1 Privoxy 3.0.7 User Manual
3 [ Copyright 2001 - 2007 by Privoxy Developers ]
5 $Id: user-manual.sgml,v 2.46 2007/11/17 17:24:44 fabiankeil Exp $
7 The Privoxy User Manual gives users information on how to install, configure
10 Privoxy is a non-caching web proxy with advanced filtering capabilities for
11 enhancing privacy, modifying web page data, managing HTTP cookies, controlling
12 access, and removing ads, banners, pop-ups and other obnoxious Internet junk.
13 Privoxy has a flexible configuration and can be customized to suit individual
14 needs and tastes. Privoxy has application for both stand-alone systems and
17 Privoxy is based on Internet Junkbuster (tm).
19 You can find the latest version of the Privoxy User Manual at http://
20 www.privoxy.org/user-manual/. Please see the Contact section on how to contact
23 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
34 2.1.1. Red Hat and Fedora RPMs
35 2.1.2. Debian and Ubuntu
44 2.2. Building from Source
45 2.3. Keeping your Installation Up-to-Date
47 3. What's New in this Release
49 3.1. Note to Upgraders
51 4. Quickstart to Using Privoxy
53 4.1. Quickstart to Ad Blocking
57 5.1. Red Hat and Fedora
60 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
65 5.9. Command Line Options
67 6. Privoxy Configuration
69 6.1. Controlling Privoxy with Your Web Browser
70 6.2. Configuration Files Overview
72 7. The Main Configuration File
74 7.1. Local Set-up Documentation
81 7.2. Configuration and Log File Locations
95 7.3.2. single-threaded
97 7.4. Access Control and Security
101 7.4.3. enable-remote-toggle
102 7.4.4. enable-remote-http-toggle
103 7.4.5. enable-edit-actions
104 7.4.6. enforce-blocks
105 7.4.7. ACLs: permit-access and deny-access
111 7.5.2. forward-socks4 and forward-socks4a
112 7.5.3. Advanced Forwarding Examples
113 7.5.4. forwarded-connect-retries
114 7.5.5. accept-intercepted-requests
115 7.5.6. allow-cgi-request-crunching
116 7.5.7. split-large-forms
118 7.6. Windows GUI Options
122 8.1. Finding the Right Mix
124 8.3. How Actions are Applied to Requests
127 8.4.1. The Domain Pattern
128 8.4.2. The Path Pattern
129 8.4.3. The Tag Pattern
135 8.5.3. client-header-filter
136 8.5.4. client-header-tagger
137 8.5.5. content-type-overwrite
138 8.5.6. crunch-client-header
139 8.5.7. crunch-if-none-match
140 8.5.8. crunch-incoming-cookies
141 8.5.9. crunch-server-header
142 8.5.10. crunch-outgoing-cookies
143 8.5.11. deanimate-gifs
144 8.5.12. downgrade-http-version
145 8.5.13. fast-redirects
147 8.5.15. force-text-mode
148 8.5.16. forward-override
149 8.5.17. handle-as-empty-document
150 8.5.18. handle-as-image
151 8.5.19. hide-accept-language
152 8.5.20. hide-content-disposition
153 8.5.21. hide-if-modified-since
154 8.5.22. hide-forwarded-for-headers
155 8.5.23. hide-from-header
156 8.5.24. hide-referrer
157 8.5.25. hide-user-agent
158 8.5.26. inspect-jpegs
160 8.5.28. limit-connect
161 8.5.29. prevent-compression
162 8.5.30. overwrite-last-modified
164 8.5.32. send-vanilla-wafer
166 8.5.34. server-header-filter
167 8.5.35. server-header-tagger
168 8.5.36. session-cookies-only
169 8.5.37. set-image-blocker
170 8.5.38. treat-forbidden-connects-like-blocks
174 8.7. Actions Files Tutorial
176 8.7.1. default.action
181 9.1. Filter File Tutorial
182 9.2. The Pre-defined Filters
184 10. Privoxy's Template Files
185 11. Contacting the Developers, Bug Reporting and Feature Requests
188 11.2. Reporting Problems
190 11.2.1. Reporting Ads or Other Configuration Problems
191 11.2.2. Reporting Bugs
193 11.3. Request New Features
196 12. Privoxy Copyright, License and History
205 14.1. Regular Expressions
206 14.2. Privoxy's Internal Pages
210 14.3. Chain of Events
211 14.4. Troubleshooting: Anatomy of an Action
215 This documentation is included with the current beta version of Privoxy,
216 v.3.0.7, and is mostly complete at this point. The most up to date reference
217 for the time being is still the comments in the source files and in the
218 individual configuration files. Development of a new version is currently
219 nearing completion, and includes significant changes and enhancements over
222 Since this is a beta version, not all new features are well tested. This
223 documentation may be slightly out of sync as a result (especially with CVS
224 sources). And there may be bugs, though hopefully not many!
226 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
230 In addition to the core features of ad blocking and cookie management, Privoxy
231 provides many supplemental features, some of them currently under development,
232 that give the end-user more control, more privacy and more freedom:
234 • Integrated browser based configuration and control utility at http://
235 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
236 and filter effects. Remote toggling.
238 • Web page filtering (text replacements, removes banners based on size,
239 invisible "web-bugs", JavaScript and HTML annoyances, pop-up windows,
240 header manipulation, etc.)
242 • Modularized configuration that allows for standard settings and user
243 settings to reside in separate files, so that installing updated actions
244 files won't overwrite individual user settings.
246 • Support for Perl Compatible Regular Expressions in the configuration files,
247 and generally a more sophisticated and flexible configuration syntax over
250 • Improved cookie management features (e.g. session based cookies).
254 • Bypass many click-tracking scripts (avoids script redirection).
256 • Multi-threaded (POSIX and native threads).
258 • User-customizable HTML templates for all proxy-generated pages (e.g.
261 • Auto-detection and re-reading of config file changes.
263 • Improved signal handling, and a true daemon mode (Unix).
265 • Every feature now controllable on a per-site or per-location basis,
266 configuration more powerful and versatile over-all.
268 • Many smaller new features added, limitations and bugs removed, and security
271 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
275 Privoxy is available both in convenient pre-compiled packages for a wide range
276 of operating systems, and as raw source code. For most users, we recommend
277 using the packages, which can be downloaded from our Privoxy Project Page.
279 Note: On some platforms, the installer may remove previously installed
280 versions, if found. (See below for your platform). In any case be sure to
281 backup your old configuration if it is valuable to you. See the note to
282 upgraders section below.
284 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
288 How to install the binary packages depends on your operating system:
290 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
292 2.1.1. Red Hat and Fedora RPMs
294 RPMs can be installed with rpm -Uvh privoxy-3.0.7-1.rpm, and will use /etc/
295 privoxy for the location of configuration files.
297 Note that on Red Hat, Privoxy will not be automatically started on system boot.
298 You will need to enable that using chkconfig, ntsysv, or similar methods.
300 If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm
301 --rebuild privoxy-3.0.7-1.src.rpm. This will use your locally installed
302 libraries and RPM version.
304 Also note that if you have a Junkbuster RPM installed on your system, you need
305 to remove it first, because the packages conflict. Otherwise, RPM will try to
306 remove Junkbuster automatically if found, before installing Privoxy.
308 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
310 2.1.2. Debian and Ubuntu
312 DEBs can be installed with apt-get install privoxy, and will use /etc/privoxy
313 for the location of configuration files.
315 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
319 Just double-click the installer, which will guide you through the installation
320 process. You will find the configuration files in the same directory as you
321 installed Privoxy in.
323 Version 3.0.5 beta introduced full Windows service functionality. On Windows
324 only, the Privoxy program has two new command line arguments to install and
325 uninstall Privoxy as a service.
329 --install[:service_name]
331 --uninstall[:service_name]
333 After invoking Privoxy with --install, you will need to bring up the Windows
334 service console to assign the user you want Privoxy to run under, and whether
335 or not you want it to run whenever the system starts. You can start the Windows
336 services console with the following command: services.msc. If you do not take
337 the manual step of modifying Privoxy's service settings, it will not start.
338 Note too that you will need to give Privoxy a user account that actually
339 exists, or it will not be permitted to write to its log and configuration
342 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
346 Create a new directory, cd to it, then unzip and untar the archive. For the
347 most part, you'll have to figure out where things go.
349 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
353 First, make sure that no previous installations of Junkbuster and / or Privoxy
354 are left on your system. Check that no Junkbuster or Privoxy objects are in
357 Then, just double-click the WarpIN self-installing archive, which will guide
358 you through the installation process. A shadow of the Privoxy executable will
359 be placed in your startup folder so it will start automatically whenever OS/2
362 The directory you choose to install Privoxy into will contain all of the
365 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
369 Unzip the downloaded file (you can either double-click on the file from the
370 finder, or from the desktop if you downloaded it there). Then, double-click on
371 the package installer icon named Privoxy.pkg and follow the installation
372 process. Privoxy will be installed in the folder /Library/Privoxy. It will
373 start automatically whenever you start up. To prevent it from starting
374 automatically, remove or rename the folder /Library/StartupItems/Privoxy.
376 To start Privoxy by hand, double-click on StartPrivoxy.command in the /Library/
377 Privoxy folder. Or, type this command in the Terminal:
379 /Library/Privoxy/StartPrivoxy.command
383 You will be prompted for the administrator password.
385 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
389 Copy and then unpack the lha archive to a suitable location. All necessary
390 files will be installed into Privoxy directory, including all configuration and
391 log files. To uninstall, just remove this directory.
393 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
397 Privoxy is part of FreeBSD's Ports Collection, you can build and install it
398 with cd /usr/ports/www/privoxy; make install clean.
400 If you don't use the ports, you can fetch and install the package with pkg_add
403 The port skeleton and the package can also be downloaded from the File Release
404 Page, but there's no reason to use them unless you're interested in the beta
405 releases which are only available there.
407 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
411 Gentoo source packages (Ebuilds) for Privoxy are contained in the Gentoo
412 Portage Tree (they are not on the download page, but there is a Gentoo section,
413 where you can see when a new Privoxy Version is added to the Portage Tree).
415 Before installing Privoxy under Gentoo just do first emerge rsync to get the
416 latest changes from the Portage tree. With emerge privoxy you install the
419 Configuration files are in /etc/privoxy, the documentation is in /usr/share/doc
420 /privoxy-3.0.7 and the Log directory is in /var/log/privoxy.
422 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
424 2.2. Building from Source
426 The most convenient way to obtain the Privoxy sources is to download the source
427 tarball from our project download page.
429 If you like to live on the bleeding edge and are not afraid of using possibly
430 unstable development versions, you can check out the up-to-the-minute version
431 directly from the CVS repository.
433 To build Privoxy from source, autoconf, GNU make (gmake), and, of course, a C
434 compiler like gcc are required.
436 When building from a source tarball, first unpack the source:
438 tar xzvf privoxy-3.0.7-beta-src* [.tgz or .tar.gz]
439 cd privoxy-3.0.7-beta
442 For retrieving the current CVS sources, you'll need a CVS client installed.
443 Note that sources from CVS are typically development quality, and may not be
444 stable, or well tested. To download CVS source, check the Sourceforge
445 documentation, which might give commands like:
447 cvs -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa login
448 cvs -z3 -d:pserver:anonymous@ijbswa.cvs.sourceforge.net:/cvsroot/ijbswa co current
452 This will create a directory named current/, which will contain the source
455 You can also check out any Privoxy "branch", just exchange the current name
456 with the wanted branch name (Example: v_3_0_branch for the 3.0 cvs tree).
458 It is also strongly recommended to not run Privoxy as root. You should
459 configure/install/run Privoxy as an unprivileged user, preferably by creating a
460 "privoxy" user and group just for this purpose. See your local documentation
461 for the correct command line to do add new users and groups (something like
462 adduser, but the command syntax may vary from platform to platform).
464 /etc/passwd might then look like:
466 privoxy:*:7777:7777:privoxy proxy:/no/home:/no/shell
469 And then /etc/group, like:
474 Some binary packages may do this for you.
476 Then, to build from either unpacked tarball or CVS source:
480 ./configure # (--help to see options)
481 make # (the make from GNU, sometimes called gmake)
482 su # Possibly required
483 make -n install # (to see where all the files will go)
484 make -s install # (to really install, -s to silence output)
487 Using GNU make, you can have the first four steps automatically done for you by
493 in the freshly downloaded or unpacked source directory.
495 To build an executable with security enhanced features so that users cannot
496 easily bypass the proxy (e.g. "Go There Anyway"), or alter their own
497 configurations, configure like this:
499 ./configure --disable-toggle --disable-editor --disable-force
502 Then build as above. In Privoxy 3.0.7 and later, all of these options can also
503 be disabled through the configuration file.
505 WARNING: If installing as root, the install will fail unless a non-root user or
506 group is specified, or a privoxy user and group already exist on the system. If
507 a non-root user is specified, and no group, then the installation will try to
508 also use a group of the same name as "user". If a group is specified (and no
509 user), then the support files will be installed as writable by that group, and
510 owned by the user running the installation.
512 configure accepts --with-user and --with-group options for setting user and
513 group ownership of the configuration files (which need to be writable by the
514 daemon). The specified user must already exist. When starting Privoxy, it must
515 be run as this same user to insure write access to configuration and log files!
517 Alternately, you can specify user and group on the make command line, but be
518 sure both already exist:
520 make -s install USER=privoxy GROUP=privoxy
523 The default installation path for make install is /usr/local. This may of
524 course be customized with the various ./configure path options. If you are
525 doing an install to anywhere besides /usr/local, be sure to set the appropriate
526 paths with the correct configure options (./configure --help). Non-privileged
527 users must of course have write access permissions to wherever the target
528 installation is going.
530 If you do install to /usr/local, the install will use sysconfdir=$prefix/etc/
531 privoxy by default. All other destinations, and the direct usage of
532 --sysconfdir flag behave like normal, i.e. will not add the extra privoxy
533 directory. This is for a safer install, as there may already exist another
534 program that uses a file with the "config" name, and thus makes /usr/local/etc
537 If installing to /usr/local, the documentation will go by default to $prefix/
538 share/doc. But if this directory doesn't exist, it will then try $prefix/doc
539 and install there before creating a new $prefix/share/doc just for Privoxy.
541 Again, if the installs goes to /usr/local, the localstatedir (ie: var/) will
542 default to /var instead of $prefix/var so the logs will go to /var/log/privoxy
543 /, and the pid file will be created in /var/run/privoxy.pid.
545 make install will attempt to set the correct values in config (main
546 configuration file). You should check this to make sure all values are correct.
547 If appropriate, an init script will be installed, but it is up to the user to
548 determine how and where to start Privoxy. The init script should be checked for
549 correct paths and values, if anything other than a default install is done.
551 If install finds previous versions of local configuration files, most of these
552 will not be overwritten, and the new ones will be installed with a "new"
553 extension. default.action, default.filter, and standard.action will be
554 overwritten. You will then need to manually update the other installed
555 configuration files as needed. All template files will be overwritten. If you
556 have customized, local templates, you should save these first, and in fact it
557 is wise to always save any important configuration files "just in case". If a
558 previous version of Privoxy is already running, you will have to restart it
561 For more detailed instructions on how to build Redhat RPMs, Windows
562 self-extracting installers, building on platforms with special requirements
563 etc, please consult the developer manual.
565 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
567 2.3. Keeping your Installation Up-to-Date
569 As user feedback comes in and development continues, we will make updated
570 versions of both the main actions file (as a separate package) and the software
571 itself (including the actions file) available for download.
573 If you wish to receive an email notification whenever we release updates of
574 Privoxy or the actions file, subscribe to our announce mailing list,
575 ijbswa-announce@lists.sourceforge.net.
577 In order not to lose your personal changes and adjustments when updating to the
578 latest default.action file we strongly recommend that you use user.action and
579 user.filter for your local customizations of Privoxy. See the Chapter on
580 actions files for details.
582 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
584 3. What's New in this Release
586 There are many improvements and new features since Privoxy 3.0.6, the last
589 • Two new actions server-header-tagger and client-header-tagger that can be
590 used to create arbitrary "tags" based on client and server headers. These
591 "tags" can then subsequently be used to control the other actions used for
592 the current request, greatly increasing Privoxy's flexibility and
593 selectivity. See tag patterns for more information on tags.
595 • Header filtering is done with dedicated header filters now. As a result the
596 actions "filter-client-headers" and "filter-server-headers" that were
597 introduced with Privoxy 3.0.5 to apply content filters to the headers have
598 been removed. See the new actions server-header-filter and
599 client-header-filter for details.
601 • There are four new options for the main config file:
603 □ allow-cgi-request-crunching which allows requests for Privoxy's
604 internal CGI pages to be blocked, redirected or (un)trusted like
607 □ split-large-forms that will work around a browser bug that caused IE6
608 and IE7 to ignore the Submit button on the Privoxy's
609 edit-actions-for-url CGI page.
611 □ accept-intercepted-requests which allows to combine Privoxy with any
612 packet filter to create an intercepting proxy for HTTP/1.1 requests
613 (and for HTTP/1.0 requests with Host header set). This means clients
614 can be forced to use Privoxy even if their proxy settings are
615 configured differently.
617 □ templdir to designate an alternate location for Privoxy's locally
618 customized CGI templates so that these are not overwritten during
621 • A new command line option --pre-chroot-nslookup hostname to initialize the
622 resolver library before chroot'ing. On some systems this reduces the number
623 of files that must be copied into the chroot tree. (Patch provided by
626 • The forward-override action allows changing of the forwarding settings
627 through the actions files. Combined with tags, this allows to choose the
628 forwarder based on client headers like the User-Agent, or the request
631 • The redirect action can now use regular expression substitutions against
634 • zlib support is now available as a compile time option to filter compressed
635 content. Patch provided by Wil Mahan.
637 • Improve various filters, and add new ones.
639 • Include support for RFC 3253 so that Subversion works with Privoxy. Patch
640 provided by Petr Kadlec.
642 • Logging can be completely turned off by not specifying a logfile directive.
644 • A number of improvements to Privoxy's internal CGI pages, including the use
645 of favicons for error and control pages.
647 • Many bugfixes, memory leaks addressed, code improvements, and logging
650 For a more detailed list of changes please have a look at the ChangeLog.
652 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
654 3.1. Note to Upgraders
656 A quick list of things to be aware of before upgrading from earlier versions of
659 • Some installers may remove earlier versions completely, including
660 configuration files. Save any important configuration files!
662 • On the other hand, other installers may not overwrite any existing
663 configuration files, thinking you will want to do that. You may want to
664 manually check your saved files against the newer versions to see if the
665 improvements have merit, or whether there are new options that you may want
666 to consider. There are a number of new features, but most won't be
667 available unless these features are incorporated into your configuration
670 • standard.action now only includes the enabled actions. Not all actions as
673 • Logging is off by default now. If you need logging, it can be turned on in
676 • Three other config file settings are now off by default:
677 enable-remote-toggle, enable-remote-http-toggle, and enable-edit-actions.
678 If you use or want these, you will need to explicitly enable them, and be
679 aware of the security issues involved.
681 • The "filter-client-headers" and "filter-server-headers" actions that were
682 introduced with Privoxy 3.0.5 to apply content filters to the headers have
683 been removed and replaced with new actions. See the What's New section
686 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
688 4. Quickstart to Using Privoxy
690 • Install Privoxy. See the Installation Section below for platform specific
693 • Advanced users and those who want to offer Privoxy service to more than
694 just their local machine should check the main config file, especially the
695 security-relevant options. These are off by default.
697 • Start Privoxy, if the installation program has not done this already (may
698 vary according to platform). See the section Starting Privoxy.
700 • Set your browser to use Privoxy as HTTP and HTTPS (SSL) proxy by setting
701 the proxy configuration for address of 127.0.0.1 and port 8118. DO NOT
702 activate proxying for FTP or any protocols besides HTTP and HTTPS (SSL)
703 unless you intend to prevent your browser from using these protocols.
705 • Flush your browser's disk and memory caches, to remove any cached ad
706 images. If using Privoxy to manage cookies, you should remove any currently
709 • A default installation should provide a reasonable starting point for most.
710 There will undoubtedly be occasions where you will want to adjust the
711 configuration, but that can be dealt with as the need arises. Little to no
712 initial configuration is required in most cases, you may want to enable the
713 web-based action editor though. Be sure to read the warnings first.
715 See the Configuration section for more configuration options, and how to
716 customize your installation. You might also want to look at the next
717 section for a quick introduction to how Privoxy blocks ads and banners.
719 • If you experience ads that slip through, innocent images that are blocked,
720 or otherwise feel the need to fine-tune Privoxy's behavior, take a look at
721 the actions files. As a quick start, you might find the richly commented
722 examples helpful. You can also view and edit the actions files through the
723 web-based user interface. The Appendix "Troubleshooting: Anatomy of an
724 Action" has hints on how to understand and debug actions that "misbehave".
726 • Please see the section Contacting the Developers on how to report bugs,
727 problems with websites or to get help.
729 • Now enjoy surfing with enhanced control, comfort and privacy!
731 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
733 4.1. Quickstart to Ad Blocking
735 Ad blocking is but one of Privoxy's array of features. Many of these features
736 are for the technically minded advanced user. But, ad and banner blocking is
737 surely common ground for everybody.
739 This section will provide a quick summary of ad blocking so you can get up to
740 speed quickly without having to read the more extensive information provided
741 below, though this is highly recommended.
743 First a bit of a warning ... blocking ads is much like blocking SPAM: the more
744 aggressive you are about it, the more likely you are to block things that were
745 not intended. And the more likely that some things may not work as intended. So
746 there is a trade off here. If you want extreme ad free browsing, be prepared to
747 deal with more "problem" sites, and to spend more time adjusting the
748 configuration to solve these unintended consequences. In short, there is not an
749 easy way to eliminate all ads. Either take the easy way and settle for most ads
750 blocked with the default configuration, or jump in and tweak it for your
751 personal surfing habits and preferences.
753 Secondly, a brief explanation of Privoxy's "actions". "Actions" in this
754 context, are the directives we use to tell Privoxy to perform some task
755 relating to HTTP transactions (i.e. web browsing). We tell Privoxy to take some
756 "action". Each action has a unique name and function. While there are many
757 potential actions in Privoxy's arsenal, only a few are used for ad blocking.
758 Actions, and action configuration files, are explained in depth below.
760 Actions are specified in Privoxy's configuration, followed by one or more URLs
761 to which the action should apply. URLs can actually be URL type patterns that
762 use wildcards so they can apply potentially to a range of similar URLs. The
763 actions, together with the URL patterns are called a section.
765 When you connect to a website, the full URL will either match one or more of
766 the sections as defined in Privoxy's configuration, or not. If so, then Privoxy
767 will perform the respective actions. If not, then nothing special happens.
768 Furthermore, web pages may contain embedded, secondary URLs that your web
769 browser will use to load additional components of the page, as it parses the
770 original page's HTML content. An ad image for instance, is just an URL embedded
771 in the page somewhere. The image itself may be on the same server, or a server
772 somewhere else on the Internet. Complex web pages will have many such embedded
773 URLs. Privoxy can deal with each URL individually, so, for instance, the main
774 page text is not touched, but images from such-and-such server are blocked.
776 The most important actions for basic ad blocking are: block, handle-as-image,
777 handle-as-empty-document,and set-image-blocker:
779 • block - this is perhaps the single most used action, and is particularly
780 important for ad blocking. This action stops any contact between your
781 browser and any URL patterns that match this action's configuration. It can
782 be used for blocking ads, but also anything that is determined to be
783 unwanted. By itself, it simply stops any communication with the remote
784 server and sends Privoxy's own built-in BLOCKED page instead to let you now
785 what has happened (with some exceptions, see below).
787 • handle-as-image - tells Privoxy to treat this URL as an image. Privoxy's
788 default configuration already does this for all common image types (e.g.
789 GIF), but there are many situations where this is not so easy to determine.
790 So we'll force it in these cases. This is particularly important for ad
791 blocking, since only if we know that it's an image of some kind, can we
792 replace it with an image of our choosing, instead of the Privoxy BLOCKED
793 page (which would only result in a "broken image" icon). There are some
794 limitations to this though. For instance, you can't just brute-force an
795 image substitution for an entire HTML page in most situations.
797 • handle-as-empty-document - sends an empty document instead of Privoxy's
798 normal BLOCKED HTML page. This is useful for file types that are neither
799 HTML nor images, such as blocking JavaScript files.
801 • set-image-blocker - tells Privoxy what to display in place of an ad image
802 that has hit a block rule. For this to come into play, the URL must match a
803 block action somewhere in the configuration, and, it must also match an
804 handle-as-image action.
806 The configuration options on what to display instead of the ad are:
808 pattern - a checkerboard pattern, so that an ad replacement is obvious.
811 blank - A very small empty GIF image is displayed. This is the so-called
812 "invisible" configuration option.
814 http://<URL> - A redirect to any image anywhere of the user's choosing
817 Advanced users will eventually want to explore Privoxy filters as well. Filters
818 are very different from blocks. A "block" blocks a site, page, or unwanted
819 contented. Filters are a way of filtering or modifying what is actually on the
820 page. An example filter usage: a text replacement of "no-no" for "nasty-word".
821 That is a very simple example. This process can be used for ad blocking, but it
822 is more in the realm of advanced usage and has some pitfalls to be wary off.
824 The quickest way to adjust any of these settings is with your browser through
825 the special Privoxy editor at http://config.privoxy.org/show-status (shortcut:
826 http://p.p/show-status). This is an internal page, and does not require
829 Note that as of Privoxy 3.0.7 beta the action editor is disabled by default.
830 Check the enable-edit-actions section in the configuration file to learn why
831 and in which cases it's safe to enable again.
833 If you decided to enable the action editor, select the appropriate "actions"
834 file, and click "Edit". It is best to put personal or local preferences in
835 user.action since this is not meant to be overwritten during upgrades, and will
836 over-ride the settings in other files. Here you can insert new "actions", and
837 URLs for ad blocking or other purposes, and make other adjustments to the
838 configuration. Privoxy will detect these changes automatically.
840 A quick and simple step by step example:
842 • Right click on the ad image to be blocked, then select "Copy Link Location"
843 from the pop-up menu.
845 • Set your browser to http://config.privoxy.org/show-status
847 • Find user.action in the top section, and click on "Edit":
849 Figure 1. Actions Files in Use
853 • You should have a section with only block listed under "Actions:". If not,
854 click a "Insert new section below" button, and in the new section that just
855 appeared, click the Edit button right under the word "Actions:". This will
856 bring up a list of all actions. Find block near the top, and click in the
857 "Enabled" column, then "Submit" just below the list.
859 • Now, in the block actions section, click the "Add" button, and paste the
860 URL the browser got from "Copy Link Location". Remove the http:// at the
861 beginning of the URL. Then, click "Submit" (or "OK" if in a pop-up window).
863 • Now go back to the original page, and press SHIFT-Reload (or flush all
864 browser caches). The image should be gone now.
866 This is a very crude and simple example. There might be good reasons to use a
867 wildcard pattern match to include potentially similar images from the same
868 site. For a more extensive explanation of "patterns", and the entire actions
869 concept, see the Actions section.
871 For advanced users who want to hand edit their config files, you might want to
872 now go to the Actions Files Tutorial. The ideas explained therein also apply to
873 the web-based editor.
875 There are also various filters that can be used for ad blocking (filters are a
876 special subset of actions). These fall into the "advanced" usage category, and
877 are explained in depth in later sections.
879 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
883 Before launching Privoxy for the first time, you will want to configure your
884 browser(s) to use Privoxy as a HTTP and HTTPS (SSL) proxy. The default is
885 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
886 used port 8000). This is the one configuration step that must be done!
888 Please note that Privoxy can only proxy HTTP and HTTPS traffic. It will not
889 work with FTP or other protocols.
891 Figure 2. Proxy Configuration Showing Mozilla/Netscape HTTP and HTTPS (SSL)
896 With Firefox, this is typically set under:
898 Tools -> Options -> General -> Connection Settings -> Manual Proxy
902 Or optionally on some platforms:
904 Edit -> Preferences -> General -> Connection Settings -> Manual Proxy
908 With Netscape (and Mozilla), this can be set under:
910 Edit -> Preferences -> Advanced -> Proxies -> HTTP Proxy
913 For Internet Explorer v.5-6:
915 Tools -> Internet Options -> Connections -> LAN Settings
917 Then, check "Use Proxy" and fill in the appropriate info (Address: 127.0.0.1,
918 Port: 8118). Include HTTPS (SSL), if you want HTTPS proxy support too
919 (sometimes labeled "Secure"). Make sure any checkboxes like "Use the same proxy
920 server for all protocols" is UNCHECKED. You want only HTTP and HTTPS (SSL)!
922 Figure 3. Proxy Configuration Showing Internet Explorer HTTP and HTTPS (Secure)
927 After doing this, flush your browser's disk and memory caches to force a
928 re-reading of all pages and to get rid of any ads that may be cached. Remove
929 any cookies, if you want Privoxy to manage that. You are now ready to start
930 enjoying the benefits of using Privoxy!
932 Privoxy itself is typically started by specifying the main configuration file
933 to be used on the command line. If no configuration file is specified on the
934 command line, Privoxy will look for a file named config in the current
935 directory. Except on Win32 where it will try config.txt.
937 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
939 5.1. Red Hat and Fedora
941 A default Red Hat installation may not start Privoxy upon boot. It will use the
942 file /etc/privoxy/config as its main configuration file.
944 # /etc/rc.d/init.d/privoxy start
949 # service privoxy start
952 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
956 We use a script. Note that Debian typically starts Privoxy upon booting per
957 default. It will use the file /etc/privoxy/config as its main configuration
960 # /etc/init.d/privoxy start
963 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
967 Click on the Privoxy Icon to start Privoxy. If no configuration file is
968 specified on the command line, Privoxy will look for a file named config.txt.
969 Note that Windows will automatically start Privoxy when the system starts if
970 you chose that option when installing.
972 Privoxy can run with full Windows service functionality. On Windows only, the
973 Privoxy program has two new command line arguments to install and uninstall
974 Privoxy as a service. See the Windows Installation instructions for details.
976 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
978 5.4. Solaris, NetBSD, FreeBSD, HP-UX and others
980 Example Unix startup command:
982 # /usr/sbin/privoxy /etc/privoxy/config
985 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
989 During installation, Privoxy is configured to start automatically when the
990 system restarts. You can start it manually by double-clicking on the Privoxy
991 icon in the Privoxy folder.
993 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
997 During installation, Privoxy is configured to start automatically when the
998 system restarts. To start Privoxy manually, double-click on the
999 StartPrivoxy.command icon in the /Library/Privoxy folder. Or, type this command
1002 /Library/Privoxy/StartPrivoxy.command
1006 You will be prompted for the administrator password.
1008 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1012 Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in
1013 s:user-startup (RoadShow), as startup program in your startup script (Genesis),
1014 or as startup action (Miami and MiamiDx). Privoxy will automatically quit when
1015 you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack
1016 may display that Privoxy is still running).
1018 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1022 A script is again used. It will use the file /etc/privoxy/config as its main
1025 /etc/init.d/privoxy start
1029 Note that Privoxy is not automatically started at boot time by default. You can
1030 change this with the rc-update command.
1032 rc-update add privoxy default
1036 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1038 5.9. Command Line Options
1040 Privoxy may be invoked with the following command-line options:
1044 Print version info and exit. Unix only.
1048 Print short usage info and exit. Unix only.
1052 Don't become a daemon, i.e. don't fork and become process group leader, and
1053 don't detach from controlling tty. Unix only.
1057 On startup, write the process ID to FILE. Delete the FILE on exit. Failure
1058 to create or delete the FILE is non-fatal. If no FILE option is given, no
1059 PID file will be used. Unix only.
1061 • --user USER[.GROUP]
1063 After (optionally) writing the PID file, assume the user ID of USER, and if
1064 included the GID of GROUP. Exit if the privileges are not sufficient to do
1069 Before changing to the user ID given in the --user option, chroot to that
1070 user's home directory, i.e. make the kernel pretend to the Privoxy process
1071 that the directory tree starts there. If set up carefully, this can limit
1072 the impact of possible vulnerabilities in Privoxy to the files contained in
1073 that hierarchy. Unix only.
1075 • --pre-chroot-nslookup hostname
1077 Specifies a hostname to look up before doing a chroot. On some systems,
1078 initializing the resolver library involves reading config files from /etc
1079 and/or loading additional shared libraries from /lib. On these systems,
1080 doing a hostname lookup before the chroot reduces the number of files that
1081 must be copied into the chroot tree.
1083 For fastest startup speed, a good value is a hostname that is not in /etc/
1084 hosts but that your local name server (listed in /etc/resolv.conf) can
1085 resolve without recursion (that is, without having to ask any other name
1086 servers). The hostname need not exist, but if it doesn't, an error message
1087 (which can be ignored) will be output.
1091 If no configfile is included on the command line, Privoxy will look for a
1092 file named "config" in the current directory (except on Win32 where it will
1093 look for "config.txt" instead). Specify full path to avoid confusion. If no
1094 config file is found, Privoxy will fail to start.
1096 On MS Windows only there are two additional command-line options to allow
1097 Privoxy to install and run as a service. See the Window Installation section
1100 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1102 6. Privoxy Configuration
1104 All Privoxy configuration is stored in text files. These files can be edited
1105 with a text editor. Many important aspects of Privoxy can also be controlled
1106 easily with a web browser.
1108 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1110 6.1. Controlling Privoxy with Your Web Browser
1112 Privoxy's user interface can be reached through the special URL http://
1113 config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works
1114 without Internet access. You will see the following section:
1117 ▪ View & change the current configuration
1118 ▪ View the source code version numbers
1119 ▪ View the request headers.
1120 ▪ Look up which actions apply to a URL and why
1121 ▪ Toggle Privoxy on or off
1125 This should be self-explanatory. Note the first item leads to an editor for the
1126 actions files, which is where the ad, banner, cookie, and URL blocking magic is
1127 configured as well as other advanced features of Privoxy. This is an easy way
1128 to adjust various aspects of Privoxy configuration. The actions file, and other
1129 configuration files, are explained in detail below.
1131 "Toggle Privoxy On or Off" is handy for sites that might have problems with
1132 your current actions and filters. You can in fact use it as a test to see
1133 whether it is Privoxy causing the problem or not. Privoxy continues to run as a
1134 proxy in this case, but all manipulation is disabled, i.e. Privoxy acts like a
1135 normal forwarding proxy. There is even a toggle Bookmarklet offered, so that
1136 you can toggle Privoxy with one click from your browser.
1138 Note that several of the features described above are disabled by default in
1139 Privoxy 3.0.7 beta and later. Check the configuration file to learn why and in
1140 which cases it's safe to enable them again.
1142 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1144 6.2. Configuration Files Overview
1146 For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/
1147 by default. For MS Windows, OS/2, and AmigaOS these are all in the same
1148 directory as the Privoxy executable. The name and number of configuration files
1149 has changed from previous versions, and is subject to change as development
1152 The installed defaults provide a reasonable starting point, though some
1153 settings may be aggressive by some standards. For the time being, the principle
1154 configuration files are:
1156 • The main configuration file is named config on Linux, Unix, BSD, OS/2, and
1157 AmigaOS and config.txt on Windows. This is a required file.
1159 • default.action (the main actions file) is used to define which "actions"
1160 relating to banner-blocking, images, pop-ups, content modification, cookie
1161 handling etc should be applied by default. It also defines many exceptions
1162 (both positive and negative) from this default set of actions that enable
1163 Privoxy to selectively eliminate the junk, and only the junk, on as many
1164 websites as possible.
1166 Multiple actions files may be defined in config. These are processed in the
1167 order they are defined. Local customizations and locally preferred
1168 exceptions to the default policies as defined in default.action (which you
1169 will most probably want to define sooner or later) are probably best
1170 applied in user.action, where you can preserve them across upgrades.
1171 standard.action is only for Privoxy's internal use.
1173 There is also a web based editor that can be accessed from http://
1174 config.privoxy.org/show-status (Shortcut: http://p.p/show-status) for the
1175 various actions files.
1177 • "Filter files" (the filter file) can be used to re-write the raw page
1178 content, including viewable text as well as embedded HTML and JavaScript,
1179 and whatever else lurks on any given web page. The filtering jobs are only
1180 pre-defined here; whether to apply them or not is up to the actions files.
1181 default.filter includes various filters made available for use by the
1182 developers. Some are much more intrusive than others, and all should be
1183 used with caution. You may define additional filter files in config as you
1184 can with actions files. We suggest user.filter for any locally defined
1185 filters or customizations.
1187 The syntax of the configuration and filter files may change between different
1188 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1190 All files use the "#" character to denote a comment (the rest of the line will
1191 be ignored) and understand line continuation through placing a backslash ("\")
1192 as the very last character in a line. If the # is preceded by a backslash, it
1193 looses its special function. Placing a # in front of an otherwise valid
1194 configuration line to prevent it from being interpreted is called "commenting
1195 out" that line. Blank lines are ignored.
1197 The actions files and filter files can use Perl style regular expressions for
1198 maximum flexibility.
1200 After making any changes, there is no need to restart Privoxy in order for the
1201 changes to take effect. Privoxy detects such changes automatically. Note,
1202 however, that it may take one or two additional requests for the change to take
1203 effect. When changing the listening address of Privoxy, these "wake up"
1204 requests must obviously be sent to the old listening address.
1206 While under development, the configuration content is subject to change. The
1207 below documentation may not be accurate by the time you read this. Also, what
1208 constitutes a "default" setting, may change, so please check all your
1209 configuration files on important issues.
1211 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1213 7. The Main Configuration File
1215 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
1216 and config.txt on Windows. Configuration lines consist of an initial keyword
1217 followed by a list of values, all separated by whitespace (any number of spaces
1218 or tabs). For example:
1220 confdir /etc/privoxy
1222 Assigns the value /etc/privoxy to the option confdir and thus indicates that
1223 the configuration directory is named "/etc/privoxy/".
1225 All options in the config file except for confdir and logdir are optional.
1226 Watch out in the below description for what happens if you leave them unset.
1228 The main config file controls all aspects of Privoxy's operation that are not
1229 location dependent (i.e. they apply universally, no matter where you may be
1232 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1234 7.1. Local Set-up Documentation
1236 If you intend to operate Privoxy for more users than just yourself, it might be
1237 a good idea to let them know how to reach you, what you block and why you do
1238 that, your policies, etc.
1240 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1246 Location of the Privoxy User Manual.
1250 A fully qualified URI
1258 http://www.privoxy.org/version/user-manual/ will be used, where version is
1259 the Privoxy version.
1263 The User Manual URI is the single best source of information on Privoxy,
1264 and is used for help links from some of the internal CGI pages. The manual
1265 itself is normally packaged with the binary distributions, so you probably
1266 want to set this to a locally installed copy.
1270 The best all purpose solution is simply to put the full local PATH to where
1271 the User Manual is located:
1273 user-manual /usr/share/doc/privoxy/user-manual
1276 The User Manual is then available to anyone with access to Privoxy, by
1277 following the built-in URL: http://config.privoxy.org/user-manual/ (or the
1278 shortcut: http://p.p/user-manual/).
1280 If the documentation is not on the local system, it can be accessed from a
1283 user-manual http://example.com/privoxy/user-manual/
1286 ┌─────────────────────────────────────────────────────────────────┐
1288 ├─────────────────────────────────────────────────────────────────┤
1289 │If set, this option should be the first option in the config │
1290 │file, because it is used while the config file is being read on │
1292 └─────────────────────────────────────────────────────────────────┘
1294 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1296 7.1.2. trust-info-url
1300 A URL to be displayed in the error page that users will see if access to an
1301 untrusted page is denied.
1309 Two example URLs are provided
1313 No links are displayed on the "untrusted" error page.
1317 The value of this option only matters if the experimental trust mechanism
1318 has been activated. (See trustfile below.)
1320 If you use the trust mechanism, it is a good idea to write up some on-line
1321 documentation about your trust policy and to specify the URL(s) here. Use
1322 multiple times for multiple URLs.
1324 The URL(s) should be added to the trustfile as well, so users don't end up
1325 locked out from the information on why they were locked out in the first
1328 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1330 7.1.3. admin-address
1334 An email address to reach the Privoxy administrator.
1346 No email address is displayed on error pages and the CGI user interface.
1350 If both admin-address and proxy-info-url are unset, the whole "Local
1351 Privoxy Support" box on all generated pages will not be shown.
1353 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1355 7.1.4. proxy-info-url
1359 A URL to documentation about the local Privoxy setup, configuration or
1372 No link to local documentation is displayed on error pages and the CGI user
1377 If both admin-address and proxy-info-url are unset, the whole "Local
1378 Privoxy Support" box on all generated pages will not be shown.
1380 This URL shouldn't be blocked ;-)
1382 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1384 7.2. Configuration and Log File Locations
1386 Privoxy can (and normally does) use a number of other files for additional
1387 configuration, help and logging. This section of the configuration file tells
1388 Privoxy where to find those other files.
1390 The user running Privoxy, must have read permission for all configuration
1391 files, and write permission to any files that would be modified, such as log
1392 files and actions files.
1394 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1400 The directory where the other configuration files are located.
1408 /etc/privoxy (Unix) or Privoxy installation dir (Windows)
1416 No trailing "/", please.
1418 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1424 An alternative directory where the templates are loaded from.
1436 The templates are assumed to be located in confdir/template.
1440 Privoxy's original templates are usually overwritten with each update. Use
1441 this option to relocate customized templates that should be kept. As
1442 template variables might change between updates, you shouldn't expect
1443 templates to work with Privoxy releases other than the one they were part
1446 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1452 The directory where all logging takes place (i.e. where logfile and jarfile
1461 /var/log/privoxy (Unix) or Privoxy installation dir (Windows)
1469 No trailing "/", please.
1471 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1477 The actions file(s) to use
1481 Complete file name, relative to confdir
1485 standard.action # Internal purposes, no editing recommended
1487 default.action # Main actions file
1489 user.action # User customizations
1493 No actions are taken at all. More or less neutral proxying.
1497 Multiple actionsfile lines are permitted, and are in fact recommended!
1499 The default values include standard.action, which is used for internal
1500 purposes and should be loaded, default.action, which is the "main" actions
1501 file maintained by the developers, and user.action, where you can make your
1504 Actions files contain all the per site and per URL configuration for ad
1505 blocking, cookie management, privacy considerations, etc. There is no point
1506 in using Privoxy without at least one actions file.
1508 Note that since Privoxy 3.0.7, the complete filename, including the
1509 ".action" extension has to be specified. The syntax change was necessary to
1510 be consistent with the other file options and to allow previously forbidden
1513 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1519 The filter file(s) to use
1523 File name, relative to confdir
1527 default.filter (Unix) or default.filter.txt (Windows)
1531 No textual content filtering takes place, i.e. all +filter{name} actions in
1532 the actions files are turned neutral.
1536 Multiple filterfile lines are permitted.
1538 The filter files contain content modification rules that use regular
1539 expressions. These rules permit powerful changes on the content of Web
1540 pages, and optionally the headers as well, e.g., you could try to disable
1541 your favorite JavaScript annoyances, re-write the actual displayed text, or
1542 just have some fun playing buzzword bingo with web pages.
1544 The +filter{name} actions rely on the relevant filter (name) to be defined
1547 A pre-defined filter file called default.filter that contains a number of
1548 useful filters for common problems is included in the distribution. See the
1549 section on the filter action for a list.
1551 It is recommended to place any locally adapted filters into a separate
1552 file, such as user.filter.
1554 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1564 File name, relative to logdir
1568 Unset (commented out). When activated: logfile (Unix) or privoxy.log
1573 Logging is disabled unless --no-daemon mode is used.
1577 The logfile is where all logging and error messages are written. The level
1578 of detail and number of messages are set with the debug option (see below).
1579 The logfile can be useful for tracking down a problem with Privoxy (e.g.,
1580 it's not blocking an ad you think it should block) and it can help you to
1581 monitor what your browser is doing.
1583 Many users will never look at it, however, and it's a privacy risk if third
1584 parties can get access to it. It is therefore disabled by default in
1585 Privoxy 3.0.7 and later.
1587 For troubleshooting purposes, you will have to explicitly enable it. Please
1588 don't file any support requests without trying to reproduce the problem
1589 with logging enabled first. Once you read the log messages, you may even be
1590 able to solve the problem on your own.
1592 Your logfile will grow indefinitely, and you will probably want to
1593 periodically remove it. On Unix systems, you can do this with a cron job
1594 (see "man cron"). For Red Hat based Linux distributions, a logrotate script
1597 Any log files must be writable by whatever user Privoxy is being run as (on
1598 Unix, default user id is "privoxy").
1600 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1606 The file to store intercepted cookies in
1610 File name, relative to logdir
1614 Unset (commented out). When activated: jarfile (Unix) or privoxy.jar
1619 Intercepted cookies are not stored in a dedicated log file.
1623 The jarfile may grow to ridiculous sizes over time.
1625 If debug 8 (show header parsing) is enabled, cookies are also written to
1626 the logfile with the rest of the headers. Therefore this option isn't very
1627 useful and may be removed in future releases. Please report to the
1628 developers if you are still using it.
1630 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1636 The name of the trust file to use
1640 File name, relative to confdir
1644 Unset (commented out). When activated: trust (Unix) or trust.txt (Windows)
1648 The entire trust mechanism is disabled.
1652 The trust mechanism is an experimental feature for building white-lists and
1653 should be used with care. It is NOT recommended for the casual user.
1655 If you specify a trust file, Privoxy will only allow access to sites that
1656 are specified in the trustfile. Sites can be listed in one of two ways:
1658 Prepending a ~ character limits access to this site only (and any sub-paths
1659 within this site), e.g. ~www.example.com allows access to ~www.example.com/
1660 features/news.html, etc.
1662 Or, you can designate sites as trusted referrers, by prepending the name
1663 with a + character. The effect is that access to untrusted sites will be
1664 granted -- but only if a link from this trusted referrer was used to get
1665 there. The link target will then be added to the "trustfile" so that
1666 future, direct accesses will be granted. Sites added via this mechanism do
1667 not become trusted referrers themselves (i.e. they are added with a ~
1668 designation). There is a limit of 512 such entries, after which new entries
1671 If you use the + operator in the trust file, it may grow considerably over
1674 It is recommended that Privoxy be compiled with the --disable-force,
1675 --disable-toggle and --disable-editor options, if this feature is to be
1678 Possible applications include limiting Internet access for children.
1680 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1684 These options are mainly useful when tracing a problem. Note that you might
1685 also want to invoke Privoxy with the --no-daemon command line option when
1688 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1694 Key values that determine what information gets logged to the logfile.
1702 12289 (i.e.: URLs plus informational and warning messages)
1706 Nothing gets logged.
1710 The available debug levels are:
1712 debug 1 # show each GET/POST/CONNECT request
1713 debug 2 # show each connection status
1714 debug 4 # show I/O status
1715 debug 8 # show header parsing
1716 debug 16 # log all data written to the network into the logfile
1717 debug 32 # debug force feature
1718 debug 64 # debug regular expression filters
1719 debug 128 # debug redirects
1720 debug 256 # debug GIF de-animation
1721 debug 512 # Common Log Format
1722 debug 1024 # debug kill pop-ups
1723 debug 2048 # CGI user interface
1724 debug 4096 # Startup banner and warnings.
1725 debug 8192 # Non-fatal errors
1728 To select multiple debug levels, you can either add them or use multiple
1731 A debug level of 1 is informative because it will show you each request as
1732 it happens. 1, 4096 and 8192 are highly recommended so that you will notice
1733 when things go wrong. The other levels are probably only of interest if you
1734 are hunting down a specific problem. They can produce a hell of an output
1737 If you want to use CLF (Common Log Format), you should set "debug 512" ONLY
1738 and not enable anything else.
1740 Privoxy has a hard-coded limit for the length of log messages. If it's
1741 reached, messages are logged truncated and marked with "... [too long,
1744 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1746 7.3.2. single-threaded
1750 Whether to run only one server thread.
1762 Multi-threaded (or, where unavailable: forked) operation, i.e. the ability
1763 to serve multiple requests simultaneously.
1767 This option is only there for debugging purposes. It will drastically
1770 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1772 7.4. Access Control and Security
1774 This section of the config file controls the security-relevant aspects of
1775 Privoxy's configuration.
1777 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1779 7.4.1. listen-address
1783 The IP address and TCP port on which Privoxy will listen for client
1796 Bind to 127.0.0.1 (localhost), port 8118. This is suitable and recommended
1797 for home users who run Privoxy on the same machine as their browser.
1801 You will need to configure your browser(s) to this proxy address and port.
1803 If you already have another service running on port 8118, or if you want to
1804 serve requests from other machines (e.g. on your local network) as well,
1805 you will need to override the default.
1807 If you leave out the IP address, Privoxy will bind to all interfaces
1808 (addresses) on your machine and may become reachable from the Internet. In
1809 that case, consider using access control lists (ACL's, see below), and/or a
1812 If you open Privoxy to untrusted users, you will also want to make sure
1813 that the following actions are disabled: enable-edit-actions and
1814 enable-remote-toggle
1818 Suppose you are running Privoxy on a machine which has the address
1819 192.168.0.1 on your local private network (192.168.0.0) and has another
1820 outside connection with a different address. You want it to serve requests
1823 listen-address 192.168.0.1:8118
1826 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1832 Initial state of "toggle" status
1844 Act as if toggled on
1848 If set to 0, Privoxy will start in "toggled off" mode, i.e. mostly behave
1849 like a normal, content-neutral proxy with both ad blocking and content
1850 filtering disabled. See enable-remote-toggle below.
1852 The windows version will only display the toggle icon in the system tray if
1853 this option is present.
1855 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1857 7.4.3. enable-remote-toggle
1861 Whether or not the web-based toggle feature may be used
1873 The web-based toggle feature is disabled.
1877 When toggled off, Privoxy mostly acts like a normal, content-neutral proxy,
1878 i.e. doesn't block ads or filter content.
1880 Access to the toggle feature can not be controlled separately by "ACLs" or
1881 HTTP authentication, so that everybody who can access Privoxy (see "ACLs"
1882 and listen-address above) can toggle it for all users. So this option is
1883 not recommended for multi-user environments with untrusted users.
1885 Note that malicious client side code (e.g Java) is also capable of using
1888 As a lot of Privoxy users don't read documentation, this feature is
1889 disabled by default.
1891 Note that you must have compiled Privoxy with support for this feature,
1892 otherwise this option has no effect.
1894 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1896 7.4.4. enable-remote-http-toggle
1900 Whether or not Privoxy recognizes special HTTP headers to change its
1913 Privoxy ignores special HTTP headers.
1917 When toggled on, the client can change Privoxy's behaviour by setting
1918 special HTTP headers. Currently the only supported special header is
1919 "X-Filter: No", to disable filtering for the ongoing request, even if it is
1920 enabled in one of the action files.
1922 This feature is disabled by default. If you are using Privoxy in a
1923 environment with trusted clients, you may enable this feature at your
1924 discretion. Note that malicious client side code (e.g Java) is also capable
1925 of using this feature.
1927 This option will be removed in future releases as it has been obsoleted by
1928 the more general header taggers.
1930 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1932 7.4.5. enable-edit-actions
1936 Whether or not the web-based actions file editor may be used
1948 The web-based actions file editor is disabled.
1952 Access to the editor can not be controlled separately by "ACLs" or HTTP
1953 authentication, so that everybody who can access Privoxy (see "ACLs" and
1954 listen-address above) can modify its configuration for all users.
1956 This option is not recommended for environments with untrusted users and as
1957 a lot of Privoxy users don't read documentation, this feature is disabled
1960 Note that malicious client side code (e.g Java) is also capable of using
1961 the actions editor and you shouldn't enable this options unless you
1962 understand the consequences and are sure your browser is configured
1965 Note that you must have compiled Privoxy with support for this feature,
1966 otherwise this option has no effect.
1968 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1970 7.4.6. enforce-blocks
1974 Whether the user is allowed to ignore blocks and can "go there anyway".
1986 Blocks are not enforced.
1990 Privoxy is mainly used to block and filter requests as a service to the
1991 user, for example to block ads and other junk that clogs the pipes.
1992 Privoxy's configuration isn't perfect and sometimes innocent pages are
1993 blocked. In this situation it makes sense to allow the user to enforce the
1994 request and have Privoxy ignore the block.
1996 In the default configuration Privoxy's "Blocked" page contains a "go there
1997 anyway" link to adds a special string (the force prefix) to the request
1998 URL. If that link is used, Privoxy will detect the force prefix, remove it
1999 again and let the request pass.
2001 Of course Privoxy can also be used to enforce a network policy. In that
2002 case the user obviously should not be able to bypass any blocks, and that's
2003 what the "enforce-blocks" option is for. If it's enabled, Privoxy hides the
2004 "go there anyway" link. If the user adds the force prefix by hand, it will
2005 not be accepted and the circumvention attempt is logged.
2011 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2013 7.4.7. ACLs: permit-access and deny-access
2017 Who can access what.
2021 src_addr[/src_masklen] [dst_addr[/dst_masklen]]
2023 Where src_addr and dst_addr are IP addresses in dotted decimal notation or
2024 valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
2025 notation, i.e. integer values from 2 to 30 representing the length (in
2026 bits) of the network address. The masks and the whole destination part are
2035 Don't restrict access further than implied by listen-address
2039 Access controls are included at the request of ISPs and systems
2040 administrators, and are not usually needed by individual users. For a
2041 typical home user, it will normally suffice to ensure that Privoxy only
2042 listens on the localhost (127.0.0.1) or internal (home) network address by
2043 means of the listen-address option.
2045 Please see the warnings in the FAQ that Privoxy is not intended to be a
2046 substitute for a firewall or to encourage anyone to defer addressing basic
2047 security weaknesses.
2049 Multiple ACL lines are OK. If any ACLs are specified, Privoxy only talks to
2050 IP addresses that match at least one permit-access line and don't match any
2051 subsequent deny-access line. In other words, the last match wins, with the
2052 default being deny-access.
2054 If Privoxy is using a forwarder (see forward below) for a particular
2055 destination URL, the dst_addr that is examined is the address of the
2056 forwarder and NOT the address of the ultimate target. This is necessary
2057 because it may be impossible for the local Privoxy to determine the IP
2058 address of the ultimate target (that's often what gateways are used for).
2060 You should prefer using IP addresses over DNS names, because the address
2061 lookups take time. All DNS names must resolve! You can not use domain
2062 patterns like "*.org" or partial domain names. If a DNS name resolves to
2063 multiple IP addresses, only the first one is used.
2065 Denying access to particular sites by ACL may have undesired side effects
2066 if the site in question is hosted on a machine which also hosts other sites
2071 Explicitly define the default behavior if no ACL and listen-address are
2072 set: "localhost" is OK. The absence of a dst_addr implies that all
2073 destination addresses are OK:
2075 permit-access localhost
2078 Allow any host on the same class C subnet as www.privoxy.org access to
2079 nothing but www.example.com (or other domains hosted on the same system):
2081 permit-access www.privoxy.org/24 www.example.com/32
2084 Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
2085 with the exception that 192.168.45.73 may not access the IP address behind
2086 www.dirty-stuff.example.com:
2088 permit-access 192.168.45.64/26
2089 deny-access 192.168.45.73 www.dirty-stuff.example.com
2092 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2098 Maximum size of the buffer for content filtering.
2110 Use a 4MB (4096 KB) limit.
2114 For content filtering, i.e. the +filter and +deanimate-gif actions, it is
2115 necessary that Privoxy buffers the entire document body. This can be
2116 potentially dangerous, since a server could just keep sending data
2117 indefinitely and wait for your RAM to exhaust -- with nasty consequences.
2120 When a document buffer size reaches the buffer-limit, it is flushed to the
2121 client unfiltered and no further attempt to filter the rest of the document
2122 is made. Remember that there may be multiple threads running, which might
2123 require up to buffer-limit Kbytes each, unless you have enabled
2124 "single-threaded" above.
2126 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2130 This feature allows routing of HTTP requests through a chain of multiple
2133 Forwarding can be used to chain Privoxy with a caching proxy to speed up
2134 browsing. Using a parent proxy may also be necessary if the machine that
2135 Privoxy runs on has no direct Internet access.
2137 Note that parent proxies can severely decrease your privacy level. For example
2138 a parent proxy could add your IP address to the request headers and if it's a
2139 caching proxy it may add the "Etag" header to revalidation requests again, even
2140 though you configured Privoxy to remove it. It may also ignore Privoxy's header
2141 time randomization and use the original values which could be used by the
2142 server as cookie replacement to track your steps between visits.
2144 Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
2147 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2153 To which parent HTTP proxy specific requests should be routed.
2157 target_pattern http_parent[:port]
2159 where target_pattern is a URL pattern that specifies to which requests
2160 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
2161 http_parent[:port] is the DNS name or IP address of the parent HTTP proxy
2162 through which the requests should be forwarded, optionally followed by its
2163 listening port (default: 8080). Use a single dot (.) to denote "no
2172 Don't use parent HTTP proxies.
2176 If http_parent is ".", then requests are not forwarded to another HTTP
2177 proxy but are made directly to the web servers.
2179 Multiple lines are OK, they are checked in sequence, and the last match
2184 Everything goes to an example parent proxy, except SSL on port 443 (which
2187 forward / parent-proxy.example.org:8080
2191 Everything goes to our example ISP's caching proxy, except for requests to
2194 forward / caching-proxy.isp.example.net:8000
2195 forward .isp.example.net .
2198 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2200 7.5.2. forward-socks4 and forward-socks4a
2204 Through which SOCKS proxy (and optionally to which parent HTTP proxy)
2205 specific requests should be routed.
2209 target_pattern socks_proxy[:port] http_parent[:port]
2211 where target_pattern is a URL pattern that specifies to which requests
2212 (i.e. URLs) this forward rule shall apply. Use / to denote "all URLs".
2213 http_parent and socks_proxy are IP addresses in dotted decimal notation or
2214 valid DNS names (http_parent may be "." to denote "no HTTP forwarding"),
2215 and the optional port parameters are TCP ports, i.e. integer values from 1
2224 Don't use SOCKS proxies.
2228 Multiple lines are OK, they are checked in sequence, and the last match
2231 The difference between forward-socks4 and forward-socks4a is that in the
2232 SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
2233 SOCKS server, while in SOCKS 4 it happens locally.
2235 If http_parent is ".", then requests are not forwarded to another HTTP
2236 proxy but are made (HTTP-wise) directly to the web servers, albeit through
2241 From the company example.com, direct connections are made to all "internal"
2242 domains, but everything outbound goes through their ISP's proxy by way of
2243 example.com's corporate SOCKS 4A gateway to the Internet.
2245 forward-socks4a / socks-gw.example.com:1080 www-cache.isp.example.net:8080
2246 forward .example.com .
2249 A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
2252 forward-socks4 / socks-gw.example.com:1080 .
2255 To chain Privoxy and Tor, both running on the same system, you would use
2258 forward-socks4a / 127.0.0.1:9050 .
2261 The public Tor network can't be used to reach your local network, if you
2262 need to access local servers you therefore might want to make some
2265 forward 192.168.*.*/ .
2267 forward 127.*.*.*/ .
2270 Unencrypted connections to systems in these address ranges will be as (un)
2271 secure as the local network is, but the alternative is that you can't reach
2272 the local network through Privoxy at all. Of course this may actually be
2273 desired and there is no reason to make these exceptions if you aren't sure
2276 If you also want to be able to reach servers in your local network by using
2277 their names, you will need additional exceptions that look like this:
2279 forward localhost/ .
2282 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2284 7.5.3. Advanced Forwarding Examples
2286 If you have links to multiple ISPs that provide various special content only to
2287 their subscribers, you can configure multiple Privoxies which have connections
2288 to the respective ISPs to act as forwarders to each other, so that your users
2289 can see the internal content of all ISPs.
2291 Assume that host-a has a PPP connection to isp-a.example.net. And host-b has a
2292 PPP connection to isp-b.example.org. Both run Privoxy. Their forwarding
2293 configuration can look like this:
2298 forward .isp-b.example.net host-b:8118
2304 forward .isp-a.example.org host-a:8118
2307 Now, your users can set their browser's proxy to use either host-a or host-b
2308 and be able to browse the internal content of both isp-a and isp-b.
2310 If you intend to chain Privoxy and squid locally, then chaining as browser ->
2311 squid -> privoxy is the recommended way.
2313 Assuming that Privoxy and squid run on the same box, your squid configuration
2314 could then look like this:
2316 # Define Privoxy as parent proxy (without ICP)
2317 cache_peer 127.0.0.1 parent 8118 7 no-query
2319 # Define ACL for protocol FTP
2322 # Do not forward FTP requests to Privoxy
2323 always_direct allow ftp
2325 # Forward all the rest to Privoxy
2326 never_direct allow all
2329 You would then need to change your browser's proxy settings to squid's address
2330 and port. Squid normally uses port 3128. If unsure consult http_port in
2333 You could just as well decide to only forward requests you suspect of leading
2334 to Windows executables through a virus-scanning parent proxy, say, on
2335 antivir.example.com, port 8010:
2338 forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010
2341 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2343 7.5.4. forwarded-connect-retries
2347 How often Privoxy retries if a forwarded connection request fails.
2359 Connections forwarded through other proxies are treated like direct
2360 connections and no retry attempts are made.
2364 forwarded-connect-retries is mainly interesting for socks4a connections,
2365 where Privoxy can't detect why the connections failed. The connection might
2366 have failed because of a DNS timeout in which case a retry makes sense, but
2367 it might also have failed because the server doesn't exist or isn't
2368 reachable. In this case the retry will just delay the appearance of
2369 Privoxy's error message.
2371 Note that in the context of this option, "forwarded connections" includes
2372 all connections that Privoxy forwards through other proxies. This option is
2373 not limited to the HTTP CONNECT method.
2375 Only use this option, if you are getting lots of forwarding-related error
2376 messages that go away when you try again manually. Start with a small value
2377 and check Privoxy's logfile from time to time, to see how many retries are
2382 forwarded-connect-retries 1
2384 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2386 7.5.5. accept-intercepted-requests
2390 Whether intercepted requests should be treated as valid.
2402 Only proxy requests are accepted, intercepted requests are treated as
2407 If you don't trust your clients and want to force them to use Privoxy,
2408 enable this option and configure your packet filter to redirect outgoing
2409 HTTP connections into Privoxy.
2411 Make sure that Privoxy's own requests aren't redirected as well.
2412 Additionally take care that Privoxy can't intentionally connect to itself,
2413 otherwise you could run into redirection loops if Privoxy's listening port
2414 is reachable by the outside or an attacker has access to the pages you
2419 accept-intercepted-requests 1
2421 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2423 7.5.6. allow-cgi-request-crunching
2427 Whether requests to Privoxy's CGI pages can be blocked or redirected.
2439 Privoxy ignores block and redirect actions for its CGI pages.
2443 By default Privoxy ignores block or redirect actions for its CGI pages.
2444 Intercepting these requests can be useful in multi-user setups to implement
2445 fine-grained access control, but it can also render the complete web
2446 interface useless and make debugging problems painful if done without care.
2448 Don't enable this option unless you're sure that you really need it.
2452 allow-cgi-request-crunching 1
2454 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2456 7.5.7. split-large-forms
2460 Whether the CGI interface should stay compatible with broken HTTP clients.
2472 The CGI form generate long GET URLs.
2476 Privoxy's CGI forms can lead to rather long URLs. This isn't a problem as
2477 far as the HTTP standard is concerned, but it can confuse clients with
2478 arbitrary URL length limitations.
2480 Enabling split-large-forms causes Privoxy to divide big forms into smaller
2481 ones to keep the URL length down. It makes editing a lot less convenient
2482 and you can no longer submit all changes at once, but at least it works
2483 around this browser bug.
2485 If you don't notice any editing problems, there is no reason to enable this
2486 option, but if one of the submit buttons appears to be broken, you should
2493 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2495 7.6. Windows GUI Options
2497 Privoxy has a number of options specific to the Windows GUI interface:
2499 If "activity-animation" is set to 1, the Privoxy icon will animate when
2500 "Privoxy" is active. To turn off, set to 0.
2502 activity-animation 1
2505 If "log-messages" is set to 1, Privoxy will log messages to the console window:
2510 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
2511 of memory used for the log messages displayed in the console window, will be
2512 limited to "log-max-lines" (see below).
2514 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
2520 log-max-lines is the maximum number of lines held in the log buffer. See above.
2525 If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
2526 log messages with a bold-faced font:
2528 log-highlight-messages 1
2531 The font used in the console window:
2533 log-font-name Comic Sans MS
2536 Font size used in the console window:
2541 "show-on-task-bar" controls whether or not Privoxy will appear as a button on
2542 the Task bar when minimized:
2547 If "close-button-minimizes" is set to 1, the Windows close button will minimize
2548 Privoxy instead of closing the program (close with the exit option on the File
2551 close-button-minimizes 1
2554 The "hide-console" option is specific to the MS-Win console version of Privoxy.
2555 If this option is used, Privoxy will disconnect from and hide the command
2561 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2565 The actions files are used to define what actions Privoxy takes for which URLs,
2566 and thus determines how ad images, cookies and various other aspects of HTTP
2567 content and transactions are handled, and on which sites (or even parts
2568 thereof). There are a number of such actions, with a wide range of
2569 functionality. Each action does something a little different. These actions
2570 give us a veritable arsenal of tools with which to exert our control,
2571 preferences and independence. Actions can be combined so that their effects are
2572 aggregated when applied against a given set of URLs.
2574 There are three action files included with Privoxy with differing purposes:
2576 • default.action - is the primary action file that sets the initial values
2577 for all actions. It is intended to provide a base level of functionality
2578 for Privoxy's array of features. So it is a set of broad rules that should
2579 work reasonably well as-is for most users. This is the file that the
2580 developers are keeping updated, and making available to users. The user's
2581 preferences as set in standard.action, e.g. either Cautious (the default),
2582 Medium, or Advanced (see below).
2584 • user.action - is intended to be for local site preferences and exceptions.
2585 As an example, if your ISP or your bank has specific requirements, and need
2586 special handling, this kind of thing should go here. This file will not be
2589 • standard.action - is used only by the web based editor at http://
2590 config.privoxy.org/edit-actions-list?f=default, to set various pre-defined
2591 sets of rules for the default actions section in default.action.
2593 Edit Set to Cautious Set to Medium Set to Advanced
2595 These have increasing levels of aggressiveness and have no influence on
2596 your browsing unless you select them explicitly in the editor. A default
2597 installation should be pre-set to Cautious (versions prior to 3.0.5 were
2598 set to Medium). New users should try this for a while before adjusting the
2599 settings to more aggressive levels. The more aggressive the settings, then
2600 the more likelihood there is of problems such as sites not working as they
2603 The Edit button allows you to turn each action on/off individually for
2604 fine-tuning. The Cautious button changes the actions list to low/safe
2605 settings which will activate ad blocking and a minimal set of Privoxy's
2606 features, and subsequently there will be less of a chance for accidental
2607 problems. The Medium button sets the list to a medium level of other
2608 features and a low level set of privacy features. The Advanced button sets
2609 the list to a high level of ad blocking and medium level of privacy. See
2610 the chart below. The latter three buttons over-ride any changes via with
2611 the Edit button. More fine-tuning can be done in the lower sections of this
2614 It is not recommend to edit the standard.action file itself.
2616 The default profiles, and their associated actions, as pre-defined in
2617 standard.action are:
2619 Table 1. Default Configurations
2621 ┌──────────────────────────┬───────────┬────────────┬───────────┐
2622 │ Feature │ Cautious │ Medium │ Advanced │
2623 ├──────────────────────────┼───────────┼────────────┼───────────┤
2624 │Ad-blocking Aggressiveness│medium │high │high │
2625 ├──────────────────────────┼───────────┼────────────┼───────────┤
2626 │Ad-filtering by size │no │yes │yes │
2627 ├──────────────────────────┼───────────┼────────────┼───────────┤
2628 │Ad-filtering by link │no │no │yes │
2629 ├──────────────────────────┼───────────┼────────────┼───────────┤
2630 │Pop-up killing │blocks only│blocks only │blocks only│
2631 ├──────────────────────────┼───────────┼────────────┼───────────┤
2632 │Privacy Features │low │medium │medium/high│
2633 ├──────────────────────────┼───────────┼────────────┼───────────┤
2634 │Cookie handling │none │session-only│kill │
2635 ├──────────────────────────┼───────────┼────────────┼───────────┤
2636 │Referer forging │no │yes │yes │
2637 ├──────────────────────────┼───────────┼────────────┼───────────┤
2638 │GIF de-animation │no │yes │yes │
2639 ├──────────────────────────┼───────────┼────────────┼───────────┤
2640 │Fast redirects │no │no │yes │
2641 ├──────────────────────────┼───────────┼────────────┼───────────┤
2642 │HTML taming │no │no │yes │
2643 ├──────────────────────────┼───────────┼────────────┼───────────┤
2644 │JavaScript taming │no │no │yes │
2645 ├──────────────────────────┼───────────┼────────────┼───────────┤
2646 │Web-bug killing │no │yes │yes │
2647 ├──────────────────────────┼───────────┼────────────┼───────────┤
2648 │Image tag reordering │no │no │yes │
2649 └──────────────────────────┴───────────┴────────────┴───────────┘
2651 The list of actions files to be used are defined in the main configuration
2652 file, and are processed in the order they are defined (e.g. default.action is
2653 typically processed before user.action). The content of these can all be viewed
2654 and edited from http://config.privoxy.org/show-status. The over-riding
2655 principle when applying actions, is that the last action that matches a given
2656 URL wins. The broadest, most general rules go first (defined in
2657 default.action), followed by any exceptions (typically also in default.action),
2658 which are then followed lastly by any local preferences (typically in
2659 user.action). Generally, user.action has the last word.
2661 An actions file typically has multiple sections. If you want to use "aliases"
2662 in an actions file, you have to place the (optional) alias section at the top
2663 of that file. Then comes the default set of rules which will apply universally
2664 to all sites and pages (be very careful with using such a universal set in
2665 user.action or any other actions file after default.action, because it will
2666 override the result from consulting any previous file). And then below that,
2667 exceptions to the defined universal policies. You can regard user.action as an
2668 appendix to default.action, with the advantage that it is a separate file,
2669 which makes preserving your personal settings across Privoxy upgrades easier.
2671 Actions can be used to block anything you want, including ads, banners, or just
2672 some obnoxious URL whose content you would rather not see. Cookies can be
2673 accepted or rejected, or accepted only during the current browser session (i.e.
2674 not written to disk), content can be modified, some JavaScripts tamed,
2675 user-tracking fooled, and much more. See below for a complete list of actions.
2677 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2679 8.1. Finding the Right Mix
2681 Note that some actions, like cookie suppression or script disabling, may render
2682 some sites unusable that rely on these techniques to work properly. Finding the
2683 right mix of actions is not always easy and certainly a matter of personal
2684 taste. And, things can always change, requiring refinements in the
2685 configuration. In general, it can be said that the more "aggressive" your
2686 default settings (in the top section of the actions file) are, the more
2687 exceptions for "trusted" sites you will have to make later. If, for example,
2688 you want to crunch all cookies per default, you'll have to make exceptions from
2689 that rule for sites that you regularly use and that require cookies for
2690 actually useful purposes, like maybe your bank, favorite shop, or newspaper.
2692 We have tried to provide you with reasonable rules to start from in the
2693 distribution actions files. But there is no general rule of thumb on these
2694 things. There just are too many variables, and sites are constantly changing.
2695 Sooner or later you will want to change the rules (and read this chapter again
2698 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2702 The easiest way to edit the actions files is with a browser by using our
2703 browser-based editor, which can be reached from http://config.privoxy.org/
2704 show-status. Note: the config file option enable-edit-actions must be enabled
2705 for this to work. The editor allows both fine-grained control over every single
2706 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2707 like "Cautious", "Medium" or "Advanced". Warning: the "Advanced" setting is
2708 more aggressive, and will be more likely to cause problems for some sites.
2709 Experienced users only!
2711 If you prefer plain text editing to GUIs, you can of course also directly edit
2712 the the actions files with your favorite text editor. Look at default.action
2713 which is richly commented with many good examples.
2715 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2717 8.3. How Actions are Applied to Requests
2719 Actions files are divided into sections. There are special sections, like the "
2720 alias" sections which will be discussed later. For now let's concentrate on
2721 regular sections: They have a heading line (often split up to multiple lines
2722 for readability) which consist of a list of actions, separated by whitespace
2723 and enclosed in curly braces. Below that, there is a list of URL and tag
2724 patterns, each on a separate line.
2726 To determine which actions apply to a request, the URL of the request is
2727 compared to all URL patterns in each "action file". Every time it matches, the
2728 list of applicable actions for the request is incrementally updated, using the
2729 heading of the section in which the pattern is located. The same is done again
2730 for tags and tag patterns later on.
2732 If multiple applying sections set the same action differently, the last match
2733 wins. If not, the effects are aggregated. E.g. a URL might match a regular
2734 section with a heading line of { +handle-as-image }, then later another one
2735 with just { +block }, resulting in both actions to apply. And there may well be
2736 cases where you will want to combine actions together. Such a section then
2739 { +handle-as-image +block }
2740 # Block these as if they were images. Send no block page.
2742 media.example.com/.*banners
2743 .example.com/images/ads/
2746 You can trace this process for URL patterns and any given URL by visiting http:
2747 //config.privoxy.org/show-url-info.
2749 Examples and more detail on this is provided in the Appendix, Troubleshooting:
2750 Anatomy of an Action section.
2752 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2756 As mentioned, Privoxy uses "patterns" to determine what actions might apply to
2757 which sites and pages your browser attempts to access. These "patterns" use
2758 wild card type pattern matching to achieve a high degree of flexibility. This
2759 allows one expression to be expanded and potentially match against many similar
2762 Generally, an URL pattern has the form <domain>/<path>, where both the <domain>
2763 and <path> are optional. (This is why the special / pattern matches all URLs).
2764 Note that the protocol portion of the URL pattern (e.g. http://) should not be
2765 included in the pattern. This is assumed already!
2767 The pattern matching syntax is different for the domain and path parts of the
2768 URL. The domain part uses a simple globbing type matching technique, while the
2769 path part uses a more flexible "Regular Expressions (PCRE)" based syntax.
2773 is a domain-only pattern and will match any request to www.example.com,
2774 regardless of which document on that server is requested. So ALL pages in
2775 this domain would be covered by the scope of this action. Note that a
2776 simple example.com is different and would NOT match.
2780 means exactly the same. For domain-only patterns, the trailing / may be
2783 www.example.com/index.html$
2785 matches all the documents on www.example.com whose name starts with /
2788 www.example.com/index.html$
2790 matches only the single document /index.html on www.example.com.
2794 matches the document /index.html, regardless of the domain, i.e. on any web
2799 matches nothing, since it would be interpreted as a domain name and there
2800 is no top-level domain called .html. So its a mistake.
2802 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2804 8.4.1. The Domain Pattern
2806 The matching of the domain part offers some flexible options: if the domain
2807 starts or ends with a dot, it becomes unanchored at that end. For example:
2811 matches any domain that ENDS in .example.com
2815 matches any domain that STARTS with www.
2819 matches any domain that CONTAINS .example.. And, by the way, also included
2820 would be any files or documents that exist within that domain since no path
2821 limitations are specified. (Correctly speaking: It matches any FQDN that
2822 contains example as a domain.) This might be www.example.com,
2823 news.example.de, or www.example.net/cgi/testing.pl for instance. All these
2826 Additionally, there are wild-cards that you can use in the domain names
2827 themselves. These work similarly to shell globbing type wild-cards: "*"
2828 represents zero or more arbitrary characters (this is equivalent to the
2829 "Regular Expression" based syntax of ".*"), "?" represents any single character
2830 (this is equivalent to the regular expression syntax of a simple "."), and you
2831 can define "character classes" in square brackets which is similar to the same
2832 regular expression technique. All of this can be freely mixed:
2836 matches "adserver.example.com", "ads.example.com", etc but not
2841 matches all of the above, and then some.
2845 matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
2847 www[1-9a-ez].example.c*
2849 matches www1.example.com, www4.example.cc, wwwd.example.cy,
2850 wwwz.example.com etc., but not wwww.example.com.
2852 While flexible, this is not the sophistication of full regular expression based
2855 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2857 8.4.2. The Path Pattern
2859 Privoxy uses Perl compatible (PCRE) "Regular Expression" based syntax (through
2860 the PCRE library) for matching the path portion (after the slash), and is thus
2863 There is an Appendix with a brief quick-start into regular expressions, and
2864 full (very technical) documentation on PCRE regex syntax is available on-line
2865 at http://www.pcre.org/man.txt. You might also find the Perl man page on
2866 regular expressions (man perlre) useful, which is available on-line at http://
2867 perldoc.perl.org/perlre.html.
2869 Note that the path pattern is automatically left-anchored at the "/", i.e. it
2870 matches as if it would start with a "^" (regular expression speak for the
2871 beginning of a line).
2873 Please also note that matching in the path is CASE INSENSITIVE by default, but
2874 you can switch to case sensitive at any point in the pattern by using the "(?
2875 -i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
2876 path starts with PaTtErN in exactly this capitalization.
2880 Is equivalent to just ".example.com", since any documents within that
2881 domain are matched with or without the ".*" regular expression. This is
2884 .example.com/.*/index.html$
2886 Will match any page in the domain of "example.com" that is named
2887 "index.html", and that is part of some path. For example, it matches
2888 "www.example.com/testing/index.html" but NOT "www.example.com/index.html"
2889 because the regular expression called for at least two "/'s", thus the path
2890 requirement. It also would match "www.example.com/testing/index_html",
2891 because of the special meta-character ".".
2893 .example.com/(.*/)?index\.html$
2895 This regular expression is conditional so it will match any page named
2896 "index.html" regardless of path which in this case can have one or more "/
2897 's". And this one must contain exactly ".html" (but does not have to end
2900 .example.com/(.*/)(ads|banners?|junk)
2902 This regular expression will match any path of "example.com" that contains
2903 any of the words "ads", "banner", "banners" (because of the "?") or "junk".
2904 The path does not have to end in these words, just contain them.
2906 .example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$
2908 This is very much the same as above, except now it must end in either
2909 ".jpg", ".jpeg", ".gif" or ".png". So this one is limited to common image
2912 There are many, many good examples to be found in default.action, and more
2913 tutorials below in Appendix on regular expressions.
2915 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2917 8.4.3. The Tag Pattern
2919 Tag patterns are used to change the applying actions based on the request's
2920 tags. Tags can be created with either the client-header-tagger or the
2921 server-header-tagger action.
2923 Tag patterns have to start with "TAG:", so Privoxy can tell them apart from URL
2924 patterns. Everything after the colon including white space, is interpreted as a
2925 regular expression with path pattern syntax, except that tag patterns aren't
2926 left-anchored automatically (Privoxy doesn't silently add a "^", you have to do
2927 it yourself if you need it).
2929 To match all requests that are tagged with "foo" your pattern line should be
2930 "TAG:^foo$", "TAG:foo" would work as well, but it would also match requests
2931 whose tags contain "foo" somewhere. "TAG: foo" wouldn't work as it requires
2934 Sections can contain URL and tag patterns at the same time, but tag patterns
2935 are checked after the URL patterns and thus always overrule them, even if they
2936 are located before the URL patterns.
2938 Once a new tag is added, Privoxy checks right away if it's matched by one of
2939 the tag patterns and updates the action settings accordingly. As a result tags
2940 can be used to activate other tagger actions, as long as these other taggers
2941 look for headers that haven't already be parsed.
2943 For example you could tag client requests which use the POST method, then use
2944 this tag to activate another tagger that adds a tag if cookies are sent, and
2945 then use a block action based on the cookie tag. This allows the outcome of one
2946 action, to be input into a subsequent action. However if you'd reverse the
2947 position of the described taggers, and activated the method tagger based on the
2948 cookie tagger, no method tags would be created. The method tagger would look
2949 for the request line, but at the time the cookie tag is created, the request
2950 line has already been parsed.
2952 While this is a limitation you should be aware of, this kind of indirection is
2953 seldom needed anyway and even the example doesn't make too much sense.
2955 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
2959 All actions are disabled by default, until they are explicitly enabled
2960 somewhere in an actions file. Actions are turned on if preceded with a "+", and
2961 turned off if preceded with a "-". So a +action means "do that action", e.g.
2962 +block means "please block URLs that match the following patterns", and -block
2963 means "don't block URLs that match the following patterns, even if +block
2964 previously applied."
2966 Again, actions are invoked by placing them on a line, enclosed in curly braces
2967 and separated by whitespace, like in {+some-action -some-other-action
2968 {some-parameter}}, followed by a list of URL patterns, one per line, to which
2969 they apply. Together, the actions line and the following pattern lines make up
2970 a section of the actions file.
2972 Actions fall into three categories:
2974 • Boolean, i.e the action can only be "enabled" or "disabled". Syntax:
2976 +name # enable action name
2977 -name # disable action name
2982 • Parameterized, where some value is required in order to enable this type of
2985 +name{param} # enable action and set parameter to param,
2986 # overwriting parameter from previous match if necessary
2987 -name # disable action. The parameter can be omitted
2990 Note that if the URL matches multiple positive forms of a parameterized
2991 action, the last match wins, i.e. the params from earlier matches are
2994 Example: +hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US;
2995 rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}
2997 • Multi-value. These look exactly like parameterized actions, but they behave
2998 differently: If the action applies multiple times to the same URL, but with
2999 different parameters, all the parameters from all matches are remembered.
3000 This is used for actions that can be executed for the same request
3001 repeatedly, like adding multiple headers, or filtering through multiple
3004 +name{param} # enable action and add param to the list of parameters
3005 -name{param} # remove the parameter param from the list of parameters
3006 # If it was the last one left, disable the action.
3007 -name # disable this action completely and remove all parameters from the list
3010 Examples: +add-header{X-Fun-Header: Some text} and +filter{html-annoyances}
3012 If nothing is specified in any actions file, no "actions" are taken. So in this
3013 case Privoxy would just be a normal, non-blocking, non-filtering proxy. You
3014 must specifically enable the privacy and blocking features you need (although
3015 the provided default actions files will give a good starting point).
3017 Later defined action sections always over-ride earlier ones of the same type.
3018 So exceptions to any rules you make, should come in the latter part of the file
3019 (or in a file that is processed later when using multiple actions files such as
3020 user.action). For multi-valued actions, the actions are applied in the order
3021 they are specified. Actions files are processed in the order they are defined
3022 in config (the default installation has three actions files). It also quite
3023 possible for any given URL to match more than one "pattern" (because of
3024 wildcards and regular expressions), and thus to trigger more than one set of
3025 actions! Last match wins.
3027 The list of valid Privoxy actions are:
3029 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3035 Confuse log analysis, custom applications
3039 Sends a user defined HTTP header to the web server.
3047 Any string value is possible. Validity of the defined HTTP headers is not
3048 checked. It is recommended that you use the "X-" prefix for custom headers.
3052 This action may be specified multiple times, in order to define multiple
3053 headers. This is rarely needed for the typical user. If you don't know what
3054 "HTTP headers" are, you definitely don't need to worry about this one.
3058 +add-header{X-User-Tracking: sucks}
3061 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3067 Block ads or other unwanted content
3071 Requests for URLs to which this action applies are blocked, i.e. the
3072 requests are trapped by Privoxy and the requested URL is never retrieved,
3073 but is answered locally with a substitute page or image, as determined by
3074 the handle-as-image, set-image-blocker, and handle-as-empty-document
3087 Privoxy sends a special "BLOCKED" page for requests to blocked pages. This
3088 page contains links to find out why the request was blocked, and a
3089 click-through to the blocked content (the latter only if compiled with the
3090 force feature enabled). The "BLOCKED" page adapts to the available screen
3091 space -- it displays full-blown if space allows, or miniaturized and
3092 text-only if loaded into a small frame or window. If you are using Privoxy
3093 right now, you can take a look at the "BLOCKED" page.
3095 A very important exception occurs if both block and handle-as-image, apply
3096 to the same request: it will then be replaced by an image. If
3097 set-image-blocker (see below) also applies, the type of image will be
3098 determined by its parameter, if not, the standard checkerboard pattern is
3101 It is important to understand this process, in order to understand how
3102 Privoxy deals with ads and other unwanted content. Blocking is a core
3103 feature, and one upon which various other features depend.
3105 The filter action can perform a very similar task, by "blocking" banner
3106 images and other content through rewriting the relevant URLs in the
3107 document's HTML source, so they don't get requested in the first place.
3108 Note that this is a totally different technique, and it's easy to confuse
3111 Example usage (section):
3114 # Block and replace with "blocked" page
3115 .nasty-stuff.example.com
3117 {+block +handle-as-image}
3118 # Block and replace with image
3122 {+block +handle-as-empty-document}
3123 # Block and then ignore
3124 adserver.exampleclick.net/.*\.js$
3127 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3129 8.5.3. client-header-filter
3133 Rewrite or remove single client headers.
3137 All client headers to which this action applies are filtered on-the-fly
3138 through the specified regular expression based substitutions.
3146 The name of a client-header filter, as defined in one of the filter files.
3150 Client-header filters are applied to each header on its own, not to all at
3151 once. This makes it easier to diagnose problems, but on the downside you
3152 can't write filters that only change header x if header y's value is z. You
3153 can do that by using tags though.
3155 Client-header filters are executed after the other header actions have
3156 finished and use their output as input.
3158 Please refer to the filter file chapter to learn which client-header
3159 filters are available by default, and how to create your own.
3161 Example usage (section):
3163 {+client-header-filter{hide-tor-exit-notation}}
3168 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3170 8.5.4. client-header-tagger
3174 Block requests based on their headers.
3178 Client headers to which this action applies are filtered on-the-fly through
3179 the specified regular expression based substitutions, the result is used as
3188 The name of a client-header tagger, as defined in one of the filter files.
3192 Client-header taggers are applied to each header on its own, and as the
3193 header isn't modified, each tagger "sees" the original.
3195 Client-header taggers are the first actions that are executed and their
3196 tags can be used to control every other action.
3198 Example usage (section):
3200 # Tag every request with the User-Agent header
3201 {+client-header-tagger{user-agent}}
3206 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3208 8.5.5. content-type-overwrite
3212 Stop useless download menus from popping up, or change the browser's
3217 Replaces the "Content-Type:" HTTP server header.
3229 The "Content-Type:" HTTP server header is used by the browser to decide
3230 what to do with the document. The value of this header can cause the
3231 browser to open a download menu instead of displaying the document by
3232 itself, even if the document's format is supported by the browser.
3234 The declared content type can also affect which rendering mode the browser
3235 chooses. If XHTML is delivered as "text/html", many browsers treat it as
3236 yet another broken HTML document. If it is send as "application/xml",
3237 browsers with XHTML support will only display it, if the syntax is correct.
3239 If you see a web site that proudly uses XHTML buttons, but sets
3240 "Content-Type: text/html", you can use Privoxy to overwrite it with
3241 "application/xml" and validate the web master's claim inside your
3242 XHTML-supporting browser. If the syntax is incorrect, the browser will
3245 You can also go the opposite direction: if your browser prints error
3246 messages instead of rendering a document falsely declared as XHTML, you can
3247 overwrite the content type with "text/html" and have it rendered as broken
3250 By default content-type-overwrite only replaces "Content-Type:" headers
3251 that look like some kind of text. If you want to overwrite it
3252 unconditionally, you have to combine it with force-text-mode. This
3253 limitation exists for a reason, think twice before circumventing it.
3255 Most of the time it's easier to replace this action with a custom
3256 server-header filter. It allows you to activate it for every document of a
3257 certain site and it will still only replace the content types you aimed at.
3259 Of course you can apply content-type-overwrite to a whole site and then
3260 make URL based exceptions, but it's a lot more work to get the same
3263 Example usage (sections):
3265 # Check if www.example.net/ really uses valid XHTML
3266 { +content-type-overwrite{application/xml} }
3269 # but leave the content type unmodified if the URL looks like a style sheet
3270 {-content-type-overwrite}
3271 www.example.net/.*\.css$
3272 www.example.net/.*style
3275 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3277 8.5.6. crunch-client-header
3281 Remove a client header Privoxy has no dedicated action for.
3285 Deletes every header sent by the client that contains the string the user
3286 supplied as parameter.
3298 This action allows you to block client headers for which no dedicated
3299 Privoxy action exists. Privoxy will remove every client header that
3300 contains the string you supplied as parameter.
3302 Regular expressions are not supported and you can't use this action to
3303 block different headers in the same request, unless they contain the same
3306 crunch-client-header is only meant for quick tests. If you have to block
3307 several different headers, or only want to modify parts of them, you should
3308 use a client-header filter.
3310 ┌─────────────────────────────────────────────────────────────────┐
3312 ├─────────────────────────────────────────────────────────────────┤
3313 │Don't block any header without understanding the consequences. │
3314 └─────────────────────────────────────────────────────────────────┘
3315 Example usage (section):
3317 # Block the non-existent "Privacy-Violation:" client header
3318 { +crunch-client-header{Privacy-Violation:} }
3323 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3325 8.5.7. crunch-if-none-match
3329 Prevent yet another way to track the user's steps between sessions.
3333 Deletes the "If-None-Match:" HTTP client header.
3345 Removing the "If-None-Match:" HTTP client header is useful for filter
3346 testing, where you want to force a real reload instead of getting status
3347 code "304" which would cause the browser to use a cached copy of the page.
3349 It is also useful to make sure the header isn't used as a cookie
3350 replacement (unlikely but possible).
3352 Blocking the "If-None-Match:" header shouldn't cause any caching problems,
3353 as long as the "If-Modified-Since:" header isn't blocked or missing as
3356 It is recommended to use this action together with hide-if-modified-since
3357 and overwrite-last-modified.
3359 Example usage (section):
3361 # Let the browser revalidate cached documents but don't
3362 # allow the server to use the revalidation headers for user tracking.
3363 {+hide-if-modified-since{-60} \
3364 +overwrite-last-modified{randomize} \
3365 +crunch-if-none-match}
3369 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3371 8.5.8. crunch-incoming-cookies
3375 Prevent the web server from setting HTTP cookies on your system
3379 Deletes any "Set-Cookie:" HTTP headers from server replies.
3391 This action is only concerned with incoming HTTP cookies. For outgoing HTTP
3392 cookies, use crunch-outgoing-cookies. Use both to disable HTTP cookies
3395 It makes no sense at all to use this action in conjunction with the
3396 session-cookies-only action, since it would prevent the session cookies
3397 from being set. See also filter-content-cookies.
3401 +crunch-incoming-cookies
3404 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3406 8.5.9. crunch-server-header
3410 Remove a server header Privoxy has no dedicated action for.
3414 Deletes every header sent by the server that contains the string the user
3415 supplied as parameter.
3427 This action allows you to block server headers for which no dedicated
3428 Privoxy action exists. Privoxy will remove every server header that
3429 contains the string you supplied as parameter.
3431 Regular expressions are not supported and you can't use this action to
3432 block different headers in the same request, unless they contain the same
3435 crunch-server-header is only meant for quick tests. If you have to block
3436 several different headers, or only want to modify parts of them, you should
3437 use a custom server-header filter.
3439 ┌─────────────────────────────────────────────────────────────────┐
3441 ├─────────────────────────────────────────────────────────────────┤
3442 │Don't block any header without understanding the consequences. │
3443 └─────────────────────────────────────────────────────────────────┘
3444 Example usage (section):
3446 # Crunch server headers that try to prevent caching
3447 { +crunch-server-header{no-cache} }
3451 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3453 8.5.10. crunch-outgoing-cookies
3457 Prevent the web server from reading any HTTP cookies from your system
3461 Deletes any "Cookie:" HTTP headers from client requests.
3473 This action is only concerned with outgoing HTTP cookies. For incoming HTTP
3474 cookies, use crunch-incoming-cookies. Use both to disable HTTP cookies
3477 It makes no sense at all to use this action in conjunction with the
3478 session-cookies-only action, since it would prevent the session cookies
3483 +crunch-outgoing-cookies
3486 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3488 8.5.11. deanimate-gifs
3492 Stop those annoying, distracting animated GIF images.
3496 De-animate GIF animations, i.e. reduce them to their first or last image.
3508 This will also shrink the images considerably (in bytes, not pixels!). If
3509 the option "first" is given, the first frame of the animation is used as
3510 the replacement. If "last" is given, the last frame of the animation is
3511 used instead, which probably makes more sense for most banner animations,
3512 but also has the risk of not showing the entire last frame (if it is only a
3513 delta to an earlier frame).
3515 You can safely use this action with patterns that will also match non-GIF
3516 objects, because no attempt will be made at anything that doesn't look like
3521 +deanimate-gifs{last}
3524 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3526 8.5.12. downgrade-http-version
3530 Work around (very rare) problems with HTTP/1.1
3534 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3546 This is a left-over from the time when Privoxy didn't support important
3547 HTTP/1.1 features well. It is left here for the unlikely case that you
3548 experience HTTP/1.1 related problems with some server out there. Not all
3549 HTTP/1.1 features and requirements are supported yet, so there is a chance
3550 you might need this action.
3552 Example usage (section):
3554 {+downgrade-http-version}
3555 problem-host.example.com
3558 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3560 8.5.13. fast-redirects
3564 Fool some click-tracking scripts and speed up indirect links.
3568 Detects redirection URLs and redirects the browser without contacting the
3569 redirection server first.
3577 □ "simple-check" to just search for the string "http://" to detect
3580 □ "check-decoded-url" to decode URLs (if necessary) before searching for
3585 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3586 will link to some script on their own servers, giving the destination as a
3587 parameter, which will then redirect you to the final target. URLs resulting
3588 from this scheme typically look like: "http://www.example.org/
3589 click-tracker.cgi?target=http%3a//www.example.net/".
3591 Sometimes, there are even multiple consecutive redirects encoded in the
3592 URL. These redirections via scripts make your web browsing more traceable,
3593 since the server from which you follow such a link can see where you go to.
3594 Apart from that, valuable bandwidth and time is wasted, while your browser
3595 asks the server for one redirect after the other. Plus, it feeds the
3598 This feature is currently not very smart and is scheduled for improvement.
3599 If it is enabled by default, you will have to create some exceptions to
3600 this action. It can lead to failures in several ways:
3602 Not every URLs with other URLs as parameters is evil. Some sites offer a
3603 real service that requires this information to work. For example a
3604 validation service needs to know, which document to validate.
3605 fast-redirects assumes that every URL parameter that looks like another URL
3606 is a redirection target, and will always redirect to the last one. Most of
3607 the time the assumption is correct, but if it isn't, the user gets
3610 Another failure occurs if the URL contains other parameters after the URL
3611 parameter. The URL: "http://www.example.org/?redirect=http%3a//
3612 www.example.net/&foo=bar". contains the redirection URL "http://
3613 www.example.net/", followed by another parameter. fast-redirects doesn't
3614 know that and will cause a redirect to "http://www.example.net/&foo=bar".
3615 Depending on the target server configuration, the parameter will be
3616 silently ignored or lead to a "page not found" error. You can prevent this
3617 problem by first using the redirect action to remove the last part of the
3618 URL, but it requires a little effort.
3620 To detect a redirection URL, fast-redirects only looks for the string
3621 "http://", either in plain text (invalid but often used) or encoded as
3622 "http%3a//". Some sites use their own URL encoding scheme, encrypt the
3623 address of the target server or replace it with a database id. In theses
3624 cases fast-redirects is fooled and the request reaches the redirection
3625 server where it probably gets logged.
3629 { +fast-redirects{simple-check} }
3632 { +fast-redirects{check-decoded-url} }
3633 another.example.com/testing
3636 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3642 Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3643 do fun text replacements, add personalized effects, etc.
3647 All instances of text-based type, most notably HTML and JavaScript, to
3648 which this action applies, can be filtered on-the-fly through the specified
3649 regular expression based substitutions. (Note: as of version 3.0.3 plain
3650 text documents are exempted from filtering, because web servers often use
3651 the text/plain MIME type for all files whose type they don't know.)
3659 The name of a content filter, as defined in the filter file. Filters can be
3660 defined in one or more files as defined by the filterfile option in the
3661 config file. default.filter is the collection of filters supplied by the
3662 developers. Locally defined filters should go in their own file, such as
3665 When used in its negative form, and without parameters, all filtering is
3666 completely disabled.
3670 For your convenience, there are a number of pre-defined filters available
3671 in the distribution filter file that you can use. See the examples below
3674 Filtering requires buffering the page content, which may appear to slow
3675 down page rendering since nothing is displayed until all content has passed
3676 the filters. (It does not really take longer, but seems that way since the
3677 page is not incrementally displayed.) This effect will be more noticeable
3678 on slower connections.
3680 "Rolling your own" filters requires a knowledge of "Regular Expressions"
3681 and "HTML". This is very powerful feature, and potentially very intrusive.
3682 Filters should be used with caution, and where an equivalent "action" is
3685 The amount of data that can be filtered is limited to the buffer-limit
3686 option in the main config file. The default is 4096 KB (4 Megs). Once this
3687 limit is exceeded, the buffered data, and all pending data, is passed
3690 Inappropriate MIME types, such as zipped files, are not filtered at all.
3691 (Again, only text-based types except plain text). Encrypted SSL data (from
3692 HTTPS servers) cannot be filtered either, since this would violate the
3693 integrity of the secure transaction. In some situations it might be
3694 necessary to protect certain text, like source code, from filtering by
3695 defining appropriate -filter exceptions.
3697 Compressed content can't be filtered either, unless Privoxy is compiled
3698 with zlib support (requires at least Privoxy 3.0.7), in which case Privoxy
3699 will decompress the content before filtering it.
3701 If you use a Privoxy version without zlib support, but want filtering to
3702 work on as much documents as possible, even those that would normally be
3703 sent compressed, you must use the prevent-compression action in conjunction
3706 Content filtering can achieve some of the same effects as the block action,
3707 i.e. it can be used to block ads and banners. But the mechanism works quite
3708 differently. One effective use, is to block ad banners based on their size
3709 (see below), since many of these seem to be somewhat standardized.
3711 Feedback with suggestions for new or improved filters is particularly
3714 The below list has only the names and a one-line description of each
3715 predefined filter. There are more verbose explanations of what these
3716 filters do in the filter file chapter.
3718 Example usage (with filters from the distribution default.filter file). See the
3719 Predefined Filters section for more explanation on each:
3721 +filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse
3724 +filter{js-events} # Kill all JS event bindings (Radically destructive! Only for extra nasty sites)
3727 +filter{html-annoyances} # Get rid of particularly annoying HTML abuse
3730 +filter{content-cookies} # Kill cookies that come in the HTML or JS content
3733 +filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups)
3736 +filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.
3739 +filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.
3742 +filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective
3745 +filter{banners-by-size} # Kill banners by size
3748 +filter{banners-by-link} # Kill banners by their links to known clicktrackers
3751 +filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking)
3754 +filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap
3757 +filter{jumping-windows} # Prevent windows from resizing and moving themselves
3760 +filter{frameset-borders} # Give frames a border and make them resizeable
3763 +filter{demoronizer} # Fix MS's non-standard use of standard charsets
3766 +filter{shockwave-flash} # Kill embedded Shockwave Flash objects
3769 +filter{quicktime-kioskmode} # Make Quicktime movies savable
3772 +filter{fun} # Text replacements for subversive browsing fun!
3775 +filter{crude-parental} # Crude parental filtering (demo only)
3778 +filter{ie-exploits} # Disable a known Internet Explorer bug exploits
3781 +filter{site-specifics} # Custom filters for specific site related problems
3784 +filter{google} # Removes text ads and other Google specific improvements
3787 +filter{yahoo} # Removes text ads and other Yahoo specific improvements
3790 +filter{msn} # Removes text ads and other MSN specific improvements
3793 +filter{blogspot} # Cleans up Blogspot blogs
3796 +filter{no-ping} # Removes non-standard ping attributes from anchor and area tags
3799 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3801 8.5.15. force-text-mode
3805 Force Privoxy to treat a document as if it was in some kind of text format.
3809 Declares a document as text, even if the "Content-Type:" isn't detected as
3822 As explained above, Privoxy tries to only filter files that are in some
3823 kind of text format. The same restrictions apply to content-type-overwrite.
3824 force-text-mode declares a document as text, without looking at the
3825 "Content-Type:" first.
3827 ┌─────────────────────────────────────────────────────────────────┐
3829 ├─────────────────────────────────────────────────────────────────┤
3830 │Think twice before activating this action. Filtering binary data │
3831 │with regular expressions can cause file damage. │
3832 └─────────────────────────────────────────────────────────────────┘
3839 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3841 8.5.16. forward-override
3845 Change the forwarding settings based on User-Agent or request origin
3849 Overrules the forward directives in the configuration file.
3857 □ "forward ." to use a direct connection without any additional proxies.
3859 □ "forward 127.0.0.1:8123" to use the HTTP proxy listening at 127.0.0.1
3862 □ "forward-socks4a 127.0.0.1:9050 ." to use the socks4a proxy listening
3863 at 127.0.0.1 port 9050. Replace "forward-socks4a" with "forward-socks4"
3864 to use a socks4 connection (with local DNS resolution) instead.
3866 □ "forward-socks4a 127.0.0.1:9050 proxy.example.org:8000" to use the
3867 socks4a proxy listening at 127.0.0.1 port 9050 to reach the HTTP proxy
3868 listening at proxy.example.org port 8000. Replace "forward-socks4a"
3869 with "forward-socks4" to use a socks4 connection (with local DNS
3870 resolution) instead.
3874 This action takes parameters similar to the forward directives in the
3875 configuration file, but without the URL pattern. It can be used as
3876 replacement, but normally it's only used in cases where matching based on
3877 the request URL isn't sufficient.
3879 ┌─────────────────────────────────────────────────────────────────┐
3881 ├─────────────────────────────────────────────────────────────────┤
3882 │Please read the description for the forward directives before │
3883 │using this action. Forwarding to the wrong people will reduce │
3884 │your privacy and increase the chances of man-in-the-middle │
3887 │If the ports are missing or invalid, default values will be used.│
3888 │This might change in the future and you shouldn't rely on it. │
3889 │Otherwise incorrect syntax causes Privoxy to exit. │
3891 │Use the show-url-info CGI page to verify that your forward │
3892 │settings do what you thought the do. │
3893 └─────────────────────────────────────────────────────────────────┘
3896 # Always use direct connections for requests previously tagged as
3897 # "User-Agent: fetch libfetch/2.0" and make sure
3898 # resuming downloads continues to work.
3899 # This way you can continue to use Tor for your normal browsing,
3900 # without overloading the Tor network with your FreeBSD ports updates
3901 # or downloads of bigger files like ISOs.
3902 {+forward-override{forward .} \
3903 -hide-if-modified-since \
3904 -overwrite-last-modified \
3906 TAG:^User-Agent: fetch libfetch/2\.0$
3910 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3912 8.5.17. handle-as-empty-document
3916 Mark URLs that should be replaced by empty documents if they get blocked
3920 This action alone doesn't do anything noticeable. It just marks URLs. If
3921 the block action also applies, the presence or absence of this mark decides
3922 whether an HTML "BLOCKED" page, or an empty document will be sent to the
3923 client as a substitute for the blocked content. The empty document isn't
3924 literally empty, but actually contains a single space.
3936 Some browsers complain about syntax errors if JavaScript documents are
3937 blocked with Privoxy's default HTML page; this option can be used to
3938 silence them. And of course this action can also be used to eliminate the
3939 Privoxy BLOCKED message in frames.
3941 The content type for the empty document can be specified with
3942 content-type-overwrite{}, but usually this isn't necessary.
3946 # Block all documents on example.org that end with ".js",
3947 # but send an empty document instead of the usual HTML message.
3948 {+block +handle-as-empty-document}
3953 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3955 8.5.18. handle-as-image
3959 Mark URLs as belonging to images (so they'll be replaced by images if they
3960 do get blocked, rather than HTML pages)
3964 This action alone doesn't do anything noticeable. It just marks URLs as
3965 images. If the block action also applies, the presence or absence of this
3966 mark decides whether an HTML "blocked" page, or a replacement image (as
3967 determined by the set-image-blocker action) will be sent to the client as a
3968 substitute for the blocked content.
3980 The below generic example section is actually part of default.action. It
3981 marks all URLs with well-known image file name extensions as images and
3982 should be left intact.
3984 Users will probably only want to use the handle-as-image action in
3985 conjunction with block, to block sources of banners, whose URLs don't
3986 reflect the file type, like in the second example section.
3988 Note that you cannot treat HTML pages as images in most cases. For
3989 instance, (in-line) ad frames require an HTML page to be sent, or they
3990 won't display properly. Forcing handle-as-image in this situation will not
3991 replace the ad frame with an image, but lead to error messages.
3993 Example usage (sections):
3995 # Generic image extensions:
3998 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4000 # These don't look like images, but they're banners and should be
4001 # blocked as images:
4003 {+block +handle-as-image}
4004 some.nasty-banner-server.com/junk.cgi\?output=trash
4006 # Banner source! Who cares if they also have non-image content?
4010 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4012 8.5.19. hide-accept-language
4016 Pretend to use different language settings.
4020 Deletes or replaces the "Accept-Language:" HTTP header in client requests.
4028 Keyword: "block", or any user defined value.
4032 Faking the browser's language settings can be useful to make a foreign
4033 User-Agent set with hide-user-agent more believable.
4035 However some sites with content in different languages check the
4036 "Accept-Language:" to decide which one to take by default. Sometimes it
4037 isn't possible to later switch to another language without changing the
4038 "Accept-Language:" header first.
4040 Therefore it's a good idea to either only change the "Accept-Language:"
4041 header to languages you understand, or to languages that aren't wide
4044 Before setting the "Accept-Language:" header to a rare language, you should
4045 consider that it helps to make your requests unique and thus easier to
4046 trace. If you don't plan to change this header frequently, you should stick
4047 to a common language.
4049 Example usage (section):
4051 # Pretend to use Canadian language settings.
4052 {+hide-accept-language{en-ca} \
4053 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4058 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4060 8.5.20. hide-content-disposition
4064 Prevent download menus for content you prefer to view inside the browser.
4068 Deletes or replaces the "Content-Disposition:" HTTP header set by some
4077 Keyword: "block", or any user defined value.
4081 Some servers set the "Content-Disposition:" HTTP header for documents they
4082 assume you want to save locally before viewing them. The
4083 "Content-Disposition:" header contains the file name the browser is
4084 supposed to use by default.
4086 In most browsers that understand this header, it makes it impossible to
4087 just view the document, without downloading it first, even if it's just a
4088 simple text file or an image.
4090 Removing the "Content-Disposition:" header helps to prevent this annoyance,
4091 but some browsers additionally check the "Content-Type:" header, before
4092 they decide if they can display a document without saving it first. In
4093 these cases, you have to change this header as well, before the browser
4094 stops displaying download menus.
4096 It is also possible to change the server's file name suggestion to another
4097 one, but in most cases it isn't worth the time to set it up.
4099 This action will probably be removed in the future, use server-header
4104 # Disarm the download link in Sourceforge's patch tracker
4106 +content-type-overwrite{text/plain}\
4107 +hide-content-disposition{block} }
4108 .sourceforge.net/tracker/download\.php
4111 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4113 8.5.21. hide-if-modified-since
4117 Prevent yet another way to track the user's steps between sessions.
4121 Deletes the "If-Modified-Since:" HTTP client header or modifies its value.
4129 Keyword: "block", or a user defined value that specifies a range of hours.
4133 Removing this header is useful for filter testing, where you want to force
4134 a real reload instead of getting status code "304", which would cause the
4135 browser to use a cached copy of the page.
4137 Instead of removing the header, hide-if-modified-since can also add or
4138 subtract a random amount of time to/from the header's value. You specify a
4139 range of minutes where the random factor should be chosen from and Privoxy
4140 does the rest. A negative value means subtracting, a positive value adding.
4142 Randomizing the value of the "If-Modified-Since:" makes sure it isn't used
4143 as a cookie replacement, but you will run into caching problems if the
4144 random range is too high.
4146 It is a good idea to only use a small negative value and let
4147 overwrite-last-modified handle the greater changes.
4149 It is also recommended to use this action together with
4150 crunch-if-none-match.
4152 Example usage (section):
4154 # Let the browser revalidate without being tracked across sessions
4155 { +hide-if-modified-since{-60} \
4156 +overwrite-last-modified{randomize} \
4157 +crunch-if-none-match}
4161 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4163 8.5.22. hide-forwarded-for-headers
4167 Improve privacy by not embedding the source of the request in the HTTP
4172 Deletes any existing "X-Forwarded-for:" HTTP header from client requests,
4173 and prevents adding a new one.
4185 It is safe to leave this on.
4189 +hide-forwarded-for-headers
4192 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4194 8.5.23. hide-from-header
4198 Keep your (old and ill) browser from telling web servers your email address
4202 Deletes any existing "From:" HTTP header, or replaces it with the specified
4211 Keyword: "block", or any user defined value.
4215 The keyword "block" will completely remove the header (not to be confused
4216 with the block action).
4218 Alternately, you can specify any value you prefer to be sent to the web
4219 server. If you do, it is a matter of fairness not to use any address that
4220 is actually used by a real person.
4222 This action is rarely needed, as modern web browsers don't send "From:"
4227 +hide-from-header{block}
4232 +hide-from-header{spam-me-senseless@sittingduck.example.com}
4235 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4237 8.5.24. hide-referrer
4241 Conceal which link you followed to get to a particular site
4245 Deletes the "Referer:" (sic) HTTP header from the client request, or
4246 replaces it with a forged one.
4254 □ "conditional-block" to delete the header completely if the host has
4257 □ "block" to delete the header unconditionally.
4259 □ "forge" to pretend to be coming from the homepage of the server we are
4262 □ Any other string to set a user defined referrer.
4266 conditional-block is the only parameter, that isn't easily detected in the
4267 server's log file. If it blocks the referrer, the request will look like
4268 the visitor used a bookmark or typed in the address directly.
4270 Leaving the referrer unmodified for requests on the same host allows the
4271 server owner to see the visitor's "click path", but in most cases she could
4272 also get that information by comparing other parts of the log file: for
4273 example the User-Agent if it isn't a very common one, or the user's IP
4274 address if it doesn't change between different requests.
4276 Always blocking the referrer, or using a custom one, can lead to failures
4277 on servers that check the referrer before they answer any requests, in an
4278 attempt to prevent their valuable content from being embedded or linked to
4281 Both conditional-block and forge will work with referrer checks, as long as
4282 content and valid referring page are on the same host. Most of the time
4285 hide-referer is an alternate spelling of hide-referrer and the two can be
4286 can be freely substituted with each other. ("referrer" is the correct
4287 English spelling, however the HTTP specification has a bug - it requires it
4288 to be spelled as "referer".)
4292 +hide-referrer{forge}
4297 +hide-referrer{http://www.yahoo.com/}
4300 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4302 8.5.25. hide-user-agent
4306 Conceal your type of browser and client operating system
4310 Replaces the value of the "User-Agent:" HTTP header in client requests with
4311 the specified value.
4319 Any user-defined string.
4323 ┌─────────────────────────────────────────────────────────────────┐
4325 ├─────────────────────────────────────────────────────────────────┤
4326 │This can lead to problems on web sites that depend on looking at │
4327 │this header in order to customize their content for different │
4328 │browsers (which, by the way, is NOT the right thing to do: good │
4329 │web sites work browser-independently). │
4330 └─────────────────────────────────────────────────────────────────┘
4332 Using this action in multi-user setups or wherever different types of
4333 browsers will access the same Privoxy is not recommended. In single-user,
4334 single-browser setups, you might use it to delete your OS version
4335 information from the headers, because it is an invitation to exploit known
4336 bugs for your OS. It is also occasionally useful to forge this in order to
4337 access sites that won't let you in otherwise (though there may be a good
4338 reason in some cases). Example of this: some MSN sites will not let Mozilla
4339 enter, yet forging to a Netscape 6.1 user-agent works just fine. (Must be
4340 just a silly MS goof, I'm sure :-).
4342 More information on known user-agent strings can be found at http://
4343 www.user-agents.org/ and http://en.wikipedia.org/wiki/User_agent.
4347 +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
4350 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4352 8.5.26. inspect-jpegs
4356 To protect against the MS buffer over-run in JPEG processing
4360 Protect against a known exploit
4372 See Microsoft Security Bulletin MS04-028. JPEG images are one of the most
4373 common image types found across the Internet. The exploit as described can
4374 allow execution of code on the target system, giving an attacker access to
4375 the system in question by merely planting an altered JPEG image, which
4376 would have no obvious indications of what lurks inside. This action
4377 prevents this exploit.
4379 Note that the described exploit is only one of many, using this action does
4380 not mean that you no longer have to patch the client.
4387 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4393 Eliminate those annoying pop-up windows (deprecated)
4397 While loading the document, replace JavaScript code that opens pop-up
4398 windows with (syntactically neutral) dummy code on the fly.
4410 This action is basically a built-in, hardwired special-purpose filter
4411 action, but there are important differences: For kill-popups, the document
4412 need not be buffered, so it can be incrementally rendered while
4413 downloading. But kill-popups doesn't catch as many pop-ups as filter
4414 {all-popups} does and is not as smart as filter{unsolicited-popups} is.
4416 Think of it as a fast and efficient replacement for a filter that you can
4417 use if you don't want any filtering at all. Note that it doesn't make sense
4418 to combine it with any filter action, since as soon as one filter applies,
4419 the whole document needs to be buffered anyway, which destroys the
4420 advantage of the kill-popups action over its filter equivalent.
4422 Killing all pop-ups unconditionally is problematic. Many shops and banks
4423 rely on pop-ups to display forms, shopping carts etc, and the filter
4424 {unsolicited-popups} does a better job of catching only the unwanted ones.
4426 If the only kind of pop-ups that you want to kill are exit consoles (those
4427 really nasty windows that appear when you close an other one), you might
4428 want to use filter{js-annoyances} instead.
4430 This action is most appropriate for browsers that don't have any controls
4431 for unwanted pop-ups. Not recommended for general usage.
4438 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4440 8.5.28. limit-connect
4444 Prevent abuse of Privoxy as a TCP proxy relay or disable SSL for untrusted
4449 Specifies to which ports HTTP CONNECT requests are allowable.
4457 A comma-separated list of ports or port ranges (the latter using dashes,
4458 with the minimum defaulting to 0 and the maximum to 65K).
4462 By default, i.e. if no limit-connect action applies, Privoxy only allows
4463 HTTP CONNECT requests to port 443 (the standard, secure HTTPS port). Use
4464 limit-connect if more fine-grained control is desired for some or all
4467 The CONNECT methods exists in HTTP to allow access to secure websites
4468 ("https://" URLs) through proxies. It works very simply: the proxy connects
4469 to the server on the specified port, and then short-circuits its
4470 connections to the client and to the remote server. This can be a big
4471 security hole, since CONNECT-enabled proxies can be abused as TCP relays
4474 Privoxy relays HTTPS traffic without seeing the decoded content. Websites
4475 can leverage this limitation to circumvent Privoxy's filters. By specifying
4476 an invalid port range you can disable HTTPS entirely. If you plan to
4477 disable SSL by default, consider enabling
4478 treat-forbidden-connects-like-blocks as well, to be able to quickly create
4483 +limit-connect{443} # This is the default and need not be specified.
4484 +limit-connect{80,443} # Ports 80 and 443 are OK.
4485 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4486 +limit-connect{-} # All ports are OK
4487 +limit-connect{,} # No HTTPS/SSL traffic is allowed
4490 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4492 8.5.29. prevent-compression
4496 Ensure that servers send the content uncompressed, so it can be passed
4501 Removes the Accept-Encoding header which can be used to ask for compressed
4514 More and more websites send their content compressed by default, which is
4515 generally a good idea and saves bandwidth. But the filter, deanimate-gifs
4516 and kill-popups actions need access to the uncompressed data.
4518 When compiled with zlib support (available since Privoxy 3.0.7), content
4519 that should be filtered is decompressed on-the-fly and you don't have to
4520 worry about this action. If you are using an older Privoxy version, or one
4521 that hasn't been compiled with zlib support, this action can be used to
4522 convince the server to send the content uncompressed.
4524 Most text-based instances compress very well, the size is seldom decreased
4525 by less than 50%, for markup-heavy instances like news feeds saving more
4526 than 90% of the original size isn't unusual.
4528 Not using compression will therefore slow down the transfer, and you should
4529 only enable this action if you really need it. As of Privoxy 3.0.7 it's
4530 disabled in all predefined action settings.
4532 Note that some (rare) ill-configured sites don't handle requests for
4533 uncompressed documents correctly. Broken PHP applications tend to send an
4534 empty document body, some IIS versions only send the beginning of the
4535 content. If you enable prevent-compression per default, you might want to
4536 add exceptions for those sites. See the example for how to do that.
4538 Example usage (sections):
4540 # Selectively turn off compression, and enable a filter
4542 { +filter{tiny-textforms} +prevent-compression }
4543 # Match only these sites
4548 # Or instead, we could set a universal default:
4550 { +prevent-compression }
4553 # Then maybe make exceptions for broken sites:
4555 { -prevent-compression }
4559 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4561 8.5.30. overwrite-last-modified
4565 Prevent yet another way to track the user's steps between sessions.
4569 Deletes the "Last-Modified:" HTTP server header or modifies its value.
4577 One of the keywords: "block", "reset-to-request-time" and "randomize"
4581 Removing the "Last-Modified:" header is useful for filter testing, where
4582 you want to force a real reload instead of getting status code "304", which
4583 would cause the browser to reuse the old version of the page.
4585 The "randomize" option overwrites the value of the "Last-Modified:" header
4586 with a randomly chosen time between the original value and the current
4587 time. In theory the server could send each document with a different
4588 "Last-Modified:" header to track visits without using cookies. "Randomize"
4589 makes it impossible and the browser can still revalidate cached documents.
4591 "reset-to-request-time" overwrites the value of the "Last-Modified:" header
4592 with the current time. You could use this option together with
4593 hided-if-modified-since to further customize your random range.
4595 The preferred parameter here is "randomize". It is safe to use, as long as
4596 the time settings are more or less correct. If the server sets the
4597 "Last-Modified:" header to the time of the request, the random range
4598 becomes zero and the value stays the same. Therefore you should later
4599 randomize it a second time with hided-if-modified-since, just to be sure.
4601 It is also recommended to use this action together with
4602 crunch-if-none-match.
4606 # Let the browser revalidate without being tracked across sessions
4607 { +hide-if-modified-since{-60} \
4608 +overwrite-last-modified{randomize} \
4609 +crunch-if-none-match}
4613 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4619 Redirect requests to other sites.
4623 Convinces the browser that the requested document has been moved to another
4624 location and the browser should get it from there.
4632 An absolute URL or a single pcrs command.
4636 Requests to which this action applies are answered with a HTTP redirect to
4637 URLs of your choosing. The new URL is either provided as parameter, or
4638 derived by applying a single pcrs command to the original URL.
4640 This action will be ignored if you use it together with block. It can be
4641 combined with fast-redirects{check-decoded-url} to redirect to a decoded
4642 version of a rewritten URL.
4644 Use this action carefully, make sure not to create redirection loops and be
4645 aware that using your own redirects might make it possible to fingerprint
4650 # Replace example.com's style sheet with another one
4651 { +redirect{http://localhost/css-replacements/example.com.css} }
4652 example.com/stylesheet\.css
4654 # Create a short, easy to remember nickname for a favorite site
4655 # (relies on the browser accept and forward invalid URLs to Privoxy)
4656 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
4659 # Always use the expanded view for Undeadly.org articles
4660 # (Note the $ at the end of the URL pattern to make sure
4661 # the request for the rewritten URL isn't redirected as well)
4662 {+redirect{s@$@&mode=expanded@}}
4663 undeadly.org/cgi\?action=article&sid=\d*$
4666 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4668 8.5.32. send-vanilla-wafer
4672 Feed log analysis scripts with useless data.
4676 Sends a cookie with each request stating that you do not accept any
4677 copyright on cookies sent to you, and asking the site operator not to track
4690 The vanilla wafer is a (relatively) unique header and could conceivably be
4693 This action is rarely used and not enabled in the default configuration.
4700 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4706 Send custom cookies or feed log analysis scripts with even more useless
4711 Sends a custom, user-defined cookie with each request.
4719 A string of the form "name=value".
4723 Being multi-valued, multiple instances of this action can apply to the same
4724 request, resulting in multiple cookies being sent.
4726 This action is rarely used and not enabled in the default configuration.
4728 Example usage (section):
4730 {+send-wafer{UsingPrivoxy=true}}
4731 my-internal-testing-server.void
4734 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4736 8.5.34. server-header-filter
4740 Rewrite or remove single server headers.
4744 All server headers to which this action applies are filtered on-the-fly
4745 through the specified regular expression based substitutions.
4753 The name of a server-header filter, as defined in one of the filter files.
4757 Server-header filters are applied to each header on its own, not to all at
4758 once. This makes it easier to diagnose problems, but on the downside you
4759 can't write filters that only change header x if header y's value is z. You
4760 can do that by using tags though.
4762 Server-header filters are executed after the other header actions have
4763 finished and use their output as input.
4765 Please refer to the filter file chapter to learn which server-header
4766 filters are available by default, and how to create your own.
4768 Example usage (section):
4770 {+server-header-filter{html-to-xml}}
4771 example.org/xml-instance-that-is-delivered-as-html
4773 {+server-header-filter{xml-to-html}}
4774 example.org/instance-that-is-delivered-as-xml-but-is-not
4778 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4780 8.5.35. server-header-tagger
4784 Enable or disable filters based on the Content-Type header.
4788 Server headers to which this action applies are filtered on-the-fly through
4789 the specified regular expression based substitutions, the result is used as
4798 The name of a server-header tagger, as defined in one of the filter files.
4802 Server-header taggers are applied to each header on its own, and as the
4803 header isn't modified, each tagger "sees" the original.
4805 Server-header taggers are executed before all other header actions that
4806 modify server headers. Their tags can be used to control all of the other
4807 server-header actions, the content filters and the crunch actions (redirect
4810 Obviously crunching based on tags created by server-header taggers doesn't
4811 prevent the request from showing up in the server's log file.
4813 Example usage (section):
4815 # Tag every request with the content type declared by the server
4816 {+server-header-tagger{content-type}}
4821 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4823 8.5.36. session-cookies-only
4827 Allow only temporary "session" cookies (for the current browser session
4832 Deletes the "expires" field from "Set-Cookie:" server headers. Most
4833 browsers will not store such cookies permanently and forget them in between
4846 This is less strict than crunch-incoming-cookies / crunch-outgoing-cookies
4847 and allows you to browse websites that insist or rely on setting cookies,
4848 without compromising your privacy too badly.
4850 Most browsers will not permanently store cookies that have been processed
4851 by session-cookies-only and will forget about them between sessions. This
4852 makes profiling cookies useless, but won't break sites which require
4853 cookies so that you can log in for transactions. This is generally turned
4854 on for all sites, and is the recommended setting.
4856 It makes no sense at all to use session-cookies-only together with
4857 crunch-incoming-cookies or crunch-outgoing-cookies. If you do, cookies will
4860 Note that it is up to the browser how it handles such cookies without an
4861 "expires" field. If you use an exotic browser, you might want to try it out
4864 This setting also has no effect on cookies that may have been stored
4865 previously by the browser before starting Privoxy. These would have to be
4868 Privoxy also uses the content-cookies filter to block some types of
4869 cookies. Content cookies are not effected by session-cookies-only.
4873 +session-cookies-only
4876 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4878 8.5.37. set-image-blocker
4882 Choose the replacement for blocked images
4886 This action alone doesn't do anything noticeable. If both block and
4887 handle-as-image also apply, i.e. if the request is to be blocked as an
4888 image, then the parameter of this action decides what will be sent as a
4897 □ "pattern" to send a built-in checkerboard pattern image. The image is
4898 visually decent, scales very well, and makes it obvious where banners
4901 □ "blank" to send a built-in transparent image. This makes banners
4902 disappear completely, but makes it hard to detect where Privoxy has
4903 blocked images on a given page and complicates troubleshooting if
4904 Privoxy has blocked innocent images, like navigation icons.
4906 □ "target-url" to send a redirect to target-url. You can redirect to any
4907 image anywhere, even in your local filesystem via "file:///" URL. (But
4908 note that not all browsers support redirecting to a local file system).
4910 A good application of redirects is to use special Privoxy-built-in
4911 URLs, which send the built-in images, as target-url. This has the same
4912 visual effect as specifying "blank" or "pattern" in the first place,
4913 but enables your browser to cache the replacement image, instead of
4914 requesting it over and over again.
4918 The URLs for the built-in images are "http://config.privoxy.org/
4919 send-banner?type=type", where type is either "blank" or "pattern".
4921 There is a third (advanced) type, called "auto". It is NOT to be used in
4922 set-image-blocker, but meant for use from filters. Auto will select the
4923 type of image that would have applied to the referring page, had it been an
4930 +set-image-blocker{pattern}
4933 Redirect to the BSD daemon:
4935 +set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}
4938 Redirect to the built-in pattern for better caching:
4940 +set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}
4943 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4945 8.5.38. treat-forbidden-connects-like-blocks
4949 Block forbidden connects with an easy to find error message.
4953 If this action is enabled, Privoxy no longer makes a difference between
4954 forbidden connects and ordinary blocks.
4966 By default Privoxy answers forbidden "Connect" requests with a short error
4967 message inside the headers. If the browser doesn't display headers (most
4968 don't), you just see an empty page.
4970 With this action enabled, Privoxy displays the message that is used for
4971 ordinary blocks instead. If you decide to make an exception for the page in
4972 question, you can do so by following the "See why" link.
4974 For "Connect" requests the clients tell Privoxy which host they are
4975 interested in, but not which document they plan to get later. As a result,
4976 the "Go there anyway" wouldn't work and is therefore suppressed.
4980 +treat-forbidden-connects-like-blocks
4983 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4987 Note that many of these actions have the potential to cause a page to
4988 misbehave, possibly even not to display at all. There are many ways a site
4989 designer may choose to design his site, and what HTTP header content, and other
4990 criteria, he may depend on. There is no way to have hard and fast rules for all
4991 sites. See the Appendix for a brief example on troubleshooting actions.
4993 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4997 Custom "actions", known to Privoxy as "aliases", can be defined by combining
4998 other actions. These can in turn be invoked just like the built-in actions.
4999 Currently, an alias name can contain any character except space, tab, "=", "{"
5000 and "}", but we strongly recommend that you only use "a" to "z", "0" to "9",
5001 "+", and "-". Alias names are not case sensitive, and are not required to start
5002 with a "+" or "-" sign, since they are merely textually expanded.
5004 Aliases can be used throughout the actions file, but they must be defined in a
5005 special section at the top of the file! And there can only be one such section
5006 per actions file. Each actions file may have its own alias section, and the
5007 aliases defined in it are only visible within that file.
5009 There are two main reasons to use aliases: One is to save typing for frequently
5010 used combinations of actions, the other one is a gain in flexibility: If you
5011 decide once how you want to handle shops by defining an alias called "shop",
5012 you can later change your policy on shops in one place, and your changes will
5013 take effect everywhere in the actions file where the "shop" alias is used.
5014 Calling aliases by their purpose also makes your actions files more readable.
5016 Currently, there is one big drawback to using aliases, though: Privoxy's
5017 built-in web-based action file editor honors aliases when reading the actions
5018 files, but it expands them before writing. So the effects of your aliases are
5019 of course preserved, but the aliases themselves are lost when you edit sections
5020 that use aliases with it.
5022 Now let's define some aliases...
5024 # Useful custom aliases we can use later.
5026 # Note the (required!) section header line and that this section
5027 # must be at the top of the actions file!
5031 # These aliases just save typing later:
5032 # (Note that some already use other aliases!)
5034 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5035 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5036 +block-as-image = +block +handle-as-image
5037 allow-all-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
5039 # These aliases define combinations of actions
5040 # that are useful for certain types of sites:
5042 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups -prevent-compression
5044 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
5046 # Short names for other aliases, for really lazy people ;-)
5048 c0 = +crunch-all-cookies
5049 c1 = -crunch-all-cookies
5052 ...and put them to use. These sections would appear in the lower part of an
5053 actions file and define exceptions to the default actions (as specified further
5054 up for the "/" pattern):
5056 # These sites are either very complex or very keen on
5057 # user data and require minimal interference to work:
5060 .office.microsoft.com
5061 .windowsupdate.microsoft.com
5062 # Gmail is really mail.google.com, not gmail.com
5066 # Allow cookies (for setting and retrieving your customer data)
5070 .worldpay.com # for quietpc.com
5073 # These shops require pop-ups:
5075 {-kill-popups -filter{all-popups} -filter{unsolicited-popups}}
5080 Aliases like "shop" and "fragile" are typically used for "problem" sites that
5081 require more than one action to be disabled in order to function properly.
5083 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5085 8.7. Actions Files Tutorial
5087 The above chapters have shown which actions files there are and how they are
5088 organized, how actions are specified and applied to URLs, how patterns work,
5089 and how to define and use aliases. Now, let's look at an example default.action
5090 and user.action file and see how all these pieces come together:
5092 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5094 8.7.1. default.action
5096 Every config file should start with a short comment stating its purpose:
5098 # Sample default.action file <ijbswa-developers@lists.sourceforge.net>
5101 Then, since this is the default.action file, the first section is a special
5102 section for internal use that you needn't change or worry about:
5104 ##########################################################################
5105 # Settings -- Don't change! For internal Privoxy use ONLY.
5106 ##########################################################################
5109 for-privoxy-version=3.0
5112 After that comes the (optional) alias section. We'll use the example section
5113 from the above chapter on aliases, that also explains why and how aliases are
5116 ##########################################################################
5118 ##########################################################################
5121 # These aliases just save typing later:
5122 # (Note that some already use other aliases!)
5124 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5125 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5126 +block-as-image = +block +handle-as-image
5127 mercy-for-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies}
5129 # These aliases define combinations of actions
5130 # that are useful for certain types of sites:
5132 fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -kill-popups
5133 shop = -crunch-all-cookies -filter{all-popups} -kill-popups
5136 Now come the regular sections, i.e. sets of actions, accompanied by URL
5137 patterns to which they apply. Remember all actions are disabled when matching
5138 starts, so we have to explicitly enable the ones we want.
5140 The first regular section is probably the most important. It has only one
5141 pattern, "/", but this pattern matches all URLs. Therefore, the set of actions
5142 used in this "default" section will be applied to all requests as a start. It
5143 can be partly or wholly overridden by later matches further down this file, or
5144 in user.action, but it will still be largely responsible for your overall
5145 browsing experience.
5147 Again, at the start of matching, all actions are disabled, so there is no need
5148 to disable any actions here. (Remember: a "+" preceding the action name enables
5149 the action, a "-" disables!). Also note how this long line has been made more
5150 readable by splitting it into multiple lines with line continuation.
5152 ##########################################################################
5153 # "Defaults" section:
5154 ##########################################################################
5157 +filter{html-annoyances} \
5158 +filter{refresh-tags} \
5160 +filter{ie-exploits} \
5161 +hide-forwarded-for-headers \
5162 +hide-from-header{block} \
5163 +hide-referrer{forge} \
5164 +prevent-compression \
5165 +session-cookies-only \
5166 +set-image-blocker{pattern} \
5168 / # forward slash will match *all* potential URL patterns.
5171 The default behavior is now set.
5173 The first of our specialized sections is concerned with "fragile" sites, i.e.
5174 sites that require minimum interference, because they are either very complex
5175 or very keen on tracking you (and have mechanisms in place that make them
5176 unusable for people who avoid being tracked). We will simply use our
5177 pre-defined fragile alias instead of stating the list of actions explicitly:
5179 ##########################################################################
5180 # Exceptions for sites that'll break under the default action set:
5181 ##########################################################################
5183 # "Fragile" Use a minimum set of actions for these sites (see alias above):
5186 .office.microsoft.com # surprise, surprise!
5187 .windowsupdate.microsoft.com
5191 Shopping sites are not as fragile, but they typically require cookies to log
5192 in, and pop-up windows for shopping carts or item details. Again, we'll use a
5199 .worldpay.com # for quietpc.com
5204 The fast-redirects action, which we enabled per default above, breaks some
5205 sites. So disable it for popular sites where we know it misbehaves:
5211 .altavista.com/.*(like|url|link):http
5212 .altavista.com/trans.*urltext=http
5216 It is important that Privoxy knows which URLs belong to images, so that if they
5217 are to be blocked, a substitute image can be sent, rather than an HTML page.
5218 Contacting the remote site to find out is not an option, since it would destroy
5219 the loading time advantage of banner blocking, and it would feed the
5220 advertisers (in terms of money and information). We can mark any URL as an
5221 image with the handle-as-image action, and marking all URLs that end in a known
5222 image file extension is a good start:
5224 ##########################################################################
5226 ##########################################################################
5228 # Define which file types will be treated as images, in case they get
5229 # blocked further down this file:
5231 { +handle-as-image }
5232 /.*\.(gif|jpe?g|png|bmp|ico)$
5235 And then there are known banner sources. They often use scripts to generate the
5236 banners, so it won't be visible from the URL that the request is for an image.
5237 Hence we block them and mark them as images in one go, with the help of our
5238 +block-as-image alias defined above. (We could of course just as well use +
5239 block +handle-as-image here.) Remember that the type of the replacement image
5240 is chosen by the set-image-blocker action. Since all URLs have matched the
5241 default section with its +set-image-blocker{pattern} action before, it still
5242 applies and needn't be repeated:
5244 # Known ad generators:
5249 .ad.*.doubleclick.net
5250 .a.yimg.com/(?:(?!/i/).)*$
5251 .a[0-9].yimg.com/(?:(?!/i/).)*$
5256 One of the most important jobs of Privoxy is to block banners. Many of these
5257 can be "blocked" by the filter{banners-by-size} action, which we enabled above,
5258 and which deletes the references to banner images from the pages while they are
5259 loaded, so the browser doesn't request them anymore, and hence they don't need
5260 to be blocked here. But this naturally doesn't catch all banners, and some
5261 people choose not to use filters, so we need a comprehensive list of patterns
5262 for banner URLs here, and apply the block action to them.
5264 First comes many generic patterns, which do most of the work, by matching
5265 typical domain and path name components of banners. Then comes a list of
5266 individual patterns for specific sites, which is omitted here to keep the
5269 ##########################################################################
5270 # Block these fine banners:
5271 ##########################################################################
5280 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
5281 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
5283 # Site-specific patterns (abbreviated):
5288 It's quite remarkable how many advertisers actually call their banner servers
5289 ads.company.com, or call the directory in which the banners are stored simply
5290 "banners". So the above generic patterns are surprisingly effective.
5292 But being very generic, they necessarily also catch URLs that we don't want to
5293 block. The pattern .*ads. e.g. catches "nasty-ads.nasty-corp.com" as intended,
5294 but also "downloads.sourcefroge.net" or "adsl.some-provider.net." So here come
5295 some well-known exceptions to the +block section above.
5297 Note that these are exceptions to exceptions from the default! Consider the URL
5298 "downloads.sourcefroge.net": Initially, all actions are deactivated, so it
5299 wouldn't get blocked. Then comes the defaults section, which matches the URL,
5300 but just deactivates the block action once again. Then it matches .*ads., an
5301 exception to the general non-blocking policy, and suddenly +block applies. And
5302 now, it'll match .*loads., where -block applies, so (unless it matches again
5303 further down) it ends up with no block action applying.
5305 ##########################################################################
5306 # Save some innocent victims of the above generic block patterns:
5307 ##########################################################################
5312 adv[io]*. # (for advogato.org and advice.*)
5313 adsl. # (has nothing to do with ads)
5314 adobe. # (has nothing to do with ads either)
5315 ad[ud]*. # (adult.* and add.*)
5316 .edu # (universities don't host banners (yet!))
5317 .*loads. # (downloads, uploads etc)
5325 www.globalintersec.com/adv # (adv = advanced)
5326 www.ugu.com/sui/ugu/adv
5329 Filtering source code can have nasty side effects, so make an exception for our
5330 friends at sourceforge.net, and all paths with "cvs" in them. Note that -filter
5331 disables all filters in one fell swoop!
5333 # Don't filter code!
5343 The actual default.action is of course much more comprehensive, but we hope
5344 this example made clear how it works.
5346 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5350 So far we are painting with a broad brush by setting general policies, which
5351 would be a reasonable starting point for many people. Now, you might want to be
5352 more specific and have customized rules that are more suitable to your personal
5353 habits and preferences. These would be for narrowly defined situations like
5354 your ISP or your bank, and should be placed in user.action, which is parsed
5355 after all other actions files and hence has the last word, over-riding any
5356 previously defined actions. user.action is also a safe place for your personal
5357 settings, since default.action is actively maintained by the Privoxy developers
5358 and you'll probably want to install updated versions from time to time.
5360 So let's look at a few examples of things that one might typically do in
5363 # My user.action file. <fred@example.com>
5366 As aliases are local to the actions file that they are defined in, you can't
5367 use the ones from default.action, unless you repeat them here:
5369 # Aliases are local to the file they are defined in.
5370 # (Re-)define aliases for this file:
5374 # These aliases just save typing later, and the alias names should
5375 # be self explanatory.
5377 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
5378 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
5379 allow-all-cookies = -crunch-all-cookies -session-cookies-only
5380 allow-popups = -filter{all-popups} -kill-popups
5381 +block-as-image = +block +handle-as-image
5382 -block-as-image = -block
5384 # These aliases define combinations of actions that are useful for
5385 # certain types of sites:
5387 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer -kill-popups
5388 shop = -crunch-all-cookies allow-popups
5390 # Allow ads for selected useful free sites:
5392 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
5394 # Alias for specific file types that are text, but might have conflicting
5395 # MIME types. We want the browser to force these to be text documents.
5396 handle-as-text = -filter +-content-type-overwrite{text/plain} +-force-text-mode -hide-content-disposition
5401 Say you have accounts on some sites that you visit regularly, and you don't
5402 want to have to log in manually each time. So you'd like to allow persistent
5403 cookies for these sites. The allow-all-cookies alias defined above does exactly
5404 that, i.e. it disables crunching of cookies in any direction, and the
5405 processing of cookies to make them only temporary.
5407 { allow-all-cookies }
5414 Your bank is allergic to some filter, but you don't know which, so you disable
5418 .your-home-banking-site.com
5421 Some file types you may not want to filter for various reasons:
5423 # Technical documentation is likely to contain strings that might
5424 # erroneously get altered by the JavaScript-oriented filters:
5429 # And this stupid host sends streaming video with a wrong MIME type,
5430 # so that Privoxy thinks it is getting HTML and starts filtering:
5432 stupid-server.example.com/
5435 Example of a simple block action. Say you've seen an ad on your favourite page
5436 on example.com that you want to get rid of. You have right-clicked the image,
5437 selected "copy image location" and pasted the URL below while removing the
5438 leading http://, into a { +block } section. Note that { +handle-as-image } need
5439 not be specified, since all URLs ending in .gif will be tagged as images by the
5440 general rules as set in default.action anyway:
5443 www.example.com/nasty-ads/sponsor\.gif
5444 another.example.net/more/junk/here/
5447 The URLs of dynamically generated banners, especially from large banner farms,
5448 often don't use the well-known image file name extensions, which makes it
5449 impossible for Privoxy to guess the file type just by looking at the URL. You
5450 can use the +block-as-image alias defined above for these cases. Note that
5451 objects which match this rule but then turn out NOT to be an image are
5452 typically rendered as a "broken image" icon by the browser. Use cautiously.
5461 Now you noticed that the default configuration breaks Forbes Magazine, but you
5462 were too lazy to find out which action is the culprit, and you were again too
5463 lazy to give feedback, so you just used the fragile alias on the site, and --
5464 whoa! -- it worked. The fragile aliases disables those actions that are most
5465 likely to break a site. Also, good for testing purposes to see if it is Privoxy
5466 that is causing the problem or not. We later find other regular sites that
5467 misbehave, and add those to our personalized list of troublemakers:
5475 You like the "fun" text replacements in default.filter, but it is disabled in
5476 the distributed actions file. So you'd like to turn it on in your private,
5477 update-safe config, once and for all:
5483 Note that the above is not really a good idea: There are exceptions to the
5484 filters in default.action for things that really shouldn't be filtered, like
5485 code on CVS->Web interfaces. Since user.action has the last word, these
5486 exceptions won't be valid for the "fun" filtering specified here.
5488 You might also worry about how your favourite free websites are funded, and
5489 find that they rely on displaying banner advertisements to survive. So you
5490 might want to specifically allow banners for those sites that you feel provide
5499 Note that allow-ads has been aliased to -block, -filter{banners-by-size}, and -
5500 filter{banners-by-link} above.
5502 Invoke another alias here to force an over-ride of the MIME type application/
5503 x-sh which typically would open a download type dialog. In my case, I want to
5504 look at the shell script, and then I can save it should I choose to.
5510 user.action is generally the best place to define exceptions and additions to
5511 the default policies of default.action. Some actions are safe to have their
5512 default policies set here though. So let's set a default policy to have a
5513 "blank" image as opposed to the checkerboard pattern for ALL sites. "/" of
5514 course matches all URL paths and patterns:
5516 { +set-image-blocker{blank} }
5520 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5524 On-the-fly text substitutions need to be defined in a "filter file". Once
5525 defined, they can then be invoked as an "action".
5527 Privoxy supports three different filter actions: filter to rewrite the content
5528 that is send to the client, client-header-filter to rewrite headers that are
5529 send by the client, and server-header-filter to rewrite headers that are send
5532 Privoxy also supports two tagger actions: client-header-tagger and
5533 server-header-tagger. Taggers and filters use the same syntax in the filter
5534 files, the difference is that taggers don't modify the text they are filtering,
5535 but use a rewritten version of the filtered text as tag. The tags can then be
5536 used to change the applying actions through sections with tag-patterns.
5538 Multiple filter files can be defined through the filterfile config directive.
5539 The filters as supplied by the developers are located in default.filter. It is
5540 recommended that any locally defined or modified filters go in a separately
5541 defined file such as user.filter.
5543 Common tasks for content filters are to eliminate common annoyances in HTML and
5544 JavaScript, such as pop-up windows, exit consoles, crippled windows without
5545 navigation tools, the infamous <BLINK> tag etc, to suppress images with certain
5546 width and height attributes (standard banner sizes or web-bugs), or just to
5549 Enabled content filters are applied to any content whose "Content Type" header
5550 is recognised as a sign of text-based content, with the exception of text/
5551 plain. Use the force-text-mode action to also filter other content.
5553 Substitutions are made at the source level, so if you want to "roll your own"
5554 filters, you should first be familiar with HTML syntax, and, of course, regular
5557 Just like the actions files, the filter file is organized in sections, which
5558 are called filters here. Each filter consists of a heading line, that starts
5559 with one of the keywords FILTER:, CLIENT-HEADER-FILTER: or
5560 SERVER-HEADER-FILTER: followed by the filter's name, and a short (one line)
5561 description of what it does. Below that line come the jobs, i.e. lines that
5562 define the actual text substitutions. By convention, the name of a filter
5563 should describe what the filter eliminates. The comment is used in the
5564 web-based user interface.
5566 Once a filter called name has been defined in the filter file, it can be
5567 invoked by using an action of the form +filter{name} in any actions file.
5569 Filter definitions start with a header line that contains the filter type, the
5570 filter name and the filter description. A content filter header line for a
5571 filter called "foo" could look like this:
5573 FILTER: foo Replace all "foo" with "bar"
5576 Below that line, and up to the next header line, come the jobs that define what
5577 text replacements the filter executes. They are specified in a syntax that
5578 imitates Perl's s/// operator. If you are familiar with Perl, you will find
5579 this to be quite intuitive, and may want to look at the PCRS documentation for
5580 the subtle differences to Perl behaviour. Most notably, the non-standard option
5581 letter U is supported, which turns the default to ungreedy matching.
5583 If you are new to "Regular Expressions", you might want to take a look at the
5584 Appendix on regular expressions, and see the Perl manual for the s///
5585 operator's syntax and Perl-style regular expressions in general. The below
5586 examples might also help to get you started.
5588 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5590 9.1. Filter File Tutorial
5592 Now, let's complete our "foo" content filter. We have already defined the
5593 heading, but the jobs are still missing. Since all it does is to replace "foo"
5594 with "bar", there is only one (trivial) job needed:
5599 But wait! Didn't the comment say that all occurrences of "foo" should be
5600 replaced? Our current job will only take care of the first "foo" on each page.
5601 For global substitution, we'll need to add the g option:
5606 Our complete filter now looks like this:
5608 FILTER: foo Replace all "foo" with "bar"
5612 Let's look at some real filters for more interesting examples. Here you see a
5613 filter that protects against some common annoyances that arise from JavaScript
5614 abuse. Let's look at its jobs one after the other:
5616 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
5618 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
5620 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg
5623 Following the header line and a comment, you see the job. Note that it uses |
5624 as the delimiter instead of /, because the pattern contains a forward slash,
5625 which would otherwise have to be escaped by a backslash (\).
5627 Now, let's examine the pattern: it starts with the text <script.* enclosed in
5628 parentheses. Since the dot matches any character, and * means: "Match an
5629 arbitrary number of the element left of myself", this matches "<script",
5630 followed by any text, i.e. it matches the whole page, from the start of the
5633 That's more than we want, but the pattern continues: document\.referrer matches
5634 only the exact string "document.referrer". The dot needed to be escaped, i.e.
5635 preceded by a backslash, to take away its special meaning as a joker, and make
5636 it just a regular dot. So far, the meaning is: Match from the start of the
5637 first <script> tag in a the page, up to, and including, the text
5638 "document.referrer", if both are present in the page (and appear in that
5641 But there's still more pattern to go. The next element, again enclosed in
5642 parentheses, is .*</script>. You already know what .* means, so the whole
5643 pattern translates to: Match from the start of the first <script> tag in a page
5644 to the end of the last <script> tag, provided that the text "document.referrer"
5645 appears somewhere in between.
5647 This is still not the whole story, since we have ignored the options and the
5648 parentheses: The portions of the page matched by sub-patterns that are enclosed
5649 in parentheses, will be remembered and be available through the variables $1,
5650 $2, ... in the substitute. The U option switches to ungreedy matching, which
5651 means that the first .* in the pattern will only "eat up" all text in between "
5652 <script" and the first occurrence of "document.referrer", and that the second
5653 .* will only span the text up to the first "</script>" tag. Furthermore, the s
5654 option says that the match may span multiple lines in the page, and the g
5655 option again means that the substitution is global.
5657 So, to summarize, the pattern means: Match all scripts that contain the text
5658 "document.referrer". Remember the parts of the script from (and including) the
5659 start tag up to (and excluding) the string "document.referrer" as $1, and the
5660 part following that string, up to and including the closing tag, as $2.
5662 Now the pattern is deciphered, but wasn't this about substituting things? So
5663 lets look at the substitute: $1"Not Your Business!"$2 is easy to read: The text
5664 remembered as $1, followed by "Not Your Business!" (including the quotation
5665 marks!), followed by the text remembered as $2. This produces an exact copy of
5666 the original string, with the middle part (the "document.referrer") replaced by
5667 "Not Your Business!".
5669 The whole job now reads: Replace "document.referrer" by "Not Your Business!"
5670 wherever it appears inside a <script> tag. Note that this job won't break
5671 JavaScript syntax, since both the original and the replacement are
5672 syntactically valid string objects. The script just won't have access to the
5673 referrer information anymore.
5675 We'll show you two other jobs from the JavaScript taming department, but this
5676 time only point out the constructs of special interest:
5678 # The status bar is for displaying link targets, not pointless blahblah
5680 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig
5683 \s stands for whitespace characters (space, tab, newline, carriage return, form
5684 feed), so that \s* means: "zero or more whitespace". The ? in .*? makes this
5685 matching of arbitrary text ungreedy. (Note that the U option is not set). The
5686 ['"] construct means: "a single or a double quote". Finally, \1 is a
5687 back-reference to the first parenthesis just like $1 above, with the difference
5688 that in the pattern, a backslash indicates a back-reference, whereas in the
5689 substitute, it's the dollar.
5691 So what does this job do? It replaces assignments of single- or double-quoted
5692 strings to the "window.status" object with a dummy assignment (using a variable
5693 name that is hopefully odd enough not to conflict with real variables in
5694 scripts). Thus, it catches many cases where e.g. pointless descriptions are
5695 displayed in the status bar instead of the link target when you move your mouse
5698 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
5700 s/(<body [^>]*)onunload(.*>)/$1never$2/iU
5703 Including the OnUnload event binding in the HTML DOM was a CRIME. When I close
5704 a browser window, I want it to close and die. Basta. This job replaces the
5705 "onunload" attribute in "<body>" tags with the dummy word never. Note that the
5706 i option makes the pattern matching case-insensitive. Also note that ungreedy
5707 matching alone doesn't always guarantee a minimal match: In the first
5708 parenthesis, we had to use [^>]* instead of .* to prevent the match from
5709 exceeding the <body> tag if it doesn't contain "OnUnload", but the page's
5712 The last example is from the fun department:
5714 FILTER: fun Fun text replacements
5716 # Spice the daily news:
5718 s/microsoft(?!\.com)/MicroSuck/ig
5721 Note the (?!\.com) part (a so-called negative lookahead) in the job's pattern,
5722 which means: Don't match, if the string ".com" appears directly following
5723 "microsoft" in the page. This prevents links to microsoft.com from being
5724 trashed, while still replacing the word everywhere else.
5726 # Buzzword Bingo (example for extended regex syntax)
5728 s* industry[ -]leading \
5730 | customer[ -]focused \
5731 | market[ -]driven \
5732 | award[ -]winning # Comments are OK, too! \
5733 | high[ -]performance \
5734 | solutions[ -]based \
5738 *<font color="red"><b>BINGO!</b></font> \
5742 The x option in this job turns on extended syntax, and allows for e.g. the
5743 liberal use of (non-interpreted!) whitespace for nicer formatting.
5747 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
5749 9.2. The Pre-defined Filters
5751 The distribution default.filter file contains a selection of pre-defined
5752 filters for your convenience:
5756 The purpose of this filter is to get rid of particularly annoying
5757 JavaScript abuse. To that end, it
5759 □ replaces JavaScript references to the browser's referrer information
5760 with the string "Not Your Business!". This compliments the
5761 hide-referrer action on the content level.
5763 □ removes the bindings to the DOM's unload event which we feel has no
5764 right to exist and is responsible for most "exit consoles", i.e. nasty
5765 windows that pop up when you close another one.
5767 □ removes code that causes new windows to be opened with undesired
5768 properties, such as being full-screen, non-resizeable, without
5769 location, status or menu bar etc.
5771 Use with caution. This is an aggressive filter, and can break sites that
5772 rely heavily on JavaScript.
5776 This is a very radical measure. It removes virtually all JavaScript event
5777 bindings, which means that scripts can not react to user actions such as
5778 mouse movements or clicks, window resizing etc, anymore. Use with caution!
5780 We strongly discourage using this filter as a default since it breaks many
5781 legitimate scripts. It is meant for use only on extra-nasty sites (should
5782 you really need to go there).
5786 This filter will undo many common instances of HTML based abuse.
5788 The BLINK and MARQUEE tags are neutralized (yeah baby!), and browser
5789 windows will be created as resizeable (as of course they should be!), and
5790 will have location, scroll and menu bars -- even if specified otherwise.
5794 Most cookies are set in the HTTP dialog, where they can be intercepted by
5795 the crunch-incoming-cookies and crunch-outgoing-cookies actions. But web
5796 sites increasingly make use of HTML meta tags and JavaScript to sneak
5797 cookies to the browser on the content level.
5799 This filter disables most HTML and JavaScript code that reads or sets
5800 cookies. It cannot detect all clever uses of these types of code, so it
5801 should not be relied on as an absolute fix. Use it wherever you would also
5802 use the cookie crunch actions.
5806 Disable any refresh tags if the interval is greater than nine seconds (so
5807 that redirections done via refresh tags are not destroyed). This is useful
5808 for dial-on-demand setups, or for those who find this HTML feature
5813 This filter attempts to prevent only "unsolicited" pop-up windows from
5814 opening, yet still allow pop-up windows that the user has explicitly chosen
5815 to open. It was added in version 3.0.1, as an improvement over earlier such
5818 Technical note: The filter works by redefining the window.open JavaScript
5819 function to a dummy function, PrivoxyWindowOpen(), during the loading and
5820 rendering phase of each HTML page access, and restoring the function
5823 This is recommended only for browsers that cannot perform this function
5824 reliably themselves. And be aware that some sites require such windows in
5825 order to function normally. Use with caution.
5829 Attempt to prevent all pop-up windows from opening. Note this should be
5830 used with even more discretion than the above, since it is more likely to
5831 break some sites that require pop-ups for normal usage. Use with caution.
5835 This is a helper filter that has no value if used alone. It makes the
5836 banners-by-size and banners-by-link (see below) filters more effective and
5837 should be enabled together with them.
5841 This filter removes image tags purely based on what size they are.
5842 Fortunately for us, many ads and banner images tend to conform to certain
5843 standardized sizes, which makes this filter quite effective for ad
5846 Occasionally this filter will cause false positives on images that are not
5847 ads, but just happen to be of one of the standard banner sizes.
5849 Recommended only for those who require extreme ad blocking. The default
5850 block rules should catch 95+% of all ads without this filter enabled.
5854 This is an experimental filter that attempts to kill any banners if their
5855 URLs seem to point to known or suspected click trackers. It is currently
5856 not of much value and is not recommended for use by default.
5860 Webbugs are small, invisible images (technically 1X1 GIF images), that are
5861 used to track users across websites, and collect information on them. As an
5862 HTML page is loaded by the browser, an embedded image tag causes the
5863 browser to contact a third-party site, disclosing the tracking information
5864 through the requested URL and/or cookies for that third-party domain,
5865 without the user ever becoming aware of the interaction with the
5866 third-party site. HTML-ized spam also uses a similar technique to verify
5869 This filter removes the HTML code that loads such "webbugs".
5873 A rather special-purpose filter that can be used to enlarge textareas
5874 (those multi-line text boxes in web forms) and turn off hard word wrap in
5875 them. It was written for the sourceforge.net tracker system where such
5876 boxes are a nuisance, but it can be handy on other sites, too.
5878 It is not recommended to use this filter as a default.
5882 Many consider windows that move, or resize themselves to be abusive. This
5883 filter neutralizes the related JavaScript code. Note that some sites might
5884 not display or behave as intended when using this filter. Use with caution.
5888 Some web designers seem to assume that everyone in the world will view
5889 their web sites using the same browser brand and version, screen resolution
5890 etc, because only that assumption could explain why they'd use static frame
5891 sizes, yet prevent their frames from being resized by the user, should they
5892 be too small to show their whole content.
5894 This filter removes the related HTML code. It should only be applied to
5895 sites which need it.
5899 Many Microsoft products that generate HTML use non-standard extensions
5900 (read: violations) of the ISO 8859-1 aka Latin-1 character set. This can
5901 cause those HTML documents to display with errors on standard-compliant
5904 This filter translates the MS-only characters into Latin-1 equivalents. It
5905 is not necessary when using MS products, and will cause corruption of all
5906 documents that use 8-bit character sets other than Latin-1. It's mostly
5907 worthwhile for Europeans on non-MS platforms, if weird garbage characters
5908 sometimes appear on some pages, or user agents that don't correct for this
5913 A filter for shockwave haters. As the name suggests, this filter strips
5914 code out of web pages that is used to embed shockwave flash objects.
5918 Change HTML code that embeds Quicktime objects so that kioskmode, which
5919 prevents saving, is disabled.
5923 Text replacements for subversive browsing fun. Make fun of your favorite
5924 Monopolist or play buzzword bingo.
5928 A demonstration-only filter that shows how Privoxy can be used to delete
5929 web content on a keyword basis.
5933 An experimental collection of text replacements to disable malicious HTML
5934 and JavaScript code that exploits known security holes in Internet
5937 Presently, it only protects against Nimda and a cross-site scripting bug,
5938 and would need active maintenance to provide more substantial protection.
5942 Some web sites have very specific problems, the cure for which doesn't
5943 apply anywhere else, or could even cause damage on other sites.
5945 This is a collection of such site-specific cures which should only be
5946 applied to the sites they were intended for, which is what the supplied
5947 default.action file does. Users shouldn't need to change anything regarding
5952 A CSS based block for Google text ads. Also removes a width limitation and
5953 the toolbar advertisement.
5957 Another CSS based block, this time for Yahoo text ads. And removes a width
5962 Another CSS based block, this time for MSN text ads. And removes tracking
5963 URLs, as well as a width limitation.
5967 Cleans up some Blogspot blogs. Read the fine print before using this one!
5969 This filter also intentionally removes some navigation stuff and sets the
5970 page width to 100%. As a result, some rounded "corners" would appear to
5971 early or not at all and as fixing this would require a browser that
5972 understands background-size (CSS3), they are removed instead.
5976 Server-header filter to change the Content-Type from xml to html.
5980 Server-header filter to change the Content-Type from html to xml.
5984 Removes the non-standard ping attribute from anchor and area HTML tags.
5986 hide-tor-exit-notation
5988 Client-header filter to remove the Tor exit node notation found in Host and
5991 If Privoxy and Tor are chained and Privoxy is configured to use socks4a,
5992 one can use "http://www.example.org.foobar.exit/" to access the host
5993 "www.example.org" through the Tor exit node "foobar".
5995 As the HTTP client isn't aware of this notation, it treats the whole string
5996 "www.example.org.foobar.exit" as host and uses it for the "Host" and
5997 "Referer" headers. From the server's point of view the resulting headers
5998 are invalid and can cause problems.
6000 An invalid "Referer" header can trigger "hot-linking" protections, an
6001 invalid "Host" header will make it impossible for the server to find the
6002 right vhost (several domains hosted on the same IP address).
6004 This client-header filter removes the "foo.exit" part in those headers to
6005 prevent the mentioned problems. Note that it only modifies the HTTP
6006 headers, it doesn't make it impossible for the server to detect your Tor
6007 exit node based on the IP address the request is coming from.
6009 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6011 10. Privoxy's Template Files
6013 All Privoxy built-in pages, i.e. error pages such as the "404 - No Such Domain"
6014 error page, the "BLOCKED" page and all pages of its web-based user interface,
6015 are generated from templates. (Privoxy must be running for the above links to
6018 These templates are stored in a subdirectory of the configuration directory
6019 called templates. On Unixish platforms, this is typically /etc/privoxy/
6022 The templates are basically normal HTML files, but with place-holders (called
6023 symbols or exports), which Privoxy fills at run time. It is possible to edit
6024 the templates with a normal text editor, should you want to customize them.
6025 (Not recommended for the casual user). Should you create your own custom
6026 templates, you should use the config setting templdir to specify an alternate
6027 location, so your templates do not get overwritten during upgrades.
6029 Note that just like in configuration files, lines starting with # are ignored
6030 when the templates are filled in.
6032 The place-holders are of the form @name@, and you will find a list of available
6033 symbols, which vary from template to template, in the comments at the start of
6034 each file. Note that these comments are not always accurate, and that it's
6035 probably best to look at the existing HTML code to find out which symbols are
6036 supported and what they are filled in with.
6038 A special application of this substitution mechanism is to make whole blocks of
6039 HTML code disappear when a specific symbol is set. We use this for many
6040 purposes, one of them being to include the beta warning in all our user
6041 interface (CGI) pages when Privoxy is in an alpha or beta development stage:
6043 <!-- @if-unstable-start -->
6045 ... beta warning HTML code goes here ...
6047 <!-- if-unstable-end@ -->
6050 If the "unstable" symbol is set, everything in between and including
6051 @if-unstable-start and if-unstable-end@ will disappear, leaving nothing but an
6057 There's also an if-then-else construct and an #include mechanism, but you'll
6058 sure find out if you are inclined to edit the templates ;-)
6060 All templates refer to a style located at http://config.privoxy.org/
6061 send-stylesheet. This is, of course, locally served by Privoxy and the source
6062 for it can be found and edited in the cgi-style.css template.
6064 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6066 11. Contacting the Developers, Bug Reporting and Feature Requests
6068 We value your feedback. In fact, we rely on it to improve Privoxy and its
6069 configuration. However, please note the following hints, so we can provide you
6070 with the best support:
6072 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6076 For casual users, our support forum at SourceForge is probably best suited:
6077 http://sourceforge.net/tracker/?group_id=11118&atid=211118
6079 All users are of course welcome to discuss their issues on the users mailing
6080 list, where the developers also hang around.
6082 Note that the Privoxy mailing lists are moderated. Posts from unsubscribed
6083 addresses have to be accepted manually by a moderator. This may cause a delay
6084 of several days and if you use a subject that doesn't clearly mention Privoxy
6085 or one of its features, your message may be accidentally discarded as spam.
6087 If you aren't subscribed, you should therefore spend a few seconds to come up
6088 with a proper subject. Additionally you should make it clear that you want to
6089 get CC'd. Otherwise some responses will be directed to the mailing list only,
6090 and you won't see them.
6092 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6094 11.2. Reporting Problems
6096 "Problems" for our purposes, come in two forms:
6098 • Configuration issues, such as ads that slip through, or sites that don't
6099 function properly due to one Privoxy "action" or another being turned "on".
6101 • "Bugs" in the programming code that makes up Privoxy, such as that might
6104 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6106 11.2.1. Reporting Ads or Other Configuration Problems
6108 Please send feedback on ads that slipped through, innocent images that were
6109 blocked, sites that don't work properly, and other configuration related
6110 problem of default.action file, to http://sourceforge.net/tracker/?group_id=
6111 11118&atid=460288, the Actions File Tracker.
6113 New, improved default.action files may occasionally be made available based on
6114 your feedback. These will be announced on the ijbswa-announce list and
6115 available from our the files section of our project page.
6117 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6119 11.2.2. Reporting Bugs
6121 Please report all bugs through our bug tracker: http://sourceforge.net/tracker
6122 /?group_id=11118&atid=111118.
6124 Before doing so, please make sure that the bug has not already been submitted
6125 and observe the additional hints at the top of the submit form. If already
6126 submitted, please feel free to add any info to the original report that might
6127 help to solve the issue.
6129 Please try to verify that it is a Privoxy bug, and not a browser or site bug or
6130 documented behaviour that just happens to be different than what you expected.
6131 If unsure, try toggling off Privoxy, and see if the problem persists.
6133 If you are using your own custom configuration, please try the stock configs to
6134 see if the problem is configuration related. If you're having problems with a
6135 feature that is disabled by default, please ask around on the mailing list if
6136 others can reproduce the problem.
6138 If you aren't using the latest Privoxy version, the bug may have been found and
6139 fixed in the meantime. We would appreciate if you could take the time to
6140 upgrade to the latest version (or even the latest CVS snapshot) and verify that
6141 your bug still exists.
6143 Please be sure to provide the following information:
6145 • The exact Privoxy version you are using (if you got the source from CVS,
6146 please also provide the source code revisions as shown in http://
6147 config.privoxy.org/show-version).
6149 • The operating system and versions you run Privoxy on, (e.g. Windows XP
6150 SP2), if you are using a Unix flavor, sending the output of "uname -a"
6151 should do, in case of GNU/Linux, please also name the distribution.
6153 • The name, platform, and version of the browser you were using (e.g.
6154 Internet Explorer v5.5 for Mac).
6156 • The URL where the problem occurred, or some way for us to duplicate the
6157 problem (e.g. http://somesite.example.com/?somethingelse=123).
6159 • Whether your version of Privoxy is one supplied by the Privoxy developers
6160 via SourceForge, or if you got your copy somewhere else.
6162 • Whether you are using Privoxy in tandem with another proxy such as Tor. If
6163 so, please temporary disable the other proxy to see if the symptoms change.
6165 • Whether you are using a personal firewall product. If so, does Privoxy work
6168 • Any other pertinent information to help identify the problem such as config
6169 or log file excerpts (yes, you should have log file entries for each action
6172 You don't have to tell us your actual name when filing a problem report, but
6173 please use a nickname so we can differentiate between your messages and the
6174 ones entered by other "anonymous" users that may respond to your request if
6175 they have the same problem or already found a solution.
6177 Please also check the status of your request a few days after submitting it, as
6178 we may request additional information. If you use a SF id, you should
6179 automatically get a mail when someone responds to your request.
6181 The appendix of the Privoxy User Manual also has helpful information on
6182 understanding actions, and action debugging.
6184 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6186 11.3. Request New Features
6188 You are welcome to submit ideas on new features or other proposals for
6189 improvement through our feature request tracker at http://sourceforge.net/
6190 tracker/?atid=361118&group_id=11118.
6192 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6196 For any other issues, feel free to use the mailing lists. Technically
6197 interested users and people who wish to contribute to the project are also
6198 welcome on the developers list! You can find an overview of all Privoxy-related
6199 mailing lists, including list archives, at: http://sourceforge.net/mail/?
6202 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6204 12. Privoxy Copyright, License and History
6206 Copyright 2001 - 2007 by Privoxy Developers <
6207 ijbswa-developers@lists.sourceforge.net>
6209 Some source code is based on code Copyright 1997 by Anonymous Coders and
6210 Junkbusters, Inc. and licensed under the GNU General Public License.
6212 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6216 Privoxy is free software; you can redistribute it and/or modify it under the
6217 terms of the GNU General Public License, version 2, as published by the Free
6218 Software Foundation.
6220 This program is distributed in the hope that it will be useful, but WITHOUT ANY
6221 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
6222 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
6223 is available from the Free Software Foundation, Inc, 51 Franklin Street, Fifth
6224 Floor, Boston, MA 02110-1301, USA
6226 You should have received a copy of the GNU General Public License along with
6227 this program; if not, write to the
6230 Foundation, Inc. 51 Franklin Street, Fifth Floor
6231 Boston, MA 02110-1301
6234 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6238 A long time ago, there was the Internet Junkbuster, by Anonymous Coders and
6239 Junkbusters Corporation. This saved many users a lot of pain in the early days
6240 of web advertising and user tracking.
6242 But the web, its protocols and standards, and with it, the techniques for
6243 forcing ads on users, give up autonomy over their browsing, and for tracking
6244 them, keeps evolving. Unfortunately, the Internet Junkbuster did not. Version
6245 2.0.2, published in 1998, was (and is) the last official release available from
6246 Junkbusters Corporation. Fortunately, it had been released under the GNU GPL,
6247 which allowed further development by others.
6249 So Stefan Waldherr started maintaining an improved version of the software, to
6250 which eventually a number of people contributed patches. It could already
6251 replace banners with a transparent image, and had a first version of pop-up
6252 killing, but it was still very closely based on the original, with all its
6253 limitations, such as the lack of HTTP/1.1 support, flexible per-site
6254 configuration, or content modification. The last release from this effort was
6255 version 2.0.2-10, published in 2000.
6257 Then, some developers picked up the thread, and started turning the software
6258 inside out, upside down, and then reassembled it, adding many new features
6261 The result of this is Privoxy, whose first stable version, 3.0, was released
6264 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6268 Current Privoxy Team:
6270 Fabian Keil, lead developer
6271 David Schmidt, developer
6277 Former Privoxy Team Members:
6302 Thanks to the many people who have tested Privoxy, reported bugs, provided
6303 patches, made suggestions or contributed in some way. These include (in
6304 alphabetical order):
6360 Privoxy is based in part on code originally developed by Junkbusters Corp. and
6363 Privoxy heavily relies on Philip Hazel's PCRE.
6365 The code to filter compressed content makes use of zlib which is written by
6366 Jean-loup Gailly and Mark Adler.
6368 On systems that lack snprintf(), Privoxy is using a version written by Mark
6369 Martinec. On systems that lack strptime(), Privoxy is using the one from the
6370 GNU C Library written by Ulrich Drepper.
6372 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6376 Other references and sites of interest to Privoxy users:
6378 http://www.privoxy.org/, the Privoxy Home page.
6380 http://www.privoxy.org/faq/, the Privoxy FAQ.
6382 http://sourceforge.net/projects/ijbswa/, the Project Page for Privoxy on
6385 http://config.privoxy.org/, the web-based user interface. Privoxy must be
6386 running for this to work. Shortcut: http://p.p/
6388 http://sourceforge.net/tracker/?group_id=11118&atid=460288, to submit "misses"
6389 and other configuration related suggestions to the developers.
6391 http://www.junkbusters.com/ht/en/cookies.html, an explanation how cookies are
6392 used to track web users.
6394 http://www.junkbusters.com/ijb.html, the original Internet Junkbuster.
6396 http://privacy.net/, a useful site to check what information about you is
6397 leaked while you browse the web.
6399 http://www.squid-cache.org/, a popular caching proxy, which is often used
6400 together with Privoxy.
6402 http://www.pps.jussieu.fr/~jch/software/polipo/, Polipo is a caching proxy with
6403 advanced features like pipelining, multiplexing and caching of partial
6404 instances. In many setups it can be used as Squid replacement.
6406 http://tor.eff.org/, Tor can help anonymize web browsing, web publishing,
6407 instant messaging, IRC, SSH, and other applications.
6409 http://www.privoxy.org/developer-manual/, the Privoxy developer manual.
6411 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6415 14.1. Regular Expressions
6417 Privoxy uses Perl-style "regular expressions" in its actions files and filter
6418 file, through the PCRE and PCRS libraries.
6420 If you are reading this, you probably don't understand what "regular
6421 expressions" are, or what they can do. So this will be a very brief
6422 introduction only. A full explanation would require a book ;-)
6424 Regular expressions provide a language to describe patterns that can be run
6425 against strings of characters (letter, numbers, etc), to see if they match the
6426 string or not. The patterns are themselves (sometimes complex) strings of
6427 literal characters, combined with wild-cards, and other special characters,
6428 called meta-characters. The "meta-characters" have special meanings and are
6429 used to build complex patterns to be matched against. Perl Compatible Regular
6430 Expressions are an especially convenient "dialect" of the regular expression
6433 To make a simple analogy, we do something similar when we use wild-card
6434 characters when listing files with the dir command in DOS. *.* matches all
6435 filenames. The "special" character here is the asterisk which matches any and
6436 all characters. We can be more specific and use ? to match just individual
6437 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
6438 are pattern matching, using a similar technique to "regular expressions"!
6440 Regular expressions do essentially the same thing, but are much, much more
6441 powerful. There are many more "special characters" and ways of building complex
6442 patterns however. Let's look at a few of the common ones, and then some
6445 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
6447 ? - The preceding character or expression is matched ZERO or ONE times. Either/
6450 + - The preceding character or expression is matched ONE or MORE times.
6452 * - The preceding character or expression is matched ZERO or MORE times.
6454 \ - The "escape" character denotes that the following character should be taken
6455 literally. This is used where one of the special characters (e.g. ".") needs to
6456 be taken literally and not as a special meta-character. Example: "example
6457 \.com", makes sure the period is recognized only as a period (and not expanded
6458 to its meta-character meaning of any single character).
6460 [ ] - Characters enclosed in brackets will be matched if any of the enclosed
6461 characters are encountered. For instance, "[0-9]" matches any numeric digit
6462 (zero through nine). As an example, we can combine this with "+" to match any
6463 digit one of more times: "[0-9]+".
6465 ( ) - parentheses are used to group a sub-expression, or multiple
6468 | - The "bar" character works like an "or" conditional statement. A match is
6469 successful if the sub-expression on either side of "|" matches. As an example:
6470 "/(this|that) example/" uses grouping and the bar character and would match
6471 either "this example" or "that example", and nothing else.
6473 These are just some of the ones you are likely to use when matching URLs with
6474 Privoxy, and is a long way from a definitive list. This is enough to get us
6475 started with a few simple examples which may be more illuminating:
6477 /.*/banners/.* - A simple example that uses the common combination of "." and
6478 "*" to denote any character, zero or more times. In other words, any string at
6479 all. So we start with a literal forward slash, then our regular expression
6480 pattern (".*") another literal forward slash, the string "banners", another
6481 forward slash, and lastly another ".*". We are building a directory path here.
6482 This will match any file with the path that has a directory named "banners" in
6483 it. The ".*" matches any characters, and this could conceivably be more forward
6484 slashes, so it might expand into a much longer looking path. For example, this
6485 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
6486 banners/annoying.html", or almost an infinite number of other possible
6487 combinations, just so it has "banners" in the path somewhere.
6489 And now something a little more complex:
6491 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
6492 slashes again ("/"), so we are building another expression that is a file path
6493 statement. We have another ".*", so we are matching against any conceivable
6494 sub-path, just so it matches our expression. The only true literal that must
6495 match our pattern is adv, together with the forward slashes. What comes after
6496 the "adv" string is the interesting part.
6498 Remember the "?" means the preceding expression (either a literal character or
6499 anything grouped with "(...)" in this case) can exist or not, since this means
6500 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
6501 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
6502 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
6503 to match either "ing" OR "ements?". What is being done here, is an attempt at
6504 matching as many variations of "advertisement", and similar, as possible. So
6505 this would expand to match just "adv", or "advert", or "adverts", or
6506 "advertising", or "advertisement", or "advertisements". You get the idea. But
6507 it would not match "advertizements" (with a "z"). We could fix that by changing
6508 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
6509 would then match either spelling.
6511 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
6512 slashes. Anything in the square brackets "[ ]" can be matched. This is using
6513 "0-9" as a shorthand expression to mean any digit one through nine. It is the
6514 same as saying "0123456789". So any digit matches. The "+" means one or more of
6515 the preceding expression must be included. The preceding expression here is
6516 what is in the square brackets -- in this case, any digit one through nine.
6517 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
6518 this needs to match the expression on either side of that bar character also. A
6519 simple "gif" on one side, and the other side will in turn match either "jpeg"
6520 or "jpg", since the "?" means the letter "e" is optional and can be matched
6521 once or not at all. So we are building an expression here to match image GIF or
6522 JPEG type image file. It must include the literal string "advert", then one or
6523 more digits, and a "." (which is now a literal, and not a special character,
6524 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
6525 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
6526 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
6527 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
6528 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
6530 We are barely scratching the surface of regular expressions here so that you
6531 can understand the default Privoxy configuration files, and maybe use this
6532 knowledge to customize your own installation. There is much, much more that can
6533 be done with regular expressions. Now that you know enough to get started, you
6534 can learn more on your own :/
6536 More reading on Perl Compatible Regular expressions: http://perldoc.perl.org/
6539 For information on regular expression based substitutions and their
6540 applications in filters, please see the filter file tutorial in this manual.
6542 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6544 14.2. Privoxy's Internal Pages
6546 Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
6547 certain special URLs. In this way, we can talk directly to Privoxy, and see how
6548 it is configured, see how our rules are being applied, change these rules and
6549 other configuration options, and even turn Privoxy's filtering off, all with a
6552 The URLs listed below are the special ones that allow direct access to Privoxy.
6553 Of course, Privoxy must be running to access these. If not, you will get a
6554 friendly error message. Internet access is not necessary either.
6556 • Privoxy main page:
6558 http://config.privoxy.org/
6560 There is a shortcut: http://p.p/ (But it doesn't provide a fall-back to a
6561 real page, in case the request is not sent through Privoxy)
6563 • Show information about the current configuration, including viewing and
6564 editing of actions files:
6566 http://config.privoxy.org/show-status
6568 • Show the source code version numbers:
6570 http://config.privoxy.org/show-version
6572 • Show the browser's request headers:
6574 http://config.privoxy.org/show-request
6576 • Show which actions apply to a URL and why:
6578 http://config.privoxy.org/show-url-info
6580 • Toggle Privoxy on or off. This feature can be turned off/on in the main
6581 config file. When toggled "off", "Privoxy" continues to run, but only as a
6582 pass-through proxy, with no actions taking place:
6584 http://config.privoxy.org/toggle
6586 Short cuts. Turn off, then on:
6588 http://config.privoxy.org/toggle?set=disable
6590 http://config.privoxy.org/toggle?set=enable
6592 These may be bookmarked for quick reference. See next.
6594 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6596 14.2.1. Bookmarklets
6598 Below are some "bookmarklets" to allow you to easily access a "mini" version of
6599 some of Privoxy's special pages. They are designed for MS Internet Explorer,
6600 but should work equally well in Netscape, Mozilla, and other browsers which
6601 support JavaScript. They are designed to run directly from your bookmarks - not
6602 by clicking the links below (although that should work for testing).
6604 To save them, right-click the link and choose "Add to Favorites" (IE) or "Add
6605 Bookmark" (Netscape). You will get a warning that the bookmark "may not be
6606 safe" - just click OK. Then you can run the Bookmarklet directly from your
6607 favorites/bookmarks. For even faster access, you can put them on the "Links"
6608 bar (IE) or the "Personal Toolbar" (Netscape), and run them with a single
6615 • Privoxy - Toggle Privoxy (Toggles between enabled and disabled)
6617 • Privoxy- View Status
6621 Credit: The site which gave us the general idea for these bookmarklets is
6622 www.bookmarklets.com. They have more information about bookmarklets.
6624 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6626 14.3. Chain of Events
6628 Let's take a quick look at how some of Privoxy's core features are triggered,
6629 and the ensuing sequence of events when a web page is requested by your
6632 • First, your web browser requests a web page. The browser knows to send the
6633 request to Privoxy, which will in turn, relay the request to the remote web
6634 server after passing the following tests:
6636 • Privoxy traps any request for its own internal CGI pages (e.g http://p.p/)
6637 and sends the CGI page back to the browser.
6639 • Next, Privoxy checks to see if the URL matches any "+block" patterns. If
6640 so, the URL is then blocked, and the remote web server will not be
6641 contacted. "+handle-as-image" and "+handle-as-empty-document" are then
6642 checked, and if there is no match, an HTML "BLOCKED" page is sent back to
6643 the browser. Otherwise, if it does match, an image is returned for the
6644 former, and an empty text document for the latter. The type of image would
6645 depend on the setting of "+set-image-blocker" (blank, checkerboard pattern,
6646 or an HTTP redirect to an image elsewhere).
6648 • Untrusted URLs are blocked. If URLs are being added to the trust file, then
6651 • If the URL pattern matches the "+fast-redirects" action, it is then
6652 processed. Unwanted parts of the requested URL are stripped.
6654 • Now the rest of the client browser's request headers are processed. If any
6655 of these match any of the relevant actions (e.g. "+hide-user-agent", etc.),
6656 headers are suppressed or forged as determined by these actions and their
6659 • Now the web server starts sending its response back (i.e. typically a web
6662 • First, the server headers are read and processed to determine, among other
6663 things, the MIME type (document type) and encoding. The headers are then
6664 filtered as determined by the "+crunch-incoming-cookies",
6665 "+session-cookies-only", and "+downgrade-http-version" actions.
6667 • If the "+kill-popups" action applies, and it is an HTML or JavaScript
6668 document, the popup-code in the response is filtered on-the-fly as it is
6671 • If any "+filter" action or "+deanimate-gifs" action applies (and the
6672 document type fits the action), the rest of the page is read into memory
6673 (up to a configurable limit). Then the filter rules (from default.filter
6674 and any other filter files) are processed against the buffered content.
6675 Filters are applied in the order they are specified in one of the filter
6676 files. Animated GIFs, if present, are reduced to either the first or last
6677 frame, depending on the action setting.The entire page, which is now
6678 filtered, is then sent by Privoxy back to your browser.
6680 If neither a "+filter" action or "+deanimate-gifs" matches, then Privoxy
6681 passes the raw data through to the client browser as it becomes available.
6683 • As the browser receives the now (possibly filtered) page content, it reads
6684 and then requests any URLs that may be embedded within the page source,
6685 e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
6686 frames), sounds, etc. For each of these objects, the browser issues a
6687 separate request (this is easily viewable in Privoxy's logs). And each such
6688 request is in turn processed just as above. Note that a complex web page
6689 will have many, many such embedded URLs. If these secondary requests are to
6690 a different server, then quite possibly a very differing set of actions is
6693 NOTE: This is somewhat of a simplistic overview of what happens with each URL
6694 request. For the sake of brevity and simplicity, we have focused on Privoxy's
6697 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
6699 14.4. Troubleshooting: Anatomy of an Action
6701 The way Privoxy applies actions and filters to any given URL can be complex,
6702 and not always so easy to understand what is happening. And sometimes we need
6703 to be able to see just what Privoxy is doing. Especially, if something Privoxy
6704 is doing is causing us a problem inadvertently. It can be a little daunting to
6705 look at the actions and filters files themselves, since they tend to be filled
6706 with regular expressions whose consequences are not always so obvious.
6708 One quick test to see if Privoxy is causing a problem or not, is to disable it
6709 temporarily. This should be the first troubleshooting step. See the
6710 Bookmarklets section on a quick and easy way to do this (be sure to flush
6711 caches afterward!). Looking at the logs is a good idea too. (Note that both the
6712 toggle feature and logging are enabled via config file settings, and may need
6715 Another easy troubleshooting step to try is if you have done any customization
6716 of your installation, revert back to the installed defaults and see if that
6717 helps. There are times the developers get complaints about one thing or
6718 another, and the problem is more related to a customized configuration issue.
6720 Privoxy also provides the http://config.privoxy.org/show-url-info page that can
6721 show us very specifically how actions are being applied to any given URL. This
6722 is a big help for troubleshooting.
6724 First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell
6725 us how the current configuration will handle it. This will not help with
6726 filtering effects (i.e. the "+filter" action) from one of the filter files
6727 since this is handled very differently and not so easy to trap! It also will
6728 not tell you about any other URLs that may be embedded within the URL you are
6729 testing. For instance, images such as ads are expressed as URLs within the raw
6730 page source of HTML pages. So you will only get info for the actual URL that is
6731 pasted into the prompt area -- not any sub-URLs. If you want to know about
6732 embedded URLs like ads, you will have to dig those out of the HTML source. Use
6733 your browser's "View Page Source" option for this. Or right click on the ad,
6736 Let's try an example, google.com, and look at it one section at a time in a
6737 sample configuration (your real configuration may vary):
6739 Matches for http://www.google.com:
6741 In file: default.action [ View ] [ Edit ]
6743 {+deanimate-gifs {last}
6744 +fast-redirects {check-decoded-url}
6745 +filter {refresh-tags}
6746 +filter {img-reorder}
6747 +filter {banners-by-size}
6749 +filter {jumping-windows}
6750 +filter {ie-exploits}
6751 +hide-forwarded-for-headers
6752 +hide-from-header {block}
6753 +hide-referrer {forge}
6754 +session-cookies-only
6755 +set-image-blocker {pattern}
6758 { -session-cookies-only }
6764 In file: user.action [ View ] [ Edit ]
6765 (no matches in this file)
6768 This is telling us how we have defined our "actions", and which ones match for
6769 our test case, "google.com". Displayed is all the actions that are available to
6770 us. Remember, the + sign denotes "on". - denotes "off". So some are "on" here,
6771 but many are "off". Each example we try may provide a slightly different end
6772 result, depending on our configuration directives.
6774 The first listing is for our default.action file. The large, multi-line
6775 listing, is how the actions are set to match for all URLs, i.e. our default
6776 settings. If you look at your "actions" file, this would be the section just
6777 below the "aliases" section near the top. This will apply to all URLs as
6778 signified by the single forward slash at the end of the listing -- " / ".
6780 But we have defined additional actions that would be exceptions to these
6781 general rules, and then we list specific URLs (or patterns) that these
6782 exceptions would apply to. Last match wins. Just below this then are two
6783 explicit matches for ".google.com". The first is negating our previous cookie
6784 setting, which was for "+session-cookies-only" (i.e. not persistent). So we
6785 will allow persistent cookies for google, at least that is how it is in this
6786 example. The second turns off any "+fast-redirects" action, allowing this to
6787 take place unmolested. Note that there is a leading dot here -- ".google.com".
6788 This will match any hosts and sub-domains, in the google.com domain also, such
6789 as "www.google.com" or "mail.google.com". But it would not match
6790 "www.google.de"! So, apparently, we have these two actions defined as
6791 exceptions to the general rules at the top somewhere in the lower part of our
6792 default.action file, and "google.com" is referenced somewhere in these latter
6795 Then, for our user.action file, we again have no hits. So there is nothing
6796 google-specific that we might have added to our own, local configuration. If
6797 there was, those actions would over-rule any actions from previously processed
6798 files, such as default.action. user.action typically has the last word. This is
6799 the best place to put hard and fast exceptions,
6801 And finally we pull it all together in the bottom section and summarize how
6802 Privoxy is applying all its "actions" to "google.com":
6808 -client-header-filter{hide-tor-exit-notation}
6809 -content-type-overwrite
6810 -crunch-client-header
6811 -crunch-if-none-match
6812 -crunch-incoming-cookies
6813 -crunch-outgoing-cookies
6814 -crunch-server-header
6815 +deanimate-gifs {last}
6816 -downgrade-http-version
6819 -filter {content-cookies}
6820 -filter {all-popups}
6821 -filter {banners-by-link}
6822 -filter {tiny-textforms}
6823 -filter {frameset-borders}
6824 -filter {demoronizer}
6825 -filter {shockwave-flash}
6826 -filter {quicktime-kioskmode}
6828 -filter {crude-parental}
6829 -filter {site-specifics}
6830 -filter {js-annoyances}
6831 -filter {html-annoyances}
6832 +filter {refresh-tags}
6833 -filter {unsolicited-popups}
6834 +filter {img-reorder}
6835 +filter {banners-by-size}
6837 +filter {jumping-windows}
6838 +filter {ie-exploits}
6845 -handle-as-empty-document
6847 -hide-accept-language
6848 -hide-content-disposition
6849 +hide-forwarded-for-headers
6850 +hide-from-header {block}
6851 -hide-if-modified-since
6852 +hide-referrer {forge}
6857 -overwrite-last-modified
6858 -prevent-compression
6862 -server-header-filter{xml-to-html}
6863 -server-header-filter{html-to-xml}
6864 -session-cookies-only
6865 +set-image-blocker {pattern}
6866 -treat-forbidden-connects-like-blocks
6869 Notice the only difference here to the previous listing, is to "fast-redirects"
6870 and "session-cookies-only", which are activated specifically for this site in
6871 our configuration, and thus show in the "Final Results".
6873 Now another example, "ad.doubleclick.net":
6881 { +block +handle-as-image }
6882 .[a-vx-z]*.doubleclick.net
6885 We'll just show the interesting part here - the explicit matches. It is matched
6886 three different times. Two "+block" sections, and a "+block +handle-as-image",
6887 which is the expanded form of one of our aliases that had been defined as:
6888 "+block-as-image". ("Aliases" are defined in the first section of the actions
6889 file and typically used to combine more than one action.)
6891 Any one of these would have done the trick and blocked this as an unwanted
6892 image. This is unnecessarily redundant since the last case effectively would
6893 also cover the first. No point in taking chances with these guys though ;-)
6894 Note that if you want an ad or obnoxious URL to be invisible, it should be
6895 defined as "ad.doubleclick.net" is done here -- as both a "+block" and an
6896 "+handle-as-image". The custom alias "+block-as-image" just simplifies the
6897 process and make it more readable.
6899 One last example. Let's try "http://www.example.net/adsl/HOWTO/". This one is
6900 giving us problems. We are getting a blank page. Hmmm ...
6902 Matches for http://www.example.net/adsl/HOWTO/:
6904 In file: default.action [ View ] [ Edit ]
6908 -client-header-filter{hide-tor-exit-notation}
6909 -content-type-overwrite
6910 -crunch-client-header
6911 -crunch-if-none-match
6912 -crunch-incoming-cookies
6913 -crunch-outgoing-cookies
6914 -crunch-server-header
6916 -downgrade-http-version
6917 +fast-redirects {check-decoded-url}
6919 -filter {content-cookies}
6920 -filter {all-popups}
6921 -filter {banners-by-link}
6922 -filter {tiny-textforms}
6923 -filter {frameset-borders}
6924 -filter {demoronizer}
6925 -filter {shockwave-flash}
6926 -filter {quicktime-kioskmode}
6928 -filter {crude-parental}
6929 -filter {site-specifics}
6930 -filter {js-annoyances}
6931 -filter {html-annoyances}
6932 +filter {refresh-tags}
6933 -filter {unsolicited-popups}
6934 +filter {img-reorder}
6935 +filter {banners-by-size}
6937 +filter {jumping-windows}
6938 +filter {ie-exploits}
6945 -handle-as-empty-document
6947 -hide-accept-language
6948 -hide-content-disposition
6949 +hide-forwarded-for-headers
6950 +hide-from-header{block}
6951 +hide-referer{forge}
6955 -overwrite-last-modified
6956 +prevent-compression
6960 -server-header-filter{xml-to-html}
6961 -server-header-filter{html-to-xml}
6962 +session-cookies-only
6963 +set-image-blocker{blank}
6964 -treat-forbidden-connects-like-blocks }
6967 { +block +handle-as-image }
6971 Ooops, the "/adsl/" is matching "/ads" in our configuration! But we did not
6972 want this at all! Now we see why we get the blank page. It is actually
6973 triggering two different actions here, and the effects are aggregated so that
6974 the URL is blocked, and Privoxy is told to treat the block as if it were an
6975 image. But this is, of course, all wrong. We could now add a new action below
6976 this (or better in our own user.action file) that explicitly un blocks ( "
6977 {-block}") paths with "adsl" in them (remember, last match in the configuration
6978 wins). There are various ways to handle such exceptions. Example:
6984 Now the page displays ;-) Remember to flush your browser's caches when making
6985 these kinds of changes to your configuration to insure that you get a freshly
6986 delivered page! Or, try using Shift+Reload.
6988 But now what about a situation where we get no explicit matches like we did
6991 { +block +handle-as-image }
6995 That actually was very helpful and pointed us quickly to where the problem was.
6996 If you don't get this kind of match, then it means one of the default rules in
6997 the first section of default.action is causing the problem. This would require
6998 some guesswork, and maybe a little trial and error to isolate the offending
6999 rule. One likely cause would be one of the "+filter" actions. These tend to be
7000 harder to troubleshoot. Try adding the URL for the site to one of aliases that
7005 .worldpay.com # for quietpc.com
7011 "{ shop }" is an "alias" that expands to "{ -filter -session-cookies-only }".
7012 Or you could do your own exception to negate filtering:
7015 # Disable ALL filter actions for sites in this section
7021 This would turn off all filtering for these sites. This is best put in
7022 user.action, for local site exceptions. Note that when a simple domain pattern
7023 is used by itself (without the subsequent path portion), all sub-pages within
7024 that domain are included automatically in the scope of the action.
7026 Images that are inexplicably being blocked, may well be hitting the "+filter
7027 {banners-by-size}" rule, which assumes that images of certain sizes are ad
7028 banners (works well most of the time since these tend to be standardized).
7030 "{ fragile }" is an alias that disables most actions that are the most likely
7031 to cause trouble. This can be used as a last resort for problem sites.
7034 # Handle with care: easy to break
7039 Remember to flush caches! Note that the mail.google reference lacks the TLD
7040 portion (e.g. ".com"). This will effectively match any TLD with google in it,
7041 such as mail.google.de., just as an example.
7043 If this still does not work, you will have to go through the remaining actions
7044 one by one to find which one(s) is causing the problem.
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