IP addresses that match at least one permit-access line and
1889 don't match any subsequent deny-access line. In other words, the last match
1890 wins, with the default being deny-access.
1892 If Privoxy is using a forwarder (see forward below) for a particular
1893 destination URL, the dst_addr that is examined is the address of the
1894 forwarder and NOT the address of the ultimate target. This is necessary
1895 because it may be impossible for the local Privoxy to determine the IP
1896 address of the ultimate target (that's often what gateways are used for).
1898 You should prefer using IP addresses over DNS names, because the address
1899 lookups take time. All DNS names must resolve! You can not use domain
1900 patterns like "*.org" or partial domain names. If a DNS name resolves to
1901 multiple IP addresses, only the first one is used.
1903 Denying access to particular sites by ACL may have undesired side effects
1904 if the site in question is hosted on a machine which also hosts other
1909 Explicitly define the default behavior if no ACL and listen-address are
1910 set: "localhost" is OK. The absence of a dst_addr implies that all
1911 destination addresses are OK:
1913 permit-access localhost
1915 Allow any host on the same class C subnet as www.privoxy.org access to
1916 nothing but www.example.com:
1918 permit-access www.privoxy.org/24 www.example.com/32
1920 Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
1921 with the exception that 192.168.45.73 may not access
1922 www.dirty-stuff.example.com:
1924 permit-access 192.168.45.64/26
1925 deny-access 192.168.45.73 www.dirty-stuff.example.com
1927 -------------------------------------------------------------------------------
1933 Maximum size of the buffer for content filtering.
1945 Use a 4MB (4096 KB) limit.
1949 For content filtering, i.e. the +filter and +deanimate-gif actions, it is
1950 necessary that Privoxy buffers the entire document body. This can be
1951 potentially dangerous, since a server could just keep sending data
1952 indefinitely and wait for your RAM to exhaust -- with nasty consequences.
1955 When a document buffer size reaches the buffer-limit, it is flushed to the
1956 client unfiltered and no further attempt to filter the rest of the document
1957 is made. Remember that there may be multiple threads running, which might
1958 require up to buffer-limit Kbytes each, unless you have enabled
1959 "single-threaded" above.
1961 -------------------------------------------------------------------------------
1965 This feature allows routing of HTTP requests through a chain of multiple
1966 proxies. It can be used to better protect privacy and confidentiality when
1967 accessing specific domains by routing requests to those domains through an
1968 anonymous public proxy. Or to use a caching proxy to speed up browsing. Or
1969 chaining to a parent proxy may be necessary because the machine that Privoxy
1970 runs on has no direct Internet access.
1972 Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
1975 -------------------------------------------------------------------------------
1981 To which parent HTTP proxy specific requests should be routed.
1985 target_pattern http_parent[:port]
1987 where target_pattern is a URL pattern that specifies to which requests
1988 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
1989 http_parent[:port] is the DNS name or IP address of the parent HTTP proxy
1990 through which the requests should be forwarded, optionally followed by its
1991 listening port (default: 8080). Use a single dot (.) to denote "no
2000 Don't use parent HTTP proxies.
2004 If http_parent is ".", then requests are not forwarded to another HTTP
2005 proxy but are made directly to the web servers.
2007 Multiple lines are OK, they are checked in sequence, and the last match
2012 Everything goes to an example anonymizing proxy, except SSL on port 443
2013 (which it doesn't handle):
2015 forward / anon-proxy.example.org:8080
2018 Everything goes to our example ISP's caching proxy, except for requests to
2021 forward / caching-proxy.example-isp.net:8000
2022 forward .example-isp.net .
2024 -------------------------------------------------------------------------------
2026 7.5.2. forward-socks4 and forward-socks4a
2030 Through which SOCKS proxy (and to which parent HTTP proxy) specific
2031 requests should be routed.
2035 target_pattern socks_proxy[:port] http_parent[:port]
2037 where target_pattern is a URL pattern that specifies to which requests
2038 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
2039 http_parent and socks_proxy are IP addresses in dotted decimal notation or
2040 valid DNS names (http_parent may be "." to denote "no HTTP forwarding"),
2041 and the optional port parameters are TCP ports, i.e. integer values from 1
2050 Don't use SOCKS proxies.
2054 Multiple lines are OK, they are checked in sequence, and the last match
2057 The difference between forward-socks4 and forward-socks4a is that in the
2058 SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
2059 SOCKS server, while in SOCKS 4 it happens locally.
2061 If http_parent is ".", then requests are not forwarded to another HTTP
2062 proxy but are made (HTTP-wise) directly to the web servers, albeit through
2067 From the company example.com, direct connections are made to all "internal"
2068 domains, but everything outbound goes through their ISP's proxy by way of
2069 example.com's corporate SOCKS 4A gateway to the Internet.
2071 forward-socks4a / socks-gw.example.com:1080 www-cache.example-isp.net:8080
2072 forward .example.com .
2074 A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
2077 forward-socks4 / socks-gw.example.com:1080 .
2079 To chain Privoxy and Tor, both running on the same system, you should use
2082 forward-socks4 / 127.0.0.1:9050 .
2084 The public Tor network can't be used to reach your local network, therefore
2085 it's a good idea to make some exceptions:
2087 forward 192.168.*.*/ .
2089 forward 127.*.*.*/ .
2091 Unencrypted connections to systems in these address ranges will be as (un)
2092 secure as the local network is, but the alternative is that you can't reach
2095 If you also want to be able to reach servers in your local network by using
2096 their names, you will need additional exceptions that look like this:
2098 forward localhost/ .
2100 -------------------------------------------------------------------------------
2102 7.5.3. Advanced Forwarding Examples
2104 If you have links to multiple ISPs that provide various special content only to
2105 their subscribers, you can configure multiple Privoxies which have connections
2106 to the respective ISPs to act as forwarders to each other, so that your users
2107 can see the internal content of all ISPs.
2109 Assume that host-a has a PPP connection to isp-a.net. And host-b has a PPP
2110 connection to isp-b.net. Both run Privoxy. Their forwarding configuration can
2116 forward .isp-b.net host-b:8118
2121 forward .isp-a.net host-a:8118
2123 Now, your users can set their browser's proxy to use either host-a or host-b
2124 and be able to browse the internal content of both isp-a and isp-b.
2126 If you intend to chain Privoxy and squid locally, then chain as browser ->
2127 squid -> privoxy is the recommended way.
2129 Assuming that Privoxy and squid run on the same box, your squid configuration
2130 could then look like this:
2132 # Define Privoxy as parent proxy (without ICP)
2133 cache_peer 127.0.0.1 parent 8118 7 no-query
2135 # Define ACL for protocol FTP
2138 # Do not forward FTP requests to Privoxy
2139 always_direct allow ftp
2141 # Forward all the rest to Privoxy
2142 never_direct allow all
2144 You would then need to change your browser's proxy settings to squid's address
2145 and port. Squid normally uses port 3128. If unsure consult http_port in
2148 You could just as well decide to only forward requests for Windows executables
2149 through a virus-scanning parent proxy, say, on antivir.example.com, port 8010:
2152 forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010
2154 -------------------------------------------------------------------------------
2156 7.5.4. forwarded-connect-retries
2160 How often Privoxy retries if a forwarded connection request fails.
2172 Forwarded connections are treated like direct connections and no retry
2177 forwarded-connect-retries is mainly interesting for socks4a connections,
2178 where Privoxy can't detect why the connections failed. The connection might
2179 have failed because of a DNS timeout in which case a retry makes sense, but
2180 it might also have failed because the server doesn't exist or isn't
2181 reachable. In this case the retry will just delay the appearance of
2182 Privoxy's error message.
2184 Only use this option, if you are getting many forwarding related error
2185 messages, that go away when you try again manually. Start with a small
2186 value and check Privoxy's logfile from time to time, to see how many
2187 retries are usually needed.
2191 forwarded-connect-retries 1
2193 -------------------------------------------------------------------------------
2195 7.6. Windows GUI Options
2197 Privoxy has a number of options specific to the Windows GUI interface:
2199 If "activity-animation" is set to 1, the Privoxy icon will animate when
2200 "Privoxy" is active. To turn off, set to 0.
2202 activity-animation 1
2205 If "log-messages" is set to 1, Privoxy will log messages to the console window:
2210 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
2211 of memory used for the log messages displayed in the console window, will be
2212 limited to "log-max-lines" (see below).
2214 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
2220 log-max-lines is the maximum number of lines held in the log buffer. See above.
2225 If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
2226 log messages with a bold-faced font:
2228 log-highlight-messages 1
2231 The font used in the console window:
2233 log-font-name Comic Sans MS
2236 Font size used in the console window:
2241 "show-on-task-bar" controls whether or not Privoxy will appear as a button on
2242 the Task bar when minimized:
2247 If "close-button-minimizes" is set to 1, the Windows close button will minimize
2248 Privoxy instead of closing the program (close with the exit option on the File
2251 close-button-minimizes 1
2254 The "hide-console" option is specific to the MS-Win console version of Privoxy.
2255 If this option is used, Privoxy will disconnect from and hide the command
2261 -------------------------------------------------------------------------------
2265 The actions files are used to define what actions Privoxy takes for which URLs,
2266 and thus determines how ad images, cookies and various other aspects of HTTP
2267 content and transactions are handled, and on which sites (or even parts
2268 thereof). There are a number of such actions, with a wide range of
2269 functionality. Each action does something a little different. These actions
2270 give us a veritable arsenal of tools with which to exert our control,
2271 preferences and independence. Actions can be combined so that their effects are
2272 aggregated when applied against a given set of URLs.
2274 There are three action files included with Privoxy with differing purposes:
2276 * default.action - is the primary action file that sets the initial values
2277 for all actions. It is intended to provide a base level of functionality
2278 for Privoxy's array of features. So it is a set of broad rules that should
2279 work reasonably well as-is for most users. This is the file that the
2280 developers are keeping updated, and making available to users. The user's
2281 preferences as set in standard.action, e.g. either Cautious (the default),
2282 Medium, or Advanced (see below).
2284 * user.action - is intended to be for local site preferences and exceptions.
2285 As an example, if your ISP or your bank has specific requirements, and need
2286 special handling, this kind of thing should go here. This file will not be
2289 * standard.action - is used only by the web based editor at http://
2290 config.privoxy.org/edit-actions-list?f=default, to set various pre-defined
2291 sets of rules for the default actions section in default.action.
2293 Edit Set to Cautious Set to Medium Set to Advanced
2295 These have increasing levels of aggressiveness and have no influence on
2296 your browsing unless you select them explicitly in the editor. A default
2297 installation should be pre-set to Cautious (versions prior to 3.0.5 were
2298 set to Medium). New users should try this for a while before adjusting the
2299 settings to more aggressive levels. The more aggressive the settings, then
2300 the more likelihood there is of problems such as sites not working as they
2303 The Edit button allows you to turn each action on/off individually for
2304 fine-tuning. The Cautious button changes the actions list to low/safe
2305 settings which will activate ad blocking and a minimal set of Privoxy's
2306 features, and subsequently there will be less of a chance for accidental
2307 problems. The Medium button sets the list to a medium level of other
2308 features and a low level set of privacy features. The Advanced button sets
2309 the list to a high level of ad blocking and medium level of privacy. See
2310 the chart below. The latter three buttons over-ride any changes via with
2311 the Edit button. More fine-tuning can be done in the lower sections of this
2314 It is not recommend to edit the standard.action file itself.
2316 The default profiles, and their associated actions, as pre-defined in
2317 standard.action are:
2319 Table 1. Default Configurations
2321 +-------------------------------------------------------------------------+
2322 |Feature |Cautious |Medium |Advanced |
2323 |------------------+-----------------+------------------+-----------------|
2324 |Ad-blocking |medium |high |high |
2325 |Aggressiveness | | | |
2326 |------------------+-----------------+------------------+-----------------|
2327 |Ad-filtering by |no |yes |yes |
2329 |------------------+-----------------+------------------+-----------------|
2330 |Ad-filtering by |no |no |yes |
2332 |------------------+-----------------+------------------+-----------------|
2333 |Pop-up killing |blocks only |blocks only |blocks only |
2334 |------------------+-----------------+------------------+-----------------|
2335 |Privacy Features |low |medium |medium/high |
2336 |------------------+-----------------+------------------+-----------------|
2337 |Cookie handling |none |session-only |kill |
2338 |------------------+-----------------+------------------+-----------------|
2339 |Referer forging |no |yes |yes |
2340 |------------------+-----------------+------------------+-----------------|
2341 |GIF de-animation |no |yes |yes |
2342 |------------------+-----------------+------------------+-----------------|
2343 |Fast redirects |no |no |yes |
2344 |------------------+-----------------+------------------+-----------------|
2345 |HTML taming |no |no |yes |
2346 |------------------+-----------------+------------------+-----------------|
2347 |JavaScript taming |no |no |yes |
2348 |------------------+-----------------+------------------+-----------------|
2349 |Web-bug killing |no |yes |yes |
2350 |------------------+-----------------+------------------+-----------------|
2351 |Image tag |no |no |yes |
2353 +-------------------------------------------------------------------------+
2355 The list of actions files to be used are defined in the main configuration
2356 file, and are processed in the order they are defined (e.g. default.action is
2357 typically process before user.action). The content of these can all be viewed
2358 and edited from http://config.privoxy.org/show-status. The over-riding
2359 principle when applying actions, is that the last action that matches a given
2360 URL, wins. The broadest, most general rules go first (defined in
2361 default.action), followed by any exceptions (typically also in default.action),
2362 which are then followed lastly by any local preferences (typically in
2363 user.action). Generally, user.action has the last word.
2365 An actions file typically has multiple sections. If you want to use "aliases"
2366 in an actions file, you have to place the (optional) alias section at the top
2367 of that file. Then comes the default set of rules which will apply universally
2368 to all sites and pages (be very careful with using such a universal set in
2369 user.action or any other actions file after default.action, because it will
2370 override the result from consulting any previous file). And then below that,
2371 exceptions to the defined universal policies. You can regard user.action as an
2372 appendix to default.action, with the advantage that is a separate file, which
2373 makes preserving your personal settings across Privoxy upgrades easier.
2375 Actions can be used to block anything you want, including ads, banners, or just
2376 some obnoxious URL that you would rather not see. Cookies can be accepted or
2377 rejected, or accepted only during the current browser session (i.e. not written
2378 to disk), content can be modified, JavaScripts tamed, user-tracking fooled, and
2379 much more. See below for a complete list of actions.
2381 -------------------------------------------------------------------------------
2383 8.1. Finding the Right Mix
2385 Note that some actions, like cookie suppression or script disabling, may render
2386 some sites unusable that rely on these techniques to work properly. Finding the
2387 right mix of actions is not always easy and certainly a matter of personal
2388 taste. And, things can always change, requiring refinements in the
2389 configuration. In general, it can be said that the more "aggressive" your
2390 default settings (in the top section of the actions file) are, the more
2391 exceptions for "trusted" sites you will have to make later. If, for example,
2392 you want to crunch all cookies per default, you'll have to make exceptions from
2393 that rule for sites that you regularly use and that require cookies for
2394 actually useful purposes, like maybe your bank, favorite shop, or newspaper.
2396 We have tried to provide you with reasonable rules to start from in the
2397 distribution actions files. But there is no general rule of thumb on these
2398 things. There just are too many variables, and sites are constantly changing.
2399 Sooner or later you will want to change the rules (and read this chapter again
2402 -------------------------------------------------------------------------------
2406 The easiest way to edit the actions files is with a browser by using our
2407 browser-based editor, which can be reached from http://config.privoxy.org/
2408 show-status. The editor allows both fine-grained control over every single
2409 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2410 like "Cautious", "Medium" or "Advanced". Warning: the "Advanced" setting is
2411 more aggressive, and will be more likely to cause problems for some sites.
2412 Experienced users only!
2414 If you prefer plain text editing to GUIs, you can of course also directly edit
2415 the the actions files with your favorite text editor. Look at default.action
2416 which is richly commented with many good examples.
2418 -------------------------------------------------------------------------------
2420 8.3. How Actions are Applied to URLs
2422 Actions files are divided into sections. There are special sections, like the "
2423 alias" sections which will be discussed later. For now let's concentrate on
2424 regular sections: They have a heading line (often split up to multiple lines
2425 for readability) which consist of a list of actions, separated by whitespace
2426 and enclosed in curly braces. Below that, there is a list of URL patterns, each
2429 To determine which actions apply to a request, the URL of the request is
2430 compared to all patterns in each "action file" file. Every time it matches, the
2431 list of applicable actions for the URL is incrementally updated, using the
2432 heading of the section in which the pattern is located. If multiple matches for
2433 the same URL set the same action differently, the last match wins. If not, the
2434 effects are aggregated. E.g. a URL might match a regular section with a heading
2435 line of { +handle-as-image }, then later another one with just { +block },
2436 resulting in both actions to apply. And there may well be cases where you will
2437 want to combine actions together. Such a section then might look like:
2439 { +handle-as-image +block }
2440 # Block these as if they were images. Send no block page.
2442 media.example.com/.*banners
2443 .example.com/images/ads/
2445 You can trace this process for any given URL by visiting http://
2446 config.privoxy.org/show-url-info.
2448 Examples and more detail on this is provided in the Appendix, Troubleshooting:
2449 Anatomy of an Action section.
2451 -------------------------------------------------------------------------------
2455 As mentioned, Privoxy uses "patterns" to determine what actions might apply to
2456 which sites and pages your browser attempts to access. These "patterns" use
2457 wild card type pattern matching to achieve a high degree of flexibility. This
2458 allows one expression to be expanded and potentially match against many similar
2461 Generally, a Privoxy pattern has the form <domain>/<path>, where both the
2462 <domain> and <path> are optional. (This is why the special / pattern matches
2463 all URLs). Note that the protocol portion of the URL pattern (e.g. http://)
2464 should not be included in the pattern. This is assumed already!
2466 The pattern matching syntax is different for the domain and path parts of the
2467 URL. The domain part uses a simple globbing type matching technique, while the
2468 path part uses a more flexible "Regular Expressions (PCRE)" based syntax.
2472 is a domain-only pattern and will match any request to www.example.com,
2473 regardless of which document on that server is requested. So ALL pages in
2474 this domain would be covered by the scope of this action. Note that a
2475 simple example.com is different and would NOT match.
2479 means exactly the same. For domain-only patterns, the trailing / may be
2482 www.example.com/index.html
2484 matches only the single document /index.html on www.example.com.
2488 matches the document /index.html, regardless of the domain, i.e. on any web
2493 matches nothing, since it would be interpreted as a domain name and there
2494 is no top-level domain called .html. So its a mistake.
2496 -------------------------------------------------------------------------------
2498 8.4.1. The Domain Pattern
2500 The matching of the domain part offers some flexible options: if the domain
2501 starts or ends with a dot, it becomes unanchored at that end. For example:
2505 matches any domain that ENDS in .example.com
2509 matches any domain that STARTS with www.
2513 matches any domain that CONTAINS .example.. And, by the way, also included
2514 would be any files or documents that exist within that domain since no path
2515 limitations are specified. (Correctly speaking: It matches any FQDN that
2516 contains example as a domain.) This might be www.example.com,
2517 news.example.de, or www.example.net/cgi/testing.pl for instance. All these
2520 Additionally, there are wild-cards that you can use in the domain names
2521 themselves. These work similarly to shell globbing type wild-cards: "*"
2522 represents zero or more arbitrary characters (this is equivalent to the
2523 "Regular Expression" based syntax of ".*"), "?" represents any single character
2524 (this is equivalent to the regular expression syntax of a simple "."), and you
2525 can define "character classes" in square brackets which is similar to the same
2526 regular expression technique. All of this can be freely mixed:
2530 matches "adserver.example.com", "ads.example.com", etc but not
2535 matches all of the above, and then some.
2539 matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
2541 www[1-9a-ez].example.c*
2543 matches www1.example.com, www4.example.cc, wwwd.example.cy,
2544 wwwz.example.com etc., but not wwww.example.com.
2546 While flexible, this is not the sophistication of full regular expression based
2549 -------------------------------------------------------------------------------
2551 8.4.2. The Path Pattern
2553 Privoxy uses Perl compatible (PCRE) "Regular Expression" based syntax (through
2554 the PCRE library) for matching the path portion (after the slash), and is thus
2557 There is an Appendix with a brief quick-start into regular expressions, and
2558 full (very technical) documentation on PCRE regex syntax is available on-line
2559 at http://www.pcre.org/man.txt. You might also find the Perl man page on
2560 regular expressions (man perlre) useful, which is available on-line at http://
2561 perldoc.perl.org/perlre.html.
2563 Note that the path pattern is automatically left-anchored at the "/", i.e. it
2564 matches as if it would start with a "^" (regular expression speak for the
2565 beginning of a line).
2567 Please also note that matching in the path is CASE INSENSITIVE by default, but
2568 you can switch to case sensitive at any point in the pattern by using the "(?
2569 -i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
2570 path starts with PaTtErN in exactly this capitalization.
2574 Is equivalent to just ".example.com", since any documents within that
2575 domain are matched with or without the ".*" regular expression. This is
2578 .example.com/.*/index.html
2580 Will match any page in the domain of "example.com" that is named
2581 "index.html", and that is part of some path. For example, it matches
2582 "www.example.com/testing/index.html" but NOT "www.example.com/index.html"
2583 because the regular expression called for at least two "/'s", thus the path
2584 requirement. It also would match "www.example.com/testing/index_html",
2585 because of the special meta-character ".".
2587 .example.com/(.*/)?index\.html
2589 This regular expression is conditional so it will match any page named
2590 "index.html" regardless of path which in this case can have one or more "/
2591 's". And this one must contain exactly ".html" (but does not have to end
2594 .example.com/(.*/)(ads|banners?|junk)
2596 This regular expression will match any path of "example.com" that contains
2597 any of the words "ads", "banner", "banners" (because of the "?") or "junk".
2598 The path does not have to end in these words, just contain them.
2600 .example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$
2602 This is very much the same as above, except now it must end in either
2603 ".jpg", ".jpeg", ".gif" or ".png". So this one is limited to common image
2606 There are many, many good examples to be found in default.action, and more
2607 tutorials below in Appendix on regular expressions.
2609 -------------------------------------------------------------------------------
2613 All actions are disabled by default, until they are explicitly enabled
2614 somewhere in an actions file. Actions are turned on if preceded with a "+", and
2615 turned off if preceded with a "-". So a +action means "do that action", e.g.
2616 +block means "please block URLs that match the following patterns", and -block
2617 means "don't block URLs that match the following patterns, even if +block
2618 previously applied."
2620 Again, actions are invoked by placing them on a line, enclosed in curly braces
2621 and separated by whitespace, like in {+some-action -some-other-action
2622 {some-parameter}}, followed by a list of URL patterns, one per line, to which
2623 they apply. Together, the actions line and the following pattern lines make up
2624 a section of the actions file.
2626 Actions fall into three categories:
2628 * Boolean, i.e the action can only be "enabled" or "disabled". Syntax:
2630 +name # enable action name
2631 -name # disable action name
2635 * Parameterized, where some value is required in order to enable this type of
2638 +name{param} # enable action and set parameter to param,
2639 # overwriting parameter from previous match if necessary
2640 -name # disable action. The parameter can be omitted
2642 Note that if the URL matches multiple positive forms of a parameterized
2643 action, the last match wins, i.e. the params from earlier matches are
2646 Example: +hide-user-agent{ Mozilla 1.0 }
2648 * Multi-value. These look exactly like parameterized actions, but they behave
2649 differently: If the action applies multiple times to the same URL, but with
2650 different parameters, all the parameters from all matches are remembered.
2651 This is used for actions that can be executed for the same request
2652 repeatedly, like adding multiple headers, or filtering through multiple
2655 +name{param} # enable action and add param to the list of parameters
2656 -name{param} # remove the parameter param from the list of parameters
2657 # If it was the last one left, disable the action.
2658 -name # disable this action completely and remove all parameters from the list
2660 Examples: +add-header{X-Fun-Header: Some text} and +filter{html-annoyances}
2662 If nothing is specified in any actions file, no "actions" are taken. So in this
2663 case Privoxy would just be a normal, non-blocking, non-anonymizing proxy. You
2664 must specifically enable the privacy and blocking features you need (although
2665 the provided default actions files will give a good starting point).
2667 Later defined actions always over-ride earlier ones. So exceptions to any rules
2668 you make, should come in the latter part of the file (or in a file that is
2669 processed later when using multiple actions files such as user.action). For
2670 multi-valued actions, the actions are applied in the order they are specified.
2671 Actions files are processed in the order they are defined in config (the
2672 default installation has three actions files). It also quite possible for any
2673 given URL to match more than one "pattern" (because of wildcards and regular
2674 expressions), and thus to trigger more than one set of actions! Last match
2677 The list of valid Privoxy actions are:
2679 -------------------------------------------------------------------------------
2685 Confuse log analysis, custom applications
2689 Sends a user defined HTTP header to the web server.
2697 Any string value is possible. Validity of the defined HTTP headers is not
2698 checked. It is recommended that you use the "X-" prefix for custom headers.
2702 This action may be specified multiple times, in order to define multiple
2703 headers. This is rarely needed for the typical user. If you don't know what
2704 "HTTP headers" are, you definitely don't need to worry about this one.
2708 +add-header{X-User-Tracking: sucks}
2710 -------------------------------------------------------------------------------
2716 Block ads or other unwanted content
2720 Requests for URLs to which this action applies are blocked, i.e. the
2721 requests are trapped by Privoxy and the requested URL is never retrieved,
2722 but is answered locally with a substitute page or image, as determined by
2723 the handle-as-image, set-image-blocker, and handle-as-empty-document
2736 Privoxy sends a special "BLOCKED" page for requests to blocked pages. This
2737 page contains links to find out why the request was blocked, and a
2738 click-through to the blocked content (the latter only if compiled with the
2739 force feature enabled). The "BLOCKED" page adapts to the available screen
2740 space -- it displays full-blown if space allows, or miniaturized and
2741 text-only if loaded into a small frame or window. If you are using Privoxy
2742 right now, you can take a look at the "BLOCKED" page.
2744 A very important exception occurs if both block and handle-as-image, apply
2745 to the same request: it will then be replaced by an image. If
2746 set-image-blocker (see below) also applies, the type of image will be
2747 determined by its parameter, if not, the standard checkerboard pattern is
2750 It is important to understand this process, in order to understand how
2751 Privoxy deals with ads and other unwanted content. Blocking is a core
2752 feature, and one upon which various other features depend.
2754 The filter action can perform a very similar task, by "blocking" banner
2755 images and other content through rewriting the relevant URLs in the
2756 document's HTML source, so they don't get requested in the first place.
2757 Note that this is a totally different technique, and it's easy to confuse
2760 Example usage (section):
2763 # Block and replace with "blocked" page
2764 .nasty-stuff.example.com
2766 {+block +handle-as-image}
2767 # Block and replace with image
2771 {+block +handle-as-empty-document}
2772 # Block and then ignore
2773 adserver.exampleclick.net/.*\.js$
2775 -------------------------------------------------------------------------------
2777 8.5.3. content-type-overwrite
2781 Stop useless download menus from popping up, or change the browser's
2786 Replaces the "Content-Type:" HTTP server header.
2798 The "Content-Type:" HTTP server header is used by the browser to decide
2799 what to do with the document. The value of this header can cause the
2800 browser to open a download menu instead of displaying the document by
2801 itself, even if the document's format is supported by the browser.
2803 The declared content type can also affect which rendering mode the browser
2804 chooses. If XHTML is delivered as "text/html", many browsers treat it as
2805 yet another broken HTML document. If it is send as "application/xml",
2806 browsers with XHTML support will only display it, if the syntax is correct.
2808 If you see a web site that proudly uses XHTML buttons, but sets
2809 "Content-Type: text/html", you can use Privoxy to overwrite it with
2810 "application/xml" and validate the web master's claim inside your
2811 XHTML-supporting browser. If the syntax is incorrect, the browser will
2814 You can also go the opposite direction: if your browser prints error
2815 messages instead of rendering a document falsely declared as XHTML, you can
2816 overwrite the content type with "text/html" and have it rendered as broken
2819 By default content-type-overwrite only replaces "Content-Type:" headers
2820 that look like some kind of text. If you want to overwrite it
2821 unconditionally, you have to combine it with force-text-mode. This
2822 limitation exists for a reason, think twice before circumventing it.
2824 Most of the time it's easier to enable filter-server-headers and replace
2825 this action with a custom regular expression. It allows you to activate it
2826 for every document of a certain site and it will still only replace the
2827 content types you aimed at.
2829 Of course you can apply content-type-overwrite to a whole site and then
2830 make URL based exceptions, but it's a lot more work to get the same
2833 Example usage (sections):
2835 # Check if www.example.net/ really uses valid XHTML
2836 { +content-type-overwrite{application/xml} }
2839 # but leave the content type unmodified if the URL looks like a style sheet
2840 {-content-type-overwrite}
2841 www.example.net/*.\.css$
2842 www.example.net/*.style
2844 -------------------------------------------------------------------------------
2846 8.5.4. crunch-client-header
2850 Remove a client header Privoxy has no dedicated action for.
2854 Deletes every header sent by the client that contains the string the user
2855 supplied as parameter.
2867 This action allows you to block client headers for which no dedicated
2868 Privoxy action exists. Privoxy will remove every client header that
2869 contains the string you supplied as parameter.
2871 Regular expressions are not supported and you can't use this action to
2872 block different headers in the same request, unless they contain the same
2875 crunch-client-header is only meant for quick tests. If you have to block
2876 several different headers, or only want to modify parts of them, you should
2877 enable filter-client-headers and create your own filter.
2879 +-----------------------------------------------------------------+
2881 |-----------------------------------------------------------------|
2882 |Don't block any header without understanding the consequences. |
2883 +-----------------------------------------------------------------+
2884 Example usage (section):
2886 # Block the non-existent "Privacy-Violation:" client header
2887 { +crunch-client-header{Privacy-Violation:} }
2891 -------------------------------------------------------------------------------
2893 8.5.5. crunch-if-none-match
2897 Prevent yet another way to track the user's steps between sessions.
2901 Deletes the "If-None-Match:" HTTP client header.
2913 Removing the "If-None-Match:" HTTP client header is useful for filter
2914 testing, where you want to force a real reload instead of getting status
2915 code "304" which would cause the browser to use a cached copy of the page.
2917 It is also useful to make sure the header isn't used as a cookie
2920 Blocking the "If-None-Match:" header shouldn't cause any caching problems,
2921 as long as the "If-Modified-Since:" header isn't blocked as well.
2923 It is recommended to use this action together with hide-if-modified-since
2924 and overwrite-last-modified.
2926 Example usage (section):
2928 # Let the browser revalidate cached documents without being tracked across sessions
2929 { +hide-if-modified-since{-60} \
2930 +overwrite-last-modified{randomize} \
2931 +crunch-if-none-match}
2934 -------------------------------------------------------------------------------
2936 8.5.6. crunch-incoming-cookies
2940 Prevent the web server from setting any cookies on your system
2944 Deletes any "Set-Cookie:" HTTP headers from server replies.
2956 This action is only concerned with incoming cookies. For outgoing cookies,
2957 use crunch-outgoing-cookies. Use both to disable cookies completely.
2959 It makes no sense at all to use this action in conjunction with the
2960 session-cookies-only action, since it would prevent the session cookies
2961 from being set. See also filter-content-cookies.
2965 +crunch-incoming-cookies
2967 -------------------------------------------------------------------------------
2969 8.5.7. crunch-server-header
2973 Remove a server header Privoxy has no dedicated action for.
2977 Deletes every header sent by the server that contains the string the user
2978 supplied as parameter.
2990 This action allows you to block server headers for which no dedicated
2991 Privoxy action exists. Privoxy will remove every server header that
2992 contains the string you supplied as parameter.
2994 Regular expressions are not supported and you can't use this action to
2995 block different headers in the same request, unless they contain the same
2998 crunch-server-header is only meant for quick tests. If you have to block
2999 several different headers, or only want to modify parts of them, you should
3000 enable filter-server-headers and create your own filter.
3002 +-----------------------------------------------------------------+
3004 |-----------------------------------------------------------------|
3005 |Don't block any header without understanding the consequences. |
3006 +-----------------------------------------------------------------+
3007 Example usage (section):
3009 # Crunch server headers that try to prevent caching
3010 { +crunch-server-header{no-cache} }
3013 -------------------------------------------------------------------------------
3015 8.5.8. crunch-outgoing-cookies
3019 Prevent the web server from reading any cookies from your system
3023 Deletes any "Cookie:" HTTP headers from client requests.
3035 This action is only concerned with outgoing cookies. For incoming cookies,
3036 use crunch-incoming-cookies. Use both to disable cookies completely.
3038 It makes no sense at all to use this action in conjunction with the
3039 session-cookies-only action, since it would prevent the session cookies
3044 +crunch-outgoing-cookies
3046 -------------------------------------------------------------------------------
3048 8.5.9. deanimate-gifs
3052 Stop those annoying, distracting animated GIF images.
3056 De-animate GIF animations, i.e. reduce them to their first or last image.
3068 This will also shrink the images considerably (in bytes, not pixels!). If
3069 the option "first" is given, the first frame of the animation is used as
3070 the replacement. If "last" is given, the last frame of the animation is
3071 used instead, which probably makes more sense for most banner animations,
3072 but also has the risk of not showing the entire last frame (if it is only a
3073 delta to an earlier frame).
3075 You can safely use this action with patterns that will also match non-GIF
3076 objects, because no attempt will be made at anything that doesn't look like
3081 +deanimate-gifs{last}
3083 -------------------------------------------------------------------------------
3085 8.5.10. downgrade-http-version
3089 Work around (very rare) problems with HTTP/1.1
3093 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3105 This is a left-over from the time when Privoxy didn't support important
3106 HTTP/1.1 features well. It is left here for the unlikely case that you
3107 experience HTTP/1.1 related problems with some server out there. Not all
3108 (optional) HTTP/1.1 features are supported yet, so there is a chance you
3109 might need this action.
3111 Example usage (section):
3113 {+downgrade-http-version}
3114 problem-host.example.com
3116 -------------------------------------------------------------------------------
3118 8.5.11. fast-redirects
3122 Fool some click-tracking scripts and speed up indirect links.
3126 Detects redirection URLs and redirects the browser without contacting the
3127 redirection server first.
3135 + "simple-check" to just search for the string "http://" to detect
3138 + "check-decoded-url" to decode URLs (if necessary) before searching for
3143 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3144 will link to some script on their own servers, giving the destination as a
3145 parameter, which will then redirect you to the final target. URLs resulting
3146 from this scheme typically look like: "http://www.example.org/
3147 click-tracker.cgi?target=http%3a//www.example.net/".
3149 Sometimes, there are even multiple consecutive redirects encoded in the
3150 URL. These redirections via scripts make your web browsing more traceable,
3151 since the server from which you follow such a link can see where you go to.
3152 Apart from that, valuable bandwidth and time is wasted, while your browser
3153 asks the server for one redirect after the other. Plus, it feeds the
3156 This feature is currently not very smart and is scheduled for improvement.
3157 If it is enabled by default, you will have to create some exceptions to
3158 this action. It can lead to failures in several ways:
3160 Not every URLs with other URLs as parameters is evil. Some sites offer a
3161 real service that requires this information to work. For example a
3162 validation service needs to know, which document to validate.
3163 fast-redirects assumes that every URL parameter that looks like another URL
3164 is a redirection target, and will always redirect to the last one. Most of
3165 the time the assumption is correct, but if it isn't, the user gets
3168 Another failure occurs if the URL contains other parameters after the URL
3169 parameter. The URL: "http://www.example.org/?redirect=http%3a//
3170 www.example.net/&foo=bar". contains the redirection URL "http://
3171 www.example.net/", followed by another parameter. fast-redirects doesn't
3172 know that and will cause a redirect to "http://www.example.net/&foo=bar".
3173 Depending on the target server configuration, the parameter will be
3174 silently ignored or lead to a "page not found" error. It is possible to fix
3175 these redirected requests with filter-client-headers but it requires a
3178 To detect a redirection URL, fast-redirects only looks for the string
3179 "http://", either in plain text (invalid but often used) or encoded as
3180 "http%3a//". Some sites use their own URL encoding scheme, encrypt the
3181 address of the target server or replace it with a database id. In theses
3182 cases fast-redirects is fooled and the request reaches the redirection
3183 server where it probably gets logged.
3187 { +fast-redirects{simple-check} }
3190 { +fast-redirects{check-decoded-url} }
3191 another.example.com/testing
3193 -------------------------------------------------------------------------------
3199 Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3200 do fun text replacements, add personalized effects, etc.
3204 All files of text-based type, most notably HTML and JavaScript, to which
3205 this action applies, can be filtered on-the-fly through the specified
3206 regular expression based substitutions. (Note: as of version 3.0.3 plain
3207 text documents are exempted from filtering, because web servers often use
3208 the text/plain MIME type for all files whose type they don't know.) By
3209 default, filtering works only on the raw document content itself (that
3210 which can be seen with View Source), not the headers.
3218 The name of a filter, as defined in the filter file. Filters can be defined
3219 in one or more files as defined by the filterfile option in the config file
3220 . default.filter is the collection of filters supplied by the developers.
3221 Locally defined filters should go in their own file, such as user.filter.
3223 When used in its negative form, and without parameters, all filtering is
3224 completely disabled.
3228 For your convenience, there are a number of pre-defined filters available
3229 in the distribution filter file that you can use. See the examples below
3232 Filtering requires buffering the page content, which may appear to slow
3233 down page rendering since nothing is displayed until all content has passed
3234 the filters. (It does not really take longer, but seems that way since the
3235 page is not incrementally displayed.) This effect will be more noticeable
3236 on slower connections.
3238 "Rolling your own" filters requires a knowledge of "Regular Expressions"
3239 and "HTML". This is very powerful feature, and potentially very intrusive.
3240 Filters should be used with caution, and where an equivalent "action" is
3243 The amount of data that can be filtered is limited to the buffer-limit
3244 option in the main config file. The default is 4096 KB (4 Megs). Once this
3245 limit is exceeded, the buffered data, and all pending data, is passed
3248 Inappropriate MIME types, such as zipped files, are not filtered at all.
3249 (Again, only text-based types except plain text). Encrypted SSL data (from
3250 HTTPS servers) cannot be filtered either, since this would violate the
3251 integrity of the secure transaction. In some situations it might be
3252 necessary to protect certain text, like source code, from filtering by
3253 defining appropriate -filter exceptions.
3255 At this time, Privoxy cannot uncompress compressed documents. If you want
3256 filtering to work on all documents, even those that would normally be sent
3257 compressed, you must use the prevent-compression action in conjunction with
3260 Filtering can achieve some of the same effects as the block action, i.e. it
3261 can be used to block ads and banners. But the mechanism works quite
3262 differently. One effective use, is to block ad banners based on their size
3263 (see below), since many of these seem to be somewhat standardized.
3265 Feedback with suggestions for new or improved filters is particularly
3268 The below list has only the names and a one-line description of each
3269 predefined filter. There are more verbose explanations of what these
3270 filters do in the filter file chapter.
3272 Example usage (with filters from the distribution default.filter file). See the
3273 Predefined Filters section for more explanation on each:
3275 +filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse
3277 +filter{js-events} # Kill all JS event bindings (Radically destructive! Only for extra nasty sites)
3279 +filter{html-annoyances} # Get rid of particularly annoying HTML abuse
3281 +filter{content-cookies} # Kill cookies that come in the HTML or JS content
3283 +filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups)
3285 +filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.
3287 +filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.
3289 +filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective
3291 +filter{banners-by-size} # Kill banners by size
3293 +filter{banners-by-link} # Kill banners by their links to known clicktrackers
3295 +filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking)
3297 +filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap
3299 +filter{jumping-windows} # Prevent windows from resizing and moving themselves
3301 +filter{frameset-borders} # Give frames a border and make them resizeable
3303 +filter{demoronizer} # Fix MS's non-standard use of standard charsets
3305 +filter{shockwave-flash} # Kill embedded Shockwave Flash objects
3307 +filter{quicktime-kioskmode} # Make Quicktime movies savable
3309 +filter{fun} # Text replacements for subversive browsing fun!
3311 +filter{crude-parental} # Crude parental filtering (demo only)
3313 +filter{ie-exploits} # Disable some known Internet Explorer bug exploits
3315 +filter{site-specifics} # Custom filters for specific site related problems
3317 +filter{google} # Removes text ads and other Google specific improvements
3319 +filter{yahoo} # Removes text ads and other Yahoo specific improvements
3321 +filter{msn} # Removes text ads and other MSN specific improvements
3323 +filter{blogspot} # Cleans up Blogspot blogs
3325 +filter{html-to-xml} # Header filter to change the Content-Type from html to xml
3327 +filter{xml-to-html} # Header filter to change the Content-Type from xml to html
3329 +filter{no-ping} # Removes non-standard ping attributes from anchor and area tags
3331 +filter{hide-tor-exit-notation} # Header filter to remove the Tor exit node notation in Host and Referer headers
3333 -------------------------------------------------------------------------------
3335 8.5.13. filter-client-headers
3339 To apply filtering to the client's (browser's) headers
3343 By default, Privoxy's filters only apply to the document content itself.
3344 This will extend those filters to include the client's headers as well.
3356 Regular expressions can be used to filter headers as well. Check your
3357 filters closely before activating this action, as it can easily lead to
3360 These filters are applied to each header on its own, not to them all at
3361 once. This makes it easier to diagnose problems, but on the downside you
3362 can't write filters that only change header x if header y's value is z.
3364 The filters are used after the other header actions have finished and can
3365 use their output as input.
3367 Whenever possible one should specify ^, $, the whole header name and the
3368 colon, to make sure the filter doesn't cause havoc to other headers or the
3369 page itself. For example if you want to transform Galeon User-Agents to
3370 Firefox User-Agents you shouldn't use:
3372 s@Galeon/\d\.\d\.\d @@
3376 s@^(User-Agent:.*) Galeon/\d\.\d\.\d (Firefox/\d\.\d\.\d\.\d)$@$1 $2@
3378 Example usage (section):
3380 {+filter-client-headers +filter{test_filter}}
3381 problem-host.example.com
3384 -------------------------------------------------------------------------------
3386 8.5.14. filter-server-headers
3390 To apply filtering to the server's headers
3394 By default, Privoxy's filters only apply to the document content itself.
3395 This will extend those filters to include the server's headers as well.
3407 Similar to filter-client-headers, but works on the server instead. To
3408 filter both server and client, use both.
3410 As with filter-client-headers, check your filters before activating this
3411 action, as it can easily lead to broken requests.
3413 These filters are applied to each header on its own, not to them all at
3414 once. This makes it easier to diagnose problems, but on the downside you
3415 can't write filters that only change header x if header y's value is z.
3417 The filters are used after the other header actions have finished and can
3418 use their output as input.
3420 Remember too, whenever possible one should specify ^, $, the whole header
3421 name and the colon, to make sure the filter doesn't cause havoc to other
3422 headers or the page itself. See above for example.
3424 Example usage (section):
3426 {+filter-server-headers +filter{test_filter}}
3427 problem-host.example.com
3430 -------------------------------------------------------------------------------
3432 8.5.15. force-text-mode
3436 Force Privoxy to treat a document as if it was in some kind of text format.
3440 Declares a document as text, even if the "Content-Type:" isn't detected as
3453 As explained above, Privoxy tries to only filter files that are in some
3454 kind of text format. The same restrictions apply to content-type-overwrite.
3455 force-text-mode declares a document as text, without looking at the
3456 "Content-Type:" first.
3458 +-----------------------------------------------------------------+
3460 |-----------------------------------------------------------------|
3461 |Think twice before activating this action. Filtering binary data |
3462 |with regular expressions can cause file damage. |
3463 +-----------------------------------------------------------------+
3469 -------------------------------------------------------------------------------
3471 8.5.16. handle-as-empty-document
3475 Mark URLs that should be replaced by empty documents if they get blocked
3479 This action alone doesn't do anything noticeable. It just marks URLs. If
3480 the block action also applies, the presence or absence of this mark decides
3481 whether an HTML "BLOCKED" page, or an empty document will be sent to the
3482 client as a substitute for the blocked content. The empty document isn't
3483 literally empty, but actually contains a single space.
3495 Some browsers complain about syntax errors if JavaScript documents are
3496 blocked with Privoxy's default HTML page; this option can be used to
3497 silence them. And of course this action can also be used to eliminate the
3498 Privoxy BLOCKED message in frames.
3500 The content type for the empty document can be specified with
3501 content-type-overwrite{}, but usually this isn't necessary.
3505 # Block all documents on example.org that end with ".js",
3506 # but send an empty document instead of the usual HTML message.
3507 {+block +handle-as-empty-document}
3511 -------------------------------------------------------------------------------
3513 8.5.17. handle-as-image
3517 Mark URLs as belonging to images (so they'll be replaced by images if they
3518 do get blocked, rather than HTML pages)
3522 This action alone doesn't do anything noticeable. It just marks URLs as
3523 images. If the block action also applies, the presence or absence of this
3524 mark decides whether an HTML "blocked" page, or a replacement image (as
3525 determined by the set-image-blocker action) will be sent to the client as a
3526 substitute for the blocked content.
3538 The below generic example section is actually part of default.action. It
3539 marks all URLs with well-known image file name extensions as images and
3540 should be left intact.
3542 Users will probably only want to use the handle-as-image action in
3543 conjunction with block, to block sources of banners, whose URLs don't
3544 reflect the file type, like in the second example section.
3546 Note that you cannot treat HTML pages as images in most cases. For
3547 instance, (in-line) ad frames require an HTML page to be sent, or they
3548 won't display properly. Forcing handle-as-image in this situation will not
3549 replace the ad frame with an image, but lead to error messages.
3551 Example usage (sections):
3553 # Generic image extensions:
3556 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
3558 # These don't look like images, but they're banners and should be
3559 # blocked as images:
3561 {+block +handle-as-image}
3562 some.nasty-banner-server.com/junk.cgi?output=trash
3564 # Banner source! Who cares if they also have non-image content?
3567 -------------------------------------------------------------------------------
3569 8.5.18. hide-accept-language
3573 Pretend to use different language settings.
3577 Deletes or replaces the "Accept-Language:" HTTP header in client requests.
3585 Keyword: "block", or any user defined value.
3589 Faking the browser's language settings can be useful to make a foreign
3590 User-Agent set with hide-user-agent more believable.
3592 However some sites with content in different languages check the
3593 "Accept-Language:" to decide which one to take by default. Sometimes it
3594 isn't possible to later switch to another language without changing the
3595 "Accept-Language:" header first.
3597 Therefore it's a good idea to either only change the "Accept-Language:"
3598 header to languages you understand, or to languages that aren't wide
3601 Before setting the "Accept-Language:" header to a rare language, you should
3602 consider that it helps to make your requests unique and thus easier to
3603 trace. If you don't plan to change this header frequently, you should stick
3604 to a common language.
3606 Example usage (section):
3608 # Pretend to use Canadian language settings.
3609 {+hide-accept-language{en-ca} \
3610 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
3614 -------------------------------------------------------------------------------
3616 8.5.19. hide-content-disposition
3620 Prevent download menus for content you prefer to view inside the browser.
3624 Deletes or replaces the "Content-Disposition:" HTTP header set by some
3633 Keyword: "block", or any user defined value.
3637 Some servers set the "Content-Disposition:" HTTP header for documents they
3638 assume you want to save locally before viewing them. The
3639 "Content-Disposition:" header contains the file name the browser is
3640 supposed to use by default.
3642 In most browsers that understand this header, it makes it impossible to
3643 just view the document, without downloading it first, even if it's just a
3644 simple text file or an image.
3646 Removing the "Content-Disposition:" header helps to prevent this annoyance,
3647 but some browsers additionally check the "Content-Type:" header, before
3648 they decide if they can display a document without saving it first. In
3649 these cases, you have to change this header as well, before the browser
3650 stops displaying download menus.
3652 It is also possible to change the server's file name suggestion to another
3653 one, but in most cases it isn't worth the time to set it up.
3657 # Disarm the download link in Sourceforge's patch tracker
3659 +content-type-overwrite{text/plain}\
3660 +hide-content-disposition{block} }
3661 .sourceforge.net/tracker/download.php
3663 -------------------------------------------------------------------------------
3665 8.5.20. hide-if-modified-since
3669 Prevent yet another way to track the user's steps between sessions.
3673 Deletes the "If-Modified-Since:" HTTP client header or modifies its value.
3681 Keyword: "block", or a user defined value that specifies a range of hours.
3685 Removing this header is useful for filter testing, where you want to force
3686 a real reload instead of getting status code "304", which would cause the
3687 browser to use a cached copy of the page.
3689 Instead of removing the header, hide-if-modified-since can also add or
3690 subtract a random amount of time to/from the header's value. You specify a
3691 range of minutes where the random factor should be chosen from and Privoxy
3692 does the rest. A negative value means subtracting, a positive value adding.
3694 Randomizing the value of the "If-Modified-Since:" makes sure it isn't used
3695 as a cookie replacement, but you will run into caching problems if the
3696 random range is too high.
3698 It is a good idea to only use a small negative value and let
3699 overwrite-last-modified handle the greater changes.
3701 It is also recommended to use this action together with
3702 crunch-if-none-match.
3704 Example usage (section):
3706 # Let the browser revalidate without being tracked across sessions
3707 { +hide-if-modified-since{-60} \
3708 +overwrite-last-modified{randomize} \
3709 +crunch-if-none-match}
3712 -------------------------------------------------------------------------------
3714 8.5.21. hide-forwarded-for-headers
3718 Improve privacy by hiding the true source of the request
3722 Deletes any existing "X-Forwarded-for:" HTTP header from client requests,
3723 and prevents adding a new one.
3735 It is fairly safe to leave this on.
3737 This action is scheduled for improvement: It should be able to generate
3738 forged "X-Forwarded-for:" headers using random IP addresses from a
3739 specified network, to make successive requests from the same client look
3740 like requests from a pool of different users sharing the same proxy.
3744 +hide-forwarded-for-headers
3746 -------------------------------------------------------------------------------
3748 8.5.22. hide-from-header
3752 Keep your (old and ill) browser from telling web servers your email address
3756 Deletes any existing "From:" HTTP header, or replaces it with the specified
3765 Keyword: "block", or any user defined value.
3769 The keyword "block" will completely remove the header (not to be confused
3770 with the block action).
3772 Alternately, you can specify any value you prefer to be sent to the web
3773 server. If you do, it is a matter of fairness not to use any address that
3774 is actually used by a real person.
3776 This action is rarely needed, as modern web browsers don't send "From:"
3781 +hide-from-header{block}
3785 +hide-from-header{spam-me-senseless@sittingduck.example.com}
3787 -------------------------------------------------------------------------------
3789 8.5.23. hide-referrer
3793 Conceal which link you followed to get to a particular site
3797 Deletes the "Referer:" (sic) HTTP header from the client request, or
3798 replaces it with a forged one.
3806 + "conditional-block" to delete the header completely if the host has
3809 + "block" to delete the header unconditionally.
3811 + "forge" to pretend to be coming from the homepage of the server we are
3814 + Any other string to set a user defined referrer.
3818 conditional-block is the only parameter, that isn't easily detected in the
3819 server's log file. If it blocks the referrer, the request will look like
3820 the visitor used a bookmark or typed in the address directly.
3822 Leaving the referrer unmodified for requests on the same host allows the
3823 server owner to see the visitor's "click path", but in most cases she could
3824 also get that information by comparing other parts of the log file: for
3825 example the User-Agent if it isn't a very common one, or the user's IP
3826 address if it doesn't change between different requests.
3828 Always blocking the referrer, or using a custom one, can lead to failures
3829 on servers that check the referrer before they answer any requests, in an
3830 attempt to prevent their valuable content from being embedded or linked to
3833 Both conditional-block and forge will work with referrer checks, as long as
3834 content and valid referring page are on the same host. Most of the time
3837 hide-referer is an alternate spelling of hide-referrer and the two can be
3838 can be freely substituted with each other. ("referrer" is the correct
3839 English spelling, however the HTTP specification has a bug - it requires it
3840 to be spelled as "referer".)
3844 +hide-referrer{forge}
3848 +hide-referrer{http://www.yahoo.com/}
3850 -------------------------------------------------------------------------------
3852 8.5.24. hide-user-agent
3856 Conceal your type of browser and client operating system
3860 Replaces the value of the "User-Agent:" HTTP header in client requests with
3861 the specified value.
3869 Any user-defined string.
3873 +-----------------------------------------------------------------+
3875 |-----------------------------------------------------------------|
3876 |This can lead to problems on web sites that depend on looking at |
3877 |this header in order to customize their content for different |
3878 |browsers (which, by the way, is NOT the right thing to do: good |
3879 |web sites work browser-independently). |
3880 +-----------------------------------------------------------------+
3882 Using this action in multi-user setups or wherever different types of
3883 browsers will access the same Privoxy is not recommended. In single-user,
3884 single-browser setups, you might use it to delete your OS version
3885 information from the headers, because it is an invitation to exploit known
3886 bugs for your OS. It is also occasionally useful to forge this in order to
3887 access sites that won't let you in otherwise (though there may be a good
3888 reason in some cases). Example of this: some MSN sites will not let Mozilla
3889 enter, yet forging to a Netscape 6.1 user-agent works just fine. (Must be
3890 just a silly MS goof, I'm sure :-).
3892 This action is scheduled for improvement.
3896 +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
3898 -------------------------------------------------------------------------------
3900 8.5.25. inspect-jpegs
3904 To protect against the MS buffer over-run in JPEG processing
3908 Protect against a known exploit
3920 See Microsoft Security Bulletin MS04-028. JPEG images are one of the most
3921 common image types found across the Internet. The exploit as described can
3922 allow execution of code on the target system, giving an attacker access to
3923 the system in question by merely planting an altered JPEG image, which
3924 would have no obvious indications of what lurks inside. This action
3925 prevents unwanted intrusion.
3931 -------------------------------------------------------------------------------
3937 Eliminate those annoying pop-up windows (deprecated)
3941 While loading the document, replace JavaScript code that opens pop-up
3942 windows with (syntactically neutral) dummy code on the fly.
3954 This action is basically a built-in, hardwired special-purpose filter
3955 action, but there are important differences: For kill-popups, the document
3956 need not be buffered, so it can be incrementally rendered while
3957 downloading. But kill-popups doesn't catch as many pop-ups as filter
3958 {all-popups} does and is not as smart as filter{unsolicited-popups} is.
3960 Think of it as a fast and efficient replacement for a filter that you can
3961 use if you don't want any filtering at all. Note that it doesn't make sense
3962 to combine it with any filter action, since as soon as one filter applies,
3963 the whole document needs to be buffered anyway, which destroys the
3964 advantage of the kill-popups action over its filter equivalent.
3966 Killing all pop-ups unconditionally is problematic. Many shops and banks
3967 rely on pop-ups to display forms, shopping carts etc, and the filter
3968 {unsolicited-popups} does a better job of catching only the unwanted ones.
3970 If the only kind of pop-ups that you want to kill are exit consoles (those
3971 really nasty windows that appear when you close an other one), you might
3972 want to use filter{js-annoyances} instead.
3974 This action is most appropriate for browsers that don't have any controls
3975 for unwanted pop-ups. Not recommended for general usage.
3981 -------------------------------------------------------------------------------
3983 8.5.27. limit-connect
3987 Prevent abuse of Privoxy as a TCP proxy relay or disable SSL for untrusted
3992 Specifies to which ports HTTP CONNECT requests are allowable.
4000 A comma-separated list of ports or port ranges (the latter using dashes,
4001 with the minimum defaulting to 0 and the maximum to 65K).
4005 By default, i.e. if no limit-connect action applies, Privoxy only allows
4006 HTTP CONNECT requests to port 443 (the standard, secure HTTPS port). Use
4007 limit-connect if more fine-grained control is desired for some or all
4010 The CONNECT methods exists in HTTP to allow access to secure websites
4011 ("https://" URLs) through proxies. It works very simply: the proxy connects
4012 to the server on the specified port, and then short-circuits its
4013 connections to the client and to the remote server. This can be a big
4014 security hole, since CONNECT-enabled proxies can be abused as TCP relays
4017 Privoxy relays HTTPS traffic without seeing the decoded content. Websites
4018 can leverage this limitation to circumvent Privoxy's filters. By specifying
4019 an invalid port range you can disable HTTPS entirely. If you plan to
4020 disable SSL by default, consider enabling
4021 treat-forbidden-connects-like-blocks as well, to be able to quickly create
4026 +limit-connect{443} # This is the default and need not be specified.
4027 +limit-connect{80,443} # Ports 80 and 443 are OK.
4028 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4029 +limit-connect{-} # All ports are OK
4030 +limit-connect{,} # No HTTPS/SSL traffic is allowed
4032 -------------------------------------------------------------------------------
4034 8.5.28. prevent-compression
4038 Ensure that servers send the content uncompressed, so it can be passed
4043 Removes the Accept-Encoding header which can be used to ask for compressed
4056 More and more websites send their content compressed by default, which is
4057 generally a good idea and saves bandwidth. But for the filter,
4058 deanimate-gifs and kill-popups actions to work, Privoxy needs access to the
4059 uncompressed data. Unfortunately, Privoxy can't yet(!) uncompress, filter,
4060 and re-compress the content on the fly. So if you want to ensure that all
4061 websites, including those that normally compress, can be filtered, you need
4064 This will slow down transfers from those websites, though. If you use any
4065 of the above-mentioned actions, you will typically want to use
4066 prevent-compression in conjunction with them.
4068 Note that some (rare) ill-configured sites don't handle requests for
4069 uncompressed documents correctly (they send an empty document body). If you
4070 use prevent-compression per default, you'll have to add exceptions for
4071 those sites. See the example for how to do that.
4073 Example usage (sections):
4075 # Selectively turn off compression, and enable a filter
4077 { +filter{tiny-textforms} +prevent-compression }
4078 # Match only these sites
4083 # Or instead, we could set a universal default:
4085 { +prevent-compression }
4088 # Then maybe make exceptions for ill-behaved sites:
4090 { -prevent-compression }
4092 www.pclinuxonline.com
4094 -------------------------------------------------------------------------------
4096 8.5.29. overwrite-last-modified
4100 Prevent yet another way to track the user's steps between sessions.
4104 Deletes the "Last-Modified:" HTTP server header or modifies its value.
4112 One of the keywords: "block", "reset-to-request-time" and "randomize"
4116 Removing the "Last-Modified:" header is useful for filter testing, where
4117 you want to force a real reload instead of getting status code "304", which
4118 would cause the browser to reuse the old version of the page.
4120 The "randomize" option overwrites the value of the "Last-Modified:" header
4121 with a randomly chosen time between the original value and the current
4122 time. In theory the server could send each document with a different
4123 "Last-Modified:" header to track visits without using cookies. "Randomize"
4124 makes it impossible and the browser can still revalidate cached documents.
4126 "reset-to-request-time" overwrites the value of the "Last-Modified:" header
4127 with the current time. You could use this option together with
4128 hided-if-modified-since to further customize your random range.
4130 The preferred parameter here is "randomize". It is safe to use, as long as
4131 the time settings are more or less correct. If the server sets the
4132 "Last-Modified:" header to the time of the request, the random range
4133 becomes zero and the value stays the same. Therefore you should later
4134 randomize it a second time with hided-if-modified-since, just to be sure.
4136 It is also recommended to use this action together with
4137 crunch-if-none-match.
4141 # Let the browser revalidate without being tracked across sessions
4142 { +hide-if-modified-since{-60} \
4143 +overwrite-last-modified{randomize} \
4144 +crunch-if-none-match}
4147 -------------------------------------------------------------------------------
4153 Redirect requests to other sites.
4157 Convinces the browser that the requested document has been moved to another
4158 location and the browser should get it from there.
4170 This action is useful to replace whole documents with ones of your
4171 choosing. This can be used to enforce safe surfing, or just as a simple
4174 You can do the same by combining the actions block, handle-as-image and
4175 set-image-blocker{URL}. It doesn't sound right for non-image documents, and
4176 that's why this action was created.
4178 This action will be ignored if you use it together with block.
4182 # Replace example.com's style sheet with another one
4183 { +redirect{http://localhost/css-replacements/example.com.css} }
4184 example.com/stylesheet.css
4186 # Create a short, easy to remember nickname for a favorite site
4187 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
4190 -------------------------------------------------------------------------------
4192 8.5.31. send-vanilla-wafer
4196 Feed log analysis scripts with useless data.
4200 Sends a cookie with each request stating that you do not accept any
4201 copyright on cookies sent to you, and asking the site operator not to track
4214 The vanilla wafer is a (relatively) unique header and could conceivably be
4217 This action is rarely used and not enabled in the default configuration.
4223 -------------------------------------------------------------------------------
4229 Send custom cookies or feed log analysis scripts with even more useless
4234 Sends a custom, user-defined cookie with each request.
4242 A string of the form "name=value".
4246 Being multi-valued, multiple instances of this action can apply to the same
4247 request, resulting in multiple cookies being sent.
4249 This action is rarely used and not enabled in the default configuration.
4251 Example usage (section):
4253 {+send-wafer{UsingPrivoxy=true}}
4254 my-internal-testing-server.void
4256 -------------------------------------------------------------------------------
4258 8.5.33. session-cookies-only
4262 Allow only temporary "session" cookies (for the current browser session
4267 Deletes the "expires" field from "Set-Cookie:" server headers. Most
4268 browsers will not store such cookies permanently and forget them in between
4281 This is less strict than crunch-incoming-cookies / crunch-outgoing-cookies
4282 and allows you to browse websites that insist or rely on setting cookies,
4283 without compromising your privacy too badly.
4285 Most browsers will not permanently store cookies that have been processed
4286 by session-cookies-only and will forget about them between sessions. This
4287 makes profiling cookies useless, but won't break sites which require
4288 cookies so that you can log in for transactions. This is generally turned
4289 on for all sites, and is the recommended setting.
4291 It makes no sense at all to use session-cookies-only together with
4292 crunch-incoming-cookies or crunch-outgoing-cookies. If you do, cookies will
4295 Note that it is up to the browser how it handles such cookies without an
4296 "expires" field. If you use an exotic browser, you might want to try it out
4299 This setting also has no effect on cookies that may have been stored
4300 previously by the browser before starting Privoxy. These would have to be
4303 Privoxy also uses the content-cookies filter to block some types of
4304 cookies. Content cookies are not effected by session-cookies-only.
4308 +session-cookies-only
4310 -------------------------------------------------------------------------------
4312 8.5.34. set-image-blocker
4316 Choose the replacement for blocked images
4320 This action alone doesn't do anything noticeable. If both block and
4321 handle-as-image also apply, i.e. if the request is to be blocked as an
4322 image, then the parameter of this action decides what will be sent as a
4331 + "pattern" to send a built-in checkerboard pattern image. The image is
4332 visually decent, scales very well, and makes it obvious where banners
4335 + "blank" to send a built-in transparent image. This makes banners
4336 disappear completely, but makes it hard to detect where Privoxy has
4337 blocked images on a given page and complicates troubleshooting if
4338 Privoxy has blocked innocent images, like navigation icons.
4340 + "target-url" to send a redirect to target-url. You can redirect to any
4341 image anywhere, even in your local filesystem via "file:///" URL. (But
4342 note that not all browsers support redirecting to a local file system).
4344 A good application of redirects is to use special Privoxy-built-in
4345 URLs, which send the built-in images, as target-url. This has the same
4346 visual effect as specifying "blank" or "pattern" in the first place,
4347 but enables your browser to cache the replacement image, instead of
4348 requesting it over and over again.
4352 The URLs for the built-in images are "http://config.privoxy.org/
4353 send-banner?type=type", where type is either "blank" or "pattern".
4355 There is a third (advanced) type, called "auto". It is NOT to be used in
4356 set-image-blocker, but meant for use from filters. Auto will select the
4357 type of image that would have applied to the referring page, had it been an
4364 +set-image-blocker{pattern}
4366 Redirect to the BSD devil:
4368 +set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}
4370 Redirect to the built-in pattern for better caching:
4372 +set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}
4374 -------------------------------------------------------------------------------
4376 8.5.35. treat-forbidden-connects-like-blocks
4380 Block forbidden connects with an easy to find error message.
4384 If this action is enabled, Privoxy no longer makes a difference between
4385 forbidden connects and ordinary blocks.
4397 By default Privoxy answers forbidden "Connect" requests with a short error
4398 message inside the headers. If the browser doesn't display headers (most
4399 don't), you just see an empty page.
4401 With this action enabled, Privoxy displays the message that is used for
4402 ordinary blocks instead. If you decide to make an exception for the page in
4403 question, you can do so by following the "See why" link.
4405 For "Connect" requests the clients tell Privoxy which host they are
4406 interested in, but not which document they plan to get later. As a result,
4407 the "Go there anyway" link becomes rather useless: it lets the client
4408 request the home page of the forbidden host through unencrypted HTTP, still
4409 using the port of the last request.
4411 If you previously configured Privoxy to do the request through a SSL
4412 tunnel, everything will work. Most likely you haven't and the server will
4413 respond with an error message because it is expecting HTTPS (SSL).
4417 +treat-forbidden-connects-like-blocks
4419 -------------------------------------------------------------------------------
4423 Note that many of these actions have the potential to cause a page to
4424 misbehave, possibly even not to display at all. There are many ways a site
4425 designer may choose to design his site, and what HTTP header content, and other
4426 criteria, he may depend on. There is no way to have hard and fast rules for all
4427 sites. See the Appendix for a brief example on troubleshooting actions.
4429 -------------------------------------------------------------------------------
4433 Custom "actions", known to Privoxy as "aliases", can be defined by combining
4434 other actions. These can in turn be invoked just like the built-in actions.
4435 Currently, an alias name can contain any character except space, tab, "=", "{"
4436 and "}", but we strongly recommend that you only use "a" to "z", "0" to "9",
4437 "+", and "-". Alias names are not case sensitive, and are not required to start
4438 with a "+" or "-" sign, since they are merely textually expanded.
4440 Aliases can be used throughout the actions file, but they must be defined in a
4441 special section at the top of the file! And there can only be one such section
4442 per actions file. Each actions file may have its own alias section, and the
4443 aliases defined in it are only visible within that file.
4445 There are two main reasons to use aliases: One is to save typing for frequently
4446 used combinations of actions, the other one is a gain in flexibility: If you
4447 decide once how you want to handle shops by defining an alias called "shop",
4448 you can later change your policy on shops in one place, and your changes will
4449 take effect everywhere in the actions file where the "shop" alias is used.
4450 Calling aliases by their purpose also makes your actions files more readable.
4452 Currently, there is one big drawback to using aliases, though: Privoxy's
4453 built-in web-based action file editor honors aliases when reading the actions
4454 files, but it expands them before writing. So the effects of your aliases are
4455 of course preserved, but the aliases themselves are lost when you edit sections
4456 that use aliases with it.
4458 Now let's define some aliases...
4460 # Useful custom aliases we can use later.
4462 # Note the (required!) section header line and that this section
4463 # must be at the top of the actions file!
4467 # These aliases just save typing later:
4468 # (Note that some already use other aliases!)
4470 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
4471 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
4472 +block-as-image = +block +handle-as-image
4473 allow-all-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
4475 # These aliases define combinations of actions
4476 # that are useful for certain types of sites:
4478 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups -prevent-compression
4480 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
4482 # Short names for other aliases, for really lazy people ;-)
4484 c0 = +crunch-all-cookies
4485 c1 = -crunch-all-cookies
4487 ...and put them to use. These sections would appear in the lower part of an
4488 actions file and define exceptions to the default actions (as specified further
4489 up for the "/" pattern):
4491 # These sites are either very complex or very keen on
4492 # user data and require minimal interference to work:
4495 .office.microsoft.com
4496 .windowsupdate.microsoft.com
4497 # Gmail is really mail.google.com, not gmail.com
4501 # Allow cookies (for setting and retrieving your customer data)
4505 .worldpay.com # for quietpc.com
4508 # These shops require pop-ups:
4510 {-kill-popups -filter{all-popups} -filter{unsolicited-popups}}
4514 Aliases like "shop" and "fragile" are typically used for "problem" sites that
4515 require more than one action to be disabled in order to function properly.
4517 -------------------------------------------------------------------------------
4519 8.7. Actions Files Tutorial
4521 The above chapters have shown which actions files there are and how they are
4522 organized, how actions are specified and applied to URLs, how patterns work,
4523 and how to define and use aliases. Now, let's look at an example default.action
4524 and user.action file and see how all these pieces come together:
4526 -------------------------------------------------------------------------------
4528 8.7.1. default.action
4530 Every config file should start with a short comment stating its purpose:
4532 # Sample default.action file <ijbswa-developers@lists.sourceforge.net>
4534 Then, since this is the default.action file, the first section is a special
4535 section for internal use that you needn't change or worry about:
4537 ##########################################################################
4538 # Settings -- Don't change! For internal Privoxy use ONLY.
4539 ##########################################################################
4542 for-privoxy-version=3.0
4544 After that comes the (optional) alias section. We'll use the example section
4545 from the above chapter on aliases, that also explains why and how aliases are
4548 ##########################################################################
4550 ##########################################################################
4553 # These aliases just save typing later:
4554 # (Note that some already use other aliases!)
4556 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
4557 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
4558 +block-as-image = +block +handle-as-image
4559 mercy-for-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
4561 # These aliases define combinations of actions
4562 # that are useful for certain types of sites:
4564 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups
4565 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
4567 Now come the regular sections, i.e. sets of actions, accompanied by URL
4568 patterns to which they apply. Remember all actions are disabled when matching
4569 starts, so we have to explicitly enable the ones we want.
4571 The first regular section is probably the most important. It has only one
4572 pattern, "/", but this pattern matches all URLs. Therefore, the set of actions
4573 used in this "default" section will be applied to all requests as a start. It
4574 can be partly or wholly overridden by later matches further down this file, or
4575 in user.action, but it will still be largely responsible for your overall
4576 browsing experience.
4578 Again, at the start of matching, all actions are disabled, so there is no real
4579 need to disable any actions here, but we will do that nonetheless, to have a
4580 complete listing for your reference. (Remember: a "+" preceding the action name
4581 enables the action, a "-" disables!). Also note how this long line has been
4582 made more readable by splitting it into multiple lines with line continuation.
4584 ##########################################################################
4585 # "Defaults" section:
4586 ##########################################################################
4590 -content-type-overwrite \
4591 -crunch-client-header \
4592 -crunch-if-none-match \
4593 -crunch-incoming-cookies \
4594 -crunch-server-header \
4595 -crunch-outgoing-cookies \
4597 -downgrade-http-version \
4598 -fast-redirects{check-decoded-url} \
4599 -filter{js-annoyances} \
4600 -filter{js-events} \
4601 +filter{html-annoyances} \
4602 -filter{content-cookies} \
4603 +filter{refresh-tags} \
4604 -filter{unsolicited-popups} \
4605 -filter{all-popups} \
4606 -filter{img-reorder} \
4607 -filter{banners-by-size} \
4608 -filter{banners-by-link} \
4610 -filter{tiny-textforms} \
4611 -filter{jumping-windows} \
4612 -filter{frameset-borders} \
4613 -filter{demoronizer} \
4614 -filter{shockwave-flash} \
4615 -filter{quicktime-kioskmode} \
4617 -filter{crude-parental} \
4618 +filter{ie-exploits} \
4619 -filter-client-headers \
4620 -filter-server-headers \
4625 -filter-xml-to-html \
4626 -filter-html-to-xml \
4628 -filter-hide-tor-exit-notation \
4630 -handle-as-empty-document \
4632 -hide-accept-language \
4633 -hide-content-disposition \
4634 -hide-if-modified-since \
4635 +hide-forwarded-for-headers \
4636 +hide-from-header{block} \
4637 +hide-referrer{forge} \
4642 +prevent-compression \
4643 -overwrite-last-modified \
4645 -send-vanilla-wafer \
4647 +session-cookies-only \
4648 +set-image-blocker{pattern} \
4649 -treat-forbidden-connects-like-blocks \
4651 / # forward slash will match *all* potential URL patterns.
4653 The default behavior is now set. Note that some actions, like not hiding the
4654 user agent, are part of a "general policy" that applies universally and won't
4655 get any exceptions defined later. Other choices, like not blocking (which is
4656 understandably the default!) need exceptions, i.e. we need to specify
4657 explicitly what we want to block in later sections.
4659 The first of our specialized sections is concerned with "fragile" sites, i.e.
4660 sites that require minimum interference, because they are either very complex
4661 or very keen on tracking you (and have mechanisms in place that make them
4662 unusable for people who avoid being tracked). We will simply use our
4663 pre-defined fragile alias instead of stating the list of actions explicitly:
4665 ##########################################################################
4666 # Exceptions for sites that'll break under the default action set:
4667 ##########################################################################
4669 # "Fragile" Use a minimum set of actions for these sites (see alias above):
4672 .office.microsoft.com # surprise, surprise!
4673 .windowsupdate.microsoft.com
4676 Shopping sites are not as fragile, but they typically require cookies to log
4677 in, and pop-up windows for shopping carts or item details. Again, we'll use a
4684 .worldpay.com # for quietpc.com
4688 The fast-redirects action, which we enabled per default above, breaks some
4689 sites. So disable it for popular sites where we know it misbehaves:
4695 .altavista.com/.*(like|url|link):http
4696 .altavista.com/trans.*urltext=http
4699 It is important that Privoxy knows which URLs belong to images, so that if they
4700 are to be blocked, a substitute image can be sent, rather than an HTML page.
4701 Contacting the remote site to find out is not an option, since it would destroy
4702 the loading time advantage of banner blocking, and it would feed the
4703 advertisers (in terms of money and information). We can mark any URL as an
4704 image with the handle-as-image action, and marking all URLs that end in a known
4705 image file extension is a good start:
4707 ##########################################################################
4709 ##########################################################################
4711 # Define which file types will be treated as images, in case they get
4712 # blocked further down this file:
4714 { +handle-as-image }
4715 /.*\.(gif|jpe?g|png|bmp|ico)$
4717 And then there are known banner sources. They often use scripts to generate the
4718 banners, so it won't be visible from the URL that the request is for an image.
4719 Hence we block them and mark them as images in one go, with the help of our
4720 +block-as-image alias defined above. (We could of course just as well use +
4721 block +handle-as-image here.) Remember that the type of the replacement image
4722 is chosen by the set-image-blocker action. Since all URLs have matched the
4723 default section with its +set-image-blocker{pattern} action before, it still
4724 applies and needn't be repeated:
4726 # Known ad generators:
4731 .ad.*.doubleclick.net
4732 .a.yimg.com/(?:(?!/i/).)*$
4733 .a[0-9].yimg.com/(?:(?!/i/).)*$
4737 One of the most important jobs of Privoxy is to block banners. Many of these
4738 can be "blocked" by the filter{banners-by-size} action, which we enabled above,
4739 and which deletes the references to banner images from the pages while they are
4740 loaded, so the browser doesn't request them anymore, and hence they don't need
4741 to be blocked here. But this naturally doesn't catch all banners, and some
4742 people choose not to use filters, so we need a comprehensive list of patterns
4743 for banner URLs here, and apply the block action to them.
4745 First comes many generic patterns, which do most of the work, by matching
4746 typical domain and path name components of banners. Then comes a list of
4747 individual patterns for specific sites, which is omitted here to keep the
4750 ##########################################################################
4751 # Block these fine banners:
4752 ##########################################################################
4761 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
4762 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
4764 # Site-specific patterns (abbreviated):
4768 It's quite remarkable how many advertisers actually call their banner servers
4769 ads.company.com, or call the directory in which the banners are stored simply
4770 "banners". So the above generic patterns are surprisingly effective.
4772 But being very generic, they necessarily also catch URLs that we don't want to
4773 block. The pattern .*ads. e.g. catches "nasty-ads.nasty-corp.com" as intended,
4774 but also "downloads.sourcefroge.net" or "adsl.some-provider.net." So here come
4775 some well-known exceptions to the +block section above.
4777 Note that these are exceptions to exceptions from the default! Consider the URL
4778 "downloads.sourcefroge.net": Initially, all actions are deactivated, so it
4779 wouldn't get blocked. Then comes the defaults section, which matches the URL,
4780 but just deactivates the block action once again. Then it matches .*ads., an
4781 exception to the general non-blocking policy, and suddenly +block applies. And
4782 now, it'll match .*loads., where -block applies, so (unless it matches again
4783 further down) it ends up with no block action applying.
4785 ##########################################################################
4786 # Save some innocent victims of the above generic block patterns:
4787 ##########################################################################
4792 adv[io]*. # (for advogato.org and advice.*)
4793 adsl. # (has nothing to do with ads)
4794 adobe. # (has nothing to do with ads either)
4795 ad[ud]*. # (adult.* and add.*)
4796 .edu # (universities don't host banners (yet!))
4797 .*loads. # (downloads, uploads etc)
4805 www.globalintersec.com/adv # (adv = advanced)
4806 www.ugu.com/sui/ugu/adv
4808 Filtering source code can have nasty side effects, so make an exception for our
4809 friends at sourceforge.net, and all paths with "cvs" in them. Note that -filter
4810 disables all filters in one fell swoop!
4812 # Don't filter code!
4821 The actual default.action is of course much more comprehensive, but we hope
4822 this example made clear how it works.
4824 -------------------------------------------------------------------------------
4828 So far we are painting with a broad brush by setting general policies, which
4829 would be a reasonable starting point for many people. Now, you might want to be
4830 more specific and have customized rules that are more suitable to your personal
4831 habits and preferences. These would be for narrowly defined situations like
4832 your ISP or your bank, and should be placed in user.action, which is parsed
4833 after all other actions files and hence has the last word, over-riding any
4834 previously defined actions. user.action is also a safe place for your personal
4835 settings, since default.action is actively maintained by the Privoxy developers
4836 and you'll probably want to install updated versions from time to time.
4838 So let's look at a few examples of things that one might typically do in
4841 # My user.action file. <fred@foobar.com>
4843 As aliases are local to the actions file that they are defined in, you can't
4844 use the ones from default.action, unless you repeat them here:
4846 # Aliases are local to the file they are defined in.
4847 # (Re-)define aliases for this file:
4851 # These aliases just save typing later, and the alias names should
4852 # be self explanatory.
4854 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
4855 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
4856 allow-all-cookies = -crunch-all-cookies -session-cookies-only
4857 allow-popups = -filter{all-popups} -kill-popups
4858 +block-as-image = +block +handle-as-image
4859 -block-as-image = -block
4861 # These aliases define combinations of actions that are useful for
4862 # certain types of sites:
4864 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer -kill-popups
4865 shop = -crunch-all-cookies allow-popups
4867 # Allow ads for selected useful free sites:
4869 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
4871 # Alias for specific file types that are text, but might have conflicting
4872 # MIME types. We want the browser to force these to be text documents.
4873 handle-as-text = -filter +-content-type-overwrite{text/plain} +-force-text-mode -hide-content-disposition
4877 Say you have accounts on some sites that you visit regularly, and you don't
4878 want to have to log in manually each time. So you'd like to allow persistent
4879 cookies for these sites. The allow-all-cookies alias defined above does exactly
4880 that, i.e. it disables crunching of cookies in any direction, and the
4881 processing of cookies to make them only temporary.
4883 { allow-all-cookies }
4889 Your bank is allergic to some filter, but you don't know which, so you disable
4893 .your-home-banking-site.com
4895 Some file types you may not want to filter for various reasons:
4897 # Technical documentation is likely to contain strings that might
4898 # erroneously get altered by the JavaScript-oriented filters:
4903 # And this stupid host sends streaming video with a wrong MIME type,
4904 # so that Privoxy thinks it is getting HTML and starts filtering:
4906 stupid-server.example.com/
4908 Example of a simple block action. Say you've seen an ad on your favourite page
4909 on example.com that you want to get rid of. You have right-clicked the image,
4910 selected "copy image location" and pasted the URL below while removing the
4911 leading http://, into a { +block } section. Note that { +handle-as-image } need
4912 not be specified, since all URLs ending in .gif will be tagged as images by the
4913 general rules as set in default.action anyway:
4916 www.example.com/nasty-ads/sponsor.gif
4917 another.popular.site.net/more/junk/here/
4919 The URLs of dynamically generated banners, especially from large banner farms,
4920 often don't use the well-known image file name extensions, which makes it
4921 impossible for Privoxy to guess the file type just by looking at the URL. You
4922 can use the +block-as-image alias defined above for these cases. Note that
4923 objects which match this rule but then turn out NOT to be an image are
4924 typically rendered as a "broken image" icon by the browser. Use cautiously.
4932 Now you noticed that the default configuration breaks Forbes Magazine, but you
4933 were too lazy to find out which action is the culprit, and you were again too
4934 lazy to give feedback, so you just used the fragile alias on the site, and --
4935 whoa! -- it worked. The fragile aliases disables those actions that are most
4936 likely to break a site. Also, good for testing purposes to see if it is Privoxy
4937 that is causing the problem or not. We later find other regular sites that
4938 misbehave, and add those to our personalized list of troublemakers:
4945 You like the "fun" text replacements in default.filter, but it is disabled in
4946 the distributed actions file. (My colleagues on the team just don't have a
4947 sense of humour, that's why! ;-). So you'd like to turn it on in your private,
4948 update-safe config, once and for all:
4953 Note that the above is not really a good idea: There are exceptions to the
4954 filters in default.action for things that really shouldn't be filtered, like
4955 code on CVS->Web interfaces. Since user.action has the last word, these
4956 exceptions won't be valid for the "fun" filtering specified here.
4958 You might also worry about how your favourite free websites are funded, and
4959 find that they rely on displaying banner advertisements to survive. So you
4960 might want to specifically allow banners for those sites that you feel provide
4968 Note that allow-ads has been aliased to -block, -filter{banners-by-size}, and -
4969 filter{banners-by-link} above.
4971 Invoke another alias here to force an over-ride of the MIME type application/
4972 x-sh which typically would open a download type dialog. In my case, I want to
4973 look at the shell script, and then I can save it should I choose to.
4978 user.action is generally the best place to define exceptions and additions to
4979 the default policies of default.action. Some actions are safe to have their
4980 default policies set here though. So let's set a default policy to have a
4981 "blank" image as opposed to the checkerboard pattern for ALL sites. "/" of
4982 course matches all URL paths and patterns:
4984 { +set-image-blocker{blank} }
4987 -------------------------------------------------------------------------------
4991 On-the-fly text substitutions that can be invoked through the filter action
4992 need to be defined in a "filter file". Once defined, they can then be invoked
4993 as an "action". Multiple filter files can be defined through the filterfile
4994 config directive. The filters as supplied by the developers will be found in
4995 default.filter. It is recommended that any locally defined or modified filters
4996 go in a separately defined file such as user.filter.
4998 Typical reasons for doing these kinds of substitutions are to eliminate common
4999 annoyances in HTML and JavaScript, such as pop-up windows, exit consoles,
5000 crippled windows without navigation tools, the infamous <BLINK> tag etc, to
5001 suppress images with certain width and height attributes (standard banner sizes
5002 or web-bugs), or just to have fun. The possibilities are endless.
5004 Filtering works on any text-based document type, including HTML, JavaScript,
5005 CSS etc. (all text/* MIME types, except text/plain). Substitutions are made at
5006 the source level, so if you want to "roll your own" filters, you should first
5007 be familiar with HTML syntax, and, of course, regular expressions. By default,
5008 filters are only applied to the raw document content, but can be extended to
5009 the HTTP headers with the supplemental actions: filter-client-headers and
5010 filter-server-headers.
5012 Just like the actions files, the filter file is organized in sections, which
5013 are called filters here. Each filter consists of a heading line, that starts
5014 with the keyword FILTER:, followed by the filter's name, and a short (one line)
5015 description of what it does. Below that line come the jobs, i.e. lines that
5016 define the actual text substitutions. By convention, the name of a filter
5017 should describe what the filter eliminates. The comment is used in the
5018 web-based user interface.
5020 Once a filter called name has been defined in the filter file, it can be
5021 invoked by using an action of the form +filter{name} in any actions file.
5023 A filter header line for a filter called "foo" could look like this:
5025 FILTER: foo Replace all "foo" with "bar"
5027 Below that line, and up to the next header line, come the jobs that define what
5028 text replacements the filter executes. They are specified in a syntax that
5029 imitates Perl's s/// operator. If you are familiar with Perl, you will find
5030 this to be quite intuitive, and may want to look at the PCRS documentation for
5031 the subtle differences to Perl behaviour. Most notably, the non-standard option
5032 letter U is supported, which turns the default to ungreedy matching.
5034 If you are new to "Regular Expressions", you might want to take a look at the
5035 Appendix on regular expressions, and see the Perl manual for the s///
5036 operator's syntax and Perl-style regular expressions in general. The below
5037 examples might also help to get you started.
5039 -------------------------------------------------------------------------------
5041 9.1. Filter File Tutorial
5043 Now, let's complete our "foo" filter. We have already defined the heading, but
5044 the jobs are still missing. Since all it does is to replace "foo" with "bar",
5045 there is only one (trivial) job needed:
5049 But wait! Didn't the comment say that all occurrences of "foo" should be
5050 replaced? Our current job will only take care of the first "foo" on each page.
5051 For global substitution, we'll need to add the g option:
5055 Our complete filter now looks like this:
5057 FILTER: foo Replace all "foo" with "bar"
5060 Let's look at some real filters for more interesting examples. Here you see a
5061 filter that protects against some common annoyances that arise from JavaScript
5062 abuse. Let's look at its jobs one after the other:
5064 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
5066 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
5068 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg
5070 Following the header line and a comment, you see the job. Note that it uses |
5071 as the delimiter instead of /, because the pattern contains a forward slash,
5072 which would otherwise have to be escaped by a backslash (\).
5074 Now, let's examine the pattern: it starts with the text <script.* enclosed in
5075 parentheses. Since the dot matches any character, and * means: "Match an
5076 arbitrary number of the element left of myself", this matches "<script",
5077 followed by any text, i.e. it matches the whole page, from the start of the
5080 That's more than we want, but the pattern continues: document\.referrer matches
5081 only the exact string "document.referrer". The dot needed to be escaped, i.e.
5082 preceded by a backslash, to take away its special meaning as a joker, and make
5083 it just a regular dot. So far, the meaning is: Match from the start of the
5084 first <script> tag in a the page, up to, and including, the text
5085 "document.referrer", if both are present in the page (and appear in that
5088 But there's still more pattern to go. The next element, again enclosed in
5089 parentheses, is .*</script>. You already know what .* means, so the whole
5090 pattern translates to: Match from the start of the first <script> tag in a page
5091 to the end of the last <script> tag, provided that the text "document.referrer"
5092 appears somewhere in between.
5094 This is still not the whole story, since we have ignored the options and the
5095 parentheses: The portions of the page matched by sub-patterns that are enclosed
5096 in parentheses, will be remembered and be available through the variables $1,
5097 $2, ... in the substitute. The U option switches to ungreedy matching, which
5098 means that the first .* in the pattern will only "eat up" all text in between "
5099 <script" and the first occurrence of "document.referrer", and that the second .
5100 * will only span the text up to the first "</script>" tag. Furthermore, the s
5101 option says that the match may span multiple lines in the page, and the g
5102 option again means that the substitution is global.
5104 So, to summarize, the pattern means: Match all scripts that contain the text
5105 "document.referrer". Remember the parts of the script from (and including) the
5106 start tag up to (and excluding) the string "document.referrer" as $1, and the
5107 part following that string, up to and including the closing tag, as $2.
5109 Now the pattern is deciphered, but wasn't this about substituting things? So
5110 lets look at the substitute: $1"Not Your Business!"$2 is easy to read: The text
5111 remembered as $1, followed by "Not Your Business!" (including the quotation
5112 marks!), followed by the text remembered as $2. This produces an exact copy of
5113 the original string, with the middle part (the "document.referrer") replaced by
5114 "Not Your Business!".
5116 The whole job now reads: Replace "document.referrer" by "Not Your Business!"
5117 wherever it appears inside a <script> tag. Note that this job won't break
5118 JavaScript syntax, since both the original and the replacement are
5119 syntactically valid string objects. The script just won't have access to the
5120 referrer information anymore.
5122 We'll show you two other jobs from the JavaScript taming department, but this
5123 time only point out the constructs of special interest:
5125 # The status bar is for displaying link targets, not pointless blahblah
5127 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig
5129 \s stands for whitespace characters (space, tab, newline, carriage return, form
5130 feed), so that \s* means: "zero or more whitespace". The ? in .*? makes this
5131 matching of arbitrary text ungreedy. (Note that the U option is not set). The
5132 ['"] construct means: "a single or a double quote". Finally, \1 is a
5133 back-reference to the first parenthesis just like $1 above, with the difference
5134 that in the pattern, a backslash indicates a back-reference, whereas in the
5135 substitute, it's the dollar.
5137 So what does this job do? It replaces assignments of single- or double-quoted
5138 strings to the "window.status" object with a dummy assignment (using a variable
5139 name that is hopefully odd enough not to conflict with real variables in
5140 scripts). Thus, it catches many cases where e.g. pointless descriptions are
5141 displayed in the status bar instead of the link target when you move your mouse
5144 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
5146 s/(<body [^>]*)onunload(.*>)/$1never$2/iU
5148 Including the OnUnload event binding in the HTML DOM was a CRIME. When I close
5149 a browser window, I want it to close and die. Basta. This job replaces the
5150 "onunload" attribute in "<body>" tags with the dummy word never. Note that the
5151 i option makes the pattern matching case-insensitive. Also note that ungreedy
5152 matching alone doesn't always guarantee a minimal match: In the first
5153 parenthesis, we had to use [^>]* instead of .* to prevent the match from
5154 exceeding the <body> tag if it doesn't contain "OnUnload", but the page's
5157 The last example is from the fun department:
5159 FILTER: fun Fun text replacements
5161 # Spice the daily news:
5163 s/microsoft(?!\.com)/MicroSuck/ig
5165 Note the (?!\.com) part (a so-called negative lookahead) in the job's pattern,
5166 which means: Don't match, if the string ".com" appears directly following
5167 "microsoft" in the page. This prevents links to microsoft.com from being
5168 trashed, while still replacing the word everywhere else.
5170 # Buzzword Bingo (example for extended regex syntax)
5172 s* industry[ -]leading \
5174 | customer[ -]focused \
5175 | market[ -]driven \
5176 | award[ -]winning # Comments are OK, too! \
5177 | high[ -]performance \
5178 | solutions[ -]based \
5182 *<font color="red"><b>BINGO!</b></font> \
5185 The x option in this job turns on extended syntax, and allows for e.g. the
5186 liberal use of (non-interpreted!) whitespace for nicer formatting.
5190 -------------------------------------------------------------------------------
5192 9.2. The Pre-defined Filters
5194 The distribution default.filter file contains a selection of pre-defined
5195 filters for your convenience:
5199 The purpose of this filter is to get rid of particularly annoying
5200 JavaScript abuse. To that end, it
5202 + replaces JavaScript references to the browser's referrer information
5203 with the string "Not Your Business!". This compliments the
5204 hide-referrer action on the content level.
5206 + removes the bindings to the DOM's unload event which we feel has no
5207 right to exist and is responsible for most "exit consoles", i.e. nasty
5208 windows that pop up when you close another one.
5210 + removes code that causes new windows to be opened with undesired
5211 properties, such as being full-screen, non-resizeable, without
5212 location, status or menu bar etc.
5214 Use with caution. This is an aggressive filter, and can break sites that
5215 rely heavily on JavaScript.
5219 This is a very radical measure. It removes virtually all JavaScript event
5220 bindings, which means that scripts can not react to user actions such as
5221 mouse movements or clicks, window resizing etc, anymore. Use with caution!
5223 We strongly discourage using this filter as a default since it breaks many
5224 legitimate scripts. It is meant for use only on extra-nasty sites (should
5225 you really need to go there).
5229 This filter will undo many common instances of HTML based abuse.
5231 The BLINK and MARQUEE tags are neutralized (yeah baby!), and browser
5232 windows will be created as resizeable (as of course they should be!), and
5233 will have location, scroll and menu bars -- even if specified otherwise.
5237 Most cookies are set in the HTTP dialog, where they can be intercepted by
5238 the crunch-incoming-cookies and crunch-outgoing-cookies actions. But web
5239 sites increasingly make use of HTML meta tags and JavaScript to sneak
5240 cookies to the browser on the content level.
5242 This filter disables most HTML and JavaScript code that reads or sets
5243 cookies. It cannot detect all clever uses of these types of code, so it
5244 should not be relied on as an absolute fix. Use it wherever you would also
5245 use the cookie crunch actions.
5249 Disable any refresh tags if the interval is greater than nine seconds (so
5250 that redirections done via refresh tags are not destroyed). This is useful
5251 for dial-on-demand setups, or for those who find this HTML feature
5256 This filter attempts to prevent only "unsolicited" pop-up windows from
5257 opening, yet still allow pop-up windows that the user has explicitly chosen
5258 to open. It was added in version 3.0.1, as an improvement over earlier such
5261 Technical note: The filter works by redefining the window.open JavaScript
5262 function to a dummy function, PrivoxyWindowOpen(), during the loading and
5263 rendering phase of each HTML page access, and restoring the function
5266 This is recommended only for browsers that cannot perform this function
5267 reliably themselves. And be aware that some sites require such windows in
5268 order to function normally. Use with caution.
5272 Attempt to prevent all pop-up windows from opening. Note this should be
5273 used with even more discretion than the above, since it is more likely to
5274 break some sites that require pop-ups for normal usage. Use with caution.
5278 This is a helper filter that has no value if used alone. It makes the
5279 banners-by-size and banners-by-link (see below) filters more effective and
5280 should be enabled together with them.
5284 This filter removes image tags purely based on what size they are.
5285 Fortunately for us, many ads and banner images tend to conform to certain
5286 standardized sizes, which makes this filter quite effective for ad
5289 Occasionally this filter will cause false positives on images that are not
5290 ads, but just happen to be of one of the standard banner sizes.
5292 Recommended only for those who require extreme ad blocking. The default
5293 block rules should catch 95+% of all ads without this filter enabled.
5297 This is an experimental filter that attempts to kill any banners if their
5298 URLs seem to point to known or suspected click trackers. It is currently
5299 not of much value and is not recommended for use by default.
5303 Webbugs are small, invisible images (technically 1X1 GIF images), that are
5304 used to track users across websites, and collect information on them. As an
5305 HTML page is loaded by the browser, an embedded image tag causes the
5306 browser to contact a third-party site, disclosing the tracking information
5307 through the requested URL and/or cookies for that third-party domain,
5308 without the user ever becoming aware of the interaction with the
5309 third-party site. HTML-ized spam also uses a similar technique to verify
5312 This filter removes the HTML code that loads such "webbugs".
5316 A rather special-purpose filter that can be used to enlarge textareas
5317 (those multi-line text boxes in web forms) and turn off hard word wrap in
5318 them. It was written for the sourceforge.net tracker system where such
5319 boxes are a nuisance, but it can be handy on other sites, too.
5321 It is not recommended to use this filter as a default.
5325 Many consider windows that move, or resize themselves to be abusive. This
5326 filter neutralizes the related JavaScript code. Note that some sites might
5327 not display or behave as intended when using this filter. Use with caution.
5331 Some web designers seem to assume that everyone in the world will view
5332 their web sites using the same browser brand and version, screen resolution
5333 etc, because only that assumption could explain why they'd use static frame
5334 sizes, yet prevent their frames from being resized by the user, should they
5335 be too small to show their whole content.
5337 This filter removes the related HTML code. It should only be applied to
5338 sites which need it.
5342 Many Microsoft products that generate HTML use non-standard extensions
5343 (read: violations) of the ISO 8859-1 aka Latin-1 character set. This can
5344 cause those HTML documents to display with errors on standard-compliant
5347 This filter translates the MS-only characters into Latin-1 equivalents. It
5348 is not necessary when using MS products, and will cause corruption of all
5349 documents that use 8-bit character sets other than Latin-1. It's mostly
5350 worthwhile for Europeans on non-MS platforms, if weird garbage characters
5351 sometimes appear on some pages, or user agents that don't correct for this
5356 A filter for shockwave haters. As the name suggests, this filter strips
5357 code out of web pages that is used to embed shockwave flash objects.
5361 Change HTML code that embeds Quicktime objects so that kioskmode, which
5362 prevents saving, is disabled.
5366 Text replacements for subversive browsing fun. Make fun of your favorite
5367 Monopolist or play buzzword bingo.
5371 A demonstration-only filter that shows how Privoxy can be used to delete
5372 web content on a keyword basis.
5376 An experimental collection of text replacements to disable malicious HTML
5377 and JavaScript code that exploits known security holes in Internet
5380 Presently, it only protects against Nimda and a cross-site scripting bug,
5381 and would need active maintenance to provide more substantial protection.
5385 Some web sites have very specific problems, the cure for which doesn't
5386 apply anywhere else, or could even cause damage on other sites.
5388 This is a collection of such site-specific cures which should only be
5389 applied to the sites they were intended for, which is what the supplied
5390 default.action file does. Users shouldn't need to change anything regarding
5395 A CSS based block for Google text ads. Also removes a width limitation and
5396 the toolbar advertisement.
5400 Another CSS based block, this time for Yahoo text ads. And removes a width
5405 Another CSS based block, this time for MSN text ads. And removes tracking
5406 URLs, as well as a width limitation.
5410 Cleans up some Blogspot blogs. Read the fine print before using this one!
5412 This filter also intentionally removes some navigation stuff and sets the
5413 page width to 100%. As a result, some rounded "corners" would appear to
5414 early or not at all and as fixing this would require a browser that
5415 understands background-size (CSS3), they are removed instead.
5419 Header filter to change the Content-Type from xml to html.
5423 Header filter to change the Content-Type from html to xml.
5427 Removes the non-standard ping attribute from anchor and area HTML tags.
5429 hide-tor-exit-notation
5431 Header filter to remove the Tor exit node notation found in Host and
5434 -------------------------------------------------------------------------------
5436 10. Privoxy's Template Files
5438 All Privoxy built-in pages, i.e. error pages such as the "404 - No Such Domain"
5439 error page, the "BLOCKED" page and all pages of its web-based user interface,
5440 are generated from templates. (Privoxy must be running for the above links to
5443 These templates are stored in a subdirectory of the configuration directory
5444 called templates. On Unixish platforms, this is typically /etc/privoxy/
5447 The templates are basically normal HTML files, but with place-holders (called
5448 symbols or exports), which Privoxy fills at run time. You can edit the
5449 templates with a normal text editor, should you want to customize them. (Not
5450 recommended for the casual user). Note that just like in configuration files,
5451 lines starting with # are ignored when the templates are filled in.
5453 The place-holders are of the form @name@, and you will find a list of available
5454 symbols, which vary from template to template, in the comments at the start of
5455 each file. Note that these comments are not always accurate, and that it's
5456 probably best to look at the existing HTML code to find out which symbols are
5457 supported and what they are filled in with.
5459 A special application of this substitution mechanism is to make whole blocks of
5460 HTML code disappear when a specific symbol is set. We use this for many
5461 purposes, one of them being to include the beta warning in all our user
5462 interface (CGI) pages when Privoxy is in an alpha or beta development stage:
5464 <!-- @if-unstable-start -->
5466 ... beta warning HTML code goes here ...
5468 <!-- if-unstable-end@ -->
5470 If the "unstable" symbol is set, everything in between and including
5471 @if-unstable-start and if-unstable-end@ will disappear, leaving nothing but an
5476 There's also an if-then-else construct and an #include mechanism, but you'll
5477 sure find out if you are inclined to edit the templates ;-)
5479 All templates refer to a style located at http://config.privoxy.org/
5480 send-stylesheet. This is, of course, locally served by Privoxy and the source
5481 for it can be found and edited in the cgi-style.css template.
5483 -------------------------------------------------------------------------------
5485 11. Contacting the Developers, Bug Reporting and Feature Requests
5487 We value your feedback. In fact, we rely on it to improve Privoxy and its
5488 configuration. However, please note the following hints, so we can provide you
5489 with the best support:
5491 -------------------------------------------------------------------------------
5495 For casual users, our support forum at SourceForge is probably best suited:
5496 http://sourceforge.net/tracker/?group_id=11118&atid=211118
5498 All users are of course welcome to discuss their issues on the users mailing
5499 list, where the developers also hang around.
5501 -------------------------------------------------------------------------------
5503 11.2. Reporting Problems
5505 "Problems" for our purposes, come in two forms:
5507 * Configuration issues, such as ads that slip through, or sites that don't
5508 function properly due to one Privoxy "action" or another being turned "on".
5510 * "Bugs" in the programming code that makes up Privoxy, such as that might
5513 -------------------------------------------------------------------------------
5515 11.2.1. Reporting Ads or Other Configuration Problems
5517 Please send feedback on ads that slipped through, innocent images that were
5518 blocked, sites that don't work properly, and other configuration related
5519 problem of default.action file, to http://sourceforge.net/tracker/?group_id=
5520 11118&atid=460288, the Actions File Tracker.
5522 New, improved default.action files may occasionally be made available based on
5523 your feedback. These will be announced on the ijbswa-announce list and
5524 available from our the files section of our project page.
5526 -------------------------------------------------------------------------------
5528 11.2.2. Reporting Bugs
5530 Please report all bugs only through our bug tracker: http://sourceforge.net/
5531 tracker/?group_id=11118&atid=111118.
5533 Before doing so, please make sure that the bug has not already been submitted
5534 and observe the additional hints at the top of the submit form. If already
5535 submitted, please feel free to add any info to the original report that might
5536 help to solve the issue.
5538 Please try to verify that it is a Privoxy bug, and not a browser or site bug
5539 first. If unsure, try toggling off Privoxy, and see if the problem persists. If
5540 you are using your own custom configuration, please try the stock configs to
5541 see if the problem is configuration related.
5543 If not using the latest version, the bug may have been found and fixed in the
5544 meantime. We would appreciate if you could take the time to upgrade to the
5545 latest version (or even the latest CVS snapshot) and verify your bug.
5547 Please be sure to provide the following information:
5549 * The exact Privoxy version of the proxy software (if you got the source from
5550 CVS, please also provide the source code revisions as shown in http://
5551 config.privoxy.org/show-version).
5553 * The operating system and versions you run Privoxy on, (e.g. Windows XP
5554 SP2), if you are using a Unix flavor, sending the output of "uname -a"
5557 * The name, platform, and version of the browser you were using (e.g.
5558 Internet Explorer v5.5 for Mac).
5560 * The URL where the problem occurred, or some way for us to duplicate the
5561 problem (e.g. http://somesite.example.com/?somethingelse=123).
5563 * Whether your version of Privoxy is one supplied by the developers of
5564 Privoxy via SourceForge, or somewhere else.
5566 * Whether you are using Privoxy in tandem with another proxy such as Tor. If
5567 so, please try disabling the other proxy.
5569 * Whether you are using a personal firewall product. If so, does Privoxy work
5572 * Any other pertinent information to help identify the problem such as config
5573 or log file excerpts (yes, you should have log file entries for each action
5576 * Please provide your SF login, or email address, in case we need to contact
5579 The appendix of the Privoxy User Manual also has helpful information on
5580 understanding actions, and action debugging.
5582 -------------------------------------------------------------------------------
5584 11.3. Request New Features
5586 You are welcome to submit ideas on new features or other proposals for
5587 improvement through our feature request tracker at http://sourceforge.net/
5588 tracker/?atid=361118&group_id=11118.
5590 -------------------------------------------------------------------------------
5594 For any other issues, feel free to use the mailing lists. Technically
5595 interested users and people who wish to contribute to the project are also
5596 welcome on the developers list! You can find an overview of all Privoxy-related
5597 mailing lists, including list archives, at: http://sourceforge.net/mail/?
5600 -------------------------------------------------------------------------------
5602 12. Privoxy Copyright, License and History
5604 Copyright © 2001 - 2006 by Privoxy Developers <
5605 ijbswa-developers@lists.sourceforge.net>
5607 Some source code is based on code Copyright © 1997 by Anonymous Coders and
5608 Junkbusters, Inc. and licensed under the GNU General Public License.
5610 -------------------------------------------------------------------------------
5614 Privoxy is free software; you can redistribute it and/or modify it under the
5615 terms of the GNU General Public License, version 2, as published by the Free
5616 Software Foundation.
5618 This program is distributed in the hope that it will be useful, but WITHOUT ANY
5619 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
5620 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
5621 is available from the Free Software Foundation, Inc, 51 Franklin Street, Fifth
5622 Floor, Boston, MA 02110-1301, USA
5624 You should have received a copy of the GNU General Public License along with
5625 this program; if not, write to the
5628 Foundation, Inc. 51 Franklin Street, Fifth Floor
5629 Boston, MA 02110-1301
5632 -------------------------------------------------------------------------------
5636 A long time ago, there was the Internet Junkbuster, by Anonymous Coders and
5637 Junkbusters Corporation. This saved many users a lot of pain in the early days
5638 of web advertising and user tracking.
5640 But the web, its protocols and standards, and with it, the techniques for
5641 forcing ads on users, give up autonomy over their browsing, and for tracking
5642 them, keeps evolving. Unfortunately, the Internet Junkbuster did not. Version
5643 2.0.2, published in 1998, was (and is) the last official release available from
5644 Junkbusters Corporation. Fortunately, it had been released under the GNU GPL,
5645 which allowed further development by others.
5647 So Stefan Waldherr started maintaining an improved version of the software, to
5648 which eventually a number of people contributed patches. It could already
5649 replace banners with a transparent image, and had a first version of pop-up
5650 killing, but it was still very closely based on the original, with all its
5651 limitations, such as the lack of HTTP/1.1 support, flexible per-site
5652 configuration, or content modification. The last release from this effort was
5653 version 2.0.2-10, published in 2000.
5655 Then, some developers picked up the thread, and started turning the software
5656 inside out, upside down, and then reassembled it, adding many new features
5659 The result of this is Privoxy, whose first stable version, 3.0, was released
5662 -------------------------------------------------------------------------------
5666 Current Privoxy Team:
5668 Fabian Keil, developer
5669 David Schmidt, developer
5675 Former Privoxy Team Members:
5699 Thanks to the many people who have tested Privoxy, reported bugs, provided
5700 patches, made suggestions or contributed in some way. These include (in
5701 alphabetical order):
5738 Privoxy is based in part on code originally developed by:
5745 -------------------------------------------------------------------------------
5749 Other references and sites of interest to Privoxy users:
5751 http://www.privoxy.org/, the Privoxy Home page.
5753 http://www.privoxy.org/faq/, the Privoxy FAQ.
5755 http://sourceforge.net/projects/ijbswa/, the Project Page for Privoxy on
5758 http://config.privoxy.org/, the web-based user interface. Privoxy must be
5759 running for this to work. Shortcut: http://p.p/
5761 http://sourceforge.net/tracker/?group_id=11118&atid=460288, to submit "misses"
5762 and other configuration related suggestions to the developers.
5764 http://www.junkbusters.com/ht/en/cookies.html, an explanation how cookies are
5765 used to track web users.
5767 http://www.junkbusters.com/ijb.html, the original Internet Junkbuster.
5769 http://privacy.net/, a useful site to check what information about you is
5770 leaked while you browse the web.
5772 http://www.squid-cache.org/, a very popular caching proxy, which is often used
5773 together with Privoxy.
5775 http://tor.eff.org/, Tor can help anonymize web browsing, web publishing,
5776 instant messaging, IRC, SSH, and other applications.
5778 http://www.privoxy.org/developer-manual/, the Privoxy developer manual.
5780 -------------------------------------------------------------------------------
5784 14.1. Regular Expressions
5786 Privoxy uses Perl-style "regular expressions" in its actions files and filter
5787 file, through the PCRE and PCRS libraries.
5789 If you are reading this, you probably don't understand what "regular
5790 expressions" are, or what they can do. So this will be a very brief
5791 introduction only. A full explanation would require a book ;-)
5793 Regular expressions provide a language to describe patterns that can be run
5794 against strings of characters (letter, numbers, etc), to see if they match the
5795 string or not. The patterns are themselves (sometimes complex) strings of
5796 literal characters, combined with wild-cards, and other special characters,
5797 called meta-characters. The "meta-characters" have special meanings and are
5798 used to build complex patterns to be matched against. Perl Compatible Regular
5799 Expressions are an especially convenient "dialect" of the regular expression
5802 To make a simple analogy, we do something similar when we use wild-card
5803 characters when listing files with the dir command in DOS. *.* matches all
5804 filenames. The "special" character here is the asterisk which matches any and
5805 all characters. We can be more specific and use ? to match just individual
5806 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
5807 are pattern matching, using a similar technique to "regular expressions"!
5809 Regular expressions do essentially the same thing, but are much, much more
5810 powerful. There are many more "special characters" and ways of building complex
5811 patterns however. Let's look at a few of the common ones, and then some
5814 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
5816 ? - The preceding character or expression is matched ZERO or ONE times. Either/
5819 + - The preceding character or expression is matched ONE or MORE times.
5821 * - The preceding character or expression is matched ZERO or MORE times.
5823 \ - The "escape" character denotes that the following character should be taken
5824 literally. This is used where one of the special characters (e.g. ".") needs to
5825 be taken literally and not as a special meta-character. Example: "example
5826 \.com", makes sure the period is recognized only as a period (and not expanded
5827 to its meta-character meaning of any single character).
5829 [ ] - Characters enclosed in brackets will be matched if any of the enclosed
5830 characters are encountered. For instance, "[0-9]" matches any numeric digit
5831 (zero through nine). As an example, we can combine this with "+" to match any
5832 digit one of more times: "[0-9]+".
5834 ( ) - parentheses are used to group a sub-expression, or multiple
5837 | - The "bar" character works like an "or" conditional statement. A match is
5838 successful if the sub-expression on either side of "|" matches. As an example:
5839 "/(this|that) example/" uses grouping and the bar character and would match
5840 either "this example" or "that example", and nothing else.
5842 These are just some of the ones you are likely to use when matching URLs with
5843 Privoxy, and is a long way from a definitive list. This is enough to get us
5844 started with a few simple examples which may be more illuminating:
5846 /.*/banners/.* - A simple example that uses the common combination of "." and "
5847 *" to denote any character, zero or more times. In other words, any string at
5848 all. So we start with a literal forward slash, then our regular expression
5849 pattern (".*") another literal forward slash, the string "banners", another
5850 forward slash, and lastly another ".*". We are building a directory path here.
5851 This will match any file with the path that has a directory named "banners" in
5852 it. The ".*" matches any characters, and this could conceivably be more forward
5853 slashes, so it might expand into a much longer looking path. For example, this
5854 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
5855 banners/annoying.html", or almost an infinite number of other possible
5856 combinations, just so it has "banners" in the path somewhere.
5858 And now something a little more complex:
5860 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
5861 slashes again ("/"), so we are building another expression that is a file path
5862 statement. We have another ".*", so we are matching against any conceivable
5863 sub-path, just so it matches our expression. The only true literal that must
5864 match our pattern is adv, together with the forward slashes. What comes after
5865 the "adv" string is the interesting part.
5867 Remember the "?" means the preceding expression (either a literal character or
5868 anything grouped with "(...)" in this case) can exist or not, since this means
5869 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
5870 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
5871 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
5872 to match either "ing" OR "ements?". What is being done here, is an attempt at
5873 matching as many variations of "advertisement", and similar, as possible. So
5874 this would expand to match just "adv", or "advert", or "adverts", or
5875 "advertising", or "advertisement", or "advertisements". You get the idea. But
5876 it would not match "advertizements" (with a "z"). We could fix that by changing
5877 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
5878 would then match either spelling.
5880 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
5881 slashes. Anything in the square brackets "[ ]" can be matched. This is using
5882 "0-9" as a shorthand expression to mean any digit one through nine. It is the
5883 same as saying "0123456789". So any digit matches. The "+" means one or more of
5884 the preceding expression must be included. The preceding expression here is
5885 what is in the square brackets -- in this case, any digit one through nine.
5886 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
5887 this needs to match the expression on either side of that bar character also. A
5888 simple "gif" on one side, and the other side will in turn match either "jpeg"
5889 or "jpg", since the "?" means the letter "e" is optional and can be matched
5890 once or not at all. So we are building an expression here to match image GIF or
5891 JPEG type image file. It must include the literal string "advert", then one or
5892 more digits, and a "." (which is now a literal, and not a special character,
5893 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
5894 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
5895 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
5896 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
5897 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
5899 We are barely scratching the surface of regular expressions here so that you
5900 can understand the default Privoxy configuration files, and maybe use this
5901 knowledge to customize your own installation. There is much, much more that can
5902 be done with regular expressions. Now that you know enough to get started, you
5903 can learn more on your own :/
5905 More reading on Perl Compatible Regular expressions: http://perldoc.perl.org/
5908 For information on regular expression based substitutions and their
5909 applications in filters, please see the filter file tutorial in this manual.
5911 -------------------------------------------------------------------------------
5913 14.2. Privoxy's Internal Pages
5915 Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
5916 certain special URLs. In this way, we can talk directly to Privoxy, and see how
5917 it is configured, see how our rules are being applied, change these rules and
5918 other configuration options, and even turn Privoxy's filtering off, all with a
5921 The URLs listed below are the special ones that allow direct access to Privoxy.
5922 Of course, Privoxy must be running to access these. If not, you will get a
5923 friendly error message. Internet access is not necessary either.
5925 * Privoxy main page:
5927 http://config.privoxy.org/
5929 There is a shortcut: http://p.p/ (But it doesn't provide a fall-back to a
5930 real page, in case the request is not sent through Privoxy)
5932 * Show information about the current configuration, including viewing and
5933 editing of actions files:
5935 http://config.privoxy.org/show-status
5937 * Show the source code version numbers:
5939 http://config.privoxy.org/show-version
5941 * Show the browser's request headers:
5943 http://config.privoxy.org/show-request
5945 * Show which actions apply to a URL and why:
5947 http://config.privoxy.org/show-url-info
5949 * Toggle Privoxy on or off. In this case, "Privoxy" continues to run, but
5950 only as a pass-through proxy, with no actions taking place:
5952 http://config.privoxy.org/toggle
5954 Short cuts. Turn off, then on:
5956 http://config.privoxy.org/toggle?set=disable
5958 http://config.privoxy.org/toggle?set=enable
5960 These may be bookmarked for quick reference. See next.
5962 -------------------------------------------------------------------------------
5964 14.2.1. Bookmarklets
5966 Below are some "bookmarklets" to allow you to easily access a "mini" version of
5967 some of Privoxy's special pages. They are designed for MS Internet Explorer,
5968 but should work equally well in Netscape, Mozilla, and other browsers which
5969 support JavaScript. They are designed to run directly from your bookmarks - not
5970 by clicking the links below (although that should work for testing).
5972 To save them, right-click the link and choose "Add to Favorites" (IE) or "Add
5973 Bookmark" (Netscape). You will get a warning that the bookmark "may not be
5974 safe" - just click OK. Then you can run the Bookmarklet directly from your
5975 favorites/bookmarks. For even faster access, you can put them on the "Links"
5976 bar (IE) or the "Personal Toolbar" (Netscape), and run them with a single
5983 * Privoxy - Toggle Privoxy (Toggles between enabled and disabled)
5985 * Privoxy- View Status
5989 Credit: The site which gave us the general idea for these bookmarklets is
5990 www.bookmarklets.com. They have more information about bookmarklets.
5992 -------------------------------------------------------------------------------
5994 14.3. Chain of Events
5996 Let's take a quick look at how some of Privoxy's core features are triggered,
5997 and the ensuing sequence of events when a web page is requested by your
6000 * First, your web browser requests a web page. The browser knows to send the
6001 request to Privoxy, which will in turn, relay the request to the remote web
6002 server after passing the following tests:
6004 * Privoxy traps any request for its own internal CGI pages (e.g http://p.p/)
6005 and sends the CGI page back to the browser.
6007 * Next, Privoxy checks to see if the URL matches any "+block" patterns. If
6008 so, the URL is then blocked, and the remote web server will not be
6009 contacted. "+handle-as-image" and "+handle-as-empty-document" are then
6010 checked, and if there is no match, an HTML "BLOCKED" page is sent back to
6011 the browser. Otherwise, if it does match, an image is returned for the
6012 former, and an empty text document for the latter. The type of image would
6013 depend on the setting of "+set-image-blocker" (blank, checkerboard pattern,
6014 or an HTTP redirect to an image elsewhere).
6016 * Untrusted URLs are blocked. If URLs are being added to the trust file, then
6019 * If the URL pattern matches the "+fast-redirects" action, it is then
6020 processed. Unwanted parts of the requested URL are stripped.
6022 * Now the rest of the client browser's request headers are processed. If any
6023 of these match any of the relevant actions (e.g. "+hide-user-agent", etc.),
6024 headers are suppressed or forged as determined by these actions and their
6027 * Now the web server starts sending its response back (i.e. typically a web
6030 * First, the server headers are read and processed to determine, among other
6031 things, the MIME type (document type) and encoding. The headers are then
6032 filtered as determined by the "+crunch-incoming-cookies",
6033 "+session-cookies-only", and "+downgrade-http-version" actions.
6035 * If the "+kill-popups" action applies, and it is an HTML or JavaScript
6036 document, the popup-code in the response is filtered on-the-fly as it is
6039 * If any "+filter" action or "+deanimate-gifs" action applies (and the
6040 document type fits the action), the rest of the page is read into memory
6041 (up to a configurable limit). Then the filter rules (from default.filter
6042 and any other filter files) are processed against the buffered content.
6043 Filters are applied in the order they are specified in one of the filter
6044 files. Animated GIFs, if present, are reduced to either the first or last
6045 frame, depending on the action setting.The entire page, which is now
6046 filtered, is then sent by Privoxy back to your browser.
6048 If neither a "+filter" action or "+deanimate-gifs" matches, then Privoxy
6049 passes the raw data through to the client browser as it becomes available.
6051 * As the browser receives the now (possibly filtered) page content, it reads
6052 and then requests any URLs that may be embedded within the page source,
6053 e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
6054 frames), sounds, etc. For each of these objects, the browser issues a
6055 separate request (this is easily viewable in Privoxy's logs). And each such
6056 request is in turn processed just as above. Note that a complex web page
6057 will have many, many such embedded URLs. If these secondary requests are to
6058 a different server, then quite possibly a very differing set of actions is
6061 NOTE: This is somewhat of a simplistic overview of what happens with each URL
6062 request. For the sake of brevity and simplicity, we have focused on Privoxy's
6065 -------------------------------------------------------------------------------
6067 14.4. Troubleshooting: Anatomy of an Action
6069 The way Privoxy applies actions and filters to any given URL can be complex,
6070 and not always so easy to understand what is happening. And sometimes we need
6071 to be able to see just what Privoxy is doing. Especially, if something Privoxy
6072 is doing is causing us a problem inadvertently. It can be a little daunting to
6073 look at the actions and filters files themselves, since they tend to be filled
6074 with regular expressions whose consequences are not always so obvious.
6076 One quick test to see if Privoxy is causing a problem or not, is to disable it
6077 temporarily. This should be the first troubleshooting step. See the
6078 Bookmarklets section on a quick and easy way to do this (be sure to flush
6079 caches afterward!). Looking at the logs is a good idea too.
6081 Another easy troubleshooting step to try is if you have done any customization
6082 of your installation, revert back to the installed defaults and see if that
6083 helps. There are times the developers get complaints about one thing or
6084 another, and the problem is more related to a customized configuration issue.
6086 Privoxy also provides the http://config.privoxy.org/show-url-info page that can
6087 show us very specifically how actions are being applied to any given URL. This
6088 is a big help for troubleshooting.
6090 First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell
6091 us how the current configuration will handle it. This will not help with
6092 filtering effects (i.e. the "+filter" action) from one of the filter files
6093 since this is handled very differently and not so easy to trap! It also will
6094 not tell you about any other URLs that may be embedded within the URL you are
6095 testing. For instance, images such as ads are expressed as URLs within the raw
6096 page source of HTML pages. So you will only get info for the actual URL that is
6097 pasted into the prompt area -- not any sub-URLs. If you want to know about
6098 embedded URLs like ads, you will have to dig those out of the HTML source. Use
6099 your browser's "View Page Source" option for this. Or right click on the ad,
6102 Let's try an example, google.com, and look at it one section at a time in a
6103 sample configuration (your real configuration may vary):
6105 Matches for http://google.com:
6107 In file: default.action [ View ] [ Edit ]
6111 -content-type-overwrite
6112 -crunch-client-header
6113 -crunch-if-none-match
6114 -crunch-incoming-cookies
6115 -crunch-outgoing-cookies
6116 -crunch-server-header
6117 +deanimate-gifs {last}
6118 -downgrade-http-version
6119 +fast-redirects {check-decoded-url}
6121 -filter {content-cookies}
6122 -filter {all-popups}
6123 -filter {banners-by-link}
6124 -filter {tiny-textforms}
6125 -filter {frameset-borders}
6126 -filter {demoronizer}
6127 -filter {shockwave-flash}
6128 -filter {quicktime-kioskmode}
6130 -filter {crude-parental}
6131 -filter {site-specifics}
6132 -filter {js-annoyances}
6133 -filter {html-annoyances}
6134 +filter {refresh-tags}
6135 -filter {unsolicited-popups}
6136 +filter {img-reorder}
6137 +filter {banners-by-size}
6139 +filter {jumping-windows}
6140 +filter {ie-exploits}
6145 -filter {xml-to-html}
6146 -filter {html-to-xml}
6148 -filter{hide-tor-exit-notation}
6149 -filter-client-headers
6150 -filter-server-headers
6152 -handle-as-empty-document
6154 -hide-accept-language
6155 -hide-content-disposition
6156 +hide-forwarded-for-headers
6157 +hide-from-header {block}
6158 -hide-if-modified-since
6159 +hide-referrer {forge}
6164 -overwrite-last-modified
6165 +prevent-compression
6169 +session-cookies-only
6170 +set-image-blocker {pattern}
6171 -treat-forbidden-connects-like-blocks }
6174 { -session-cookies-only }
6180 In file: user.action [ View ] [ Edit ]
6181 (no matches in this file)
6183 This is telling us how we have defined our "actions", and which ones match for
6184 our test case, "google.com". Displayed is all the actions that are available to
6185 us. Remember, the + sign denotes "on". - denotes "off". So some are "on" here,
6186 but many are "off". Each example we try may provide a slightly different end
6187 result, depending on our configuration directives.
6189 The first listing is for our default.action file. The large, multi-line
6190 listing, is how the actions are set to match for all URLs, i.e. our default
6191 settings. If you look at your "actions" file, this would be the section just
6192 below the "aliases" section near the top. This will apply to all URLs as
6193 signified by the single forward slash at the end of the listing -- " / ".
6195 But we have defined additional actions that would be exceptions to these
6196 general rules, and then we list specific URLs (or patterns) that these
6197 exceptions would apply to. Last match wins. Just below this then are two
6198 explicit matches for ".google.com". The first is negating our previous cookie
6199 setting, which was for "+session-cookies-only" (i.e. not persistent). So we
6200 will allow persistent cookies for google, at least that is how it is in this
6201 example. The second turns off any "+fast-redirects" action, allowing this to
6202 take place unmolested. Note that there is a leading dot here -- ".google.com".
6203 This will match any hosts and sub-domains, in the google.com domain also, such
6204 as "www.google.com" or "mail.google.com". But it would not match
6205 "www.google.de"! So, apparently, we have these two actions defined as
6206 exceptions to the general rules at the top somewhere in the lower part of our
6207 default.action file, and "google.com" is referenced somewhere in these latter
6210 Then, for our user.action file, we again have no hits. So there is nothing
6211 google-specific that we might have added to our own, local configuration. If
6212 there was, those actions would over-rule any actions from previously processed
6213 files, such as default.action. user.action typically has the last word. This is
6214 the best place to put hard and fast exceptions,
6216 And finally we pull it all together in the bottom section and summarize how
6217 Privoxy is applying all its "actions" to "google.com":
6223 -content-type-overwrite
6224 -crunch-client-header
6225 -crunch-if-none-match
6226 -crunch-incoming-cookies
6227 -crunch-outgoing-cookies
6228 -crunch-server-header
6229 +deanimate-gifs {last}
6230 -downgrade-http-version
6231 +fast-redirects {check-decoded-url}
6233 -filter {content-cookies}
6234 -filter {all-popups}
6235 -filter {banners-by-link}
6236 -filter {tiny-textforms}
6237 -filter {frameset-borders}
6238 -filter {demoronizer}
6239 -filter {shockwave-flash}
6240 -filter {quicktime-kioskmode}
6242 -filter {crude-parental}
6243 -filter {site-specifics}
6244 -filter {js-annoyances}
6245 -filter {html-annoyances}
6246 +filter {refresh-tags}
6247 -filter {unsolicited-popups}
6248 +filter {img-reorder}
6249 +filter {banners-by-size}
6251 +filter {jumping-windows}
6252 +filter {ie-exploits}
6257 -filter {xml-to-html}
6258 -filter {html-to-xml}
6260 -filter{hide-tor-exit-notation}
6261 -filter-client-headers
6262 -filter-server-headers
6264 -handle-as-empty-document
6266 -hide-accept-language
6267 -hide-content-disposition
6268 +hide-forwarded-for-headers
6269 +hide-from-header {block}
6270 -hide-if-modified-since
6271 +hide-referrer {forge}
6276 -overwrite-last-modified
6277 +prevent-compression
6281 -session-cookies-only
6282 +set-image-blocker {pattern}
6283 -treat-forbidden-connects-like-blocks
6285 Notice the only difference here to the previous listing, is to "fast-redirects"
6286 and "session-cookies-only", which are activated specifically for this site in
6287 our configuration, and thus show in the "Final Results".
6289 Now another example, "ad.doubleclick.net":
6297 { +block +handle-as-image }
6298 .[a-vx-z]*.doubleclick.net
6300 We'll just show the interesting part here - the explicit matches. It is matched
6301 three different times. Two "+block" sections, and a "+block +handle-as-image",
6302 which is the expanded form of one of our aliases that had been defined as:
6303 "+block-as-image". ("Aliases" are defined in the first section of the actions
6304 file and typically used to combine more than one action.)
6306 Any one of these would have done the trick and blocked this as an unwanted
6307 image. This is unnecessarily redundant since the last case effectively would
6308 also cover the first. No point in taking chances with these guys though ;-)
6309 Note that if you want an ad or obnoxious URL to be invisible, it should be
6310 defined as "ad.doubleclick.net" is done here -- as both a "+block" and an
6311 "+handle-as-image". The custom alias "+block-as-image" just simplifies the
6312 process and make it more readable.
6314 One last example. Let's try "http://www.example.net/adsl/HOWTO/". This one is
6315 giving us problems. We are getting a blank page. Hmmm ...
6317 Matches for http://www.example.net/adsl/HOWTO/:
6319 In file: default.action [ View ] [ Edit ]
6323 -content-type-overwrite
6324 -crunch-client-header
6325 -crunch-if-none-match
6326 -crunch-incoming-cookies
6327 -crunch-outgoing-cookies
6328 -crunch-server-header
6330 -downgrade-http-version
6331 +fast-redirects {check-decoded-url}
6333 -filter {content-cookies}
6334 -filter {all-popups}
6335 -filter {banners-by-link}
6336 -filter {tiny-textforms}
6337 -filter {frameset-borders}
6338 -filter {demoronizer}
6339 -filter {shockwave-flash}
6340 -filter {quicktime-kioskmode}
6342 -filter {crude-parental}
6343 -filter {site-specifics}
6344 -filter {js-annoyances}
6345 -filter {html-annoyances}
6346 +filter {refresh-tags}
6347 -filter {unsolicited-popups}
6348 +filter {img-reorder}
6349 +filter {banners-by-size}
6351 +filter {jumping-windows}
6352 +filter {ie-exploits}
6357 -filter {xml-to-html}
6358 -filter {html-to-xml}
6360 -filter{hide-tor-exit-notation}
6361 -filter-client-headers
6362 -filter-server-headers
6364 -handle-as-empty-document
6366 -hide-accept-language
6367 -hide-content-disposition
6368 +hide-forwarded-for-headers
6369 +hide-from-header{block}
6370 +hide-referer{forge}
6374 -overwrite-last-modified
6375 +prevent-compression
6379 +session-cookies-only
6380 +set-image-blocker{blank}
6381 -treat-forbidden-connects-like-blocks }
6384 { +block +handle-as-image }
6387 Ooops, the "/adsl/" is matching "/ads" in our configuration! But we did not
6388 want this at all! Now we see why we get the blank page. It is actually
6389 triggering two different actions here, and the effects are aggregated so that
6390 the URL is blocked, and Privoxy is told to treat the block as if it were an
6391 image. But this is, of course, all wrong. We could now add a new action below
6392 this (or better in our own user.action file) that explicitly un blocks ( "
6393 {-block}") paths with "adsl" in them (remember, last match in the configuration
6394 wins). There are various ways to handle such exceptions. Example:
6399 Now the page displays ;-) Remember to flush your browser's caches when making
6400 these kinds of changes to your configuration to insure that you get a freshly
6401 delivered page! Or, try using Shift+Reload.
6403 But now what about a situation where we get no explicit matches like we did
6406 { +block +handle-as-image }
6409 That actually was very helpful and pointed us quickly to where the problem was.
6410 If you don't get this kind of match, then it means one of the default rules in
6411 the first section of default.action is causing the problem. This would require
6412 some guesswork, and maybe a little trial and error to isolate the offending
6413 rule. One likely cause would be one of the "+filter" actions. These tend to be
6414 harder to troubleshoot. Try adding the URL for the site to one of aliases that
6419 .worldpay.com # for quietpc.com
6424 "{ shop }" is an "alias" that expands to "{ -filter -session-cookies-only }".
6425 Or you could do your own exception to negate filtering:
6428 # Disable ALL filter actions for sites in this section
6433 This would turn off all filtering for these sites. This is best put in
6434 user.action, for local site exceptions. Note that when a simple domain pattern
6435 is used by itself (without the subsequent path portion), all sub-pages within
6436 that domain are included automatically in the scope of the action.
6438 Images that are inexplicably being blocked, may well be hitting the "+filter
6439 {banners-by-size}" rule, which assumes that images of certain sizes are ad
6440 banners (works well most of the time since these tend to be standardized).
6442 "{ fragile }" is an alias that disables most actions that are the most likely
6443 to cause trouble. This can be used as a last resort for problem sites.
6446 # Handle with care: easy to break
6450 Remember to flush caches! Note that the mail.google reference lacks the TLD
6451 portion (e.g. ".com". This will effectively match any TLD with google in it,
6452 such as mail.google.de, just as an example.
6454 If this still does not work, you will have to go through the remaining actions
6455 one by one to find which one(s) is causing the problem.
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