1 Privoxy Frequently Asked Questions
3 [Copyright[ (c) 2001-2008 by Privoxy Developers]]
5 $Id: faq.txt,v 1.56 2008/01/19 21:41:36 hal9 Exp $
7 This FAQ gives quick answers to frequently asked questions about Privoxy.
8 It is not a substitute for the Privoxy User Manual.
12 Privoxy is a non-caching web proxy with advanced filtering capabilities
13 for enhancing privacy, modifying web page data, managing HTTP cookies,
14 controlling access, and removing ads, banners, pop-ups and other obnoxious
15 Internet junk. Privoxy has a flexible configuration and can be customized
16 to suit individual needs and tastes. Privoxy has application for both
17 stand-alone systems and multi-user networks.
19 Privoxy is based on Internet Junkbuster (tm).
21 Please note that this document is a work in progress. This copy represents
22 the state at the release of version 3.0.8. You can find the latest version
23 of the document at http://www.privoxy.org/faq/. Please see the Contact
24 section if you want to contact the developers.
26 --------------------------------------------------------------------------
30 1. General Information
32 1.1. Who should give Privoxy a try?
34 1.2. Is Privoxy the best choice for me?
36 1.3. What is a "proxy"? How does Privoxy work?
38 1.4. Does Privoxy do anything more than ad blocking?
40 1.5. What is this new version of "Junkbuster"?
42 1.6. Why "Privoxy"? Why change the name from Junkbuster at
45 1.7. How does Privoxy differ from the old Junkbuster?
47 1.8. How does Privoxy know what is an ad, and what is not?
49 1.9. Can Privoxy make mistakes? This does not sound very
52 1.10. Will I have to configure Privoxy before I can use it?
54 1.11. Can Privoxy run as a server on a network?
56 1.12. My browser does the same things as Privoxy. Why should
59 1.13. Why should I trust Privoxy?
61 1.14. Is there is a license or fee? What about a warranty?
64 1.15. Can Privoxy remove spyware? Adware? Viruses?
66 1.16. Can I use Privoxy with other ad-blocking software?
68 1.17. I would like to help you, what can I do?
70 1.17.1. Would you like to participate?
78 2.1. Which browsers are supported by Privoxy?
80 2.2. Which operating systems are supported?
82 2.3. Can I use Privoxy with my email client?
84 2.4. I just installed Privoxy. Is there anything special I
87 2.5. What is the proxy address of Privoxy?
89 2.6. I just installed Privoxy, and nothing is happening. All
90 the ads are there. What's wrong?
92 2.7. I get a "Privoxy is not being used" dummy page although
93 Privoxy is running and being used.
97 3.1. What exactly is an "actions" file?
99 3.2. The "actions" concept confuses me. Please list some of
102 3.3. How are actions files configured? What is the easiest
105 3.4. There are several different "actions" files. What are
108 3.5. Where can I get updated Actions Files?
110 3.6. Can I use my old config files?
112 3.7. Why is the configuration so complicated?
114 3.8. How can I make my Yahoo/Hotmail/Gmail account work?
116 3.9. What's the difference between the "Cautious", "Medium"
117 and "Advanced" defaults?
119 3.10. Why can I change the configuration with a browser? Does
120 that not raise security issues?
122 3.11. What is the default.filter file? What is a "filter"?
124 3.12. How can I set up Privoxy to act as a proxy for my LAN?
126 3.13. Instead of ads, now I get a checkerboard pattern. I
127 don't want to see anything.
129 3.14. Why would anybody want to see a checkerboard pattern?
131 3.15. I see some images being replaced with text instead of
132 the checkerboard image. Why and how do I get rid of this?
134 3.16. Can Privoxy run as a service on Win2K/NT/XP?
136 3.17. How can I make Privoxy work with other proxies like
139 3.18. Can I just set Privoxy to use port 80 and thus avoid
140 individual browser configuration?
142 3.19. Can Privoxy run as a "transparent" proxy?
144 3.20. Can Privoxy run as a "intercepting" proxy?
146 3.21. How can I configure Privoxy for use with Outlook
149 3.22. How can I have separate rules just for HTML mail?
151 3.23. I sometimes notice cookies sneaking through. How?
153 3.24. Are all cookies bad? Why?
155 3.25. How can I allow permanent cookies for my trusted sites?
157 3.26. Can I have separate configurations for different users?
159 3.27. Can I set-up Privoxy as a whitelist of "good" sites?
161 3.28. How can I turn off ad-blocking?
163 3.29. How can I have custom template pages, like the BLOCKED
166 3.30. How can I remove the "Go There Anyway" link from the
171 4.1. How much does Privoxy slow my browsing down? This has to
172 add extra time to browsing.
174 4.2. I notice considerable delays in page requests. What's
177 4.3. What are "http://config.privoxy.org/" and "http://p.p/"?
179 4.4. How can I submit new ads, or report problems?
181 4.5. If I do submit missed ads, will they be included in
184 4.6. Why doesn't anyone answer my support request?
186 4.7. How can I hide my IP address?
188 4.8. Can Privoxy guarantee I am anonymous?
190 4.9. A test site says I am not using a Proxy.
192 4.10. How do I use Privoxy together with Tor?
194 4.11. Might some things break because header information or
195 content is being altered?
197 4.12. Can Privoxy act as a "caching" proxy to speed up web
200 4.13. What about as a firewall? Can Privoxy protect me?
202 4.14. I have large empty spaces / a checkerboard pattern now
203 where ads used to be. Why?
205 4.15. How can Privoxy filter Secure (HTTPS) URLs?
207 4.16. Privoxy runs as a "server". How secure is it? Do I need
208 to take any special precautions?
210 4.17. Can I temporarily disable Privoxy?
212 4.18. When "disabled" is Privoxy totally out of the picture?
214 4.19. How can I tell Privoxy to totally ignore certain sites?
216 4.20. My logs show Privoxy "crunches" ads, but also its own
217 internal CGI pages. What is a "crunch"?
219 4.21. Can Privoxy effect files that I download from a
220 webserver? FTP server?
222 4.22. I just downloaded a Perl script, and Privoxy altered
223 it! Yikes, what is wrong!
225 4.23. Should I continue to use a "HOSTS" file for
228 4.24. Where can I find more information about Privoxy and
231 4.25. I've noticed that Privoxy changes "Microsoft" to
232 "MicroSuck"! Why are you manipulating my browsing?
234 4.26. Does Privoxy produce "valid" HTML (or XHTML)?
238 5.1. I cannot connect to any websites. Or, I am getting
239 "connection refused" message with every web page. Why?
241 5.2. Why am I getting a 503 Error (WSAECONNREFUSED) on every
244 5.3. I just added a new rule, but the steenkin ad is still
245 getting through. How?
247 5.4. One of my favorite sites does not work with Privoxy.
250 5.5. After installing Privoxy, I have to log in every time I
251 start IE. What gives?
253 5.6. I cannot connect to any FTP sites. Privoxy is blocking
256 5.7. In Mac OSX, I can't configure Microsoft Internet
257 Explorer to use Privoxy as the HTTP proxy.
259 5.8. In Mac OSX, I dragged the Privoxy folder to the trash in
260 order to uninstall it. Now the finder tells me I don't have
261 sufficient privileges to empty the trash.
263 5.9. In Mac OSX Panther (10.3), images often fail to load
264 and/or I experience random delays in page loading. I'm using
265 localhost as my browser's proxy setting.
267 5.10. I get a completely blank page at one site. "View
268 Source" shows only: <html><body></body></html>. Without
269 Privoxy the page loads fine.
271 5.11. My logs show many "Unable to get my own hostname"
274 5.12. When I try to launch Privoxy, I get an error message
275 "port 8118 is already in use" (or similar wording). Why?
277 5.13. Pages with UTF-8 fonts are garbled.
279 5.14. Why are binary files (such as images) corrupted when
282 5.15. What is the "demoronizer" and why is it there?
284 5.16. Why do I keep seeing "PrivoxyWindowOpen()" in raw
287 5.17. I am getting too many DNS errors like "404 No Such
288 Domain". Why can't Privoxy do this better?
290 5.18. At one site Privoxy just hangs, and starts taking all
293 5.19. I just installed Privoxy, and all my browsing has
294 slowed to a crawl. What gives?
296 5.20. Why do my filters work on some sites but not on others?
298 6. Contacting the developers, Bug Reporting and Feature Requests
302 6.2. Reporting Problems
304 6.2.1. Reporting Ads or Other Configuration
307 6.2.2. Reporting Bugs
309 6.3. Request New Features
313 7. Privoxy Copyright, License and History
319 1. General Information
321 1.1. Who should give Privoxy a try?
323 Anyone who is interested in security, privacy, or in finer-grained control
324 over their web and Internet experience.
326 --------------------------------------------------------------------------
328 1.2. Is Privoxy the best choice for me?
330 Privoxy is certainly a good choice, especially for those who want more
331 control and security. Those with the willingness to read the documentation
332 and the ability to fine-tune their installation will benefit the most.
334 One of Privoxy's strengths is that it is highly configurable giving you
335 the ability to completely personalize your installation. Being familiar
336 with, or at least having an interest in learning about HTTP and other
337 networking protocols, HTML, and "Regular Expressions" will be a big plus
338 and will help you get the most out of Privoxy. A new installation just
339 includes a very basic configuration. The user should take this as a
340 starting point only, and enhance it as he or she sees fit. In fact, the
341 user is encouraged, and expected to, fine-tune the configuration.
343 Much of Privoxy's configuration can be done with a Web browser. But there
344 are areas where configuration is done using a text editor to edit
345 configuration files. Also note that the web-based action editor doesn't
346 use authentication and should only be enabled in environments where all
347 clients with access to Privoxy listening port can be trusted.
349 --------------------------------------------------------------------------
351 1.3. What is a "proxy"? How does Privoxy work?
353 A web proxy is a service, based on a software such as Privoxy, that
354 clients (i.e. browsers) can use instead of connecting directly to web
355 servers on the Internet. The clients then ask the proxy to fetch the
356 objects they need (web pages, images, movies etc) on their behalf, and
357 when the proxy has done so, it hands the results back to the client. It is
358 a "go-between". See the Wikipedia proxy definition for more.
360 There are many reasons to use web proxies, such as security (firewalling),
361 efficiency (caching) and others, and there are any number of proxies to
362 accommodate those needs.
364 Privoxy is a proxy that is primarily focused on privacy protection, ad and
365 junk elimination and freeing the user from restrictions placed on his
366 activities. Sitting between your browser(s) and the Internet, it is in a
367 perfect position to filter outbound personal information that your browser
368 is leaking, as well as inbound junk. It uses a variety of techniques to do
369 this, all of which are under your complete control via the various
370 configuration files and options. Being a proxy also makes it easier to
371 share configurations among multiple browsers and/or users.
373 --------------------------------------------------------------------------
375 1.4. Does Privoxy do anything more than ad blocking?
377 Yes, ad blocking is but one possible use. There are many, many ways
378 Privoxy can be used to sanitize and customize web browsing.
380 --------------------------------------------------------------------------
382 1.5. What is this new version of "Junkbuster"?
384 A long time ago, there was the Internet Junkbuster, by Anonymous Coders
385 and Junkbusters Corporation. This saved many users a lot of pain in the
386 early days of web advertising and user tracking.
388 But the web, its protocols and standards, and with it, the techniques for
389 forcing ads on users, give up autonomy over their browsing, and for
390 tracking them, keeps evolving. Unfortunately, the Internet Junkbuster did
391 not. Version 2.0.2, published in 1998, was (and is) the last official
392 release available from Junkbusters Corporation. Fortunately, it had been
393 released under the GNU GPL, which allowed further development by others.
395 So Stefan Waldherr started maintaining an improved version of the
396 software, to which eventually a number of people contributed patches. It
397 could already replace banners with a transparent image, and had a first
398 version of pop-up killing, but it was still very closely based on the
399 original, with all its limitations, such as the lack of HTTP/1.1 support,
400 flexible per-site configuration, or content modification. The last release
401 from this effort was version 2.0.2-10, published in 2000.
403 Then, some developers picked up the thread, and started turning the
404 software inside out, upside down, and then reassembled it, adding many new
405 features along the way.
407 The result of this is Privoxy, whose first stable version, 3.0, was
408 released August, 2002.
410 --------------------------------------------------------------------------
412 1.6. Why "Privoxy"? Why change the name from Junkbuster at all?
414 Though outdated, Junkbusters Corporation continues to offer their original
415 version of the Internet Junkbuster, so publishing our Junkbuster-derived
416 software under the same name led to confusion.
418 There are also potential legal complications from our use of the
419 Junkbuster name, which is a registered trademark of Junkbusters
420 Corporation. There are, however, no objections from Junkbusters
421 Corporation to the Privoxy project itself, and they, in fact, still share
422 our ideals and goals.
424 The developers also believed that there are so many improvements over the
425 original code, that it was time to make a clean break from the past and
426 make a name in their own right.
428 Privoxy is the "Privacy Enhancing Proxy". Also, its content modification
429 and junk suppression gives you, the user, more control, more freedom, and
430 allows you to browse your personal and "private edition" of the web.
432 --------------------------------------------------------------------------
434 1.7. How does Privoxy differ from the old Junkbuster?
436 Privoxy picks up where Junkbuster left off. All the old features remain.
437 The new Privoxy still blocks ads and banners, still manages cookies, and
438 still helps protect your privacy. But, most of these features have been
439 enhanced, and many new ones have been added, all in the same vein.
441 Privoxy's new features include:
443 * Can be run as an "intercepting" proxy, which obviates the need to
444 configure browsers individually.
446 * Sophisticated actions and filters for manipulating both server and
449 * Can be chained with other proxies.
451 * Integrated browser based configuration and control utility at
452 http://config.privoxy.org/ (shortcut: http://p.p/). Browser-based
453 tracing of rule and filter effects. Remote toggling.
455 * Web page filtering (text replacements, removes banners based on size,
456 invisible "web-bugs", JavaScript and HTML annoyances, pop-up windows,
459 * Modularized configuration that allows for standard settings and user
460 settings to reside in separate files, so that installing updated
461 actions files won't overwrite individual user settings.
463 * Support for Perl Compatible Regular Expressions in the configuration
464 files, and a more sophisticated and flexible configuration syntax.
466 * Improved cookie management features (e.g. session based cookies).
470 * Bypass many click-tracking scripts (avoids script redirection).
472 * Multi-threaded (POSIX and native threads).
474 * User-customizable HTML templates for all proxy-generated pages (e.g.
477 * Auto-detection and re-reading of config file changes.
479 * Improved signal handling, and a true daemon mode (Unix).
481 * Every feature now controllable on a per-site or per-location basis,
482 configuration more powerful and versatile over-all.
484 * Many smaller new features added, limitations and bugs removed, and
485 security holes fixed.
487 --------------------------------------------------------------------------
489 1.8. How does Privoxy know what is an ad, and what is not?
491 Privoxy's approach to blocking ads is twofold:
493 First, there are certain patterns in the locations (URLs) of banner
494 images. This applies to both the path (you wouldn't guess how many web
495 sites serve their banners from a directory called "banners"!) and the host
496 (blocking the big banner hosting services like doublecklick.net already
497 helps a lot). Privoxy takes advantage of this fact by using URL patterns
498 to sort out and block the requests for things that sound like they would
501 Second, banners tend to come in certain sizes. But you can't tell the size
502 of an image by its URL without downloading it, and if you do, it's too
503 late to save bandwidth. Therefore, Privoxy also inspects the HTML sources
504 of web pages while they are loaded, and replaces references to images with
505 standard banner sizes by dummy references, so that your browser doesn't
506 request them anymore in the first place.
508 Both of this involves a certain amount of guesswork and is, of course,
509 freely and readily configurable.
511 --------------------------------------------------------------------------
513 1.9. Can Privoxy make mistakes? This does not sound very scientific.
515 Actually, it's a black art ;-) And yes, it is always possible to have a
516 broad rule accidentally block or change something by mistake. You will
517 almost surely run into such situations at some point. It is tricky writing
518 rules to cover every conceivable possibility, and not occasionally get
521 But this should not be a big concern since the Privoxy configuration is
522 very flexible, and includes tools to help identify these types of
523 situations so they can be addressed as needed, allowing you to customize
524 your installation. (See the Troubleshooting section below.)
526 --------------------------------------------------------------------------
528 1.10. Will I have to configure Privoxy before I can use it?
530 That depends on your expectations. The default installation should give
531 you a good starting point, and block most ads and unwanted content, but
532 many of the more advanced features are off by default, and require you to
535 You do have to set up your browser to use Privoxy (see the Installation
538 And you will certainly run into situations where there are false
539 positives, or ads not being blocked that you may not want to see. In these
540 cases, you would certainly benefit by customizing Privoxy's configuration
541 to more closely match your individual situation. And we encourage you to
542 do this. This is where the real power of Privoxy lies!
544 --------------------------------------------------------------------------
546 1.11. Can Privoxy run as a server on a network?
548 Yes, Privoxy runs as a server already, and can easily be configured to
549 "serve" more than one client. See How can I set up Privoxy to act as a
550 proxy for my LAN below.
552 --------------------------------------------------------------------------
554 1.12. My browser does the same things as Privoxy. Why should I use Privoxy
557 Modern browsers do indeed have some of the same functionality as Privoxy.
558 Maybe this is adequate for you. But Privoxy is very versatile and
559 powerful, and can probably do a number of things your browser just can't.
561 In addition, a proxy is good choice if you use multiple browsers, or have
562 a LAN with multiple computers since Privoxy can run as a server
563 application. This way all the configuration is in one place, and you don't
564 have to maintain a similar configuration for possibly many browsers or
567 Note, however, that it's recommended to leverage both your browser's and
568 Privoxy's privacy enhancing features at the same time. While your browser
569 probably lacks some features Privoxy offers, it should also be able to do
570 some things more reliable, for example restricting and suppressing
573 --------------------------------------------------------------------------
575 1.13. Why should I trust Privoxy?
577 The most important reason is because you have access to everything, and
578 you can control everything. You can check every line of every
579 configuration file yourself. You can check every last bit of source code
580 should you desire. And even if you can't read code, there should be some
581 comfort in knowing that other people can, and do read it. You can build
582 the software from scratch, if you want, so that you know the executable is
583 clean, and that it is yours. In fact, we encourage this level of scrutiny.
584 It is one reason we use Privoxy ourselves.
586 --------------------------------------------------------------------------
588 1.14. Is there is a license or fee? What about a warranty? Registration?
590 Privoxy is free software and licensed under the GNU General Public License
591 (GPL) version 2. It is free to use, copy, modify or distribute as you wish
592 under the terms of this license. Please see the Copyright section for more
593 information on the license and copyright. Or the LICENSE file that should
596 There is no warranty of any kind, expressed, implied or otherwise. That is
597 something that would cost real money ;-) There is no registration either.
599 --------------------------------------------------------------------------
601 1.15. Can Privoxy remove spyware? Adware? Viruses?
603 No, at least not reliably enough to trust it. Privoxy is not designed to
604 be a malware removal tool and the default configuration doesn't even try
605 to filter out any malware.
607 Privoxy could help prevent contact from (known) sites that use such
608 tactics with appropriate configuration rules, and thus could conceivably
609 prevent contamination from such sites. However, keeping such a
610 configuration up to date would require a lot of time and effort that would
611 be better spend on keeping your software itself up to date so it doesn't
612 have known vulnerabilities.
614 --------------------------------------------------------------------------
616 1.16. Can I use Privoxy with other ad-blocking software?
618 Privoxy should work fine with other proxies and other software in general.
620 But it is probably not necessary to use Privoxy in conjunction with other
621 ad-blocking products, and this could conceivably cause undesirable
622 results. It might be better to choose one software or the other and work a
623 little to tweak its configuration to your liking.
625 Note that this is an advice specific to ad blocking.
627 --------------------------------------------------------------------------
629 1.17. I would like to help you, what can I do?
631 1.17.1. Would you like to participate?
633 Well, we always need help. There is something for everybody who wants to
634 help us. We welcome new developers, packagers, testers, documentation
635 writers or really anyone with a desire to help in any way. You DO NOT need
636 to be a "programmer". There are many other tasks available. In fact, the
637 programmers often can't spend as much time programming because of some of
638 the other, more mundane things that need to be done, like checking the
639 Tracker feedback sections.
641 So first thing, get an account on SourceForge.net and mail your id to the
642 developers mailing list. Then, please read the Developer's Manual, at
643 least the pertinent sections.
645 You can also start helping out without SourceForge.net account, simply by
646 showing up on the mailing list, helping out other users, providing general
647 feedback or reporting problems you noticed.
649 --------------------------------------------------------------------------
653 We, of course, welcome donations and could use money for domain
654 registering, buying software to test Privoxy with, and, of course, for
655 regular world-wide get-togethers (hahaha). If you enjoy the software and
656 feel like helping us with a donation, just drop us a note and get your
657 name on the list of contributors.
659 --------------------------------------------------------------------------
663 If you are a vendor of a web-related software like a browser, web server
664 or proxy, and would like us to ensure that Privoxy runs smoothly with your
665 product, you might consider supplying us with a copy or license. We can't,
666 however, guarantee that we will fix all potential compatibility issues as
669 --------------------------------------------------------------------------
673 2.1. Which browsers are supported by Privoxy?
675 Any browser that can be configured to use a proxy, which should be
676 virtually all browsers, including Firefox, Internet Explorer, Opera, and
677 Safari among others. Direct browser support is not an absolute requirement
678 since Privoxy runs as a separate application and talks to the browser in
679 the standardized HTTP protocol, just like a web server does.
681 --------------------------------------------------------------------------
683 2.2. Which operating systems are supported?
685 At present, Privoxy is known to run on Windows(95, 98, ME, 2000, XP,
686 Vista), GNU/Linux (RedHat, SuSE, Debian, Fedora, Gentoo, Slackware and
687 others), Mac OSX, OS/2, AmigaOS, FreeBSD, NetBSD, OpenBSD, Solaris, and
688 various other flavors of Unix.
690 But any operating system that runs TCP/IP, can conceivably take advantage
691 of Privoxy in a networked situation where Privoxy would run as a server on
692 a LAN gateway. Then only the "gateway" needs to be running one of the
693 above operating systems.
695 Source code is freely available, so porting to other operating systems is
696 always a possibility.
698 --------------------------------------------------------------------------
700 2.3. Can I use Privoxy with my email client?
702 As long as there is some way to set a HTTP proxy for the client, then yes,
703 any application can be used, whether it is strictly speaking a "browser"
704 or not. Though this may not be the best approach for dealing with some of
705 the common abuses of HTML in email. See How can I configure Privoxy with
706 Outlook Express? below for more on this.
708 Be aware that HTML email presents a number of unique security and privacy
709 related issues, that can require advanced skills to overcome. The
710 developers recommend using email clients that can be configured to convert
711 HTML to plain text for these reasons.
713 --------------------------------------------------------------------------
715 2.4. I just installed Privoxy. Is there anything special I have to do now?
717 All browsers should be told to use Privoxy as a proxy by specifying the
718 correct proxy address and port number in the appropriate configuration
719 area for the browser. It's possible to combine Privoxy with a packet
720 filter to intercept HTTP requests even if the client isn't explicitly
721 configured to use Privoxy, but where possible, configuring the client is
722 recommended. See the User Manual for more details. You should also flush
723 your browser's memory and disk cache to get rid of any cached junk items,
724 and remove any stored cookies.
726 --------------------------------------------------------------------------
728 2.5. What is the proxy address of Privoxy?
730 If you set up the Privoxy to run on the computer you browse from (rather
731 than your ISP's server or some networked computer on a LAN), the proxy
732 will be on 127.0.0.1 (sometimes referred to as "localhost", which is the
733 special name used by every computer on the Internet to refer to itself)
734 and the port will be 8118 (unless you used the listen-address config
735 option to tell Privoxy to run on a different port).
737 When configuring your browser's proxy settings you typically enter the
738 word "localhost" or the IP address "127.0.0.1" in the boxes next to "HTTP"
739 and "Secure" (HTTPS) and then the number "8118" for "port". This tells
740 your browser to send all web requests to Privoxy instead of directly to
743 Privoxy can also be used to proxy for a Local Area Network. In this case,
744 your would enter either the IP address of the LAN host where Privoxy is
745 running, or the equivalent hostname, e.g. 192.168.1.1. Port assignment
746 would be same as above. Note that Privoxy doesn't listen on any LAN
747 interfaces by default.
749 Privoxy does not currently handle any other protocols such as FTP, SMTP,
752 --------------------------------------------------------------------------
754 2.6. I just installed Privoxy, and nothing is happening. All the ads are
757 Did you configure your browser to use Privoxy as a proxy? It does not
758 sound like it. See above. You might also try flushing the browser's caches
759 to force a full re-reading of pages. You can verify that Privoxy is
760 running, and your browser is correctly configured by entering the special
761 URL: http://p.p/. This should take you to a page titled "This is
762 Privoxy.." with access to Privoxy's internal configuration. If you see
763 this, then you are good to go. If you receive a page saying "Privoxy is
764 not running", then the browser is not set up to use your Privoxy
765 installation. If you receive anything else (probably nothing at all), it
766 could either be that the browser is not set up correctly, or that Privoxy
767 is not running at all. Check the log file. For instructions on starting
768 Privoxy and browser configuration, see the chapter on starting Privoxy in
771 --------------------------------------------------------------------------
773 2.7. I get a "Privoxy is not being used" dummy page although Privoxy is
774 running and being used.
776 First, make sure that Privoxy is really running and being used by visiting
777 http://p.p/. You should see the Privoxy main page. If not, see the chapter
778 on starting Privoxy in the User Manual.
780 Now if http://p.p/ works for you, but other parts of Privoxy's web
781 interface show the dummy page, your browser has cached a redirection it
782 encountered before Privoxy was being used. You need to clear your
783 browser's cache. Note that shift-reloading the dummy page won't help,
784 since that'll only refresh the dummy page, not the redirection that lead
787 The procedure for clearing the cache varies from browser to browser. For
788 example, Mozilla/Netscape users would click Edit --> Preferences -->
789 Advanced --> Cache and then click both "Clear Memory Cache" and "Clear
790 Disk Cache". In some Firefox versions it's Tools --> Options --> Privacy
791 --> Cache and then click "Clear Cache Now".
793 --------------------------------------------------------------------------
797 3.1. What exactly is an "actions" file?
799 Privoxy utilizes the concept of " actions" that are used to manipulate and
800 control web page data. Actions files are where these actions that Privoxy
801 could take while processing a certain request, are configured. Typically,
802 you would define a set of default actions that apply globally to all URLs,
803 then add exceptions to these defaults where needed. There is a wide array
804 of actions available that give the user a high degree of control and
805 flexibility on how to process each and every web page.
807 Actions can be defined on a URL pattern basis, i.e. for single URLs, whole
808 web sites, groups or parts thereof etc. Actions can also be grouped
809 together and then applied to requests matching one or more patterns. There
810 are many possible actions that might apply to any given site. As an
811 example, if you are blocking cookies as one of your default actions, but
812 need to accept cookies from a given site, you would need to define an
813 exception for this site in one of your actions files, preferably in
816 --------------------------------------------------------------------------
818 3.2. The "actions" concept confuses me. Please list some of these "actions".
820 For a comprehensive discussion of the actions concept, please refer to the
821 actions file chapter in the User Manual. It includes a list of all actions
822 and an actions file tutorial to get you started.
824 --------------------------------------------------------------------------
826 3.3. How are actions files configured? What is the easiest way to do this?
828 Actions files are just text files in a special syntax and can be edited
829 with a text editor. But probably the easiest way is to access Privoxy's
830 user interface with your web browser at http://config.privoxy.org/
831 (Shortcut: http://p.p/) and then select "View & change the current
832 configuration" from the menu. Note that this feature must be explicitly
833 enabled in the main config file (see enable-edit-actions).
835 --------------------------------------------------------------------------
837 3.4. There are several different "actions" files. What are the differences?
839 Three actions files are being included by the developers, to be used for
840 different purposes: These are default.action, the "main" actions file
841 which is actively maintained by the Privoxy developers and typically sets
842 the default policies, user.action, where users are encouraged to make
843 their private customizations, and standard.action, which is for internal
844 Privoxy use only. Please see the actions chapter in the User Manual for a
845 more detailed explanation.
847 Earlier versions included three different versions of the default.action
848 file. The new scheme allows for greater flexibility of local
849 configuration, and for browser based selection of pre-defined
850 "aggressiveness" levels.
852 --------------------------------------------------------------------------
854 3.5. Where can I get updated Actions Files?
856 Based on your feedback and the continuing development, updates of
857 default.action will be made available from time to time on the files
858 section of our project page.
860 If you wish to receive an email notification whenever we release updates
861 of Privoxy or the actions file, subscribe to our announce mailing list,
862 ijbswa-announce@lists.sourceforge.net.
864 --------------------------------------------------------------------------
866 3.6. Can I use my old config files?
868 The syntax and purpose of configuration files has remained roughly the
869 same throughout the 3.x series, but backwards compatibility is not
870 guaranteed. Also each release contains updated, "improved" versions and it
871 is therefore strongly recommended to install the newer configuration files
872 and merge back your modifications.
874 --------------------------------------------------------------------------
876 3.7. Why is the configuration so complicated?
878 "Complicated" is in the eye of the beholder. Those that are familiar with
879 some of the underlying concepts, such as regular expression syntax, take
880 to it like a fish takes to water. Also, software that tries hard to be
881 "user friendly", often lacks sophistication and flexibility. There is
882 always that trade-off there between power vs. easy-of-use. Furthermore,
883 anyone is welcome to contribute ideas and implementations to enhance
886 --------------------------------------------------------------------------
888 3.8. How can I make my Yahoo/Hotmail/Gmail account work?
890 The default configuration shouldn't impact the usability of any of these
891 services. It may, however, make all cookies temporary, so that your
892 browser will forget your login credentials in between browser sessions. If
893 you would like not to have to log in manually each time you access those
894 websites, simply turn off all cookie handling for them in the user.action
895 file. An example for yahoo might look like:
897 # Allow all cookies for Yahoo login:
899 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only }
902 These kinds of sites are often quite complex and heavy with Javascript and
903 thus "fragile". So if still a problem, we have an alias just for such
906 # Gmail is a _fragile_ site:
912 Be sure to flush your browser's caches whenever making these kinds of
913 changes, just to make sure the changes "take".
915 Make sure the domain, host and path are appropriate as well. Your browser
916 can tell you where you are specifically and you should use that
917 information for your configuration settings. Note that above it is not
918 referenced as gmail.com, which is a valid domain name.
920 --------------------------------------------------------------------------
922 3.9. What's the difference between the "Cautious", "Medium" and "Advanced"
925 Configuring Privoxy is not entirely trivial. To help you get started, we
926 provide you with three different default action "profiles" in the web
927 based actions file editor at http://config.privoxy.org/show-status. See
928 the User Manual for a list of actions, and how the default profiles are
931 Where the defaults are likely to break some sites, exceptions for known
932 popular "problem" sites are included, but in general, the more aggressive
933 your default settings are, the more exceptions you will have to make
934 later. New users are best to start off in "Cautious" setting. This is
935 safest and will have the fewest problems. See the User Manual for a more
938 It should be noted that the "Advanced" profile (formerly known as the
939 "Adventuresome" profile) is more aggressive, and will make use of some of
940 Privoxy's advanced features. Use at your own risk!
942 --------------------------------------------------------------------------
944 3.10. Why can I change the configuration with a browser? Does that not raise
947 It may seem strange that regular users can edit the config files with
948 their browsers, although the whole /etc/privoxy hierarchy belongs to the
949 user "privoxy", with only 644 permissions.
951 When you use the browser-based editor, Privoxy itself is writing to the
952 config files. Because Privoxy is running as the user "privoxy", it can
953 update its own config files.
955 If you run Privoxy for multiple untrusted users (e.g. in a LAN) or aren't
956 entirely in control of your own browser, you will probably want to make
957 sure that the the web-based editor and remote toggle features are "off" by
958 setting "enable-edit-actions 0" and "enable-remote-toggle 0" in the main
961 As of Privoxy 3.0.7 these options are disabled by default.
963 --------------------------------------------------------------------------
965 3.11. What is the default.filter file? What is a "filter"?
967 The default.filter file is where filters as supplied by the developers are
968 defined. Filters are a special subset of actions that can be used to
969 modify or remove web page content or headers on the fly. Content filters
970 can be applied to anything in the page source, header filters can be
971 applied to either server or client headers. Regular expressions are used
974 There are a number of pre-defined filters to deal with common annoyances.
975 The filters are only defined here, to invoke them, you need to use the
976 filter action in one of the actions files. Content filtering is
977 automatically disabled for inappropriate MIME types, but if you now better
978 than Privoxy what should or should not be filtered you can filter any
981 Filters should not be confused with blocks, which is a completely
982 different action, and is more typically used to block ads and unwanted
985 If you are familiar with regular expressions, and HTML, you can look at
986 the provided default.filter with a text editor and define your own
987 filters. This is potentially a very powerful feature, but requires some
988 expertise in both regular expressions and HTML/HTTP. You should place any
989 modifications to the default filters, or any new ones you create in a
990 separate file, such as user.filter, so they won't be overwritten during
991 upgrades. The ability to define multiple filter files in config is a new
992 feature as of v. 3.0.5.
994 There is no GUI editor option for this part of the configuration, but you
995 can disable/enable the various pre-defined filters of the included
996 default.filter file with the web-based actions file editor. Note that the
997 custom actions editor must be explicitly enabled in the main config file
998 (see enable-edit-actions).
1000 If you intend to develop your own filters, you might want to have a look
1001 at Privoxy-Filter-Test.
1003 --------------------------------------------------------------------------
1005 3.12. How can I set up Privoxy to act as a proxy for my LAN?
1007 By default, Privoxy only responds to requests from 127.0.0.1 (localhost).
1008 To have it act as a server for a network, this needs to be changed in the
1009 main configuration file. Look for the listen-address option, which may be
1010 commented out with a "#" symbol. Make sure it is uncommented, and assign
1011 it the address of the LAN gateway interface, and port number to use.
1012 Assuming your LAN address is 192.168.1.1 and you wish to run Privoxy on
1013 port 8118, this line should look like:
1015 listen-address 192.168.1.1:8118
1017 Save the file, and restart Privoxy. Configure all browsers on the network
1018 then to use this address and port number.
1020 Alternately, you can have Privoxy listen on all available interfaces:
1022 listen-address :8118
1024 And then use Privoxy's permit-access feature to limit connections. A
1025 firewall in this situation is recommended as well.
1027 The above steps should be the same for any TCP network, regardless of
1030 If you run Privoxy on a LAN with untrusted users, we recommend that you
1031 double-check the access control and security options!
1033 --------------------------------------------------------------------------
1035 3.13. Instead of ads, now I get a checkerboard pattern. I don't want to see
1038 The replacement for blocked images can be controlled with the
1039 set-image-blocker action. You have the choice of a checkerboard pattern, a
1040 transparent 1x1 GIF image (aka "blank"), or a redirect to a custom image
1041 of your choice. Note that this choice only has effect for images which are
1042 blocked as images, i.e. whose URLs match both a handle-as-image and block
1045 If you want to see nothing, then change the set-image-blocker action to
1046 "blank". This can be done by editing the user.action file, or through the
1047 web-based actions file editor.
1049 --------------------------------------------------------------------------
1051 3.14. Why would anybody want to see a checkerboard pattern?
1053 Remember that telling which image is an ad and which isn't, is an educated
1054 guess. While we hope that the standard configuration is rather smart, it
1055 will make occasional mistakes. The checkerboard image is visually decent,
1056 and it shows you where images have been blocked, which can be very helpful
1057 in case some navigation aid or otherwise innocent image was erroneously
1058 blocked. It is recommended for new users so they can "see" what is
1059 happening. Some people might also enjoy seeing how many banners they don't
1062 --------------------------------------------------------------------------
1064 3.15. I see some images being replaced with text instead of the checkerboard
1065 image. Why and how do I get rid of this?
1067 This happens when the banners are not embedded in the HTML code of the
1068 page itself, but in separate HTML (sub)documents that are loaded into
1069 (i)frames or (i)layers, and these external HTML documents are blocked.
1070 Being non-images they get replaced by a substitute HTML page rather than a
1071 substitute image, which wouldn't work out technically, since the browser
1072 expects and accepts only HTML when it has requested an HTML document.
1074 The substitute page adapts to the available space and shows itself as a
1075 miniature two-liner if loaded into small frames, or full-blown with a
1076 large red "BLOCKED" banner if space allows.
1078 If you prefer the banners to be blocked by images, you must see to it that
1079 the HTML documents in which they are embedded are not blocked. Clicking
1080 the "See why" link offered in the substitute page will show you which rule
1081 blocked the page. After changing the rule and un-blocking the HTML
1082 documents, the browser will try to load the actual banner images and the
1083 usual image blocking will (hopefully!) kick in.
1085 --------------------------------------------------------------------------
1087 3.16. Can Privoxy run as a service on Win2K/NT/XP?
1089 Yes. Version 3.0.5 introduces full Windows service functionality. See the
1090 User Manual for details on how to install and configure Privoxy as a
1093 Earlier 3.x versions could run as a system service using srvany.exe. See
1095 http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118,
1096 for details, and a sample configuration.
1098 --------------------------------------------------------------------------
1100 3.17. How can I make Privoxy work with other proxies like Squid or Tor?
1102 This can be done and is often useful to combine the benefits of Privoxy
1103 with those of a another proxy. See the forwarding chapter in the User
1104 Manual which describes how to do this, and the How do I use Privoxy
1105 together with Tor section below.
1107 --------------------------------------------------------------------------
1109 3.18. Can I just set Privoxy to use port 80 and thus avoid individual
1110 browser configuration?
1112 No, its more complicated than that. This only works with special kinds of
1113 proxies known as "intercepting" proxies (see below).
1115 --------------------------------------------------------------------------
1117 3.19. Can Privoxy run as a "transparent" proxy?
1119 The whole idea of Privoxy is to modify client requests and server
1120 responses in all sorts of ways and therefore it's not a transparent proxy
1121 as described in RFC 2616.
1123 However, some people say "transparent proxy" when they mean "intercepting
1124 proxy". If you are one of them, please read the next entry.
1126 --------------------------------------------------------------------------
1128 3.20. Can Privoxy run as a "intercepting" proxy?
1130 Privoxy can't intercept traffic itself, but it can handle requests that
1131 where intercepted and redirected with a packet filter (like PF or
1132 iptables), as long as the Host header is present.
1134 As the Host header is required by HTTP/1.1 and as most web sites rely on
1135 it anyway, this limitation shouldn't be a problem.
1137 Please refer to your packet filter's documentation to learn how to
1138 intercept and redirect traffic into Privoxy. Afterward you just have to
1139 configure Privoxy to accept intercepted requests.
1141 --------------------------------------------------------------------------
1143 3.21. How can I configure Privoxy for use with Outlook Express?
1145 Outlook Express uses Internet Explorer components to both render HTML, and
1146 fetch any HTTP requests that may be embedded in an HTML email. So however
1147 you have Privoxy configured to work with IE, this configuration should
1148 automatically be shared.
1150 --------------------------------------------------------------------------
1152 3.22. How can I have separate rules just for HTML mail?
1154 The short answer is, you can't. Privoxy has no way of knowing which
1155 particular application makes a request, so there is no way to distinguish
1156 between web pages and HTML mail. Privoxy just blindly proxies all
1157 requests. In the case of Outlook Express (see above), OE uses IE anyway,
1158 and there is no way for Privoxy to ever be able to distinguish between
1159 them (nor could any other proxy type application for that matter).
1161 For a good discussion of some of the issues involved (including privacy
1162 and security issues), see
1163 http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118.
1165 --------------------------------------------------------------------------
1167 3.23. I sometimes notice cookies sneaking through. How?
1169 Cookies can be set in several ways. The classic method is via the
1170 Set-Cookie HTTP header. This is straightforward, and an easy one to
1171 manipulate, such as the Privoxy concept of session-cookies-only. There is
1172 also the possibility of using Javascript to set cookies (Privoxy calls
1173 these content-cookies). This is trickier because the syntax can vary
1174 widely, and thus requires a certain amount of guesswork. It is not
1175 realistic to catch all of these short of disabling Javascript, which would
1176 break many sites. And lastly, if the cookies are embedded in a HTTPS/SSL
1177 secure session via Javascript, they are beyond Privoxy's reach.
1179 All in all, Privoxy can help manage cookies in general, can help minimize
1180 the loss of privacy posed by cookies, but can't realistically stop all
1183 --------------------------------------------------------------------------
1185 3.24. Are all cookies bad? Why?
1187 No, in fact there are many beneficial uses of cookies. Cookies are just a
1188 method that browsers can use to store data between pages, or between
1189 browser sessions. Sometimes there is a good reason for this, and the
1190 user's life is a bit easier as a result. But there is a long history of
1191 some websites taking advantage of this layer of trust, and using the data
1192 they glean from you and your browsing habits for their own purposes, and
1193 maybe to your potential detriment. Such sites are using you and storing
1194 their data on your system. That is why the privacy conscious watch from
1195 whom those cookies come, and why they really need to be there.
1197 See the Wikipedia cookie definition for more.
1199 --------------------------------------------------------------------------
1201 3.25. How can I allow permanent cookies for my trusted sites?
1203 There are several actions that relate to cookies. The default behavior is
1204 to allow only "session cookies", which means the cookies only last for the
1205 current browser session. This eliminates most kinds of abuse related to
1206 cookies. But there may be cases where you want cookies to last.
1208 To disable all cookie actions, so that cookies are allowed unrestricted,
1209 both in and out, for example.com:
1211 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1214 Place the above in user.action. Note that some of these may be off by
1215 default anyway, so this might be redundant, but there is no harm being
1216 explicit in what you want to happen. user.action includes an alias for
1217 this situation, called allow-all-cookies.
1219 --------------------------------------------------------------------------
1221 3.26. Can I have separate configurations for different users?
1223 Each instance of Privoxy has its own configuration, including such
1224 attributes as the TCP port that it listens on. What you can do is run
1225 multiple instances of Privoxy, each with a unique listen-address
1226 configuration setting, and configuration path, and then each of these can
1227 have their own configurations. Think of it as per-port configuration.
1229 Simple enough for a few users, but for large installations, consider
1230 having groups of users that might share like configurations.
1232 --------------------------------------------------------------------------
1234 3.27. Can I set-up Privoxy as a whitelist of "good" sites?
1236 Sure. There are a couple of things you can do for simple white-listing.
1237 Here's one real easy one:
1239 ############################################################
1241 ############################################################
1243 / # Block *all* URLs
1245 ############################################################
1247 ############################################################
1253 This allows access to only those three sites by first blocking all URLs,
1254 and then subsequently allowing three specific exceptions.
1256 Another approach is Privoxy's trustfile concept, which incorporates the
1257 notion of "trusted referrers". See the Trust documentation for details.
1259 These are fairly simple approaches and are not completely foolproof. There
1260 are various other configuration options that should be disabled (described
1261 elsewhere here and in the User Manual) so that users can't modify their
1262 own configuration and easily circumvent the whitelist.
1264 --------------------------------------------------------------------------
1266 3.28. How can I turn off ad-blocking?
1268 Ad blocking is achieved through a complex application of various Privoxy
1269 actions. These actions are deployed against simple images, banners, flash
1270 animations, text pages, JavaScript, pop-ups and pop-unders, etc., so its
1271 not as simple as just turning one or two actions off. The various actions
1272 that make up Privoxy ad blocking are hard-coded into the default
1273 configuration files. It has been assumed that everyone using Privoxy is
1274 interested in this particular feature.
1276 If you want to do without this, there are several approaches you can take:
1277 You can manually undo the many block rules in default.action. Or even
1278 easier, just create your own default.action file from scratch without the
1279 many ad blocking rules, and corresponding exceptions. Or lastly, if you
1280 are not concerned about the additional blocks that are done for privacy
1281 reasons, you can very easily over-ride all blocking with the following
1282 very simple rule in your user.action:
1284 # Unblock everybody, everywhere
1286 / # UN-Block *all* URLs
1288 Or even a more comprehensive reversing of various ad related actions:
1290 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1292 -filter{banners-by-size} \
1293 -filter{banners-by-link} \
1296 / # UN-Block *all* URLs and allow ads
1298 This last "action" in this compound statement, allow-popups, is an alias
1299 that disables various pop-up blocking features.
1301 --------------------------------------------------------------------------
1303 3.29. How can I have custom template pages, like the BLOCKED page?
1305 Privoxy "templates" are specialized text files utilized by Privoxy for
1306 various purposes and can easily be modified using any text editor. All the
1307 template pages are installed in a sub-directory appropriately named:
1308 templates. Knowing something about HTML syntax will of course be helpful.
1310 Be forewarned that the default templates are subject to being overwritten
1311 during upgrades. You can, however, create completely new templates, place
1312 them in another directory and specify the alternate path in the main
1313 config. For details, have a look at the templdir option.
1315 --------------------------------------------------------------------------
1317 3.30. How can I remove the "Go There Anyway" link from the BLOCKED page?
1319 There is more than one way to do it (although Perl is not involved).
1321 Editing the BLOCKED template page (see above) may dissuade some users, but
1322 this method is easily circumvented. Where you need this level of control,
1323 you might want to build Privoxy from source, and disable various features
1324 that are available as compile-time options. You should configure the
1327 ./configure --disable-toggle --disable-editor --disable-force
1329 This will create an executable with hard-coded security features so that
1330 Privoxy does not allow easy bypassing of blocked sites, or changing the
1331 current configuration via any connected user's web browser.
1333 Finally, all of these features can also be toggled on/off via options in
1334 Privoxy's main config file which means you don't have to recompile
1337 --------------------------------------------------------------------------
1341 4.1. How much does Privoxy slow my browsing down? This has to add extra time
1344 How much of an impact depends on many things, including the CPU of the
1345 host system, how aggressive the configuration is, which specific actions
1346 are being triggered, the size of the page, the bandwidth of the
1349 Overall, it should not slow you down any in real terms, and may actually
1350 help speed things up since ads, banners and other junk are not typically
1351 being retrieved and displayed. The actual processing time required by
1352 Privoxy itself for each page, is relatively small in the overall scheme of
1353 things, and happens very quickly. This is typically more than offset by
1354 time saved not downloading and rendering ad images and other junk content
1355 (if ad blocking is being used).
1357 "Filtering" content via the filter or deanimate-gifs actions may cause a
1358 perceived slowdown, since the entire document needs to be buffered before
1359 displaying. And on very large documents, filtering may have some
1360 measurable impact. How much depends on the page size, the actual
1361 definition of the filter(s), etc. See below. Most other actions have
1362 little to no impact on speed.
1364 Also, when filtering is enabled but zlib support isn't available,
1365 compression is often disabled (see prevent-compression). This can have an
1366 impact on speed as well, although it's probably smaller than you might
1367 think. Again, the page size, etc. will determine how much of an impact.
1369 --------------------------------------------------------------------------
1371 4.2. I notice considerable delays in page requests. What's wrong?
1373 If you use any filter action, such as filtering banners by size, web-bugs
1374 etc, or the deanimate-gifs action, the entire document must be loaded into
1375 memory in order for the filtering mechanism to work, and nothing is sent
1376 to the browser during this time.
1378 The loading time typically does not really change much in real numbers,
1379 but the feeling is different, because most browsers are able to start
1380 rendering incomplete content, giving the user a feeling of "it works".
1381 This effect is more noticeable on slower dialup connections. Extremely
1382 large documents may have some impact on the time to load the page where
1383 there is filtering being done. But overall, the difference should be very
1384 minimal. If there is a big impact, then probably some other situation is
1385 contributing (like anti-virus software).
1387 Filtering is automatically disabled for inappropriate MIME types. But note
1388 that if the web server mis-reports the MIME type, then content that should
1389 not be filtered, could be. Privoxy only knows how to differentiate
1390 filterable content because of the MIME type as reported by the server, or
1391 because of some configuration setting that enables/disables filtering.
1393 --------------------------------------------------------------------------
1395 4.3. What are "http://config.privoxy.org/" and "http://p.p/"?
1397 http://config.privoxy.org/ is the address of Privoxy's built-in user
1398 interface, and http://p.p/ is a shortcut for it.
1400 Since Privoxy sits between your web browser and the Internet, it can
1401 simply intercept requests for these addresses and answer them with its
1402 built-in "web server".
1404 This also makes for a good test for your browser configuration: If
1405 entering the URL http://config.privoxy.org/ takes you to a page saying
1406 "This is Privoxy ...", everything is OK. If you get a page saying "Privoxy
1407 is not working" instead, then your browser didn't use Privoxy for the
1408 request, hence it could not be intercepted, and you have accessed the real
1409 web site at config.privoxy.org.
1411 --------------------------------------------------------------------------
1413 4.4. How can I submit new ads, or report problems?
1415 Please see the Contact section for various ways to interact with the
1418 --------------------------------------------------------------------------
1420 4.5. If I do submit missed ads, will they be included in future updates?
1422 Whether such submissions are eventually included in the default.action
1423 configuration file depends on how significant the issue is. We of course
1424 want to address any potential problem with major, high-profile sites such
1425 as Google, Yahoo, etc. Any site with global or regional reach, has a good
1426 chance of being a candidate. But at the other end of the spectrum are any
1427 number of smaller, low-profile sites such as for local clubs or schools.
1428 Since their reach and impact are much less, they are best handled by
1429 inclusion in the user's user.action, and thus would be unlikely to be
1432 --------------------------------------------------------------------------
1434 4.6. Why doesn't anyone answer my support request?
1436 Rest assured that it has been read and considered. Why it is not answered,
1437 could be for various reasons, including no one has a good answer for it,
1438 no one has had time to yet investigate it thoroughly, it has been reported
1439 numerous times already, or because not enough information was provided to
1440 help us help you. Your efforts are not wasted, and we do appreciate them.
1442 --------------------------------------------------------------------------
1444 4.7. How can I hide my IP address?
1446 If you run both the browser and Privoxy locally, you cannot hide your IP
1447 address with Privoxy or ultimately any other software alone. The server
1448 needs to know your IP address so that it knows where to send the responses
1451 There are many publicly usable "anonymous" proxies out there, which
1452 provide a further level of indirection between you and the web server.
1454 However, these proxies are called "anonymous" because you don't need to
1455 authenticate, not because they would offer any real anonymity. Most of
1456 them will log your IP address and make it available to the authorities in
1457 case you violate the law of the country they run in. In fact you can't
1458 even rule out that some of them only exist to *collect* information on
1459 (those suspicious) people with a more than average preference for privacy.
1461 If you want to hide your IP address from most adversaries, you should
1462 consider chaining Privoxy with Tor. The configuration details can be found
1463 in How do I use Privoxy together with Tor section just below.
1465 --------------------------------------------------------------------------
1467 4.8. Can Privoxy guarantee I am anonymous?
1469 No. Your chances of remaining anonymous are improved, but unless you chain
1470 Privoxy with Tor or a similar proxy and know what you're doing when it
1471 comes to configuring the rest of your system, you should assume that
1472 everything you do on the Web can be traced back to you.
1474 Privoxy can remove various information about you, and allows you more
1475 freedom to decide which sites you can trust, and what details you want to
1476 reveal. But it neither hides your IP address, nor can it guarantee that
1477 the rest of the system behaves correctly. There are several possibilities
1478 how a web sites can find out who you are, even if you are using a strict
1479 Privoxy configuration and chained it with Tor.
1481 Most of Privoxy's privacy-enhancing features can be easily subverted by an
1482 insecure browser configuration, therefore you should use a browser that
1483 can be configured to only execute code from trusted sites, and be careful
1484 which sites you trust. For example there is no point in having Privoxy
1485 modify the User-Agent header, if websites can get all the information they
1486 want through JavaScript, ActiveX, Flash, Java etc.
1488 A few browsers disclose the user's email address in certain situations,
1489 such as when transferring a file by FTP. Privoxy does not filter FTP. If
1490 you need this feature, or are concerned about the mail handler of your
1491 browser disclosing your email address, you might consider products such as
1494 Browsers available only as binaries could use non-standard headers to give
1495 out any information they can have access to: see the manufacturer's
1496 license agreement. It's impossible to anticipate and prevent every breach
1497 of privacy that might occur. The professionally paranoid prefer browsers
1498 available as source code, because anticipating their behavior is easier.
1499 Trust the source, Luke!
1501 --------------------------------------------------------------------------
1503 4.9. A test site says I am not using a Proxy.
1505 Good! Actually, they are probably testing for some other kinds of proxies.
1506 Hiding yourself completely would require additional steps.
1508 --------------------------------------------------------------------------
1510 4.10. How do I use Privoxy together with Tor?
1512 Before you configure Privoxy to use Tor, please follow the User Manual
1513 chapters 2. Installation and 5. Startup to make sure Privoxy itself is
1516 If it is, refer to Tor's extensive documentation to learn how to install
1517 Tor, and make sure Tor's logfile says that "Tor has successfully opened a
1518 circuit" and it "looks like client functionality is working".
1520 If either Tor or Privoxy isn't working, their combination most likely will
1521 neither. Testing them on their own will also help you to direct problem
1522 reports to the right audience. If Privoxy isn't working, don't bother the
1523 Tor developers. If Tor isn't working, don't send bug reports to the
1526 If you verified that Privoxy and Tor are working, it is time to connect
1527 them. As far as Privoxy is concerned, Tor is just another proxy that can
1528 be reached by socks4 or socks4a. Most likely you are interested in Tor to
1529 increase your anonymity level, therefore you should use socks4a, to make
1530 sure DNS requests are done through Tor and thus invisible to your local
1533 Since Privoxy 3.0.5, its main configuration file is already prepared for
1534 Tor, if you are using a default Tor configuration and run it on the same
1535 system as Privoxy, you just have to edit the forwarding section and
1538 # forward-socks4a / 127.0.0.1:9050 .
1541 This is enough to reach the Internet, but additionally you might want to
1542 uncomment the following forward rules, to make sure your local network is
1543 still reachable through Privoxy:
1545 # forward 192.168.*.*/ .
1546 # forward 10.*.*.*/ .
1547 # forward 127.*.*.*/ .
1550 Unencrypted connections to systems in these address ranges will be as
1551 (un)secure as the local network is, but the alternative is that your
1552 browser can't reach the network at all. Then again, that may actually be
1553 desired and if you don't know for sure that your browser has to be able to
1554 reach the local network, there's no reason to allow it.
1556 If you want your browser to be able to reach servers in your local network
1557 by using their names, you will need additional exceptions that look like
1560 # forward localhost/ .
1563 Save the modified configuration file and open
1564 http://config.privoxy.org/show-status/ in your browser, confirm that
1565 Privoxy has reloaded its configuration and that there are no other forward
1566 lines, unless you know that you need them. If everything looks good, refer
1567 to Tor Faq 4.2 to learn how to verify that you are really using Tor.
1569 Afterward, please take the time to at least skim through the rest of Tor's
1570 documentation. Make sure you understand what Tor does, why it is no
1571 replacement for application level security, and why you probably don't
1572 want to use it for unencrypted logins.
1574 --------------------------------------------------------------------------
1576 4.11. Might some things break because header information or content is being
1579 Definitely. It is common for sites to use browser type, browser version,
1580 HTTP header content, and various other techniques in order to dynamically
1581 decide what to display and how to display it. What you see, and what I
1582 see, might be very different. There are many, many ways that this can be
1583 handled, so having hard and fast rules, is tricky.
1585 The "User-Agent" is sometimes used in this way to identify the browser,
1586 and adjust content accordingly.
1588 Also, different browsers use different encodings of non-English
1589 characters, certain web servers convert pages on-the-fly according to the
1590 User Agent header. Giving a "User Agent" with the wrong operating system
1591 or browser manufacturer causes some sites in these languages to be
1592 garbled; Surfers to Eastern European sites should change it to something
1593 closer. And then some page access counters work by looking at the
1594 "Referer" header; they may fail or break if unavailable. The weather maps
1595 of Intellicast have been blocked by their server when no "Referer" or
1596 cookie is provided, is another example. (But you can forge both headers
1597 without giving information away). There are many other ways things can go
1598 wrong when trying to fool a web server. The results of which could
1599 inadvertently cause pages to load incorrectly, partially, or even not at
1600 all. And there may be no obvious clues as to just what went wrong, or why.
1601 Nowhere will there be a message that says "Turn off fast-redirects or
1604 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1607 If you have problems with a site, you will have to adjust your
1608 configuration accordingly. Cookies are probably the most likely adjustment
1609 that may be required, but by no means the only one.
1611 --------------------------------------------------------------------------
1613 4.12. Can Privoxy act as a "caching" proxy to speed up web browsing?
1615 No, it does not have this ability at all. You want something like Squid or
1616 Polipo for this. And, yes, before you ask, Privoxy can co-exist with other
1617 kinds of proxies like Squid. See the forwarding chapter in the user manual
1620 --------------------------------------------------------------------------
1622 4.13. What about as a firewall? Can Privoxy protect me?
1624 Not in the way you mean, or in the way some firewall vendors claim they
1625 can. Privoxy can help protect your privacy, but can't protect your system
1626 from intrusion attempts. It is, of course, perfectly possible to use both.
1628 --------------------------------------------------------------------------
1630 4.14. I have large empty spaces / a checkerboard pattern now where ads used
1633 It is technically possible to eliminate banners and ads in a way that
1634 frees their allocated page space. This could easily be done by blocking
1635 with Privoxy's filters, and eliminating the entire image references from
1636 the HTML page source.
1638 But, this would consume considerably more CPU resources (IOW, slow things
1639 down), would likely destroy the layout of some web pages which rely on the
1640 banners utilizing a certain amount of page space, and might fail in other
1641 cases, where the screen space is reserved (e.g. by HTML tables for
1642 instance). Also, making ads and banners disappear without any trace
1643 complicates troubleshooting, and would sooner or later be problematic.
1645 The better alternative is to instead let them stay, and block the
1646 resulting requests for the banners themselves as is now the case. This
1647 leaves either empty space, or the familiar checkerboard pattern.
1649 So the developers won't support this in the default configuration, but you
1650 can of course define appropriate filters yourself to achieve this.
1652 --------------------------------------------------------------------------
1654 4.15. How can Privoxy filter Secure (HTTPS) URLs?
1656 Since secure HTTP connections are encrypted SSL sessions between your
1657 browser and the secure site, and are meant to be reliably secure, there is
1658 little that Privoxy can do but hand the raw gibberish data though from one
1659 end to the other unprocessed.
1661 The only exception to this is blocking by host patterns, as the client
1662 needs to tell Privoxy the name of the remote server, so that Privoxy can
1663 establish the connection. If that name matches a host-only pattern, the
1664 connection will be blocked.
1666 As far as ad blocking is concerned, this is less of a restriction than it
1667 may seem, since ad sources are often identifiable by the host name, and
1668 often the banners to be placed in an encrypted page come unencrypted
1669 nonetheless for efficiency reasons, which exposes them to the full power
1670 of Privoxy's ad blocking.
1672 "Content cookies" (those that are embedded in the actual HTML or JS page
1673 content, see filter{content-cookies}), in an SSL transaction will be
1674 impossible to block under these conditions. Fortunately, this does not
1675 seem to be a very common scenario since most cookies come by traditional
1678 --------------------------------------------------------------------------
1680 4.16. Privoxy runs as a "server". How secure is it? Do I need to take any
1681 special precautions?
1683 On Unix-like systems, Privoxy can run as a non-privileged user, which is
1684 how we recommend it be run. Also, by default Privoxy listens to requests
1685 from "localhost" only.
1687 The server aspect of Privoxy is not itself directly exposed to the
1688 Internet in this configuration. If you want to have Privoxy serve as a LAN
1689 proxy, this will have to be opened up to allow for LAN requests. In this
1690 case, we'd recommend you specify only the LAN gateway address, e.g.
1691 192.168.1.1, in the main Privoxy configuration file and check all access
1692 control and security options. All LAN hosts can then use this as their
1693 proxy address in the browser proxy configuration, but Privoxy will not
1694 listen on any external interfaces. ACLs can be defined in addition, and
1695 using a firewall is always good too. Better safe than sorry.
1697 --------------------------------------------------------------------------
1699 4.17. Can I temporarily disable Privoxy?
1701 Privoxy doesn't have a transparent proxy mode, but you can toggle off
1702 blocking and content filtering.
1704 The easiest way to do that is to point your browser to the remote toggle
1705 URL: http://config.privoxy.org/toggle.
1707 See the Bookmarklets section of the User Manual for an easy way to access
1708 this feature. Note that this is a feature that may need to be enabled in
1709 the main config file.
1711 --------------------------------------------------------------------------
1713 4.18. When "disabled" is Privoxy totally out of the picture?
1715 No, this just means all optional filtering and actions are disabled.
1716 Privoxy is still acting as a proxy, but just doing less of the things that
1717 Privoxy would normally be expected to do. It is still a "middle-man" in
1718 the interaction between your browser and web sites. See below to bypass
1721 --------------------------------------------------------------------------
1723 4.19. How can I tell Privoxy to totally ignore certain sites?
1725 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a
1726 browser configuration issue, not a Privoxy issue. Modern browsers
1727 typically do have settings for not proxying certain sites. Check your
1728 browser's help files.
1730 --------------------------------------------------------------------------
1732 4.20. My logs show Privoxy "crunches" ads, but also its own internal CGI
1733 pages. What is a "crunch"?
1735 A "crunch" simply means Privoxy intercepted something, nothing more. Often
1736 this is indeed ads or banners, but Privoxy uses the same mechanism for
1737 trapping requests for its own internal pages. For instance, a request for
1738 Privoxy's configuration page at: http://config.privoxy.org, is intercepted
1739 (i.e. it does not go out to the 'net), and the familiar CGI configuration
1740 is returned to the browser, and the log consequently will show a "crunch".
1742 Since version 3.0.7, Privoxy will also log the crunch reason. If you are
1743 using an older version you might want to upgrade.
1745 --------------------------------------------------------------------------
1747 4.21. Can Privoxy effect files that I download from a webserver? FTP server?
1749 From the webserver's perspective, there is no difference between viewing a
1750 document (i.e. a page), and downloading a file. The same is true of
1751 Privoxy. If there is a match for a block pattern, it will still be
1752 blocked, and of course this is obvious.
1754 Filtering is potentially more of a concern since the results are not
1755 always so obvious, and the effects of filtering are there whether the file
1756 is simply viewed, or downloaded. And potentially whether the content is
1757 some obnoxious advertisement, or Mr. Jimmy's latest/greatest source code
1758 jewel. Of course, one of these presumably is "bad" content that we don't
1759 want, and the other is "good" content that we do want. Privoxy is blind to
1760 the differences, and can only distinguish "good from bad" by the
1761 configuration parameters we give it.
1763 Privoxy knows the differences in files according to the "Content Type" as
1764 reported by the webserver. If this is reported accurately (e.g.
1765 "application/zip" for a zip archive), then Privoxy knows to ignore these
1766 where appropriate. Privoxy potentially can filter HTML as well as plain
1767 text documents, subject to configuration parameters of course. Also,
1768 documents that are of an unknown type (generally assumed to be
1769 "text/plain") can be filtered, as will those that might be incorrectly
1770 reported by the webserver. If such a file is a downloaded file that is
1771 intended to be saved to disk, then any content that might have been
1772 altered by filtering, will be saved too, for these (probably rare) cases.
1774 Note that versions later than 3.0.2 do NOT filter document types reported
1775 as "text/plain". Prior to this, Privoxy did filter this document type.
1777 In short, filtering is "ON" if a) the content type as reported by the
1778 webserver is appropriate and b) the configuration allows it (or at least
1779 does not disallow it). That's it. There is no magic cookie anywhere to say
1780 this is "good" and this is "bad". It's the configuration that lets it all
1783 If you download text files, you probably do not want these to be filtered,
1784 particularly if the content is source code, or other critical content.
1785 Source code sometimes might be mistaken for Javascript (i.e. the kind that
1786 might open a pop-up window). It is recommended to turn off filtering for
1787 download sites (particularly if the content may be plain text files and
1788 you are using version 3.0.2 or earlier) in your user.action file. And
1789 also, for any site or page where making any changes at all to the content
1792 Privoxy does not do FTP at all, only HTTP and HTTPS (SSL) protocols, so
1795 --------------------------------------------------------------------------
1797 4.22. I just downloaded a Perl script, and Privoxy altered it! Yikes, what
1802 --------------------------------------------------------------------------
1804 4.23. Should I continue to use a "HOSTS" file for ad-blocking?
1806 One time-tested technique to defeat common ads is to trick the local DNS
1807 system by giving a phony IP address for the ad generator in the local
1808 HOSTS file, typically using 127.0.0.1, aka localhost. This effectively
1811 There is no reason to use this technique in conjunction with Privoxy.
1812 Privoxy does essentially the same thing, much more elegantly and with much
1813 more flexibility. A large HOSTS file, in fact, not only duplicates effort,
1814 but may get in the way and seriously slow down your system. It is
1815 recommended to remove such entries from your HOSTS file. If you think your
1816 hosts list is neglected by Privoxy's configuration, consider adding your
1817 list to your user.action file:
1822 ads.galore.example.com
1825 --------------------------------------------------------------------------
1827 4.24. Where can I find more information about Privoxy and related issues?
1829 Other references and sites of interest to Privoxy users:
1831 http://www.privoxy.org/, the Privoxy Home page.
1833 http://www.privoxy.org/faq/, the Privoxy FAQ.
1835 http://sourceforge.net/projects/ijbswa/, the Project Page for Privoxy on
1838 http://config.privoxy.org/, the web-based user interface. Privoxy must be
1839 running for this to work. Shortcut: http://p.p/
1841 http://sourceforge.net/tracker/?group_id=11118&atid=460288, to submit
1842 "misses" and other configuration related suggestions to the developers.
1844 http://www.junkbusters.com/ht/en/cookies.html, an explanation how cookies
1845 are used to track web users.
1847 http://www.junkbusters.com/ijb.html, the original Internet Junkbuster.
1849 http://privacy.net/, a useful site to check what information about you is
1850 leaked while you browse the web.
1852 http://www.squid-cache.org/, a popular caching proxy, which is often used
1853 together with Privoxy.
1855 http://www.pps.jussieu.fr/~jch/software/polipo/, Polipo is a caching proxy
1856 with advanced features like pipelining, multiplexing and caching of
1857 partial instances. In many setups it can be used as Squid replacement.
1859 http://tor.eff.org/, Tor can help anonymize web browsing, web publishing,
1860 instant messaging, IRC, SSH, and other applications.
1862 http://www.privoxy.org/developer-manual/, the Privoxy developer manual.
1864 --------------------------------------------------------------------------
1866 4.25. I've noticed that Privoxy changes "Microsoft" to "MicroSuck"! Why are
1867 you manipulating my browsing?
1869 We're not. The text substitutions that you are seeing are disabled in the
1870 default configuration as shipped. You have either manually activated the
1871 "fun" filter which is clearly labeled "Text replacements for subversive
1872 browsing fun!" or you are using an older Privoxy version and have
1873 implicitly activated it by choosing the "Adventuresome" profile in the
1874 web-based editor. Please upgrade.
1876 --------------------------------------------------------------------------
1878 4.26. Does Privoxy produce "valid" HTML (or XHTML)?
1880 Privoxy generates HTML in both its own "templates", and possibly whenever
1881 there are text substitutions via a Privoxy filter. While this should
1882 always conform to the HTML 4.01 specifications, it has not been validated
1883 against this or any other standard.
1885 --------------------------------------------------------------------------
1889 5.1. I cannot connect to any websites. Or, I am getting "connection refused"
1890 message with every web page. Why?
1892 There are several possibilities:
1894 * Privoxy is not running. Solution: verify that Privoxy is installed
1895 correctly, has not crashed, and is indeed running. Turn on Privoxy's
1896 logging, and look at the logs to see what they say.
1898 * Or your browser is configured for a different port than what Privoxy
1899 is using. Solution: verify that Privoxy and your browser are set to
1900 the same port (listen-address).
1902 * Or if using a forwarding rule, you have a configuration problem or a
1903 problem with a host in the forwarding chain. Solution: temporarily
1904 alter your configuration and take the forwarders out of the equation.
1906 * Or you have a firewall that is interfering and blocking you. Solution:
1907 try disabling or removing the firewall as a simple test.
1909 --------------------------------------------------------------------------
1911 5.2. Why am I getting a 503 Error (WSAECONNREFUSED) on every page?
1913 More than likely this is a problem with your TCP/IP networking. ZoneAlarm
1914 has been reported to cause this symptom -- even if not running! The
1915 solution is to either fight the ZA configuration, or uninstall ZoneAlarm,
1916 and then find something better behaved in its place. Other personal
1917 firewall type products may cause similar type problems if not configured
1920 --------------------------------------------------------------------------
1922 5.3. I just added a new rule, but the steenkin ad is still getting through.
1925 If the ad had been displayed before you added its URL, it will probably be
1926 held in the browser's cache for some time, so it will be displayed without
1927 the need for any request to the server, and Privoxy will not be involved.
1928 Flush the browser's caches, and then try again.
1930 If this doesn't help, you probably have an error in the rule you applied.
1931 Try pasting the full URL of the offending ad into
1932 http://config.privoxy.org/show-url-info and see if it really matches your
1933 new rule. Blocking ads is like blocking spam: a lot of tinkering is
1934 required to stay ahead of the game. And remember you need to block the URL
1935 of the ad in question, which may be entirely different from the site URL
1936 itself. Most ads are hosted on different servers than the main site
1937 itself. If you right-click on the ad, you should be able to get all the
1938 relevant information you need. Alternately, you can find the correct URL
1939 by looking at Privoxy's logs (you may need to enable logging in the main
1940 config file if its disabled).
1942 Below is a slightly modified real-life log snippet that originates with
1943 one requested URL: www.example.com (name of site was changed for this
1944 example, the number of requests is real). You can see in this the
1945 complexity of what goes into making up this one "page". There are eight
1946 different domains involved here, with thirty two separate URLs requested
1947 in all, making up all manner of images, Shockwave Flash, JavaScript, CSS
1948 stylesheets, scripts, and other related content. Some of this content is
1949 obviously "good" or "bad", but not all. Many of the more questionable
1950 looking requests, are going to outside domains that seem to be identifying
1951 themselves with suspicious looking names, making our job a little easier.
1952 Privoxy has "crunched" (meaning caught and BLOCKED) quite a few items in
1953 this example, but perhaps missed a few as well.
1955 Request: www.example.com/
1956 Request: www.example.com/favicon.ico
1957 Request: img.example.com/main.css
1958 Request: img.example.com/sr.js
1959 Request: example.betamarker.com/example.html
1960 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
1961 Request: img.example.com/pb.png
1962 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
1963 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
1964 Request: img.example.com/p.gif
1965 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
1966 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
1967 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
1968 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
1969 Request: www.adtrak.net/adx.js crunch! (Blocked)
1970 Request: img.example.com/hbg.gif
1971 Request: img.example.com/example.jpg
1972 Request: img.example.com/mt.png
1973 Request: img.example.com/mm.png
1974 Request: img.example.com/mb.png
1975 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
1976 Request: www.example.com/tracker.js
1977 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
1978 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
1979 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
1980 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
1981 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
1982 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
1983 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
1984 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
1985 Request: 66.70.21.80/img/pixel.gif
1986 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
1987 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
1989 Despite 12 out of 32 requests being blocked, the page looked, and seemed
1990 to behave perfectly "normal" (minus some ads, of course).
1992 --------------------------------------------------------------------------
1994 5.4. One of my favorite sites does not work with Privoxy. What can I do?
1996 First verify that it is indeed a Privoxy problem, by toggling off Privoxy
1997 through http://config.privoxy.org/toggle (the toggle feature may need to
1998 be enabled in the main config), and then shift-reloading the problem page
1999 (i.e. holding down the shift key while clicking reload. Alternatively,
2000 flush your browser's disk and memory caches).
2002 If the problem went away, we know we have a configuration related problem.
2003 Now go to http://config.privoxy.org/show-url-info and paste the full URL
2004 of the page in question into the prompt. See which actions are being
2005 applied to the URL, and which matches in which actions files are
2006 responsible for that. It might be helpful also to look at your logs for
2007 this site too, to see what else might be happening (note: logging may need
2008 to be enabled in the main config file). Many sites are complex and require
2009 a number of related pages to help present their content. Look at what else
2010 might be used by the page in question, and what of that might be required.
2011 Now, armed with this information, go to
2012 http://config.privoxy.org/show-status and select the appropriate actions
2015 You can now either look for a section which disables the actions that you
2016 suspect to cause the problem and add a pattern for your site there, or
2017 make up a completely new section for your site. In any case, the
2018 recommended way is to disable only the prime suspect, reload the problem
2019 page, and only if the problem persists, disable more and more actions
2020 until you have identified the culprit. You may or may not want to turn the
2021 other actions on again. Remember to flush your browser's caches in between
2024 Alternately, if you are comfortable with a text editor, you can accomplish
2025 the same thing by editing the appropriate actions file. Probably the
2026 easiest way to deal with such problems when editing by hand is to add your
2027 site to a { fragile } section in user.action, which is an alias that turns
2028 off most "dangerous" actions, but is also likely to turn off more actions
2029 then needed, and thus lower your privacy and protection more than
2032 Troubleshooting actions is discussed in more detail in the User Manual
2033 appendix, Troubleshooting: the Anatomy of an Action. There is also an
2034 actions tutorial with general configuration information and examples.
2036 As a last resort, you can always see if your browser has a setting that
2037 will bypass the proxy setting for selective sites. Modern browsers can do
2040 --------------------------------------------------------------------------
2042 5.5. After installing Privoxy, I have to log in every time I start IE. What
2045 This is a quirk that effects the installation of Privoxy, in conjunction
2046 with Internet Explorer and Internet Connection Sharing on Windows 2000 and
2047 Windows XP. The symptoms may appear to be corrupted or invalid DUN
2048 settings, or passwords.
2050 When setting up an NT based Windows system with Privoxy you may find that
2051 things do not seem to be doing what you expect. When you set your system
2052 up you will probably have set up Internet Connection Sharing (ICS) with
2053 Dial up Networking (DUN) when logged in with administrator privileges. You
2054 will probably have made this DUN connection available to other accounts
2055 that you may have set-up on your system. E.g. Mum or Dad sets up the
2056 system and makes accounts suitably configured for the kids.
2058 When setting up Privoxy in this environment you will have to alter the
2059 proxy set-up of Internet Explorer (IE) for the specific DUN connection on
2060 which you wish to use Privoxy. When you do this the ICS DUN set-up becomes
2061 user specific. In this instance you will see no difference if you change
2062 the DUN connection under the account used to set-up the connection.
2063 However when you do this from another user you will notice that the DUN
2064 connection changes to make available to "Me only". You will also find that
2065 you have to store the password under each different user!
2067 The reason for this is that each user's set-up for IE is user specific.
2068 Each set-up DUN connection and each LAN connection in IE store the
2069 settings for each user individually. As such this enforces individual
2070 configurations rather than common ones. Hence the first time you use a DUN
2071 connection after re-booting your system it may not perform as you expect,
2072 and prompt you for the password. Just set and save the password again and
2075 [Thanks to Ray Griffith for this submission.]
2077 --------------------------------------------------------------------------
2079 5.6. I cannot connect to any FTP sites. Privoxy is blocking me.
2081 Privoxy cannot act as a proxy for FTP traffic, so do not configure your
2082 browser to use Privoxy as an FTP proxy. The same is true for any protocol
2083 other than HTTP or HTTPS (SSL).
2085 Most browsers understand FTP as well as HTTP. If you connect to a site,
2086 with a URL like ftp://ftp.example.com, your browser is making an FTP
2087 connection, and not a HTTP connection. So while your browser may speak
2088 FTP, Privoxy does not, and cannot proxy such traffic.
2090 To complicate matters, some systems may have a generic "proxy" setting,
2091 which will enable various protocols, including both HTTP and FTP proxying!
2092 So it is possible to accidentally enable FTP proxying in these cases. And
2093 of course, if this happens, Privoxy will indeed cause problems since it
2094 does not know FTP. Newer version will give a sane error message if a FTP
2095 connection is attempted. Just disable the FTP setting and all will be well
2098 Will Privoxy ever proxy FTP traffic? Unlikely. There just is not much
2099 reason, and the work to make this happen is more than it may seem.
2101 --------------------------------------------------------------------------
2103 5.7. In Mac OSX, I can't configure Microsoft Internet Explorer to use
2104 Privoxy as the HTTP proxy.
2106 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2107 network settings. In order to change the HTTP proxy, open System
2108 Preferences, and click on the Network icon. In the settings pane that
2109 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2110 is checked and enter 127.0.0.1 in the entry field. Enter 8118 in the Port
2111 field. The next time you start IE, it should reflect these values.
2113 --------------------------------------------------------------------------
2115 5.8. In Mac OSX, I dragged the Privoxy folder to the trash in order to
2116 uninstall it. Now the finder tells me I don't have sufficient privileges to
2119 Just dragging the Privoxy folder to the trash is not enough to delete it.
2120 Privoxy supplies an uninstall.command file that takes care of these
2121 details. Open the trash, drag the uninstall.command file out of the trash
2122 and double-click on it. You will be prompted for confirmation and the
2123 administration password.
2125 The trash may still appear full after this command; emptying the trash
2126 from the desktop should make it appear empty again.
2128 --------------------------------------------------------------------------
2130 5.9. In Mac OSX Panther (10.3), images often fail to load and/or I
2131 experience random delays in page loading. I'm using localhost as my
2132 browser's proxy setting.
2134 We believe this is due to an IPv6-related bug in OSX, but don't fully
2135 understand the issue yet. In any case, changing the proxy setting to
2136 127.0.0.1 instead of localhost works around the problem.
2138 --------------------------------------------------------------------------
2140 5.10. I get a completely blank page at one site. "View Source" shows only:
2141 <html><body></body></html>. Without Privoxy the page loads fine.
2143 Chances are that the site suffers from a bug in PHP, which results in
2144 empty pages being sent if the client explicitly requests an uncompressed
2145 page, like Privoxy does. This bug has been fixed in PHP 4.2.3.
2147 To find out if this is in fact the source of the problem, try adding the
2148 site to a -prevent-compression section in user.action:
2150 # Make exceptions for ill-behaved sites:
2152 {-prevent-compression}
2155 If that works, you may also want to report the problem to the site's
2156 webmasters, telling them to use zlib.output_compression instead of
2157 ob_gzhandler in their PHP applications (workaround) or upgrade to PHP
2158 4.2.3 or later (fix).
2160 --------------------------------------------------------------------------
2162 5.11. My logs show many "Unable to get my own hostname" lines. Why?
2164 Privoxy tries to get the hostname of the system its running on from the IP
2165 address of the system interface it is bound to (from the config file
2166 listen-address setting). If the system cannot supply this information,
2167 Privoxy logs this condition.
2169 Typically, this would be considered a minor system configuration error. It
2170 is not a fatal error to Privoxy however, but may result in a much slower
2171 response from Privoxy on some platforms due to DNS timeouts.
2173 This can be caused by a problem with the local HOSTS file. If this file
2174 has been changed from the original, try reverting it to see if that helps.
2175 Make sure whatever name(s) are used for the local system, that they
2178 --------------------------------------------------------------------------
2180 5.12. When I try to launch Privoxy, I get an error message "port 8118 is
2181 already in use" (or similar wording). Why?
2183 Port 8118 is Privoxy's default TCP "listening" port. Typically this
2184 message would mean that there is already one instance of Privoxy running,
2185 and your system is actually trying to start a second Privoxy on the same
2186 port, which will not work. (You can have multiple instances but they must
2187 be assigned different ports.) How and why this might happen varies from
2188 platform to platform, but you need to check your installation and start-up
2191 --------------------------------------------------------------------------
2193 5.13. Pages with UTF-8 fonts are garbled.
2195 This is caused by the "demoronizer" filter. You should either upgrade
2196 Privoxy, or at least upgrade to the most recent default.action file
2197 available from SourceForge. Or you can simply disable the demoronizer
2200 --------------------------------------------------------------------------
2202 5.14. Why are binary files (such as images) corrupted when Privoxy is used?
2204 This may also be caused by the "demoronizer" filter, in conjunction with a
2205 web server that is misreporting the content type. Binary files are
2206 exempted from Privoxy's filtering (unless the web server by mistake says
2207 the file is something else). Either upgrade Privoxy, or go to the most
2208 recent default.action file available from SourceForge.
2210 --------------------------------------------------------------------------
2212 5.15. What is the "demoronizer" and why is it there?
2214 The original demoronizer was a Perl script that cleaned up HTML pages
2215 which were created with certain Microsoft products. MS has used
2216 proprietary extensions to standardized font encodings (ISO 8859-1), which
2217 has caused problems for pages that are viewed with non-Microsoft products
2218 (and are expecting to see a standard set of fonts). The demoronizer
2219 corrected these errors so the pages displayed correctly. Privoxy borrowed
2220 from this script, introducing a filter based on the original demoronizer,
2221 which in turn could correct these errors on the fly.
2223 But this is only needed in some situations, and will cause serious
2224 problems in some other situations.
2226 If you are using Microsoft products, you do not need it. If you need to
2227 view pages with UTF-8 characters (such as Cyrillic or Chinese), then it
2228 will cause corruption of the fonts, and thus should not be on.
2230 On the other hand, if you use non-Microsoft products, and you occasionally
2231 notice weird characters on pages, you might want to try it.
2233 --------------------------------------------------------------------------
2235 5.16. Why do I keep seeing "PrivoxyWindowOpen()" in raw source code?
2237 Privoxy is attempting to disable malicious Javascript in this case, with
2238 the unsolicited-popups filter. Privoxy cannot tell very well "good" code
2239 snippets from "bad" code snippets.
2241 If you see this in HTML source, and the page displays without problems,
2242 then this is good, and likely some pop-up window was disabled. If you see
2243 this where it is causing a problem, such as a downloaded program source
2244 code file, then you should set an exception for this site or page such
2245 that the integrity of the page stays in tact by disabling all filtering.
2247 --------------------------------------------------------------------------
2249 5.17. I am getting too many DNS errors like "404 No Such Domain". Why can't
2250 Privoxy do this better?
2252 There are potentially several factors here. First of all, the DNS
2253 resolution is done by the underlying operating system -- not Privoxy
2254 itself. Privoxy merely initiates the process and hands it off, and then
2255 later reports whatever the outcome was. And tries to give a coherent
2256 message if there seems to be a problem. In some cases, this might
2257 otherwise be mitigated by the browser itself which might try some
2258 work-arounds and alternate approaches (e.g adding "www." to the URL).
2260 In other cases, if Privoxy is being chained with another proxy, this could
2261 complicate the issue, and cause undue delays and timeouts. In the case of
2262 a "socks4a" proxy, the socks server handles all the DNS. Privoxy would
2263 just be the "messenger" which is reporting whatever problem occurred
2264 downstream, and not the root cause of the error.
2266 In any case, versions newer than 3.0.3 include various improvements to
2267 help Privoxy better handle these cases.
2269 --------------------------------------------------------------------------
2271 5.18. At one site Privoxy just hangs, and starts taking all CPU. Why is
2274 This is probably a manifestation of the "100% cpu" problem that occurs on
2275 pages containing many (thousands upon thousands) of blank lines. The blank
2276 lines are in the raw HTML source of the page, and the browser just ignores
2277 them. But the pattern matching in Privoxy's page filtering mechanism is
2278 trying to match against absurdly long strings and this becomes very
2279 CPU-intensive, taking a long, long time to complete. Until a better
2280 solution comes along, disable filtering on these pages, particularly the
2281 js-annoyances and unsolicited-popups filters.
2283 --------------------------------------------------------------------------
2285 5.19. I just installed Privoxy, and all my browsing has slowed to a crawl.
2288 This should not happen, and for the overwhelming number of users
2289 world-wide, it does not happen. I would suspect some inadvertent
2290 interaction of software components such as anti-virus software, spyware
2291 protectors, personal firewalls or similar components. Try disabling (or
2292 uninstalling) these one at a time and see if that helps.
2294 --------------------------------------------------------------------------
2296 5.20. Why do my filters work on some sites but not on others?
2298 It's probably due to compression. It is a common practice for web servers
2299 to send their content "compressed" in order to speed things up, and then
2300 let the browser "uncompress" them. When compiled with zlib support Privoxy
2301 can decompress content before filtering, otherwise you may want to enable
2302 prevent-compression.
2304 --------------------------------------------------------------------------
2306 6. Contacting the developers, Bug Reporting and Feature Requests
2308 We value your feedback. In fact, we rely on it to improve Privoxy and its
2309 configuration. However, please note the following hints, so we can provide
2310 you with the best support:
2312 --------------------------------------------------------------------------
2316 For casual users, our support forum at SourceForge is probably best
2317 suited: http://sourceforge.net/tracker/?group_id=11118&atid=211118
2319 All users are of course welcome to discuss their issues on the users
2320 mailing list, where the developers also hang around.
2322 Note that the Privoxy mailing lists are moderated. Posts from unsubscribed
2323 addresses have to be accepted manually by a moderator. This may cause a
2324 delay of several days and if you use a subject that doesn't clearly
2325 mention Privoxy or one of its features, your message may be accidentally
2328 If you aren't subscribed, you should therefore spend a few seconds to come
2329 up with a proper subject. Additionally you should make it clear that you
2330 want to get CC'd. Otherwise some responses will be directed to the mailing
2331 list only, and you won't see them.
2333 --------------------------------------------------------------------------
2335 6.2. Reporting Problems
2337 "Problems" for our purposes, come in two forms:
2339 * Configuration issues, such as ads that slip through, or sites that
2340 don't function properly due to one Privoxy "action" or another being
2343 * "Bugs" in the programming code that makes up Privoxy, such as that
2344 might cause a crash.
2346 --------------------------------------------------------------------------
2348 6.2.1. Reporting Ads or Other Configuration Problems
2350 Please send feedback on ads that slipped through, innocent images that
2351 were blocked, sites that don't work properly, and other configuration
2352 related problem of default.action file, to
2353 http://sourceforge.net/tracker/?group_id=11118&atid=460288, the Actions
2356 New, improved default.action files may occasionally be made available
2357 based on your feedback. These will be announced on the ijbswa-announce
2358 list and available from our the files section of our project page.
2360 --------------------------------------------------------------------------
2362 6.2.2. Reporting Bugs
2364 Please report all bugs through our bug tracker:
2365 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
2367 Before doing so, please make sure that the bug has not already been
2368 submitted and observe the additional hints at the top of the submit form.
2369 If already submitted, please feel free to add any info to the original
2370 report that might help to solve the issue.
2372 Please try to verify that it is a Privoxy bug, and not a browser or site
2373 bug or documented behaviour that just happens to be different than what
2374 you expected. If unsure, try toggling off Privoxy, and see if the problem
2377 If you are using your own custom configuration, please try the stock
2378 configs to see if the problem is configuration related. If you're having
2379 problems with a feature that is disabled by default, please ask around on
2380 the mailing list if others can reproduce the problem.
2382 If you aren't using the latest Privoxy version, the bug may have been
2383 found and fixed in the meantime. We would appreciate if you could take the
2384 time to upgrade to the latest version (or even the latest CVS snapshot)
2385 and verify that your bug still exists.
2387 Please be sure to provide the following information:
2389 * The exact Privoxy version you are using (if you got the source from
2390 CVS, please also provide the source code revisions as shown in
2391 http://config.privoxy.org/show-version).
2393 * The operating system and versions you run Privoxy on, (e.g. Windows XP
2394 SP2), if you are using a Unix flavor, sending the output of "uname -a"
2395 should do, in case of GNU/Linux, please also name the distribution.
2397 * The name, platform, and version of the browser you were using (e.g.
2398 Internet Explorer v5.5 for Mac).
2400 * The URL where the problem occurred, or some way for us to duplicate
2401 the problem (e.g. http://somesite.example.com/?somethingelse=123).
2403 * Whether your version of Privoxy is one supplied by the Privoxy
2404 developers via SourceForge, or if you got your copy somewhere else.
2406 * Whether you are using Privoxy in tandem with another proxy such as
2407 Tor. If so, please temporary disable the other proxy to see if the
2410 * Whether you are using a personal firewall product. If so, does Privoxy
2413 * Any other pertinent information to help identify the problem such as
2414 config or log file excerpts (yes, you should have log file entries for
2417 You don't have to tell us your actual name when filing a problem report,
2418 but please use a nickname so we can differentiate between your messages
2419 and the ones entered by other "anonymous" users that may respond to your
2420 request if they have the same problem or already found a solution.
2422 Please also check the status of your request a few days after submitting
2423 it, as we may request additional information. If you use a SF id, you
2424 should automatically get a mail when someone responds to your request.
2426 The appendix of the Privoxy User Manual also has helpful information on
2427 understanding actions, and action debugging.
2429 --------------------------------------------------------------------------
2431 6.3. Request New Features
2433 You are welcome to submit ideas on new features or other proposals for
2434 improvement through our feature request tracker at
2435 http://sourceforge.net/tracker/?atid=361118&group_id=11118.
2437 --------------------------------------------------------------------------
2441 For any other issues, feel free to use the mailing lists. Technically
2442 interested users and people who wish to contribute to the project are also
2443 welcome on the developers list! You can find an overview of all
2444 Privoxy-related mailing lists, including list archives, at:
2445 http://sourceforge.net/mail/?group_id=11118.
2447 --------------------------------------------------------------------------
2449 7. Privoxy Copyright, License and History
2451 Copyright (c) 2001-2008 by Privoxy Developers
2452 <ijbswa-developers@lists.sourceforge.net>
2454 Some source code is based on code Copyright (c) 1997 by Anonymous Coders
2455 and Junkbusters, Inc. and licensed under the GNU General Public License.
2457 Portions of this document are "borrowed" from the original Junkbuster (tm)
2458 FAQ, and modified as appropriate for Privoxy.
2460 --------------------------------------------------------------------------
2464 Privoxy is free software; you can redistribute it and/or modify it under
2465 the terms of the GNU General Public License, version 2, as published by
2466 the Free Software Foundation.
2468 This program is distributed in the hope that it will be useful, but
2469 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
2470 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
2471 for more details, which is available from the Free Software Foundation,
2472 Inc, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
2474 You should have received a copy of the GNU General Public License along
2475 with this program; if not, write to the
2478 Foundation, Inc. 51 Franklin Street, Fifth Floor
2479 Boston, MA 02110-1301
2482 --------------------------------------------------------------------------
2486 A long time ago, there was the Internet Junkbuster, by Anonymous Coders
2487 and Junkbusters Corporation. This saved many users a lot of pain in the
2488 early days of web advertising and user tracking.
2490 But the web, its protocols and standards, and with it, the techniques for
2491 forcing ads on users, give up autonomy over their browsing, and for
2492 tracking them, keeps evolving. Unfortunately, the Internet Junkbuster did
2493 not. Version 2.0.2, published in 1998, was (and is) the last official
2494 release available from Junkbusters Corporation. Fortunately, it had been
2495 released under the GNU GPL, which allowed further development by others.
2497 So Stefan Waldherr started maintaining an improved version of the
2498 software, to which eventually a number of people contributed patches. It
2499 could already replace banners with a transparent image, and had a first
2500 version of pop-up killing, but it was still very closely based on the
2501 original, with all its limitations, such as the lack of HTTP/1.1 support,
2502 flexible per-site configuration, or content modification. The last release
2503 from this effort was version 2.0.2-10, published in 2000.
2505 Then, some developers picked up the thread, and started turning the
2506 software inside out, upside down, and then reassembled it, adding many new
2507 features along the way.
2509 The result of this is Privoxy, whose first stable version, 3.0, was
2510 released August, 2002.
projects / privoxy.git / blob