5 $Id: user-manual.sgml,v 1.95 2002/04/26 17:23:29 swa Exp $
7 The user manual gives users information on how to install, configure and use
10 Privoxy is a web proxy with advanced filtering capabilities for protecting
11 privacy, filtering web page content, managing cookies, controlling access, and
12 removing ads, banners, pop-ups and other obnoxious Internet junk. Privoxy has a
13 very flexible configuration and can be customized to suit individual needs and
14 tastes. Privoxy has application for both stand-alone systems and multi-user
17 Privoxy is based on Internet Junkbuster (tm).
19 You can find the latest version of the user manual at http://www.privoxy.org/
20 user-manual/. Please see the Contact section on how to contact the developers.
22 -------------------------------------------------------------------------------
32 3.1. Red Hat and SuSE RPMs
35 3.4. Solaris, NetBSD, FreeBSD, HP-UX
41 5. Quickstart to Using Privoxy
44 6.1. Command Line Options
46 7. Privoxy Configuration
48 7.1. Controlling Privoxy with Your Web Browser
49 7.2. Configuration Files Overview
50 7.3. The Main Configuration File
52 7.3.1. Configuration and Log File Locations
62 7.3.2. Local Set-up Documentation
64 7.3.2.1. trust-info-url
65 7.3.2.2. admin-address
66 7.3.2.3. proxy-info-url
71 7.3.3.2. single-threaded
73 7.3.4. Access Control and Security
75 7.3.4.1. listen-address
77 7.3.4.3. enable-remote-toggle
78 7.3.4.4. enable-edit-actions
79 7.3.4.5. ACLs: permit-access and deny-access
85 7.3.5.2. forward-socks4 and forward-socks4a
86 7.3.5.3. Advanced Forwarding Examples
88 7.3.6. Windows GUI Options
92 7.4.1. Finding the Right Mix
94 7.4.3. How Actions are Applied to URLs
97 7.4.4.1. The Domain Pattern
98 7.4.4.2. The Path Pattern
104 7.4.5.3. +deanimate-gifs
105 7.4.5.4. +downgrade-http-version
106 7.4.5.5. +fast-redirects
108 7.4.5.7. +hide-forwarded-for-headers
109 7.4.5.8. +hide-from-header
110 7.4.5.9. +hide-referer
111 7.4.5.10. +hide-user-agent
112 7.4.5.11. +handle-as-image
113 7.4.5.12. +set-image-blocker
114 7.4.5.13. +limit-connect
115 7.4.5.14. +prevent-compression
116 7.4.5.15. +session-cookies-only
117 7.4.5.16. +prevent-reading-cookies
118 7.4.5.17. +prevent-setting-cookies
119 7.4.5.18. +kill-popups
120 7.4.5.19. +send-vanilla-wafer
121 7.4.5.20. +send-wafer
122 7.4.5.21. Actions Examples
128 7.5.1. The +filter Action
132 8. Contacting the Developers, Bug Reporting and Feature Requests
136 8.3. Request new features
137 8.4. Report ads or other filter problems
140 9. Copyright and History
148 11.1. Regular Expressions
149 11.2. Privoxy's Internal Pages
153 11.3. Chain of Events
154 11.4. Anatomy of an Action
156 -------------------------------------------------------------------------------
160 This documentation is included with the current beta version of Privoxy,
161 v.2.9.14, and is mostly complete at this point. The most up to date reference
162 for the time being is still the comments in the source files and in the
163 individual configuration files. Development of version 3.0 is currently nearing
164 completion, and includes many significant changes and enhancements over earlier
165 versions. The target release date for stable v3.0 is "soon" ;-).
167 Since this is a beta version, not all new features are well tested. This
168 documentation may be slightly out of sync as a result (especially with CVS
169 sources). And there may be bugs, though hopefully not many!
171 -------------------------------------------------------------------------------
175 In addition to Internet Junkbuster's traditional features of ad and banner
176 blocking and cookie management, Privoxy provides new features, some of them
177 currently under development:
179 * FIXME: complete the list of features. change the order: most important
180 features to the top of the list. prefix new features with "NEW".
182 * Integrated browser based configuration and control utility at http://
183 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
184 and filter effects. Remote toggling.
186 * Blocking of annoying pop-up browser windows.
188 * HTTP/1.1 compliant (but not all optional 1.1 features are supported).
190 * Support for Perl Compatible Regular Expressions in the configuration files,
191 and generally a more sophisticated and flexible configuration syntax over
196 * Web page content filtering (removes banners based on size, invisible
197 "web-bugs", JavaScript and HTML annoyances, pop-ups, etc.)
199 * Bypass many click-tracking scripts (avoids script redirection).
201 * Multi-threaded (POSIX and native threads).
203 * Auto-detection and re-reading of config file changes.
205 * User-customizable HTML templates (e.g. 404 error page).
207 * Improved cookie management features (e.g. session based cookies).
209 * Improved signal handling, and a true daemon mode (Unix).
211 * Every feature now controllable on a per-site or per-location basis,
212 configuration more powerful and versatile over-all.
214 * Many smaller new features added, limitations and bugs removed, and security
217 -------------------------------------------------------------------------------
221 Privoxy is available both in convenient pre-compiled packages for a wide range
222 of operating systems, and as raw source code. For most users, we recommend
223 using the packages, which can be downloaded from our Privoxy Project Page. For
224 installing and compiling the source code, please look into our Developer
227 If you like to live on the bleeding edge and are not afraid of using possibly
228 unstable development versions, you can check out the up-to-the-minute version
229 directly from the CVS repository or simply download the nightly CVS tarball.
230 Again, we refer you to the Developer Manual.
232 At present, Privoxy is known to run on Windows(95, 98, ME, 2000, XP), Linux
233 (RedHat, Suse, Debian), Mac OSX, OS/2, AmigaOS, FreeBSD, NetBSD, BeOS, and many
234 more flavors of Unix.
236 Note: If you have a previous Junkbuster or Privoxy installation on your system,
237 you will need to remove it. Some platforms do this for you as part of their
238 installation procedure. (See below for your platform).
240 In any case be sure to backup your old configuration if it is valuable to you.
241 See the note to upgraders section below.
243 -------------------------------------------------------------------------------
245 3.1. Red Hat and SuSE RPMs
247 RPMs can be installed with rpm -Uvh privoxy-2.9.14-1.rpm, and will use /etc/
248 privoxy for the location of configuration files.
250 Note that on Red Hat, Privoxy will not be automatically started on system boot.
251 You will need to enable that using chkconfig, ntsysv, or similar methods. Note
252 that SuSE will automatically start Privoxy in the boot process.
254 If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm
255 --rebuild privoxy-2.9.14-1.src.rpm;. This will use your locally installed
256 libraries and RPM version.
258 Also note that if you have a Junkbuster RPM installed on your system, you need
259 to remove it first, because the packages conflict. Otherwise, RPM will try to
260 remove Junkbuster automatically, before installing Privoxy.
262 -------------------------------------------------------------------------------
268 -------------------------------------------------------------------------------
272 Just double-click the installer, which will guide you through the installation
273 process. You will find the configuration files in the same directory as you
274 installed Privoxy in. We do not use the registry of Windows.
276 -------------------------------------------------------------------------------
278 3.4. Solaris, NetBSD, FreeBSD, HP-UX
280 Create a new directory, cd to it, then unzip and untar the archive. For the
281 most part, you'll have to figure out where things go. FIXME.
283 -------------------------------------------------------------------------------
287 First, make sure that no previous installations of Junkbuster and / or Privoxy
288 are left on your system. You can do this by
290 Then, just double-click the WarpIN self-installing archive, which will guide
291 you through the installation process. A shadow of the Privoxy executable will
292 be placed in your startup folder so it will start automatically whenever OS/2
295 The directory you choose to install Privoxy into will contain all of the
298 -------------------------------------------------------------------------------
302 Unzip the downloaded package (you can either double-click on the file in the
303 finder, or on the desktop if you downloaded it there). Then, double-click on
304 the package installer icon and follow the installation process. Privoxy will be
305 installed in the subdirectory /Applications/Privoxy.app. Privoxy will set
306 itself up to start automatically on system bring-up via /System/Library/
307 StartupItems/Privoxy.
309 -------------------------------------------------------------------------------
313 Copy and then unpack the lha archive to a suitable location. All necessary
314 files will be installed into Privoxy directory, including all configuration and
315 log files. To uninstall, just remove this directory.
317 Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in s:
318 user-startup (RoadShow), as startup program in your startup script (Genesis),
319 or as startup action (Miami and MiamiDx). Privoxy will automatically quit when
320 you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack
321 may display that Privoxy is still running).
323 -------------------------------------------------------------------------------
327 There are very significant changes from older versions of Junkbuster to the
328 current Privoxy. Configuration is substantially changed. Junkbuster 2.0.x and
329 earlier configuration files will not migrate. The functionality of the old
330 blockfile, cookiefile and imagelist, are now combined into the "actions files".
331 default.action, is the main actions file. Local exceptions should best be put
334 A "filter file" (typically default.filter) is new as of Privoxy 2.9.x, and
335 provides some of the new sophistication (explained below). config is much the
338 If upgrading from a 2.0.x version, you will have to use the new config files,
339 and possibly adapt any personal rules from your older files. When porting
340 personal rules over from the old blockfile to the new actions files, please
341 note that even the pattern syntax has changed. If upgrading from 2.9.x
342 development versions, it is still recommended to use the new configuration
345 A quick list of things to be aware of before upgrading:
347 * The default listening port is now 8118 due to a conflict with another
350 * Some installers may remove earlier versions completely. Save any important
353 * Privoxy is controllable with a web browser at the special URL: http://
354 config.privoxy.org/ (Shortcut: http://p.p/). Many aspects of configuration
355 can be done here, including temporarily disabling Privoxy.
357 * The primary configuration file for cookie management, ad and banner
358 blocking, and many other aspects of Privoxy configuration is in the
359 "actions" files. It is strongly recommended to become familiar with the new
360 actions concept below, before modifying these files. Locally defined rules
361 should go into user.action.
363 * Some installers may not automatically start Privoxy after installation.
365 -------------------------------------------------------------------------------
367 5. Quickstart to Using Privoxy
369 * Install Privoxy. See the section Installing.
371 * Start Privoxy. See the section Starting Privoxy.
373 * Change your browser's configuration to use the proxy localhost on port
374 8118. See the section Starting Privoxy.
376 * Enjoy surfing with enhanced comfort and privacy. Please see the section
377 Contacting the Developers on how to report bugs or problems with websites
378 or to get help. You may want to change the file user.action to further
379 tweak your new browsing experience.
381 -------------------------------------------------------------------------------
385 Before launching Privoxy for the first time, you will want to configure your
386 browser(s) to use Privoxy as a HTTP and HTTPS proxy. The default is localhost
387 for the proxy address, and port 8118 (earlier versions used port 8000). This is
388 the one configuration step that must be done!
390 With Netscape (and Mozilla), this can be set under Edit -> Preferences ->
391 Advanced -> Proxies -> HTTP Proxy. For Internet Explorer: Tools -> Internet
392 Properties -> Connections -> LAN Setting. Then, check "Use Proxy" and fill in
393 the appropriate info (Address: localhost, Port: 8118). Include if HTTPS proxy
396 After doing this, flush your browser's disk and memory caches to force a
397 re-reading of all pages and to get rid of any ads that may be cached. You are
398 now ready to start enjoying the benefits of using Privoxy!
400 Privoxy is typically started by specifying the main configuration file to be
401 used on the command line. Example Unix startup command:
403 # /usr/sbin/privoxy /etc/privoxy/config
405 See below for other command line options.
407 An init script is provided for SuSE and Red Hat.
409 For for SuSE: rcprivoxy start
411 For Red Hat and Debian: /etc/rc.d/init.d/privoxy start
413 If no configuration file is specified on the command line, Privoxy will look
414 for a file named config in the current directory. Except on Win32 where it will
415 try config.txt. If no file is specified on the command line and no default
416 configuration file can be found, Privoxy will fail to start.
418 The included default configuration files should give a reasonable starting
419 point. Most of the per site configuration is done in the "actions" files. These
420 are where various cookie actions are defined, ad and banner blocking, and other
421 aspects of Privoxy configuration. There are several such files included, with
422 varying levels of aggressiveness.
424 You will probably want to keep an eye out for sites for which you may prefer
425 persistent cookies, and add these to your actions configuration as needed. By
426 default, most of these will be accepted only during the current browser session
427 (aka "session cookies"), unless you add them to the configuration. If you want
428 the browser to handle this instead, you will need to edit user.action (or
429 through the web based interface) and disable this feature. If you use more than
430 one browser, it would make more sense to let Privoxy handle this. In which
431 case, the browser(s) should be set to accept all cookies.
433 Another feature where you will probably want to define exceptions for trusted
434 sites is the popup-killing (through the +popup and +filter{popups} actions),
435 because your favorite shopping, banking, or leisure site may need popups
438 Privoxy is HTTP/1.1 compliant, but not all of the optional 1.1 features are as
439 yet supported. In the unlikely event that you experience inexplicable problems
440 with browsers that use HTTP/1.1 per default (like Mozilla or recent versions of
441 I.E.), you might try to force HTTP/1.0 compatibility. For Mozilla, look under
442 Edit -> Preferences -> Debug -> Networking. Alternatively, set the
443 "+downgrade-http-version" config option in default.action which will downgrade
444 your browser's HTTP requests from HTTP/1.1 to HTTP/1.0 before processing them.
446 After running Privoxy for a while, you can start to fine tune the configuration
447 to suit your personal, or site, preferences and requirements. There are many,
448 many aspects that can be customized. "Actions" can be adjusted by pointing your
449 browser to http://config.privoxy.org/ (shortcut: http://p.p/), and then follow
450 the link to "View & Change the Current Configuration". (This is an internal
451 page and does not require Internet access.)
453 In fact, various aspects of Privoxy configuration can be viewed from this page,
454 including current configuration parameters, source code version numbers, the
455 browser's request headers, and "actions" that apply to a given URL. In addition
456 to the actions file editor mentioned above, Privoxy can also be turned "on" and
457 "off" (toggled) from this page.
459 If you encounter problems, try loading the page without Privoxy. If that helps,
460 enter the URL where you have the problems into the browser based rule tracing
461 utility. See which rules apply and why, and then try turning them off for that
462 site one after the other, until the problem is gone. When you have found the
463 culprit, you might want to turn the rest on again.
465 If the above paragraph sounds gibberish to you, you might want to read more
466 about the actions concept or even dive deep into the Appendix on actions.
468 If you can't get rid of the problem at all, think you've found a bug in
469 Privoxy, want to propose a new feature or smarter rules, please see the section
470 "Contacting the Developers" below.
472 -------------------------------------------------------------------------------
474 6.1. Command Line Options
476 Privoxy may be invoked with the following command-line options:
480 Print version info and exit. Unix only.
484 Print short usage info and exit. Unix only.
488 Don't become a daemon, i.e. don't fork and become process group leader, and
489 don't detach from controlling tty. Unix only.
493 On startup, write the process ID to FILE. Delete the FILE on exit. Failure
494 to create or delete the FILE is non-fatal. If no FILE option is given, no
495 PID file will be used. Unix only.
497 * --user USER[.GROUP]
499 After (optionally) writing the PID file, assume the user ID of USER, and if
500 included the GID of GROUP. Exit if the privileges are not sufficient to do
505 If no configfile is included on the command line, Privoxy will look for a
506 file named "config" in the current directory (except on Win32 where it will
507 look for "config.txt" instead). Specify full path to avoid confusion. If no
508 config file is found, Privoxy will fail to start.
510 -------------------------------------------------------------------------------
512 7. Privoxy Configuration
514 All Privoxy configuration is stored in text files. These files can be edited
515 with a text editor. Many important aspects of Privoxy can also be controlled
516 easily with a web browser.
518 -------------------------------------------------------------------------------
520 7.1. Controlling Privoxy with Your Web Browser
522 Privoxy's user interface can be reached through the special URL http://
523 config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works
524 without Internet access. You will see the following section:
527 ? View & change the current configuration
528 ? View the source code version numbers
529 ? View the request headers.
530 ? Look up which actions apply to a URL and why
531 ? Toggle Privoxy on or off
534 This should be self-explanatory. Note the first item leads to an editor for the
535 "actions list", which is where the ad, banner, cookie, and URL blocking magic
536 is configured as well as other advanced features of Privoxy. This is an easy
537 way to adjust various aspects of Privoxy configuration. The actions file, and
538 other configuration files, are explained in detail below.
540 "Toggle Privoxy On or Off" is handy for sites that might have problems with
541 your current actions and filters. You can in fact use it as a test to see
542 whether it is Privoxy causing the problem or not. Privoxy continues to run as a
543 proxy in this case, but all filtering is disabled. There is even a toggle
544 Bookmarklet offered, so that you can toggle Privoxy with one click from your
547 -------------------------------------------------------------------------------
549 7.2. Configuration Files Overview
551 For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/
552 by default. For MS Windows, OS/2, and AmigaOS these are all in the same
553 directory as the Privoxy executable. The name and number of configuration files
554 has changed from previous versions, and is subject to change as development
557 The installed defaults provide a reasonable starting point, though some
558 settings may be aggressive by some standards. For the time being, the principle
559 configuration files are:
561 * The main configuration file is named config on Linux, Unix, BSD, OS/2, and
562 AmigaOS and config.txt on Windows. This is a required file.
564 * default.action (the main actions file) is used to define the default
565 settings for various "actions" relating to images, banners, pop-ups, access
566 restrictions, banners and cookies.
568 Multiple actions files may be defined in config. These are processed in the
569 order they are defined. Local customizations and locally preferred
570 exceptions to the default policies as defined in default.action are
571 probably best applied in user.action, which should be preserved across
572 upgrades. standard.action is also included. This is mostly for Privoxy's
575 There is also a web based editor that can be accessed from http://
576 config.privoxy.org/show-status/ (Shortcut: http://p.p/show-status/) for the
577 various actions files.
579 * default.filter (the filter file) can be used to re-write the raw page
580 content, including viewable text as well as embedded HTML and JavaScript,
581 and whatever else lurks on any given web page. The filtering jobs are only
582 pre-defined here; whether to apply them or not is up to the actions files.
584 All files use the "#" character to denote a comment (the rest of the line will
585 be ignored) angd understand line continuation through placing a backslash ("\")
586 as the very last character in a line. If the # is preceded by a backslash, it
587 looses its special function. Placing a # in front of an otherwise valid
588 configuration line to prevent it from being interpreted is called "commenting
591 The actions files and default.filter can use Perl style regular expressions for
594 After making any changes, there is no need to restart Privoxy in order for the
595 changes to take effect. Privoxy detects such changes automatically. Note,
596 however, that it may take one or two additional requests for the change to take
597 effect. When changing the listening address of Privoxy, these "wake up"
598 requests must obviously be sent to the old listening address.
600 While under development, the configuration content is subject to change. The
601 below documentation may not be accurate by the time you read this. Also, what
602 constitutes a "default" setting, may change, so please check all your
603 configuration files on important issues.
605 -------------------------------------------------------------------------------
607 7.3. The Main Configuration File
609 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
610 and config.txt on Windows. Configuration lines consist of an initial keyword
611 followed by a list of values, all separated by whitespace (any number of spaces
612 or tabs). For example:
617 Assigns the value /etc/privoxy to the option confdir and thus indicates that
618 the configuration directory is named "/etc/privoxy/".
620 All options in the config file except for confdir and logdir are optional.
621 Watch out in the below description for what happens if you leave them unset.
623 The main config file controls all aspects of Privoxy's operation that are not
624 location dependent (i.e. they apply universally, no matter where you may be
627 -------------------------------------------------------------------------------
629 7.3.1. Configuration and Log File Locations
631 Privoxy can (and normally does) use a number of other files for additional
632 configuration and logging. This section of the configuration file tells Privoxy
633 where to find those other files.
635 -------------------------------------------------------------------------------
641 The directory where the other configuration files are located
649 /etc/privoxy (Unix) or Privoxy installation dir (Windows)
657 No trailing "/", please
659 When development goes modular and multi-user, the blocker, filter, and
660 per-user config will be stored in subdirectories of "confdir". For now, the
661 configuration directory structure is flat, except for confdir/templates,
662 where the HTML templates for CGI output reside (e.g. Privoxy's 404 error
665 -------------------------------------------------------------------------------
671 The directory where all logging takes place (i.e. where logfile and jarfile
680 /var/log/privoxy (Unix) or Privoxy installation dir (Windows)
688 No trailing "/", please
690 -------------------------------------------------------------------------------
696 The actions file(s) to use
700 File name, relative to confdir
704 standard # Internal purposes, recommended not editing
706 default # Main actions file
708 user # User customizations
712 No actions are taken at all. Simple neutral proxying.
716 Multiple actionsfile lines are OK and are in fact recommended!
718 The default values include standard.action, which is used for internal
719 purposes and should be loaded, default.action, which is the "main" actions
720 file maintained by the developers, and user.action, where you can make your
723 There is no point in using Privoxy without an actions file.
725 -------------------------------------------------------------------------------
731 The filter file to use
735 File name, relative to confdir
739 default.filter (Unix) or default.filter.txt (Windows)
743 No textual content filtering takes place, i.e. all +filter{name} actions in
744 the actions files are turned off
748 The "default.filter" file contains content modification rules that use
749 "regular expressions". These rules permit powerful changes on the content
750 of Web pages, e.g., you could disable your favorite JavaScript annoyances,
751 re-write the actual displayed text, or just have some fun replacing
752 "Microsoft" with "MicroSuck" wherever it appears on a Web page.
754 -------------------------------------------------------------------------------
764 File name, relative to logdir
768 logfile (Unix) or privoxy.log (Windows)
772 No log file is used, all log messages go to the console (stderr).
776 The windows version will additionally log to the console.
778 The logfile is where all logging and error messages are written. The level
779 of detail and number of messages are set with the debug option (see below).
780 The logfile can be useful for tracking down a problem with Privoxy (e.g.,
781 it's not blocking an ad you think it should block) but in most cases you
782 probably will never look at it.
784 Your logfile will grow indefinitely, and you will probably want to
785 periodically remove it. On Unix systems, you can do this with a cron job
786 (see "man cron"). For Red Hat, a logrotate script has been included.
788 On SuSE Linux systems, you can place a line like "/var/log/privoxy.* +1024k
789 644 nobody.nogroup" in /etc/logfiles, with the effect that cron.daily will
790 automatically archive, gzip, and empty the log, when it exceeds 1M size.
792 -------------------------------------------------------------------------------
798 The file to store intercepted cookies in
802 File name, relative to logdir
806 jarfile (Unix) or privoxy.jar (Windows)
810 Intercepted cookies are not stored at all.
814 The jarfile may grow to ridiculous sizes over time.
816 -------------------------------------------------------------------------------
822 The trust file to use
826 File name, relative to confdir
830 Unset (commented out). When activated: trust (Unix) or trust.txt (Windows)
834 The whole trust mechanism is turned off.
838 The trust mechanism is an experimental feature for building white-lists and
839 should be used with care. It is NOT recommended for the casual user.
841 If you specify a trust file, Privoxy will only allow access to sites that
842 are named in the trustfile. You can also mark sites as trusted referrers
843 (with +), with the effect that access to untrusted sites will be granted,
844 if a link from a trusted referrer was used. The link target will then be
845 added to the "trustfile". Possible applications include limiting Internet
848 If you use + operator in the trust file, it may grow considerably over
851 -------------------------------------------------------------------------------
853 7.3.2. Local Set-up Documentation
855 If you intend to operate Privoxy for more users that just yourself, it might be
856 a good idea to let them know how to reach you, what you block and why you do
857 that, your policies etc.
859 -------------------------------------------------------------------------------
861 7.3.2.1. trust-info-url
865 A URL to be displayed in the error page that users will see if access to an
866 untrusted page is denied.
874 Two example URL are provided
878 No links are displayed on the "untrusted" error page.
882 The value of this option only matters if the experimental trust mechanism
883 has been activated. (See trustfile above.)
885 If you use the trust mechanism, it is a good idea to write up some on-line
886 documentation about your trust policy and to specify the URL(s) here. Use
887 multiple times for multiple URLs.
889 The URL(s) should be added to the trustfile as well, so users don't end up
890 locked out from the information on why they were locked out in the first
893 -------------------------------------------------------------------------------
895 7.3.2.2. admin-address
899 An email address to reach the proxy administrator.
911 No email address is displayed on error pages and the CGI user interface.
915 If both admin-address and proxy-info-url are unset, the whole "Local
916 Privoxy Support" box on all generated pages will not be shown.
918 -------------------------------------------------------------------------------
920 7.3.2.3. proxy-info-url
924 A URL to documentation about the local Privoxy setup, configuration or
937 No link to local documentation is displayed on error pages and the CGI user
942 If both admin-address and proxy-info-url are unset, the whole "Local
943 Privoxy Support" box on all generated pages will not be shown.
945 This URL shouldn't be blocked ;-)
947 -------------------------------------------------------------------------------
951 These options are mainly useful when tracing a problem. Note that you might
952 also want to invoke Privoxy with the --no-daemon command line option when
955 -------------------------------------------------------------------------------
961 Key values that determine what information gets logged.
969 12289 (i.e.: URLs plus informational and warning messages)
977 The available debug levels are:
979 debug 1 # show each GET/POST/CONNECT request
980 debug 2 # show each connection status
981 debug 4 # show I/O status
982 debug 8 # show header parsing
983 debug 16 # log all data into the logfile
984 debug 32 # debug force feature
985 debug 64 # debug regular expression filter
986 debug 128 # debug fast redirects
987 debug 256 # debug GIF de-animation
988 debug 512 # Common Log Format
989 debug 1024 # debug kill pop-ups
990 debug 4096 # Startup banner and warnings.
991 debug 8192 # Non-fatal errors
993 To select multiple debug levels, you can either add them or use multiple
996 A debug level of 1 is informative because it will show you each request as
997 it happens. 1, 4096 and 8192 are highly recommended so that you will notice
998 when things go wrong. The other levels are probably only of interest if you
999 are hunting down a specific problem. They can produce a hell of an output
1002 The reporting of fatal errors (i.e. ones which crash Privoxy) is always on
1003 and cannot be disabled.
1005 If you want to use CLF (Common Log Format), you should set "debug 512" ONLY
1006 and not enable anything else.
1008 -------------------------------------------------------------------------------
1010 7.3.3.2. single-threaded
1014 Whether to run only one server thread
1026 Multi-threaded (or, where unavailable: forked) operation, i.e. the ability
1027 to serve multiple requests simultaneously.
1031 This option is only there for debug purposes and you should never need to
1032 use it. It will drastically reduce performance.
1034 -------------------------------------------------------------------------------
1036 7.3.4. Access Control and Security
1038 This section of the config file controls the security-relevant aspects of
1039 Privoxy's configuration.
1041 -------------------------------------------------------------------------------
1043 7.3.4.1. listen-address
1047 The IP address and TCP port on which Privoxy will listen for client
1060 Bind to localhost (127.0.0.1), port 8118. This is suitable and recommended
1061 for home users who run Privoxy on the same machine as their browser.
1065 You will need to configure your browser(s) to this proxy address and port.
1067 If you already have another service running on port 8118, or if you want to
1068 serve requests from other machines (e.g. on your local network) as well,
1069 you will need to override the default.
1071 If you leave out the IP address, Privoxy will bind to all interfaces
1072 (addresses) on your machine and may become reachable from the Internet. In
1073 that case, consider using access control lists (ACL's) (see "ACLs" below),
1078 Suppose you are running Privoxy on a machine which has the address
1079 192.168.0.1 on your local private network (192.168.0.0) and has another
1080 outside connection with a different address. You want it to serve requests
1083 listen-address 192.168.0.1:8118
1085 -------------------------------------------------------------------------------
1091 Initial state of "toggle" status
1103 Act as if toggled on
1107 If set to 0, Privoxy will start in "toggled off" mode, i.e. behave like a
1108 normal, content-neutral proxy. See enable-remote-toggle below. This is not
1109 really useful anymore, since toggling is much easier via the web interface
1110 then via editing the conf file.
1112 The windows version will only display the toggle icon in the system tray if
1113 this option is present.
1115 -------------------------------------------------------------------------------
1117 7.3.4.3. enable-remote-toggle
1121 Whether or not the web-based toggle feature may be used
1133 The web-based toggle feature is disabled.
1137 When toggled off, Privoxy acts like a normal, content-neutral proxy, i.e.
1138 it acts as if none of the actions applied to any URL.
1140 For the time being, access to the toggle feature can not be controlled
1141 separately by "ACLs" or HTTP authentication, so that everybody who can
1142 access Privoxy (see "ACLs" and listen-address above) can toggle it for all
1143 users. So this option is not recommended for multi-user environments with
1146 Note that you must have compiled Privoxy with support for this feature,
1147 otherwise this option has no effect.
1149 -------------------------------------------------------------------------------
1151 7.3.4.4. enable-edit-actions
1155 Whether or not the web-based actions file editor may be used
1167 The web-based actions file editor is disabled.
1171 For the time being, access to the editor can not be controlled separately
1172 by "ACLs" or HTTP authentication, so that everybody who can access Privoxy
1173 (see "ACLs" and listen-address above) can modify its configuration for all
1174 users. So this option is not recommended for multi-user environments with
1177 Note that you must have compiled Privoxy with support for this feature,
1178 otherwise this option has no effect.
1180 -------------------------------------------------------------------------------
1182 7.3.4.5. ACLs: permit-access and deny-access
1186 Who can access what.
1190 src_addr[/src_masklen] [dst_addr[/dst_masklen]]
1192 Where src_addr and dst_addr are IP addresses in dotted decimal notation or
1193 valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
1194 notation, i.e. integer values from 2 to 30 representing the length (in
1195 bits) of the network address. The masks and the whole destination part are
1204 Don't restrict access further than implied by listen-address
1208 Access controls are included at the request of ISPs and systems
1209 administrators, and are not usually needed by individual users. For a
1210 typical home user, it will normally suffice to ensure that Privoxy only
1211 listens on the localhost or internal (home) network address by means of the
1212 listen-address option.
1214 Please see the warnings in the FAQ that this proxy is not intended to be a
1215 substitute for a firewall or to encourage anyone to defer addressing basic
1216 security weaknesses.
1218 Multiple ACL lines are OK. If any ACLs are specified, then the Privoxy
1219 talks only to IP addresses that match at least one permit-access line and
1220 don't match any subsequent deny-access line. In other words, the last match
1221 wins, with the default being deny-access.
1223 If Privoxy is using a forwarder (see forward below) for a particular
1224 destination URL, the dst_addr that is examined is the address of the
1225 forwarder and NOT the address of the ultimate target. This is necessary
1226 because it may be impossible for the local Privoxy to determine the IP
1227 address of the ultimate target (that's often what gateways are used for).
1229 You should prefer using IP addresses over DNS names, because the address
1230 lookups take time. All DNS names must resolve! You can not use domain
1231 patterns like "*.org" or partial domain names. If a DNS name resolves to
1232 multiple IP addresses, only the first one is used.
1234 Denying access to particular sites by ACL may have undesired side effects
1235 if the site in question is hosted on a machine which also hosts other
1240 Explicitly define the default behavior if no ACL and listen-address are
1241 set: "localhost" is OK. The absence of a dst_addr implies that all
1242 destination addresses are OK:
1244 permit-access localhost
1246 Allow any host on the same class C subnet as www.privoxy.org access to
1247 nothing but www.example.com:
1249 permit-access www.privoxy.org/24 www.example.com/32
1251 Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
1252 with the exception that 192.168.45.73 may not access
1253 www.dirty-stuff.example.com:
1255 permit-access 192.168.45.64/26
1256 deny-access 192.168.45.73 www.dirty-stuff.example.com
1258 -------------------------------------------------------------------------------
1260 7.3.4.6. buffer-limit
1264 Maximum size of the buffer for content filtering.
1276 Use a 4MB (4096 KB) limit.
1280 For content filtering, i.e. the +filter and +deanimate-gif actions, it is
1281 necessary that Privoxy buffers the entire document body. This can be
1282 potentially dangerous, since a server could just keep sending data
1283 indefinitely and wait for your RAM to exhaust -- with nasty consequences.
1286 When a document buffer size reaches the buffer-limit, it is flushed to the
1287 client unfiltered and no further attempt to filter the rest of the document
1288 is made. Remember that there may be multiple threads running, which might
1289 require up to buffer-limit Kbytes each, unless you have enabled
1290 "single-threaded" above.
1292 -------------------------------------------------------------------------------
1296 This feature allows routing of HTTP requests through a chain of multiple
1297 proxies. It can be used to better protect privacy and confidentiality when
1298 accessing specific domains by routing requests to those domains through an
1299 anonymous public proxy (see e.g. http://www.multiproxy.org/anon_list.htm) Or to
1300 use a caching proxy to speed up browsing. Or chaining to a parent proxy may be
1301 necessary because the machine that Privoxy runs on has no direct Internet
1304 Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
1307 -------------------------------------------------------------------------------
1313 To which parent HTTP proxy specific requests should be routed.
1317 target_domain[:port] http_parent[/port]
1319 Where target_domain is a domain name pattern (see the chapter on domain
1320 matching in the default.action file), http_parent is the address of the
1321 parent HTTP proxy as an IP addresses in dotted decimal notation or as a
1322 valid DNS name (or "." to denote "no forwarding", and the optional port
1323 parameters are TCP ports, i.e. integer values from 1 to 64535
1331 Don't use parent HTTP proxies.
1335 If http_parent is ".", then requests are not forwarded to another HTTP
1336 proxy but are made directly to the web servers.
1338 Multiple lines are OK, they are checked in sequence, and the last match
1343 Everything goes to an example anonymizing proxy, except SSL on port 443
1344 (which it doesn't handle):
1346 forward .* anon-proxy.example.org:8080
1349 Everything goes to our example ISP's caching proxy, except for requests to
1352 forward .*. caching-proxy.example-isp.net:8000
1353 forward .example-isp.net .
1355 -------------------------------------------------------------------------------
1357 7.3.5.2. forward-socks4 and forward-socks4a
1361 Through which SOCKS proxy (and to which parent HTTP proxy) specific
1362 requests should be routed.
1366 target_domain[:port] socks_proxy[/port] http_parent[/port]
1368 Where target_domain is a domain name pattern (see the chapter on domain
1369 matching in the default.action file), http_parent and socks_proxy are IP
1370 addresses in dotted decimal notation or valid DNS names (http_parent may be
1371 "." to denote "no HTTP forwarding"), and the optional port parameters are
1372 TCP ports, i.e. integer values from 1 to 64535
1380 Don't use SOCKS proxies.
1384 Multiple lines are OK, they are checked in sequence, and the last match
1387 The difference between forward-socks4 and forward-socks4a is that in the
1388 SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
1389 SOCKS server, while in SOCKS 4 it happens locally.
1391 If http_parent is ".", then requests are not forwarded to another HTTP
1392 proxy but are made (HTTP-wise) directly to the web servers, albeit through
1397 From the company example.com, direct connections are made to all "internal"
1398 domains, but everything outbound goes through their ISP's proxy by way of
1399 example.com's corporate SOCKS 4A gateway to the Internet.
1401 forward-socks4a .*. socks-gw.example.com:1080 www-cache.example-isp.net:8080
1402 forward .example.com .
1404 A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
1407 forward-socks4 .*. socks-gw.example.com:1080 .
1409 -------------------------------------------------------------------------------
1411 7.3.5.3. Advanced Forwarding Examples
1413 If you have links to multiple ISPs that provide various special content only to
1414 their subscribers, you can configure multiple Privoxies which have connections
1415 to the respective ISPs to act as forwarders to each other, so that your users
1416 can see the internal content of all ISPs.
1418 Assume that host-a has a PPP connection to isp-a.net. And host-b has a PPP
1419 connection to isp-b.net. Both run Privoxy. Their forwarding configuration can
1425 forward .isp-b.net host-b:8118
1430 forward .isp-a.net host-a:8118
1432 Now, your users can set their browser's proxy to use either host-a or host-b
1433 and be able to browse the internal content of both isp-a and isp-b.
1435 If you intend to chain Privoxy and squid locally, then chain as browser ->
1436 squid -> privoxy is the recommended way.
1438 Assuming that Privoxy and squid run on the same box, your squid configuration
1439 could then look like this:
1441 # Define Privoxy as parent proxy (without ICP)
1442 cache_peer 127.0.0.1 parent 8118 7 no-query
1444 # Define ACL for protocol FTP
1447 # Do not forward FTP requests to Privoxy
1448 always_direct allow ftp
1450 # Forward all the rest to Privoxy
1451 never_direct allow all
1453 You would then need to change your browser's proxy settings to squid's address
1454 and port. Squid normally uses port 3128. If unsure consult http_port in
1457 -------------------------------------------------------------------------------
1459 7.3.6. Windows GUI Options
1461 Privoxy has a number of options specific to the Windows GUI interface:
1463 If "activity-animation" is set to 1, the Privoxy icon will animate when
1464 "Privoxy" is active. To turn off, set to 0.
1466 activity-animation 1
1469 If "log-messages" is set to 1, Privoxy will log messages to the console window:
1474 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
1475 of memory used for the log messages displayed in the console window, will be
1476 limited to "log-max-lines" (see below).
1478 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
1484 log-max-lines is the maximum number of lines held in the log buffer. See above.
1489 If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
1490 log messages with a bold-faced font:
1492 log-highlight-messages 1
1495 The font used in the console window:
1497 log-font-name Comic Sans MS
1500 Font size used in the console window:
1505 "show-on-task-bar" controls whether or not Privoxy will appear as a button on
1506 the Task bar when minimized:
1511 If "close-button-minimizes" is set to 1, the Windows close button will minimize
1512 Privoxy instead of closing the program (close with the exit option on the File
1515 close-button-minimizes 1
1518 The "hide-console" option is specific to the MS-Win console version of Privoxy.
1519 If this option is used, Privoxy will disconnect from and hide the command
1525 -------------------------------------------------------------------------------
1529 The actions files are used to define what actions Privoxy takes for which URLs,
1530 and thus determines how ad images, cookies and various other aspects of HTTP
1531 content and transactions are handled, and on which sites (or even parts
1532 thereof). There are three such files included with Privoxy, with slightly
1533 different purposes. default.action sets the default policies. standard.action
1534 is used by Privoxy and the web based editor to set pre-defined values (and
1535 normally should not be edited). Local exceptions are best done in user.action.
1536 The content of these can all be viewed and edited from http://
1537 config.privoxy.org/show-status.
1539 Anything you want can be blocked, including ads, banners, or just some
1540 obnoxious URL that you would rather not see is done here. Cookies can be
1541 accepted or rejected, or accepted only during the current browser session (i.e.
1542 not written to disk), content can be modified, JavaScripts tamed, user-tracking
1543 fooled, and much more. See below for a complete list of available actions.
1545 An actions file typically has sections. Near the top, "aliases" are optionally
1546 defined (discussed below), then the default set of rules which will apply
1547 universally to all sites and pages. And then below that, exceptions to the
1548 defined universal policies.
1550 -------------------------------------------------------------------------------
1552 7.4.1. Finding the Right Mix
1554 Note that some actions like cookie suppression or script disabling may render
1555 some sites unusable, which rely on these techniques to work properly. Finding
1556 the right mix of actions is not easy and certainly a matter of personal taste.
1557 In general, it can be said that the more "aggressive" your default settings (in
1558 the top section of the actions file) are, the more exceptions for "trusted"
1559 sites you will have to make later. If, for example, you want to kill popup
1560 windows per default, you'll have to make exceptions from that rule for sites
1561 that you regularly use and that require popups for actually useful content,
1562 like maybe your bank, favorite shop, or newspaper.
1564 We have tried to provide you with reasonable rules to start from in the
1565 distribution actions files. But there is no general rule of thumb on these
1566 things. There just are too many variables, and sites are constantly changing.
1567 Sooner or later you will want to change the rules (and read this chapter again
1570 -------------------------------------------------------------------------------
1574 The easiest way to edit the "actions" files is with a browser by using our
1575 browser-based editor, which can be reached from http://config.privoxy.org/
1578 If you prefer plain text editing to GUIs, you can of course also directly edit
1579 the the actions files.
1581 -------------------------------------------------------------------------------
1583 7.4.3. How Actions are Applied to URLs
1585 Actions files are divided into sections. There are special sections, like the "
1586 alias" sections which will be discussed later. For now let's concentrate on
1587 regular sections: They have a heading line (often split up to multiple lines
1588 for readability) which consist of a list of actions, separated by whitespace
1589 and enclosed in curly braces. Below that, there is a list of URL patterns, each
1592 To determine which actions apply to a request, the URL of the request is
1593 compared to all patterns in this file. Every time it matches, the list of
1594 applicable actions for the URL is incrementally updated, using the heading of
1595 the section in which the pattern is located. If multiple matches for the same
1596 URL set the same action differently, the last match wins. If not, the effects
1597 are aggregated (e.g. a URL might match both the "+handle-as-image" and "+block"
1600 You can trace this process by visiting http://config.privoxy.org/show-url-info.
1602 More detail on this is provided in the Appendix, Anatomy of an Action.
1604 -------------------------------------------------------------------------------
1608 Generally, a pattern has the form <domain>/<path>, where both the <domain> and
1609 <path> are optional. (This is why the pattern / matches all URLs).
1613 is a domain-only pattern and will match any request to www.example.com,
1614 regardless of which document on that server is requested.
1618 means exactly the same. For domain-only patterns, the trailing / may be
1621 www.example.com/index.html
1623 matches only the single document /index.html on www.example.com.
1627 matches the document /index.html, regardless of the domain, i.e. on any web
1632 matches nothing, since it would be interpreted as a domain name and there
1633 is no top-level domain called .html.
1635 -------------------------------------------------------------------------------
1637 7.4.4.1. The Domain Pattern
1639 The matching of the domain part offers some flexible options: if the domain
1640 starts or ends with a dot, it becomes unanchored at that end. For example:
1644 matches any domain that ENDS in .example.com
1648 matches any domain that STARTS with www.
1652 matches any domain that CONTAINS .example. (Correctly speaking: It matches
1653 any FQDN that contains example as a domain.)
1655 Additionally, there are wild-cards that you can use in the domain names
1656 themselves. They work pretty similar to shell wild-cards: "*" stands for zero
1657 or more arbitrary characters, "?" stands for any single character, you can
1658 define character classes in square brackets and all of that can be freely
1663 matches "adserver.example.com", "ads.example.com", etc but not
1668 matches all of the above, and then some.
1672 matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
1674 www[1-9a-ez].example.c*
1676 matches www1.example.com, www4.example.cc, wwwd.example.cy,
1677 wwwz.example.com etc., but not wwww.example.com.
1679 -------------------------------------------------------------------------------
1681 7.4.4.2. The Path Pattern
1683 Privoxy uses Perl compatible regular expressions (through the PCRE library) for
1686 There is an Appendix with a brief quick-start into regular expressions, and
1687 full (very technical) documentation on PCRE regex syntax is available on-line
1688 at http://www.pcre.org/man.txt. You might also find the Perl man page on
1689 regular expressions (man perlre) useful, which is available on-line at http://
1690 www.perldoc.com/perl5.6/pod/perlre.html.
1692 Note that the path pattern is automatically left-anchored at the "/", i.e. it
1693 matches as if it would start with a "^" (regular expression speak for the
1694 beginning of a line).
1696 Please also note that matching in the path is case INSENSITIVE by default, but
1697 you can switch to case sensitive at any point in the pattern by using the "(?
1698 -i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
1699 path starts with PaTtErN in exactly this capitalization.
1701 -------------------------------------------------------------------------------
1705 All actions are disabled by default, until they are explicitly enabled
1706 somewhere in an actions file. Actions are turned on if preceded with a "+", and
1707 turned off if preceded with a "-". So a "+action" means "do that action", e.g.
1708 "+block" means please "block the following URL patterns".
1710 Actions are invoked by enclosing the action name in curly braces (e.g.
1711 {+some_action}), followed by a list of URLs (or patterns that match URLs) to
1712 which the action applies. There are three classes of actions:
1714 * Boolean, i.e the action can only be "on" or "off". Examples:
1716 {+name} # enable this action
1717 {-name} # disable this action
1720 * Parameterized, e.g. "+/-hide-user-agent{ Mozilla 1.0 }", where some value
1721 is required in order to enable this type of action. Examples:
1723 {+name{param}} # enable action and set parameter to "param"
1724 {-name} # disable action ("parameter") can be omitted
1727 * Multi-value, e.g. "{+/-add-header{Name: value}}" or "{+/-send-wafer{name=
1728 value}}"), where some value needs to be defined in addition to simply
1729 enabling the action. Examples:
1731 {+name{param=value}} # enable action and set "param" to "value"
1732 {-name{param=value}} # remove the parameter "param" completely
1733 {-name} # disable this action totally and remove param too
1736 If nothing is specified in any actions file, no "actions" are taken. So in this
1737 case Privoxy would just be a normal, non-blocking, non-anonymizing proxy. You
1738 must specifically enable the privacy and blocking features you need (although
1739 the provided default actions files will give a good starting point).
1741 Later defined actions always over-ride earlier ones. So exceptions to any rules
1742 you make, should come in the latter part of the file (or in a file that is
1743 processed later when using multiple actions files). For multi-valued actions,
1744 the actions are applied in the order they are specified. Actions files are
1745 processed in the order they are defined in config (the default installation has
1746 three actions files). It also quite possible for any given URL pattern to match
1747 more than one action!
1749 The list of valid Privoxy "actions" are:
1751 -------------------------------------------------------------------------------
1753 7.4.5.1. +add-header
1761 Send a user defined HTTP header to the web server.
1765 Any value is possible. Validity of the defined HTTP headers is not checked.
1769 {+add-header{X-User-Tracking: sucks}}
1775 This action may be specified multiple times, in order to define multiple
1776 headers. This is rarely needed for the typical user. If you don't know what
1777 "HTTP headers" are, you definitely don't need to worry about this one.
1779 -------------------------------------------------------------------------------
1789 Used to block a URL from reaching your browser. The URL may be anything,
1790 but is typically used to block ads or other obnoxious content.
1799 .banners.example.com
1805 If a URL matches one of the blocked patterns, Privoxy will intercept the
1806 URL and display its special "BLOCKED" page instead. If there is sufficient
1807 space, a large red banner will appear with a friendly message about why the
1808 page was blocked, and a way to go there anyway. If there is insufficient
1809 space a smaller "BLOCKED" page will appear without the red banner. Click
1810 here to view the default blocked HTML page (Privoxy must be running for
1811 this to work as intended!).
1813 A very important exception is if the URL matches both "+block" and
1814 "+handle-as-image", then it will be handled by "+set-image-blocker" (see
1815 below). It is important to understand this process, in order to understand
1816 how Privoxy is able to deal with ads and other objectionable content.
1818 The "+filter" action can also perform some of the same functionality as
1819 "+block", but by virtue of very different programming techniques, and is
1820 most often used for different reasons.
1822 -------------------------------------------------------------------------------
1824 7.4.5.3. +deanimate-gifs
1832 To stop those annoying, distracting animated GIF images.
1840 {+deanimate-gifs{last}}
1846 De-animate all animated GIF images, i.e. reduce them to their last frame.
1847 This will also shrink the images considerably (in bytes, not pixels!). If
1848 the option "first" is given, the first frame of the animation is used as
1849 the replacement. If "last" is given, the last frame of the animation is
1850 used instead, which probably makes more sense for most banner animations,
1851 but also has the risk of not showing the entire last frame (if it is only a
1852 delta to an earlier frame).
1854 -------------------------------------------------------------------------------
1856 7.4.5.4. +downgrade-http-version
1864 "+downgrade-http-version" will downgrade HTTP/1.1 client requests to HTTP/
1865 1.0 and downgrade the responses as well.
1873 {+downgrade-http-version}
1879 Use this action for servers that use HTTP/1.1 protocol features that
1880 Privoxy doesn't handle well yet. HTTP/1.1 is only partially implemented.
1881 Default is not to downgrade requests. This is an infrequently needed
1882 action, and is used to help with rare problem sites only.
1884 -------------------------------------------------------------------------------
1886 7.4.5.5. +fast-redirects
1894 The "+fast-redirects" action enables interception of "redirect" requests
1895 from one server to another, which are used to track users.Privoxy can cut
1896 off all but the last valid URL in a redirect request and send a local
1897 redirect back to your browser without contacting the intermediate site(s).
1911 Many sites, like yahoo.com, don't just link to other sites. Instead, they
1912 will link to some script on their own server, giving the destination as a
1913 parameter, which will then redirect you to the final target. URLs resulting
1914 from this scheme typically look like: http://some.place/some_script?http://
1917 Sometimes, there are even multiple consecutive redirects encoded in the
1918 URL. These redirections via scripts make your web browsing more traceable,
1919 since the server from which you follow such a link can see where you go to.
1920 Apart from that, valuable bandwidth and time is wasted, while your browser
1921 ask the server for one redirect after the other. Plus, it feeds the
1924 This is a normally "on" feature, and often requires exceptions for sites
1925 that are sensitive to defeating this mechanism.
1927 -------------------------------------------------------------------------------
1937 Apply page filtering as defined by named sections of the default.filter
1938 file to the specified site(s). "Filtering" can be any modification of the
1939 raw page content, including re-writing or deletion of content.
1943 "+filter" must include the name of one of the section identifiers from
1944 default.filter (or whatever filterfile is specified in config).
1946 Example usage (from the current default.filter):
1948 +filter{html-annoyances}: Get rid of particularly annoying HTML abuse.
1950 +filter{js-annoyances}: Get rid of particularly annoying JavaScript abuse
1952 +filter{content-cookies}: Kill cookies that come in the HTML or JS content
1954 +filter{popups}: Kill all popups in JS and HTML
1956 +filter{frameset-borders}: Give frames a border and make them resizable
1958 +filter{webbugs}: Squish WebBugs (1x1 invisible GIFs used for user
1961 +filter{refresh-tags}: Kill automatic refresh tags (for dial-on-demand
1964 +filter{fun}: Text replacements for subversive browsing fun!
1966 +filter{nimda}: Remove Nimda (virus) code.
1968 +filter{banners-by-size}: Kill banners by size (very efficient!)
1970 +filter{shockwave-flash}: Kill embedded Shockwave Flash objects
1972 +filter{crude-parental}: Kill all web pages that contain the words "sex" or
1977 This is potentially a very powerful feature! And requires a knowledge of
1978 regular expressions if you want to "roll your own". Filtering operates on a
1979 line by line basis throughout the entire page.
1981 Filtering requires buffering the page content, which may appear to slow
1982 down page rendering since nothing is displayed until all content has passed
1983 the filters. (It does not really take longer, but seems that way since the
1984 page is not incrementally displayed.) This effect will be more noticeable
1985 on slower connections.
1987 Filtering can achieve some of the effects as the "+block" action, i.e. it
1988 can be used to block ads and banners. In the overall scheme of things,
1989 filtering is one of the first things "Privoxy" does with a web page. So
1990 other most other actions are applied to the already "filtered" page.
1992 -------------------------------------------------------------------------------
1994 7.4.5.7. +hide-forwarded-for-headers
2002 Block any existing X-Forwarded-for HTTP header, and do not add a new one.
2010 {+hide-forwarded-for-headers}
2016 It is fairly safe to leave this on. It does not seem to break many sites.
2018 -------------------------------------------------------------------------------
2020 7.4.5.8. +hide-from-header
2028 To block the browser from sending your email address in a "From:" header.
2032 Keyword: "block", or any user defined value.
2036 {+hide-from-header{block}}
2042 The keyword "block" will completely remove the header (not to be confused
2043 with the "+block" action). Alternately, you can specify any value you
2044 prefer to send to the web server.
2046 -------------------------------------------------------------------------------
2048 7.4.5.9. +hide-referer
2056 Don't send the "Referer:" (sic) HTTP header to the web site. Or,
2057 alternately send a forged header instead.
2061 Prevent the header from being sent with the keyword, "block". Or, "forge" a
2062 URL to one from the same server as the request. Or, set to user defined
2063 value of your choice.
2067 {+hide-referer{forge}}
2073 "forge" is the preferred option here, since some servers will not send
2074 images back otherwise.
2076 "+hide-referrer" is an alternate spelling of "+hide-referer". It has the
2077 exact same parameters, and can be freely mixed with, "+hide-referer".
2078 ("referrer" is the correct English spelling, however the HTTP specification
2079 has a bug - it requires it to be spelled as "referer".)
2081 -------------------------------------------------------------------------------
2083 7.4.5.10. +hide-user-agent
2091 To change the "User-Agent:" header so web servers can't tell your browser
2092 type. Who's business is it anyway?
2096 Any user defined string.
2100 {+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}}
2106 Warning! This breaks many web sites that depend on this in order to
2107 determine how the target browser will respond to various requests. Use with
2110 -------------------------------------------------------------------------------
2112 7.4.5.11. +handle-as-image
2120 To define what Privoxy should treat automatically as an image, and is an
2121 important ingredient of how ads are handled.
2130 /.*\.(gif|jpg|jpeg|png|bmp|ico)
2135 This only has meaning if the URL (or pattern) also is "+block"ed, in which
2136 case a user definable image can be sent rather than a HTML page. This is
2137 integral to the whole concept of ad blocking: the URL must match both a
2138 "+block" rule, and "+handle-as-image". (See "+set-image-blocker" below for
2139 control over what will actually be displayed by the browser.)
2141 There is little reason to change the default definition for this action.
2143 -------------------------------------------------------------------------------
2145 7.4.5.12. +set-image-blocker
2153 Decide what to do with URLs that end up tagged with both "+block" and
2154 "+handle-as-image", e.g an advertisement.
2158 There are four available options: "-set-image-blocker" will send a HTML
2159 "blocked" page, usually resulting in a "broken image" icon.
2160 "+set-image-blocker{blank}" will send a 1x1 transparent GIF image.
2161 "+set-image-blocker{pattern}" will send a checkerboard type pattern (the
2162 default). And finally, "+set-image-blocker{http://xyz.com}" will send a
2163 HTTP temporary redirect to the specified image. This has the advantage of
2164 the icon being being cached by the browser, which will speed up the
2169 {+set-image-blocker{blank}}
2175 If you want invisible ads, they need to meet criteria as matching both
2176 images and blocked actions. And then, "image-blocker" should be set to
2177 "blank" for invisibility. Note you cannot treat HTML pages as images in
2178 most cases. For instance, frames require an HTML page to display. So a
2179 frame that is an ad, typically cannot be treated as an image. Forcing an
2180 "image" in this situation just will not work reliably.
2182 -------------------------------------------------------------------------------
2184 7.4.5.13. +limit-connect
2192 By default, Privoxy only allows HTTP CONNECT requests to port 443 (the
2193 standard, secure HTTPS port). Use "+limit-connect" to disable this
2194 altogether, or to allow more ports.
2198 Any valid port number, or port number range.
2202 +limit-connect{443} #
2203 This is the default and need not be specified.
2204 +limit-connect{80,443} # Ports 80 and 443 are OK.
2205 +limit-connect{-3, 7, 20-100, 500-} #
2206 Port less than 3, 7, 20 to 100 and above 500 are OK.
2211 The CONNECT methods exists in HTTP to allow access to secure websites
2212 (https:// URLs) through proxies. It works very simply: the proxy connects
2213 to the server on the specified port, and then short-circuits its
2214 connections to the client and to the remote proxy. This can be a big
2215 security hole, since CONNECT-enabled proxies can be abused as TCP relays
2218 If you want to allow CONNECT for more ports than this, or want to forbid
2219 CONNECT altogether, you can specify a comma separated list of ports and
2220 port ranges (the latter using dashes, with the minimum defaulting to 0 and
2223 If you don't know what any of this means, there probably is no reason to
2226 -------------------------------------------------------------------------------
2228 7.4.5.14. +prevent-compression
2236 Prevent the specified websites from compressing HTTP data.
2244 {+prevent-compression}
2250 Some websites do this, which can be a problem for Privoxy, since "+filter",
2251 "+kill-popups" and "+gif-deanimate" will not work on compressed data. This
2252 will slow down connections to those websites, though. Default typically is
2253 to turn "prevent-compression" on.
2255 -------------------------------------------------------------------------------
2257 7.4.5.15. +session-cookies-only
2265 Allow cookies for the current browser session only.
2271 Example usage (disabling):
2273 {-session-cookies-only}
2279 If websites set cookies, "+session-cookies-only" will make sure they are
2280 erased when you exit and restart your web browser. This makes profiling
2281 cookies useless, but won't break sites which require cookies so that you
2282 can log in for transactions. This is generally turned on for all sites, and
2283 is the recommended setting.
2285 "+prevent-*-cookies" actions should be turned off as well (see below), for
2286 "+session-cookies-only" to work. Or, else no cookies will get through at
2287 all. For, "persistent" cookies that survive across browser sessions, see
2290 -------------------------------------------------------------------------------
2292 7.4.5.16. +prevent-reading-cookies
2300 Explicitly prevent the web server from reading any cookies on your system.
2308 {+prevent-reading-cookies}
2314 Often used in conjunction with "+prevent-setting-cookies" to disable
2315 cookies completely. Note that "+session-cookies-only" requires these to
2316 both be disabled (or else it never gets any cookies to cache).
2318 For "persistent" cookies to work (i.e. they survive across browser sessions
2319 and reboots), all three cookie settings should be "off" for the specified
2322 -------------------------------------------------------------------------------
2324 7.4.5.17. +prevent-setting-cookies
2332 Explicitly block the web server from storing cookies on your system.
2340 {+prevent-setting-cookies}
2346 Often used in conjunction with "+prevent-reading-cookies" to disable
2347 cookies completely (see above).
2349 -------------------------------------------------------------------------------
2351 7.4.5.18. +kill-popups
2359 Stop those annoying JavaScript pop-up windows!
2373 "+kill-popups" uses a built in filter to disable pop-ups that use the
2374 window.open() function, etc. This is one of the first actions processed by
2375 Privoxy as it contacts the remote web server. This action is not always
2376 100% reliable, and is supplemented by "+filter{popups}".
2378 -------------------------------------------------------------------------------
2380 7.4.5.19. +send-vanilla-wafer
2388 Sends a cookie for every site stating that you do not accept any copyright
2389 on cookies sent to you, and asking them not to track you.
2397 {+send-vanilla-wafer}
2403 This action only applies if you are using a jarfile for saving cookies. Of
2404 course, this is a (relatively) unique header and could conceivably be used
2407 -------------------------------------------------------------------------------
2409 7.4.5.20. +send-wafer
2417 This allows you to send an arbitrary, user definable cookie.
2421 User specified cookie name and corresponding value.
2425 {+send-wafer{name=value}}
2431 This can be specified multiple times in order to add as many cookies as you
2434 -------------------------------------------------------------------------------
2436 7.4.5.21. Actions Examples
2438 Note that the meaning of any of the above examples is reversed by preceding the
2439 action with a "-", in place of the "+". Also, that some actions are turned on
2440 in the default section of the actions file, and require little to no additional
2441 configuration. These are just "on". But, other actions that are turned on the
2442 default section do typically require exceptions to be listed in the latter
2443 sections of one of our actions file. For instance, by default no URLs are
2444 "blocked" (i.e. in the default definitions of default.action). We need
2445 exceptions to this in order to enable ad blocking in the lower sections. But we
2446 need to be very selective about what we do block.
2448 Below is a liberally commented default.action file to demonstrate the pieces
2449 all come together. And to show how exceptions to the default policies can be
2450 handled. This is followed by a user.action with similar examples.
2453 ##########################################################################
2454 # Aliases must be defined *before* they are used. These are
2455 # easier to remember, and combine several actions into one:
2456 ##########################################################################
2458 # Some useful aliases.
2459 +prevent-cookies = +prevent-setting-cookies +prevent-reading-cookies
2460 -prevent-cookies = -prevent-setting-cookies -prevent-reading-cookies
2461 +imageblock = +block +handle-as-image
2463 # Fragile sites should have the minimum changes:
2464 fragile = -block -deanimate-gifs -fast-redirects -filter -hide-referer \
2465 -prevent-cookies -kill-popups
2467 # Shops should be allowed to set persistent cookies
2468 shop = -filter -prevent-cookies -prevent-keeping-cookies
2471 ##########################################################################
2472 # Begin default action settings. Anything in this section will match
2473 # all URLs -- UNLESS we have exceptions defined below this section.
2474 # We will show all potential actions here whether they are on or off.
2475 # We could omit any disabled action if we wanted, since all actions are
2476 # 'off' by default anyway. Shown for completeness only.
2477 ##########################################################################
2482 -downgrade-http-version \
2484 +filter{html-annoyances} \
2485 +filter{js-annoyances} \
2486 -filter{content-cookies} \
2489 -filter{refresh-tags} \
2492 +filter{banners-by-size} \
2493 -filter{shockwave-flash} \
2494 -filter{crude-prental} \
2495 +hide-forwarded-for-headers \
2496 +hide-from-header{block} \
2500 +set-image-blocker{pattern} \
2502 +prevent-compression \
2503 -session-cookies-only \
2504 -prevent-reading-cookies \
2505 -prevent-setting-cookies \
2507 -send-vanilla-wafer \
2510 / # forward slash will match all potential URLs patterns.
2512 ##########################################################################
2513 # Default behavior is now set. Time for some exceptions to our
2515 ##########################################################################
2517 # These sites are very complex and require very minimal interference.
2518 # We'll disable most actions with our 'fragile' alias.
2520 .office.microsoft.com
2521 .windowsupdate.microsoft.com
2524 # Shopping sites - not as fragile. We still want to block ads.
2527 .worldpay.com # for quietpc.com
2532 # These sites require pop-ups too :( We'll combine our 'shop'
2533 # alias with two other actions into one rule to allow all popups.
2534 {shop -no-popups -filter{popups}}
2539 # The 'Fast-redirects' action breaks some sites. Disable this action
2540 # for these known sensitive sites.
2542 www.ukc.ac.uk/cgi-bin/wac\.cgi\?
2544 edit.europe.yahoo.com
2546 .altavista.com/.*(like|url|link):http
2547 .altavista.com/trans.*urltext=http
2551 # Define which file types will be treated as images. Important
2554 /.*\.(gif|jpe?g|png|bmp|ico)
2557 # Now lets list some domains that are known ad generators. And
2558 # our alias here will block these as well as force them to be
2559 # treated as images. This combination of actions is important
2560 # for ad blocking. What the browser will show instead is
2561 # determined by the setting of "+set-image-blocker"
2565 .a.yimg.com/(?:(?!/i/).)*$
2566 .a[0-9].yimg.com/(?:(?!/i/).)*$
2570 ad.*.doubleclick.net
2573 # These will just simply be blocked. They will generate the BLOCKED
2574 # banner page, if matched. Heavy use of wildcards and regular
2575 # expressions in this example.
2581 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
2582 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
2586 # The above block section will catch some sites we DO NOT want
2587 # blocked via wildcards and regular expressions. Now set exceptions
2588 # to the exceptions so the good guys get better treatment.
2594 # Let's just trust universities
2596 www.ugu.com/sui/ugu/adv
2597 # We'll need to access to path names containing 'download'
2600 # 'adv' is for globalintersec means advanced, not advertisement
2601 www.globalintersec.com/adv
2604 # Don't filter *anything* from our friends at sourceforge.
2605 # Notice we don't have to name the individual filter
2606 # identifiers -- we just turn them all off.
2614 Turn off cookies by default, then allow a few through for specified sites
2615 (showing an excerpt from the "default" section of an actions file ONLY):
2618 # Allow cookies to and from the server, but
2619 # for this browser session ONLY
2621 # other actions normally listed here...
2622 -prevent-setting-cookies \
2623 -prevent-reading-cookies \
2624 +session-cookies-only \
2628 # Exceptions to the above, sites that benefit from persistent cookies
2629 # that are saved from one browser session to the next.
2630 { -session-cookies-only }
2639 Now turn off "fast redirects", and then we allow two exceptions:
2641 # Turn them off (excerpt only)!
2643 # other actions normally listed here...
2648 # Reverse it for these two sites, which don't work right without it.
2650 www.ukc.ac.uk/cgi-bin/wac\.cgi\?
2654 Turn on page filtering according to rules in the defined sections of
2655 default.filter, and make one exception for Sourceforge:
2657 # Run everything through the filter file, using only certain
2658 # specified sections:
2660 # other actions normally listed here...
2661 +filter{html-annoyances} +filter{js-annoyances} +filter{kill-popups}\
2662 +filter{webbugs} +filter{nimda} +filter{banners-by-size}
2666 # Then disable filtering of code from all sourceforge domains!
2671 Now some URLs that we want "blocked" (normally generates the "blocked" banner).
2672 Typically, the "block" action is off by default in the upper section of an
2673 actions file, then enabled against certain URLs and patterns in the lower part
2674 of the file. Many of these use regular expressions that will expand to match
2683 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
2684 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
2686 /.*/(ng)?adclient\.cgi
2687 /.*/(plain|live|rotate)[-_.]?ads?/
2692 Note that many of these actions have the potential to cause a page to
2693 misbehave, possibly even not to display at all. There are many ways a site
2694 designer may choose to design his site, and what HTTP header content, and other
2695 criteria, he may depend on. There is no way to have hard and fast rules for all
2696 sites. See the Appendix for a brief example on troubleshooting actions.
2698 -------------------------------------------------------------------------------
2702 Custom "actions", known to Privoxy as "aliases", can be defined by combining
2703 other "actions". These can in turn be invoked just like the built-in "actions".
2704 Currently, an alias can contain any character except space, tab, "=", "{" or "}
2705 ". But please use only "a"- "z", "0"-"9", "+", and "-". Alias names are not
2706 case sensitive, and must be defined before other actions in the actions file!
2707 And there can only be one set of "aliases" defined per file. Each actions file
2708 may have its own aliases, but they are only visible within that file.
2710 Now let's define a few aliases:
2712 # Useful custom aliases we can use later. These must come first!
2714 +prevent-cookies = +prevent-setting-cookies +prevent-reading-cookies
2715 -prevent-cookies = -prevent-setting-cookies -prevent-reading-cookies
2717 -block -prevent-cookies -filter -fast-redirects -hide-referer -kill-popups
2718 shop = -prevent-cookies -filter -fast-redirects
2719 +imageblock = +block +handle-as-image
2721 # Aliases defined from other aliases, for people who don't like to type
2723 c0 = +prevent-cookies
2724 c1 = -prevent-cookies
2725 #... etc. Customize to your heart's content.
2728 Some examples using our "shop" and "fragile" aliases from above. These would
2729 appear in the lower sections of an actions file as exceptions to the default
2730 actions (as defined in the upper section):
2732 # These sites are very complex and require
2733 # minimal interference.
2735 .office.microsoft.com
2736 .windowsupdate.microsoft.com
2739 # Shopping sites - but we still want to block ads.
2742 .worldpay.com # for quietpc.com
2745 # These shops require pop-ups also
2751 The "shop" and "fragile" aliases are often used for "problem" sites that
2752 require most actions to be disabled in order to function properly.
2754 -------------------------------------------------------------------------------
2756 7.5. The Filter File
2758 Any web page can be dynamically modified with the filter file. This
2759 modification can be removal, or re-writing, of any web page content, including
2760 tags and non-visible content. The default filter file is default.filter,
2761 located in the config directory.
2763 This is potentially a very powerful feature, and requires knowledge of both
2764 "regular expression" and HTML in order create custom filters. But, there are a
2765 number of useful filters included with Privoxy for many common situations.
2767 The included example file is divided into sections. Each section begins with
2768 the FILTER keyword, followed by the identifier for that section, e.g. "FILTER:
2769 webbugs". Each section performs a similar type of filtering, such as
2772 This file uses regular expressions to alter or remove any string in the target
2773 page. The expressions can only operate on one line at a time. Some examples
2774 from the included default default.filter:
2776 Stop web pages from displaying annoying messages in the status bar by deleting
2779 FILTER: html-annoyances
2781 # New browser windows should be resizeable and have a location and status
2784 s/resizable="?(no|0)"?/resizable=1/ig s/noresize/yesresize/ig
2785 s/location="?(no|0)"?/location=1/ig s/status="?(no|0)"?/status=1/ig
2786 s/scrolling="?(no|0|Auto)"?/scrolling=1/ig
2787 s/menubar="?(no|0)"?/menubar=1/ig
2789 # The <BLINK> tag was a crime!
2791 s*<blink>|</blink>**ig
2795 #s/framespacing="?(no|0)"?//ig
2796 #s/margin(height|width)=[0-9]*//gi
2799 Just for kicks, replace any occurrence of "Microsoft" with "MicroSuck", and
2800 have a little fun with topical buzzwords:
2804 s/microsoft(?!.com)/MicroSuck/ig
2808 s/industry-leading|cutting-edge|award-winning/<font color=red><b>BINGO!</b></
2812 Kill those pesky little web-bugs:
2814 # webbugs: Squish WebBugs (1x1 invisible GIFs used for user tracking)
2817 s/<img\s+[^>]*?(width|height)\s*=\s*['"]?1\D[^>]*?(width|height)\s*=\s*['"]?1
2818 (\D[^>]*?)?>/<!-- Squished WebBug -->/sig
2821 -------------------------------------------------------------------------------
2823 7.5.1. The +filter Action
2825 Filters are enabled with the "+filter" action from within one of the actions
2826 files. "+filter" requires one parameter, which should match one of the section
2827 identifiers in the filter file itself. Example:
2829 +filter{html-annoyances}
2832 This would activate that particular filter. Similarly, "+filter" can be turned
2833 off for selected sites as: "-filter{html-annoyances}". Remember, all actions
2834 are off by default, unless they are explicity enabled in one of the actions
2837 -------------------------------------------------------------------------------
2841 When Privoxy displays one of its internal pages, such as a 404 Not Found error
2842 page, it uses the appropriate template. On Linux, BSD, and Unix, these are
2843 located in /etc/privoxy/templates by default. These may be customized, if
2844 desired. cgi-style.css is used to control the HTML attributes (fonts, etc).
2846 The default "Blocked" banner page with the bright red top banner, is called
2847 just "blocked". This may be customized or replaced with something else if
2850 -------------------------------------------------------------------------------
2852 8. Contacting the Developers, Bug Reporting and Feature Requests
2854 We value your feedback. However, to provide you with the best support, please
2855 note the following sections.
2857 -------------------------------------------------------------------------------
2861 To get support, use the Sourceforge Support Forum:
2863 http://sourceforge.net/tracker/?group_id=11118&atid=211118
2866 -------------------------------------------------------------------------------
2870 To submit bugs, use the Sourceforge Bug Forum:
2872 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
2875 Make sure that the bug has not already been submitted. Please try to verify
2876 that it is a Privoxy bug, and not a browser or site bug first. If you are using
2877 your own custom configuration, please try the stock configs to see if the
2878 problem is a configuration related bug. And if not using the latest development
2879 snapshot, please try the latest one. Or even better, CVS sources. Please be
2880 sure to include the Privoxy version, platform, browser, any pertinent log data,
2881 any other relevant details (please be specific) and, if possible, some way to
2884 -------------------------------------------------------------------------------
2886 8.3. Request new features
2888 To submit ideas on new features, use the Sourceforge feature request forum:
2890 http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
2893 -------------------------------------------------------------------------------
2895 8.4. Report ads or other filter problems
2897 You can also send feedback on websites that Privoxy has problems with. Please
2898 bookmark the following link: "Privoxy - Submit Filter Feedback". Once you surf
2899 to a page with problems, use the bookmark to send us feedback. We will look
2900 into the issue as soon as possible.
2902 New, improved default.action files will occasionally be made available based on
2903 your feedback. These will be announced on the ijbswa-announce list.
2905 -------------------------------------------------------------------------------
2909 For any other issues, feel free to use the mailing lists:
2911 http://sourceforge.net/mail/?group_id=11118.
2914 Anyone interested in actively participating in development and related
2915 discussions can also join the appropriate mailing list. Archives are available,
2916 too. See the page on Sourceforge.
2918 -------------------------------------------------------------------------------
2920 9. Copyright and History
2924 Privoxy is free software; you can redistribute it and/or modify it under the
2925 terms of the GNU General Public License as published by the Free Software
2926 Foundation; either version 2 of the License, or (at your option) any later
2929 This program is distributed in the hope that it will be useful, but WITHOUT ANY
2930 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
2931 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
2932 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
2933 330, Boston, MA 02111-1307, USA.
2935 You should have received a copy of the GNU General Public License along with
2936 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
2937 Place, Suite 330, Boston, MA 02111-1307 USA.
2939 -------------------------------------------------------------------------------
2943 Privoxy is evolved, and derived from, the Internet Junkbuster, with many
2944 improvments and enhancements over the original.
2946 Junkbuster was originally written by Anonymous Coders and Junkbusters
2947 Corporation, and was released as free open-source software under the GNU GPL.
2948 Stefan Waldherr made many improvements, and started the SourceForge project
2949 Privoxy to rekindle development. There are now several active developers
2950 contributing. The last stable release of Junkbuster was v2.0.2, which has now
2953 -------------------------------------------------------------------------------
2957 Other references and sites of interest to Privoxy users:
2959 http://www.privoxy.org/, The Privoxy Home page.
2961 http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
2964 http://p.p/, access Privoxy from your browser. Alternately, http://
2965 config.privoxy.org may work in some situations where the first does not.
2967 http://p.p/, and select "actions file feedback system" to submit "misses" to
2970 http://www.junkbusters.com/ht/en/cookies.html
2972 http://www.waldherr.org/junkbuster/
2974 http://privacy.net/analyze/
2976 http://www.squid-cache.org/
2980 -------------------------------------------------------------------------------
2984 11.1. Regular Expressions
2986 Privoxy can use "regular expressions" in various config files. Assuming support
2987 for "pcre" (Perl Compatible Regular Expressions) is compiled in, which is the
2988 default. Such configuration directives do not require regular expressions, but
2989 they can be used to increase flexibility by matching a pattern with wild-cards
2992 If you are reading this, you probably don't understand what "regular
2993 expressions" are, or what they can do. So this will be a very brief
2994 introduction only. A full explanation would require a book ;-)
2996 "Regular expressions" is a way of matching one character expression against
2997 another to see if it matches or not. One of the "expressions" is a literal
2998 string of readable characters (letter, numbers, etc), and the other is a
2999 complex string of literal characters combined with wild-cards, and other
3000 special characters, called meta-characters. The "meta-characters" have special
3001 meanings and are used to build the complex pattern to be matched against. Perl
3002 Compatible Regular Expressions is an enhanced form of the regular expression
3003 language with backward compatibility.
3005 To make a simple analogy, we do something similar when we use wild-card
3006 characters when listing files with the dir command in DOS. *.* matches all
3007 filenames. The "special" character here is the asterisk which matches any and
3008 all characters. We can be more specific and use ? to match just individual
3009 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
3010 are pattern matching, using a similar technique to "regular expressions"!
3012 Regular expressions do essentially the same thing, but are much, much more
3013 powerful. There are many more "special characters" and ways of building complex
3014 patterns however. Let's look at a few of the common ones, and then some
3017 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
3019 ? - The preceding character or expression is matched ZERO or ONE times. Either/
3022 + - The preceding character or expression is matched ONE or MORE times.
3024 * - The preceding character or expression is matched ZERO or MORE times.
3026 \ - The "escape" character denotes that the following character should be taken
3027 literally. This is used where one of the special characters (e.g. ".") needs to
3028 be taken literally and not as a special meta-character. Example: "example
3029 \.com", makes sure the period is recognized only as a period (and not expanded
3030 to its meta-character meaning of any single character).
3032 [] - Characters enclosed in brackets will be matched if any of the enclosed
3033 characters are encountered. For instance, "[0-9]" matches any numeric digit
3034 (zero through nine). As an example, we can combine this with "+" to match any
3035 digit one of more times: "[0-9]+".
3037 () - parentheses are used to group a sub-expression, or multiple
3040 | - The "bar" character works like an "or" conditional statement. A match is
3041 successful if the sub-expression on either side of "|" matches. As an example:
3042 "/(this|that) example/" uses grouping and the bar character and would match
3043 either "this example" or "that example", and nothing else.
3045 s/string1/string2/g - This is used to rewrite strings of text. "string1" is
3046 replaced by "string2" in this example. There must of course be a match on
3049 These are just some of the ones you are likely to use when matching URLs with
3050 Privoxy, and is a long way from a definitive list. This is enough to get us
3051 started with a few simple examples which may be more illuminating:
3053 /.*/banners/.* - A simple example that uses the common combination of "." and "
3054 *" to denote any character, zero or more times. In other words, any string at
3055 all. So we start with a literal forward slash, then our regular expression
3056 pattern (".*") another literal forward slash, the string "banners", another
3057 forward slash, and lastly another ".*". We are building a directory path here.
3058 This will match any file with the path that has a directory named "banners" in
3059 it. The ".*" matches any characters, and this could conceivably be more forward
3060 slashes, so it might expand into a much longer looking path. For example, this
3061 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
3062 banners/annoying.html", or almost an infinite number of other possible
3063 combinations, just so it has "banners" in the path somewhere.
3065 A now something a little more complex:
3067 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
3068 slashes again ("/"), so we are building another expression that is a file path
3069 statement. We have another ".*", so we are matching against any conceivable
3070 sub-path, just so it matches our expression. The only true literal that must
3071 match our pattern is adv, together with the forward slashes. What comes after
3072 the "adv" string is the interesting part.
3074 Remember the "?" means the preceding expression (either a literal character or
3075 anything grouped with "(...)" in this case) can exist or not, since this means
3076 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
3077 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
3078 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
3079 to match either "ing" OR "ements?". What is being done here, is an attempt at
3080 matching as many variations of "advertisement", and similar, as possible. So
3081 this would expand to match just "adv", or "advert", or "adverts", or
3082 "advertising", or "advertisement", or "advertisements". You get the idea. But
3083 it would not match "advertizements" (with a "z"). We could fix that by changing
3084 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
3085 would then match either spelling.
3087 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
3088 slashes. Anything in the square brackets "[]" can be matched. This is using
3089 "0-9" as a shorthand expression to mean any digit one through nine. It is the
3090 same as saying "0123456789". So any digit matches. The "+" means one or more of
3091 the preceding expression must be included. The preceding expression here is
3092 what is in the square brackets -- in this case, any digit one through nine.
3093 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
3094 this needs to match the expression on either side of that bar character also. A
3095 simple "gif" on one side, and the other side will in turn match either "jpeg"
3096 or "jpg", since the "?" means the letter "e" is optional and can be matched
3097 once or not at all. So we are building an expression here to match image GIF or
3098 JPEG type image file. It must include the literal string "advert", then one or
3099 more digits, and a "." (which is now a literal, and not a special character,
3100 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
3101 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
3102 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
3103 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
3104 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
3106 s/microsoft(?!.com)/MicroSuck/i - This is a substitution. "MicroSuck" will
3107 replace any occurrence of "microsoft". The "i" at the end of the expression
3108 means ignore case. The "(?!.com)" means the match should fail if "microsoft" is
3109 followed by ".com". In other words, this acts like a "NOT" modifier. In case
3110 this is a hyperlink, we don't want to break it ;-).
3112 We are barely scratching the surface of regular expressions here so that you
3113 can understand the default Privoxy configuration files, and maybe use this
3114 knowledge to customize your own installation. There is much, much more that can
3115 be done with regular expressions. Now that you know enough to get started, you
3116 can learn more on your own :/
3118 More reading on Perl Compatible Regular expressions: http://www.perldoc.com/
3119 perl5.6/pod/perlre.html
3121 -------------------------------------------------------------------------------
3123 11.2. Privoxy's Internal Pages
3125 Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
3126 certain special URLs. In this way, we can talk directly to Privoxy, and see how
3127 it is configured, see how our rules are being applied, change these rules and
3128 other configuration options, and even turn Privoxy's filtering off, all with a
3131 The URLs listed below are the special ones that allow direct access to Privoxy.
3132 Of course, Privoxy must be running to access these. If not, you will get a
3133 friendly error message. Internet access is not necessary either.
3135 * Privoxy main page:
3137 http://config.privoxy.org/
3139 Alternately, this may be reached at http://p.p/, but this variation may not
3140 work as reliably as the above in some configurations.
3142 * Show information about the current configuration, including viewing and
3143 editing of actions files:
3145 http://config.privoxy.org/show-status
3147 * Show the source code version numbers:
3149 http://config.privoxy.org/show-version
3151 * Show the browser's request headers:
3153 http://config.privoxy.org/show-request
3155 * Show which actions apply to a URL and why:
3157 http://config.privoxy.org/show-url-info
3159 * Toggle Privoxy on or off. In this case, "Privoxy" continues to run, but
3160 only as a pass-through proxy, with no actions taking place:
3162 http://config.privoxy.org/toggle
3164 Short cuts. Turn off, then on:
3166 http://config.privoxy.org/toggle?set=disable
3168 http://config.privoxy.org/toggle?set=enable
3170 These may be bookmarked for quick reference. See next.
3172 -------------------------------------------------------------------------------
3174 11.2.1. Bookmarklets
3176 Below are some "bookmarklets" to allow you to easily access a "mini" version of
3177 some of Privoxy's special pages. They are designed for MS Internet Explorer,
3178 but should work equally well in Netscape, Mozilla, and other browsers which
3179 support JavaScript. They are designed to run directly from your bookmarks - not
3180 by clicking the links below (although that should work for testing).
3182 To save them, right-click the link and choose "Add to Favorites" (IE) or "Add
3183 Bookmark" (Netscape). You will get a warning that the bookmark "may not be
3184 safe" - just click OK. Then you can run the Bookmarklet directly from your
3185 favorites/bookmarks. For even faster access, you can put them on the "Links"
3186 bar (IE) or the "Personal Toolbar" (Netscape), and run them with a single
3193 * Privoxy - Toggle Privoxy (Toggles between enabled and disabled)
3195 * Privoxy- View Status
3197 * Privoxy - Submit Filter Feedback
3199 Credit: The site which gave me the general idea for these bookmarklets is
3200 www.bookmarklets.com. They have more information about bookmarklets.
3202 -------------------------------------------------------------------------------
3204 11.3. Chain of Events
3206 Let's take a quick look at the basic sequence of events when a web page is
3207 requested by your browser and Privoxy is on duty:
3209 * First, your web browser requests a web page. The browser knows to send the
3210 request to Privoxy, which will in turn, relay the request to the remote web
3211 server after passing the following tests:
3213 * Privoxy traps any request for its own internal CGI pages (e.g http://p.p/)
3214 and sends the CGI page back to the browser.
3216 * Next, Privoxy checks to see if the URL matches any "+block" patterns. If
3217 so, the URL is then blocked, and the remote web server will not be
3218 contacted. "+handle-as-image" is then checked and if it does not match, an
3219 HTML "BLOCKED" page is sent back. Otherwise, if it does match, an image is
3220 returned. The type of image depends on the setting of "+set-image-blocker"
3221 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
3223 * Untrusted URLs are blocked. If URLs are being added to the trust file, then
3226 * If the URL pattern matches the "+fast-redirects" action, it is then
3227 processed. Unwanted parts of the requested URL are stripped.
3229 * Now the rest of the client browser's request headers are processed. If any
3230 of these match any of the relevant actions (e.g. "+hide-user-agent", etc.),
3231 headers are suppressed or forged as determined by these actions and their
3234 * Now the web server starts sending its response back (i.e. typically a web
3235 page and related data).
3237 * First, the server headers are read and processed to determine, among other
3238 things, the MIME type (document type) and encoding. The headers are then
3239 filtered as deterimed by the "+prevent-setting-cookies",
3240 "+session-cookies-only", and "+downgrade-http-version" actions.
3242 * If the "+kill-popups" action applies, and it is an HTML or JavaScript
3243 document, the popup-code in the response is filtered on-the-fly as it is
3246 * If a "+filter" or "+deanimate-gifs" action applies (and the document type
3247 fits the action), the rest of the page is read into memory (up to a
3248 configurable limit). Then the filter rules (from default.filter) are
3249 processed against the buffered content. Filters are applied in the order
3250 they are specified in the default.filter file. Animated GIFs, if present,
3251 are reduced to either the first or last frame, depending on the action
3252 setting.The entire page, which is now filtered, is then sent by Privoxy
3253 back to your browser.
3255 If neither "+filter" or "+deanimate-gifs" matches, then Privoxy passes the
3256 raw data through to the client browser as it becomes available.
3258 * As the browser receives the now (probably filtered) page content, it reads
3259 and then requests any URLs that may be embedded within the page source,
3260 e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
3261 frames), sounds, etc. For each of these objects, the browser issues a new
3262 request. And each such request is in turn processed as above. Note that a
3263 complex web page may have many such embedded URLs.
3265 -------------------------------------------------------------------------------
3267 11.4. Anatomy of an Action
3269 The way Privoxy applies "actions" and "filters" to any given URL can be
3270 complex, and not always so easy to understand what is happening. And sometimes
3271 we need to be able to see just what Privoxy is doing. Especially, if something
3272 Privoxy is doing is causing us a problem inadvertently. It can be a little
3273 daunting to look at the actions and filters files themselves, since they tend
3274 to be filled with "regular expressions" whose consequences are not always so
3277 One quick test to see if Privoxy is causing a problem or not, is to disable it
3278 temporarily. This should be the first troubleshooting step. See the
3279 Bookmarklets section on a quick and easy way to do this (be sure to flush
3282 Privoxy also provides the http://config.privoxy.org/show-url-info page that can
3283 show us very specifically how actions are being applied to any given URL. This
3284 is a big help for troubleshooting.
3286 First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell
3287 us how the current configuration will handle it. This will not help with
3288 filtering effects (i.e. the "+filter" action) from the default.filter file
3289 since this is handled very differently and not so easy to trap! It also will
3290 not tell you about any other URLs that may be embedded within the URL you are
3291 testing. For instance, images such as ads are expressed as URLs within the raw
3292 page source of HTML pages. So you will only get info for the actual URL that is
3293 pasted into the prompt area -- not any sub-URLs. If you want to know about
3294 embedded URLs like ads, you will have to dig those out of the HTML source. Use
3295 your browser's "View Page Source" option for this. Or right click on the ad,
3298 Let's try an example, google.com, and look at it one section at a time:
3300 Matches for http://google.com:
3302 --- File standard ---
3303 (no matches in this file)
3305 --- File default ---
3307 { -add-header -block +deanimate-gifs{last} -downgrade-http-version +fast-redirects
3308 -filter{popups} -filter{fun} -filter{shockwave-flash} -filter{crude-parental}
3309 +filter{html-annoyances} +filter{js-annoyances} +filter{content-cookies}
3310 +filter{webbugs} +filter{refresh-tags} +filter{nimda} +filter{banners-by-size}
3311 +hide-forwarded-for-headers +hide-from-header{block} +hide-referer{forge}
3312 -hide-user-agent -handle-as-image +set-image-blocker{pattern} -limit-connect
3313 +prevent-compression +session-cookies-only -prevent-reading-cookies
3314 -prevent-setting-cookies -kill-popups -send-vanilla-wafer -send-wafer }
3317 { -session-cookies-only }
3324 (no matches in this file)
3326 This tells us how we have defined our "actions", and which ones match for our
3327 example, "google.com". The first listing is any matches for the standard.action
3328 file. No hits at all here on "standard". Then next is "default", or our
3329 default.action file. The large, multi-line listing, is how the actions are set
3330 to match for all URLs, i.e. our default settings. If you look at your "actions"
3331 file, this would be the section just below the "aliases" section near the top.
3332 This will apply to all URLs as signified by the single forward slash at the end
3333 of the listing -- "/".
3335 But we can define additional actions that would be exceptions to these general
3336 rules, and then list specific URLs (or patterns) that these exceptions would
3337 apply to. Last match wins. Just below this then are two explicit matches for
3338 ".google.com". The first is negating our previous cookie setting, which was for
3339 "+session-cookies-only" (i.e. not persistent). So we will allow persistent
3340 cookies for google. The second turns off any "+fast-redirects" action, allowing
3341 this to take place unmolested. Note that there is a leading dot here --
3342 ".google.com". This will match any hosts and sub-domains, in the google.com
3343 domain also, such as "www.google.com". So, apparently, we have these two
3344 actions defined somewhere in the lower part of our default.action file, and
3345 "google.com" is referenced somewhere in these latter sections.
3347 Then, for our user.action file, we again have no hits.
3349 And finally we pull it all together in the bottom section and summarize how
3350 Privoxy is applying all its "actions" to "google.com":
3353 -add-header -block +deanimate-gifs{last} -downgrade-http-version -fast-redirects
3354 -filter{popups} -filter{fun} -filter{shockwave-flash} -filter{crude-parental}
3355 +filter{html-annoyances} +filter{js-annoyances} +filter{content-cookies}
3356 +filter{webbugs} +filter{refresh-tags} +filter{nimda} +filter{banners-by-size}
3357 +hide-forwarded-for-headers +hide-from-header{block} +hide-referer{forge}
3358 -hide-user-agent -handle-as-image +set-image-blocker{pattern} -limit-connect
3359 +prevent-compression -session-cookies-only -prevent-reading-cookies
3360 -prevent-setting-cookies -kill-popups -send-vanilla-wafer -send-wafer
3362 Notice the only difference here to the previous listing, is to "fast-redirects"
3363 and "session-cookies-only".
3365 Now another example, "ad.doubleclick.net":
3367 { +block +handle-as-image }
3370 { +block +handle-as-image }
3373 { +block +handle-as-image }
3376 We'll just show the interesting part here, the explicit matches. It is matched
3377 three different times. Each as an "+block +handle-as-image", which is the
3378 expanded form of one of our aliases that had been defined as: "+imageblock". (
3379 "Aliases" are defined in the first section of the actions file and typically
3380 used to combine more than one action.)
3382 Any one of these would have done the trick and blocked this as an unwanted
3383 image. This is unnecessarily redundant since the last case effectively would
3384 also cover the first. No point in taking chances with these guys though ;-)
3385 Note that if you want an ad or obnoxious URL to be invisible, it should be
3386 defined as "ad.doubleclick.net" is done here -- as both a "+block" and an
3387 "+handle-as-image". The custom alias "+imageblock" just simplifies the process
3388 and make it more readable.
3390 One last example. Let's try "http://www.rhapsodyk.net/adsl/HOWTO/". This one is
3391 giving us problems. We are getting a blank page. Hmmm...
3393 Matches for http://www.rhapsodyk.net/adsl/HOWTO/:
3395 { -add-header -block +deanimate-gifs -downgrade-http-version +fast-redirects
3396 +filter{html-annoyances} +filter{js-annoyances} +filter{kill-popups}
3397 +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal}
3398 +filter{fun} +hide-forwarded-for-headers +hide-from-header{block}
3399 +hide-referer{forge} -hide-user-agent -handle-as-image +set-image-blocker{blank}
3400 +prevent-compression +session-cookies-only -prevent-setting-cookies
3401 -prevent-reading-cookies +kill-popups -send-vanilla-wafer -send-wafer }
3404 { +block +handle-as-image }
3407 Ooops, the "/adsl/" is matching "/ads"! But we did not want this at all! Now we
3408 see why we get the blank page. We could now add a new action below this that
3409 explicitly does not block ("{-block}") paths with "adsl". There are various
3410 ways to handle such exceptions. Example:
3415 Now the page displays ;-) Be sure to flush your browser's caches when making
3416 such changes. Or, try using Shift+Reload.
3418 But now what about a situation where we get no explicit matches like we did
3421 { +block +handle-as-image }
3424 That actually was very telling and pointed us quickly to where the problem was.
3425 If you don't get this kind of match, then it means one of the default rules in
3426 the first section is causing the problem. This would require some guesswork,
3427 and maybe a little trial and error to isolate the offending rule. One likely
3428 cause would be one of the "{+filter}" actions. Try adding the URL for the site
3429 to one of aliases that turn off "+filter":
3433 .worldpay.com # for quietpc.com
3438 "{shop}" is an "alias" that expands to "{ -filter -session-cookies-only }". Or
3439 you could do your own exception to negate filtering:
3444 This would probably be most appropriately put in user.action, for local site
3447 "{fragile}" is an alias that disables most actions. This can be used as a last
3448 resort for problem sites. Remember to flush caches! If this still does not
3449 work, you will have to go through the remaining actions one by one to find
3450 which one(s) is causing the problem.
projects / privoxy.git / blob