1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN"[
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity contacting SYSTEM "contacting.sgml">
8 <!entity history SYSTEM "history.sgml">
9 <!entity copyright SYSTEM "copyright.sgml">
10 <!entity license SYSTEM "license.sgml">
11 <!entity p-version "3.0.29">
12 <!entity p-status "stable">
13 <!entity % p-not-stable "IGNORE">
14 <!entity % p-stable "INCLUDE">
15 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
16 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
17 <!entity % p-supp-userman "INCLUDE"> <!-- Include all from supported.sgml -->
18 <!entity my-copy "©"> <!-- kludge for docbook2man -->
19 <!entity % p-newstuff "INCLUDE"> <!-- exclude stuff from devel versions -->
20 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
21 <!entity my-app "<application>Privoxy</application>">
24 File : doc/source/faq.sgml
28 Copyright (C) 2001-2020 Privoxy Developers https://www.privoxy.org/
31 Based partially on the Internet Junkbuster FAQ originally written by and
32 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
33 http://www.junkbusters.com/
35 <Qandaset defaultlabel='qanda'>
50 ========================================================================
51 NOTE: Please read developer-manual/documentation.html before touching
54 Please we keep the info in this file as version independent as possible
55 so we only have to maintain one FAQ. Where significant changes are
56 made to Privoxy configuration, please note the change in such a way that
57 it makes sense to both users of older and newer versions.
58 ========================================================================
64 <article id="index" class="faq">
66 <title>Privoxy Frequently Asked Questions</title>
70 <!-- Completely the wrong markup, but very little is allowed -->
71 <!-- in this part of an article. FIXME -->
72 <link linkend="copyright">Copyright</link> &my-copy; 2001-2020 by
73 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
79 Note: this should generate a separate page, and a live link to it.
80 But it doesn't for some mysterious reason. Please leave commented
81 unless it can be fixed proper. For the time being, the copyright
82 statement will be in copyright.smgl.
86 <legalnotice id="legalnotice">
88 text goes here ........
98 <orgname>By: Privoxy Developers</orgname>
107 This is here to keep vim syntax file from breaking :/
108 If I knew enough to fix it, I would.
109 PLEASE DO NOT REMOVE! HB: hal@foobox.net
114 This FAQ gives quick answers to frequently asked questions about
115 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
116 It is not a substitute for the
117 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
120 <!-- Include privoxy.sgml boilerplate: -->
121 <para>What is Privoxy?</para> &p-intro;
122 <!-- end boilerplate -->
125 Please note that this document is a work in progress. This copy represents
126 the state at the release of version &p-version;.
127 You can find the latest version of the document at <ulink
128 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
129 Please see the <link linkend="contact">Contact section</link> if you want to
130 contact the developers.
137 <!-- ~~~~~ New section ~~~~~ -->
139 <sect1 id="general"><title>General Information</title>
140 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
142 Anyone who is interested in security, privacy, or in
143 finer-grained control over their web and Internet experience.
147 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
150 &my-app; is certainly a good choice, especially for those who want more
151 control and security. Those with the willingness to read the documentation
152 and the ability to fine-tune their installation will benefit the most.
155 One of <application>Privoxy's</application>
156 strengths is that it is highly configurable giving you the ability to
157 completely personalize your installation. Being familiar with, or at least
158 having an interest in learning about <ulink
159 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
160 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
161 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
162 Expressions</quote></ulink>
163 will be a big plus and will help you get the most out of &my-app;.
164 A new installation just includes a very basic configuration. The user
165 should take this as a starting point only, and enhance it as he or she
166 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
170 Much of <application>Privoxy's</application> configuration can be done
171 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
172 But there are areas where configuration is done using a
173 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
174 to edit configuration files. Also note that the web-based action editor
175 doesn't use authentication and should only be enabled in environments
176 where all clients with access to &my-app; listening port can be trusted.
180 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
181 Privoxy work? </title>
183 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
184 is a service, based on a software such as &my-app;, that clients
185 (i.e. browsers) can use instead of connecting to web servers directly.
186 The clients then ask the proxy to request objects (web pages, images, movies etc)
187 on their behalf and to forward the data to the clients.
188 It is a <quote>go-between</quote>. For details, see
189 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
192 There are many reasons to use web proxies, such as security (firewalling),
193 efficiency (caching) and others, and there are any number of proxies
194 to accommodate those needs.
197 &my-app; is a proxy that is primarily focused on
198 privacy enhancement, ad and junk elimination and freeing the user from
199 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
200 it is in a perfect position to filter outbound personal information that your
201 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
202 this, all of which are under your complete control via the various configuration
203 files and options. Being a proxy also makes it easier to share
204 configurations among multiple browsers and/or users.
208 <sect2 renderas="sect3" id="otherstuff">
209 <title>Does Privoxy do anything more than ad blocking?</title>
211 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
212 can be used to sanitize and customize web browsing.
216 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
217 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
219 <!-- Include history.sgml -->
226 <sect2 renderas="sect3" id="whyprivoxy">
227 <title>Why <quote>Privoxy</quote>? Why change the name from
228 Junkbuster at all?</title>
230 Though outdated, Junkbusters Corporation continued to offer their original
231 version of the <application>Internet Junkbuster</application> for a while,
232 so publishing our <application> Junkbuster</application>-derived software
233 under the same name would have led to confusion.
236 There were also potential legal reasons not to use the
237 <application>Junkbuster</application> name, as it was (and maybe still is)
238 a registered trademark of Junkbusters Corporation.
239 There were, however, no objections from Junkbusters Corporation to the
240 <application>Privoxy</application> project itself, and they, in fact,
241 shared our ideals and goals.
244 The Privoxy developers also believed that there were so many improvements
245 over the original code, that it was time to make a clean break from the past
246 and make a name in their own right.
249 <application>Privoxy</application> is the
250 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
251 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
252 control, more freedom, and allows you to browse your personal and
253 <quote><emphasis>private</emphasis> edition</quote> of the web.
257 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
258 from the old Junkbuster?</title>
260 <application>Privoxy</application> picks up where
261 <application>Junkbuster</application> left off.
262 <application>Privoxy</application> still blocks ads and banners,
264 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
265 helps protect your privacy. But, most of these features have been enhanced,
266 and many new ones have been added, all in the same vein.
269 <application>Privoxy</application>'s new features include:
272 <!-- Include newfeatures.sgml: -->
278 <sect2 renderas="sect3" id="whatsanad">
279 <title>How does Privoxy know what is an ad, and what is not?</title>
281 <application>Privoxy</application>'s approach to blocking ads is twofold:
284 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
285 of banner images. This applies to both the path (you wouldn't guess how many
286 web sites serve their banners from a directory called <quote>banners</quote>!)
287 and the host (blocking the big banner hosting services like doublecklick.net
288 already helps a lot). <application>Privoxy</application> takes advantage of this
289 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
290 patterns</ulink> to sort out and block the requests for things that sound
291 like they would be ads or banners.
294 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
295 can't tell the size of an image by its URL without downloading it, and if you
296 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
297 also inspects the HTML sources of web pages while they are loaded, and replaces
298 references to images with standard banner sizes by dummy references, so that
299 your browser doesn't request them anymore in the first place.
302 Both of this involves a certain amount of guesswork and is, of course, freely
303 and readily configurable.
307 <sect2 renderas="sect3" id="mistakes">
308 <title>Can Privoxy make mistakes?
309 This does not sound very scientific.</title>
311 Actually, it's a black art ;-) And yes, it is always possible to have a broad
312 rule accidentally block or change something by mistake. You will almost surely
313 run into such situations at some point. It is tricky writing rules to
314 cover every conceivable possibility, and not occasionally get false positives.
318 But this should not be a big concern since the
319 <application>Privoxy</application> configuration is very flexible, and
320 includes tools to help identify these types of situations so they can be
321 addressed as needed, allowing you to customize your installation.
322 (<link linkend="badsite">See the Troubleshooting section below</link>.)
327 <sect2 renderas="sect3" id="configornot">
328 <title>Will I have to configure Privoxy
329 before I can use it?</title>
331 That depends on your expectations.
332 The default installation should give you a good starting
333 point, and block <emphasis>most</emphasis> ads and unwanted content,
334 but many of the more advanced features are off by default, and require
335 you to activate them.
338 You do have to set up your browser to use
339 <application>Privoxy</application> (see the <link
340 linkend="firststep">Installation section below</link>).
343 And you will certainly run into situations where there are false positives,
344 or ads not being blocked that you may not want to see. In these cases, you
345 would certainly benefit by customizing <application>Privoxy's</application>
346 configuration to more closely match your individual situation. And we
347 encourage you to do this. This is where the real power of
348 <application>Privoxy</application> lies!
353 <sect2 renderas="sect3" id="lan">
354 <title>Can Privoxy run as a server on a network?</title>
356 Yes, &my-app; runs as a server already, and can easily be configured to
357 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
358 How can I set up Privoxy to act as a proxy for my LAN</link> below.
362 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
363 Privoxy. Why should I use Privoxy at all?</title>
365 Modern browsers do indeed have <emphasis>some</emphasis> of the same
366 functionality as <application>Privoxy</application>. Maybe this is
367 adequate for you. But <application>Privoxy</application> is very
368 versatile and powerful, and can probably do a number of things
369 your browser just can't.
372 In addition, a proxy is good choice if you use multiple browsers, or
373 have a LAN with multiple computers since &my-app; can run as a server
374 application. This way all the configuration is in one place, and you don't
375 have to maintain a similar configuration for possibly many browsers or
379 Note, however, that it's recommended to leverage both your browser's
380 and <application>Privoxy's</application> privacy enhancing features
381 at the same time. While your browser probably lacks some features
382 &my-app; offers, it should also be able to do some things more
383 reliably, for example restricting and suppressing JavaScript.
387 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
389 The most important reason is because you have access to
390 <emphasis>everything</emphasis>, and you can control everything. You can
391 check every line of every configuration file yourself. You can check every
392 last bit of source code should you desire. And even if you can't read code,
393 there should be some comfort in knowing that <!-- thousands of -->other people can,
394 and do read it. You can build the software from scratch, if you want,
395 so that you know the executable is clean, and that it is
396 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
397 is one reason we use &my-app; ourselves.
401 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
402 warranty? Registration?</title>
404 <application>Privoxy</application> is free software and licensed under the <ulink
405 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
406 It is free to use, copy, modify or distribute as you wish under the terms of this
407 license. Please see the <link linkend="copyright">Copyright</link> section for more
408 information on the license and copyright. Or the <filename>LICENSE</filename> file
409 that should be included.
412 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
413 That is something that would cost real money ;-) There is no registration either.
418 <sect2 renderas="sect3" id="spyware">
419 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
421 No, at least not reliably enough to trust it. &my-app; is not designed to be
422 a malware removal tool and the default configuration doesn't even try to
423 filter out any malware.
426 &my-app; could help prevent contact from (known) sites that use such
427 tactics with appropriate configuration rules, and thus could conceivably
428 prevent contamination from such sites. However, keeping such a configuration
429 up to date would require a lot of time and effort that would be better spend
430 on keeping your software itself up to date so it doesn't have known
436 <sect2 renderas="sect3" id="otherads">
437 <title>Can I use Privoxy with other ad-blocking software?</title>
439 &my-app; should work fine with other proxies and other software in general.
442 But it is probably not necessary to use &my-app; in conjunction with other
443 ad-blocking products, and this could conceivably cause undesirable results.
444 It might be better to choose one software or the other and work a little to
445 tweak its configuration to your liking.
448 Note that this is an advice specific to ad blocking.
452 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
454 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
456 Well, we <emphasis>always</emphasis> need help. There is something for
457 everybody who wants to help us. We welcome new developers, packagers,
458 testers, documentation writers or really anyone with a desire to help in
459 any way. You <emphasis>DO NOT</emphasis> need to be a
460 <quote>programmer</quote>. There are many other tasks available. In fact,
461 the programmers often can't spend as much time programming because of some
462 of the other, more mundane things that need to be done, like checking the
463 Tracker feedback sections or responding to user questions on the mailing
467 So first thing, subscribe to the <ulink
468 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
469 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
470 Developers</ulink> mailing list, join the discussion, help out other users, provide general
471 feedback or report problems you noticed.
474 If you intend to help out with the trackers, you also might want to <ulink
475 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
476 so we don't confuse you with the other name-less users.
479 We also have a <ulink
480 url="../developer-manual/index.html">Developer's Manual</ulink>.
481 While it is partly out of date, it's still worth reading.
484 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
485 may be of interest to you as well.
486 Please let us know if you want to work on one of the items listed.
490 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
492 Donations are welcome. Our
493 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
494 is rather long and being able to pay one (or more) developers to work on Privoxy
495 would make a huge difference, even if it was only for a couple of weeks. Donations may
496 also be used for Privoxy-related travel expenses (for example to attend conferences),
497 for hardware used for Privoxy development and for hosting expenses etc.
501 <application>Privoxy</application> is an associated
502 project of <ulink url="https://www.spi-inc.org/">Software
503 in the Public Interest (SPI)</ulink>, which allows us to receive
504 tax-deductible donations in the United States.
505 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
506 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
507 For details, please have a look at
508 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
512 If you have any questions regarding donations please mail to either the
513 public user mailing list or, if it's a private matter, to
514 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
519 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
521 We are currently offering the following sponsor levels as an experiment:
525 <term>Gold (12000 USD/year)</term>
528 Logo or text link shown at the bottom of the
529 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
530 Logo, link and self description on the
531 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
536 <term>Silver (1200 USD/year)</term>
539 Logo or text link shown at the bottom of the
540 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
541 Logo, link and self description on the
542 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
547 <term>Bronze (600 USD/year)</term>
550 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
556 The logo sizes depend on the sponsor level. Logos are served from
557 our server, no requests are made to the sponsor website unless
558 the links are being used.
561 The details may change over time but changes will only affect new sponsors
562 (or existing sponsors that explicitly agreed to the changes).
565 If you want to become a sponsor, please contact
566 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
567 New sponsors are only accepted if no developer objects.
575 <!-- ~~~~~ New section ~~~~~ -->
577 <sect1 id="installation"><title>Installation</title>
579 <sect2 renderas="sect3" id="whichbrowsers">
580 <title>Which browsers are supported by Privoxy?</title>
582 Any browser that can be configured to use a proxy, which
583 should be virtually all browsers, including
584 <application>Firefox</application>, <application>Internet
585 Explorer</application>, <application>Opera</application>, and
586 <application>Safari</application> among others.
587 Direct browser support is not an absolute requirement since
588 <application>Privoxy</application> runs as a separate application and talks
589 to the browser in the standardized HTTP protocol, just like a web server
594 <sect2 renderas="sect3" id="whichos">
595 <title>Which operating systems are supported?</title>
597 Include supported.sgml here:
602 <sect2 renderas="sect3" id="email-client">
603 <title>Can I use Privoxy with my email client?</title>
605 As long as there is some way to set a HTTP proxy for the client, then yes,
606 any application can be used, whether it is strictly speaking a
607 <quote>browser</quote> or not. Though this may not be the best approach for
608 dealing with some of the common abuses of HTML in email. See <link
609 linkend="outlook">How can I configure <application>Privoxy</application>
610 with <application>Outlook</application>?</link> below for more on
614 Be aware that HTML email presents a number of unique security and privacy
615 related issues, that can require advanced skills to overcome. The developers
616 recommend using email clients that can be configured to convert HTML to plain
617 text for these reasons.
621 <!-- Nobody is going to still be doing this!
622 <sect2 renderas="sect3" id="newinstall"><title>Can I install
623 Privoxy over Junkbuster?</title>
625 We recommend you un-install <application>Junkbuster</application>
626 first to minimize conflicts and confusion. You may want to
627 save your old configuration files for future reference. The configuration
628 files and syntax have substantially changed, so you will need to manually
629 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
630 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
631 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
635 Note: Some installers may automatically un-install
636 <application>Junkbuster</application>, if present!
642 <sect2 renderas="sect3" id="firststep">
643 <title>I just installed Privoxy. Is there anything
644 special I have to do now?</title>
647 All browsers should be told to use <application>Privoxy</application>
648 as a proxy by specifying the correct proxy address and port number
649 in the appropriate configuration area for the browser. It's possible
650 to combine &my-app; with a packet filter to intercept HTTP requests
651 even if the client isn't explicitly configured to use &my-app;,
652 but where possible, configuring the client is recommended. See
653 <ulink url="../user-manual/startup.html">the User Manual for more
654 details</ulink>. You should also flush your browser's memory and disk
655 cache to get rid of any cached junk items, and remove any stored
656 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
661 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
663 If you set up the <application>Privoxy</application> to run on
664 the computer you browse from (rather than your ISP's server or some
665 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
666 (sometimes referred to as <quote>localhost</quote>,
667 which is the special name used by every computer on the Internet to refer
668 to itself) and the port will be 8118 (unless you used the <ulink
669 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
670 config option to tell <application>Privoxy</application> to run on
674 When configuring your browser's proxy settings you typically enter
675 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
676 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
677 then the number <quote>8118</quote> for <quote>port</quote>.
678 This tells your browser to send all web requests to <application>Privoxy</application>
679 instead of directly to the Internet.
682 <application>Privoxy</application> can also be used to proxy for
683 a Local Area Network. In this case, your would enter either the IP
684 address of the LAN host where <application>Privoxy</application>
685 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
686 Port assignment would be same as above. Note that
687 <application>Privoxy</application> doesn't listen on any LAN interfaces by
691 <application>Privoxy</application> does not currently handle
692 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
696 <sect2 renderas="sect3" id="nothing">
697 <title>I just installed Privoxy, and nothing is happening.
698 All the ads are there. What's wrong?</title>
701 Did you configure your browser to use <application>Privoxy</application>
702 as a proxy? It does not sound like it. See above. You might also try flushing
703 the browser's caches to force a full re-reading of pages. You can verify
704 that <application>Privoxy</application> is running, and your browser
705 is correctly configured by entering the special URL:
706 <ulink url="http://p.p/">http://p.p/</ulink>.
707 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
708 of potential redirect caching problem (see next Q). -->
709 This should take you to a page titled <quote>This is Privoxy..</quote> with
710 access to <application>Privoxy's</application> internal configuration.
711 If you see this, then you are good to go. If you receive a page saying
712 <quote>Privoxy is not running</quote>, then the browser is not set up to use
713 your <application>Privoxy</application> installation.
714 If you receive anything else (probably nothing at all), it could either
715 be that the browser is not set up correctly, or that
716 <application>Privoxy</application> is not running at all. Check the <ulink
717 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
718 on starting <application>Privoxy</application> and browser configuration,
719 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
720 on starting <application>Privoxy</application></ulink> in the
721 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
726 <sect2 renderas="sect3" id="notused">
727 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
728 Privoxy is running and being used.</title>
731 First, make sure that Privoxy is <emphasis>really</emphasis> running and
732 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
733 should see the <application>Privoxy</application> main page. If not, see
734 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
735 on starting <application>Privoxy</application></ulink> in the
736 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
740 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
741 other parts of <application>Privoxy</application>'s web interface show
742 the dummy page, your browser has cached a redirection it encountered before
743 <application>Privoxy</application> was being used. You need to clear your
744 browser's cache. Note that shift-reloading the dummy page won't help, since
745 that'll only refresh the dummy page, not the redirection that lead you there.
749 The procedure for clearing the cache varies from browser to browser. For
750 example, <application>Mozilla/Netscape</application> users would click
751 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
752 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
753 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
754 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
755 In some <application>Firefox</application> versions it's
756 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
757 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
758 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
759 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
766 <!-- ~~~~~ New section ~~~~~ -->
768 <sect1 id="configuration"><title>Configuration</title>
769 <sect2 renderas="sect3" id="actionsfile">
770 <title>What exactly is an <quote>actions</quote> file?</title>
773 &my-app; utilizes the concept of <quote>
774 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
775 that are used to manipulate and control web page data.
776 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
777 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
778 that <application>Privoxy</application> could take while processing a certain
779 request, are configured. Typically, you would define a set of default actions
780 that apply globally to all URLs, then add exceptions to these defaults where needed.
781 There is a wide array of actions available that give the user a high degree
782 of control and flexibility on how to process each and every web page.
786 Actions can be defined on a <ulink
787 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
788 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
789 grouped together and then applied to requests matching one or more patterns.
790 There are many possible actions that might apply to any given site. As an example,
791 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
792 as one of your default actions, but need to accept cookies from a given site,
793 you would need to define an exception for this site in one of your actions
794 files, preferably in <filename>user.action</filename>.
799 <sect2 renderas="sect3" id="actionss">
800 <title>The <quote>actions</quote> concept confuses me. Please list
801 some of these <quote>actions</quote>.</title>
803 For a comprehensive discussion of the actions concept, please refer
804 to the <ulink url="../user-manual/actions-file.html">actions file
805 chapter</ulink> in the <ulink url="../user-manual/index.html">User
806 Manual</ulink>. It includes a <ulink
807 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
808 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
809 file tutorial</ulink> to get you started.
814 <sect2 renderas="sect3" id="actconfig">
815 <title>How are actions files configured? What is the easiest
816 way to do this?</title>
819 Actions files are just text files in a special syntax and can be edited
820 with a text editor. But probably the easiest way is to access
821 <application>Privoxy</application>'s user interface with your web browser
822 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
823 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
824 <quote><ulink url="http://config.privoxy.org/show-status">View &
825 change the current configuration</ulink></quote> from the menu. Note
826 that this feature must be explicitly enabled in the main config file
828 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
833 <sect2 renderas="sect3">
834 <title>There are several different <quote>actions</quote> files. What are
835 the differences?</title>
837 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
838 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
843 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
845 Based on your feedback and the continuing development, updates of
846 <filename>default.action</filename> are available from
848 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>.
852 If you wish to receive an email notification whenever we release updates of
853 <application>Privoxy</application> or the actions file, <ulink
854 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
855 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
860 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
862 The syntax and purpose of configuration files has remained roughly the
863 same throughout the 3.x series, but backwards compatibility is not guaranteed.
864 Also each release contains updated, <quote>improved</quote> versions and it is
865 therefore strongly recommended to install the newer configuration files
866 and merge back your modifications.
870 <sect2 renderas="sect3" id="difficult">
871 <title>Why is the configuration so complicated?</title>
873 <quote>Complicated</quote> is in the eye of the beholder.
876 Privoxy is currently mainly written by and for people who are already
877 familiar with the underlying concepts like regular expressions, HTTP and HTML,
878 or are willing to become familiar with them to be able to get the most
879 out of a powerful and flexible tool such as Privoxy.
882 While everybody is expected to be able to get a Privoxy default installation
883 up and running, fine-tuning requires a certain amount of background
884 information and Privoxy's documentation mainly concentrates on the
885 Privoxy-specific parts while only providing references to the rest.
888 If you or anyone you know has the skills, time and energy to
889 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
893 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
895 The default configuration shouldn't impact the usability of any of these services.
896 It may, however, make all <ulink
897 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
898 temporary, so that your browser will forget your
899 login credentials in between browser sessions. If you would like not to have to log
900 in manually each time you access those websites, simply turn off all cookie handling
901 for them in the <filename>user.action</filename> file. An example for yahoo might
904 <screen># Allow all cookies for Yahoo login:
906 { -<ulink url="../user-manual/actions-file.html#CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</ulink> -<ulink url="../user-manual/actions-file.html#CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</ulink> -<ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink> }
907 .login.yahoo.com</screen>
909 These kinds of sites are often quite complex and heavy with
910 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
911 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
913 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
916 <screen># Gmail is a _fragile_ site:
918 { <literal>fragile</literal> }
920 mail.google.com</screen>
922 Be sure to flush your browser's caches whenever making these kinds of
923 changes, just to make sure the changes <quote>take</quote>.
926 Make sure the domain, host and path are appropriate as well. Your browser can
927 tell you where you are specifically and you should use that information for
928 your configuration settings. Note that above it is not referenced as
929 <literal>gmail.com</literal>, which is a valid domain name.
934 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
935 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
937 Configuring <application>Privoxy</application> is not entirely trivial. To
938 help you get started, we provide you with three different default action
939 <quote>profiles</quote> in the web based actions file editor at <ulink
940 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
941 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
942 Manual</citetitle></ulink> for a list of actions, and how the default
947 Where the defaults are likely to break some sites, exceptions for
948 known popular <quote>problem</quote> sites are included, but in
949 general, the more aggressive your default settings are, the more exceptions
950 you will have to make later. New users are best to start off in
951 <quote>Cautious</quote> setting. This is safest and will have the fewest
952 problems. See the <ulink
953 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
954 for a more detailed discussion.
958 It should be noted that the <quote>Advanced</quote> profile (formerly known
959 as the <quote>Adventuresome</quote> profile) is more
960 aggressive, and will make use of some of
961 <application>Privoxy's</application> advanced features. Use at your own risk!
966 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
967 with a browser? Does that not raise security issues?</title>
969 It may seem strange that regular users can edit the config files with their
970 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
971 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
974 When you use the browser-based editor, <application>Privoxy</application>
975 itself is writing to the config files. Because
976 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
977 it can update its own config files.
980 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
981 a LAN) or aren't entirely in control of your own browser, you will probably want
982 to make sure that the web-based editor and remote toggle features are
983 <quote>off</quote> by setting <quote><literal><ulink
984 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
985 0</literal></quote> and <quote><literal><ulink
986 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
987 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
990 As of &my-app; 3.0.7 these options are disabled by default.
995 <sect2 renderas="sect3" id="filterfile">
996 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
998 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
999 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1000 Filters are a special subset of actions that can be used to modify or
1001 remove web page content or headers on the fly. Content filters can
1002 be applied to <emphasis>anything</emphasis> in the page source,
1003 header filters can be applied to either server or client headers.
1004 Regular expressions are used to accomplish this.
1007 There are a number of pre-defined filters to deal with common annoyances. The
1008 filters are only defined here, to invoke them, you need to use the
1010 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1011 action</ulink> in one of the actions files. Content filtering is automatically
1012 disabled for inappropriate MIME types, but if you know better than Privoxy
1013 what should or should not be filtered you can filter any content you like.
1017 <emphasis>not</emphasis> be confused with <ulink
1018 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1019 is a completely different action, and is more typically used to block ads and
1024 If you are familiar with regular expressions, and HTML, you can look at
1025 the provided <filename>default.filter</filename> with a text editor and define
1026 your own filters. This is potentially a very powerful feature, but
1027 requires some expertise in both regular expressions and HTML/HTTP.
1028 <![%p-newstuff;[ You should
1029 place any modifications to the default filters, or any new ones you create
1030 in a separate file, such as <filename>user.filter</filename>, so they won't
1031 be overwritten during upgrades.
1032 The ability to define multiple filter files
1033 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1037 There is no GUI editor option for this part of the configuration,
1038 but you can disable/enable the various pre-defined filters of the included
1039 <filename>default.filter</filename> file with the <ulink
1040 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1041 Note that the custom actions editor must be explicitly enabled in
1042 the main config file (see <ulink
1043 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1047 If you intend to develop your own filters, you might want to have a look at
1049 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1054 <sect2 renderas="sect3" id="lanconfig">
1055 <title>How can I set up Privoxy to act as a proxy for my
1058 By default, <application>Privoxy</application> only responds to requests
1059 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1060 a network, this needs to be changed in the <ulink
1061 url="../user-manual/config.html">main configuration file</ulink>. Look for
1063 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1064 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1065 it is uncommented, and assign it the address of the LAN gateway interface,
1066 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1067 wish to run <application>Privoxy</application> on port 8118, this line
1072 listen-address 192.168.1.1:8118</screen>
1075 Save the file, and restart <application>Privoxy</application>. Configure
1076 all browsers on the network then to use this address and port number.
1080 Alternately, you can have <application>Privoxy</application> listen on
1081 all available interfaces:
1085 listen-address :8118</screen>
1088 And then use <application>Privoxy's</application>
1090 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1091 feature to limit connections. A firewall in this situation is recommended
1096 The above steps should be the same for any TCP network, regardless of
1101 If you run <application>Privoxy</application> on a LAN with untrusted users,
1102 we recommend that you double-check the <ulink
1103 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1110 <sect2 renderas="sect3" id="noseeum">
1111 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1113 The replacement for blocked images can be controlled with the <ulink
1114 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1115 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1116 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1117 Note that this choice only has effect for images which are blocked as images, i.e.
1118 whose URLs match both a <literal><ulink
1119 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1120 <emphasis>and</emphasis> <literal><ulink
1121 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1124 If you want to see nothing, then change the <ulink
1125 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1126 action</ulink> to <quote>blank</quote>. This can be done by editing the
1127 <filename>user.action</filename> file, or through the <ulink
1128 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1133 <sect2 renderas="sect3" id="whyseeum">
1134 <title>Why would anybody want to see a checkerboard pattern?</title>
1136 Remember that <link linkend="whatsanad">telling which image is an ad and which
1137 isn't</link>, is an educated guess. While we hope that the standard configuration
1138 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1139 decent, and it shows you where images have been blocked, which can be very
1140 helpful in case some navigation aid or otherwise innocent image was
1141 erroneously blocked. It is recommended for new users so they can
1142 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1143 many banners they <emphasis>don't</emphasis> have to see.
1148 <sect2 renderas="sect3" id="blockedbytext">
1149 <title>I see some images being replaced with text
1150 instead of the checkerboard image. Why and how do I get rid of this?</title>
1152 This happens when the banners are not embedded in the HTML code of the
1153 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1154 or (i)layers, and these external HTML documents are blocked. Being non-images
1155 they get replaced by a substitute HTML page rather than a substitute image,
1156 which wouldn't work out technically, since the browser expects and accepts
1157 only HTML when it has requested an HTML document.
1160 The substitute page adapts to the available space and shows itself as a
1161 miniature two-liner if loaded into small frames, or full-blown with a
1162 large red "BLOCKED" banner if space allows.
1165 If you prefer the banners to be blocked by images, you must see to it that
1166 the HTML documents in which they are embedded are not blocked. Clicking
1167 the <quote>See why</quote> link offered in the substitute page will show
1168 you which rule blocked the page. After changing the rule and un-blocking
1169 the HTML documents, the browser will try to load the actual banner images
1170 and the usual image blocking will (hopefully!) kick in.
1175 <sect2 renderas="sect3" id="srvany">
1176 <title>Can Privoxy run as a service
1177 on Win2K/NT/XP?</title>
1180 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1181 functionality. See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1182 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1183 <application>Privoxy</application> as a service.
1186 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1187 See the discussion at <ulink
1188 url="https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</ulink>,
1189 for details, and a sample configuration.
1194 <sect2 renderas="sect3" id="otherproxy">
1195 <title>How can I make Privoxy work with other proxies?</title>
1197 This can be done and is often useful to combine the benefits of
1198 <application>Privoxy</application> with those of a another proxy,
1199 for example to cache content.
1201 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1202 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1203 describes how to do this. If you intend to use Privoxy with Tor,
1204 please also have a look at
1205 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1209 <sect2 renderas="sect3" id="port-80">
1210 <title>Can I just set Privoxy to use port 80
1211 and thus avoid individual browser configuration?</title>
1214 No, its more complicated than that. This only works with special kinds
1215 of proxies known as <quote>intercepting</quote> proxies
1216 (<link linkend="INTERCEPTING">see below</link>).
1221 <sect2 renderas="sect3" id="transparent">
1222 <title>Can Privoxy run as a <quote>transparent
1223 </quote> proxy?</title>
1225 The whole idea of Privoxy is to modify client requests
1226 and server responses in all sorts of ways and therefore
1227 it's not a transparent proxy as described in
1228 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1231 However, some people say <quote>transparent proxy</quote> when they
1232 mean <quote>intercepting proxy</quote>. If you are one of them,
1233 please read the <link linkend="INTERCEPTING">next entry</link>.
1238 <sect2 renderas="sect3" id="intercepting">
1239 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1241 <application>Privoxy</application> can't intercept traffic itself,
1242 but it can handle requests that where intercepted and redirected
1243 with a packet filter (like <application>PF</application> or
1244 <application>iptables</application>), as long as the <literal>Host</literal>
1248 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1249 web sites rely on it anyway, this limitation shouldn't be a problem.
1252 Please refer to your packet filter's documentation to learn how to
1253 intercept and redirect traffic into <application>Privoxy</application>.
1254 Afterward you just have to configure <application>Privoxy</application> to
1255 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1256 intercepted requests</ulink>.
1261 <sect2 renderas="sect3" id="outlook">
1262 <title>How can I configure Privoxy for use with Outlook?</title>
1264 Versions of <application>Outlook</application> prior to Office 2007, use
1265 <application>Internet Explorer</application> components to both render HTML,
1266 and fetch any HTTP requests that may be embedded in an HTML email. So however
1267 you have <application>Privoxy</application> configured to work with IE, this
1268 configuration should automatically be shared, at least with older version of
1272 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1273 engine with Outlook. It is unknown whether this can be configured to use a
1275 <!-- FIXME HB 2009-02-15 -->
1279 <sect2 renderas="sect3" id="outlook-more">
1280 <title>How can I have separate rules just for HTML mail?</title>
1282 The short answer is, you can't. <application>Privoxy</application> has no way
1283 of knowing which particular application makes a request, so there is no way to
1284 distinguish between web pages and HTML mail.
1285 <application>Privoxy</application> just blindly proxies all requests. In the
1286 case of <application>Outlook Express</application> (see above), OE uses
1287 IE anyway, and there is no way for <application>Privoxy</application> to ever
1288 be able to distinguish between them (nor could any other proxy type application for
1292 For a good discussion of some of the issues involved (including privacy and
1293 security issues), see
1294 <ulink url="https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1298 <sect2 renderas="sect3" id="sneaky-cookies">
1299 <title>I sometimes notice cookies sneaking through. How?</title>
1302 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1303 set in several ways. The classic method is via the
1304 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1305 easy one to manipulate, such as the &my-app; concept of
1306 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1307 There is also the possibility of using
1308 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1309 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1310 is trickier because the syntax can vary widely, and thus requires a certain
1311 amount of guesswork. It is not realistic to catch all of these short of
1312 disabling Javascript, which would break many sites. And lastly, if the
1313 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1314 <application>Privoxy's</application> reach unless you enable
1315 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1318 All in all, &my-app; can help manage cookies in general, can help minimize
1319 the loss of privacy posed by cookies, but can't realistically stop all
1324 <sect2 renderas="sect3" id="evil-cookies">
1325 <title>Are all cookies bad? Why?</title>
1327 No, in fact there are many beneficial uses of
1329 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1330 method that browsers can use to store data between pages, or between browser
1331 sessions. Sometimes there is a good reason for this, and the user's life is a
1332 bit easier as a result. But there is a long history of some websites taking
1333 advantage of this layer of trust, and using the data they glean from you and
1334 your browsing habits for their own purposes, and maybe to your potential
1335 detriment. Such sites are using you and storing their data on your system.
1336 That is why the privacy conscious watch from whom those cookies come, and why
1337 they really <emphasis>need</emphasis> to be there.
1341 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1342 definition</ulink> for more.
1346 <sect2 renderas="sect3" id="allow-cookies">
1347 <title>How can I allow permanent cookies for my trusted sites?</title>
1350 There are several actions that relate to cookies. The default behavior is to
1351 allow only <quote>session cookies</quote>, which means the cookies only last
1352 for the current browser session. This eliminates most kinds of abuse related
1353 to cookies. But there may be cases where you want cookies to last.
1356 To disable all cookie actions, so that cookies are allowed unrestricted,
1357 both in and out, for <literal>example.com</literal>:
1360 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1361 .example.com</screen>
1363 Place the above in <filename>user.action</filename>. Note that some of these may
1364 be off by default anyway, so this might be redundant, but there is no harm
1365 being explicit in what you want to happen. <filename>user.action</filename>
1366 includes an alias for this situation, called
1367 <literal>allow-all-cookies</literal>.
1371 <sect2 renderas="sect3" id="multiples">
1372 <title>Can I have separate configurations for different users?</title>
1374 Each instance of <application>Privoxy</application> has its own
1375 configuration, including such attributes as the TCP port that it listens on.
1376 What you can do is run multiple instances of <application>Privoxy</application>, each with
1378 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1379 configuration setting, and configuration path, and then
1380 each of these can have their own configurations. Think of it as per-port
1384 Simple enough for a few users, but for large installations, consider having
1385 groups of users that might share like configurations.
1389 <sect2 renderas="sect3" id="whitelists">
1390 <title>Can I set-up Privoxy as a whitelist of
1391 <quote>good</quote> sites?</title>
1393 Sure. There are a couple of things you can do for simple white-listing.
1394 Here's one real easy one:
1397 ############################################################
1399 ############################################################
1400 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1401 / # Block *all* URLs
1403 ############################################################
1405 ############################################################
1406 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1409 games.example.com</screen>
1411 This allows access to only those three sites by first blocking all URLs, and
1412 then subsequently allowing three specific exceptions.
1415 Another approach is <application>Privoxy's</application>
1416 <literal>trustfile</literal> concept, which incorporates the notion of
1417 <quote>trusted referrers</quote>. See the <ulink
1418 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1422 These are fairly simple approaches and are not completely foolproof. There
1423 are various other configuration options that should be disabled (described
1424 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1425 so that users can't modify their own configuration and easily circumvent the
1430 <sect2 renderas="sect3" id="no-adblock">
1431 <title>How can I turn off ad-blocking?</title>
1433 Ad blocking is achieved through a complex application of various &my-app;
1434 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1435 actions are deployed against simple images, banners, flash animations,
1436 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1437 just turning one or two actions off. The various actions that make up
1438 &my-app; ad blocking are hard-coded into the default configuration files. It
1439 has been assumed that everyone using &my-app; is interested in this
1443 If you want to do without this, there are several approaches you can take:
1444 You can manually undo the many block rules in
1445 <filename>default.action</filename>. Or even easier, just create your own
1446 <filename>default.action</filename> file from scratch without the many ad
1447 blocking rules, and corresponding exceptions. Or lastly, if you are not
1448 concerned about the additional blocks that are done for privacy reasons, you
1449 can very easily over-ride <emphasis>all</emphasis> blocking with the
1450 following very simple rule in your <filename>user.action</filename>:
1453 # Unblock everybody, everywhere
1454 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1455 / # UN-Block *all* URLs</screen>
1457 Or even a more comprehensive reversing of various ad related actions:
1460 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1461 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1462 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1463 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1464 <literal>allow-popups</literal> \
1466 / # UN-Block *all* URLs and allow ads</screen>
1468 This last <quote>action</quote> in this compound statement,
1469 <literal>allow-popups</literal>, is an <ulink
1470 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1471 various pop-up blocking features.
1475 <sect2 renderas="sect3" id="templates">
1476 <title>How can I have custom template pages, like the
1477 <emphasis>BLOCKED</emphasis> page?</title>
1479 &my-app; <quote>templates</quote> are specialized text files utilized by
1480 &my-app; for various purposes and can easily be modified using any text
1481 editor. All the template pages are installed in a sub-directory appropriately
1482 named: <filename>templates</filename>. Knowing something about HTML syntax
1483 will of course be helpful.
1486 Be forewarned that the default templates are subject to being overwritten
1487 during upgrades. You can, however, create completely new templates,
1488 place them in another directory and specify the alternate path in the main
1489 <filename>config</filename>. For details, have a look at the <ulink
1490 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1494 <sect2 renderas="sect3" id="blockall">
1495 <title>How can I remove the <quote>Go There Anyway</quote> link from
1496 the <emphasis>BLOCKED</emphasis> page?</title>
1498 There is more than one way to do it (although Perl is not involved).
1501 Editing the BLOCKED template page (see above) may dissuade some users, but
1502 this method is easily circumvented. Where you need this level of control, you
1503 might want to build &my-app; from source, and disable various features that are
1504 available as compile-time options. You should
1505 <command>configure</command> the sources as follows:
1508 ./configure --disable-toggle --disable-editor --disable-force</screen>
1510 This will create an executable with hard-coded security features so that
1511 &my-app; does not allow easy bypassing of blocked sites, or changing the
1512 current configuration via any connected user's web browser.
1515 Finally, all of these features can also be toggled on/off via options in
1516 <application>Privoxy's</application> main <ulink
1517 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1518 means you don't have to recompile anything.
1524 <!-- ~ End section ~ -->
1527 <!-- ~~~~~ New section ~~~~~ -->
1529 <sect1 id="misc"><title>Miscellaneous</title>
1531 <sect2 renderas="sect3" id="slowsme">
1532 <title>How much does Privoxy slow my browsing down? This
1533 has to add extra time to browsing.</title>
1535 How much of an impact depends on many things, including the CPU of the host
1536 system, how aggressive the configuration is, which specific actions are being triggered,
1537 the size of the page, the bandwidth of the connection, etc.
1540 Overall, it should not slow you down any in real terms, and may actually help
1541 speed things up since ads, banners and other junk are not typically being
1542 retrieved and displayed. The actual processing time required by
1543 <application>Privoxy</application> itself for each page, is relatively small
1544 in the overall scheme of things, and happens very quickly. This is typically
1545 more than offset by time saved not downloading and rendering ad images and
1546 other junk content (if ad blocking is being used).
1550 <quote>Filtering</quote> content via the <literal><ulink
1551 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1553 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1554 actions may cause a perceived slowdown, since the entire document
1555 needs to be buffered before displaying. And on very large documents,
1556 filtering may have some measurable impact. How much depends on the page size,
1557 the actual definition of the filter(s), etc. See below. Most other actions
1558 have little to no impact on speed.
1561 Also, when filtering is enabled but zlib support isn't available, compression
1562 is often disabled (see <ulink
1563 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1564 This can have an impact on speed as well, although it's probably smaller than
1565 you might think. Again, the page size, etc. will determine how much of an impact.
1571 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1572 delays in page requests. What's wrong?</title>
1574 If you use any <literal><ulink
1575 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1576 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1577 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1578 action, the entire document must be loaded into memory in order for the filtering
1579 mechanism to work, and nothing is sent to the browser during this time.
1582 The loading time typically does not really change much in real numbers, but
1583 the feeling is different, because most browsers are able to start rendering
1584 incomplete content, giving the user a feeling of "it works". This effect is
1585 more noticeable on slower dialup connections. Extremely large documents
1586 may have some impact on the time to load the page where there is filtering
1587 being done. But overall, the difference should be very minimal. If there is a
1588 big impact, then probably some other situation is contributing (like
1589 anti-virus software).
1592 Filtering is automatically disabled for inappropriate MIME types. But note
1593 that if the web server mis-reports the MIME type, then content that should
1594 not be filtered, could be. <application>Privoxy</application> only knows how
1595 to differentiate filterable content because of the MIME type as reported by
1596 the server, or because of some configuration setting that enables/disables
1601 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1602 "http://p.p/"?</title>
1604 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1605 address of <application>Privoxy</application>'s built-in user interface, and
1606 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1609 Since <application>Privoxy</application> sits between your web browser and the Internet,
1610 it can simply intercept requests for these addresses and answer them with its built-in
1611 <quote>web server</quote>.
1614 This also makes for a good test for your browser configuration: If entering the
1615 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1616 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1617 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1618 your browser didn't use <application>Privoxy</application> for the request,
1619 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1620 web site at config.privoxy.org.
1623 Note that config.privoxy.org resolves to a public IP address.
1624 If you use config.privoxy.org as ping or traceroute target you will
1625 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1626 If you want to ping the system Privoxy runs on,
1627 you should use its IP address or local DNS name (if it has got one).
1633 out of date 09/02/06 HB
1634 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1636 No. The patterns for blocking now reside (among other things) in the <ulink
1637 url="../user-manual/actions-file.html">actions files</ulink>, which are
1638 actively maintained instead. See next question ...
1642 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1645 Please see the <link linkend="contact">Contact section</link> for
1646 various ways to interact with the developers.
1651 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1652 they be included in future updates?</title>
1654 Whether such submissions are eventually included in the
1655 <filename>default.action</filename> configuration file depends on how
1656 significant the issue is. We of course want to address any potential
1657 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1658 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1659 has a good chance of being a candidate. But at the other end of the spectrum
1660 are any number of smaller, low-profile sites such as for local clubs or
1661 schools. Since their reach and impact are much less, they are best handled by
1662 inclusion in the user's <filename>user.action</filename>, and thus would be
1663 unlikely to be included.
1669 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1672 Rest assured that it has been read and considered. Why it is not answered,
1673 could be for various reasons, including no one has a good answer for it, no
1674 one has had time to yet investigate it thoroughly, it has been reported
1675 numerous times already, or because not enough information was provided to help
1676 us help you. Your efforts are not wasted, and we do appreciate them.
1682 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1684 If you run both the browser and &my-app; locally, you cannot hide your IP
1685 address with <application>Privoxy</application> or ultimately any other
1686 software alone. The server needs to know your IP address so that it knows
1687 where to send the responses back.
1690 There are many publicly usable "anonymous" proxies out there, which
1691 provide a further level of indirection between you and the web server.
1694 However, these proxies are called "anonymous" because you don't need
1695 to authenticate, not because they would offer any real anonymity.
1696 Most of them will log your IP address and make it available to the
1697 authorities in case you violate the law of the country they run in. In fact
1698 you can't even rule out that some of them only exist to *collect* information
1699 on (those suspicious) people with a more than average preference for privacy.
1702 If you want to hide your IP address from most adversaries,
1703 you should consider chaining <application>Privoxy</application>
1704 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1705 The configuration details can be found in
1706 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1707 with <application>Tor</application> section</ulink>
1712 <sect2 renderas="sect3" id="anonforsure">
1713 <title>Can Privoxy guarantee I am anonymous?</title>
1715 No. Your chances of remaining anonymous are improved, but unless you
1716 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1717 or a similar proxy and know what you're doing when it comes to configuring
1718 the rest of your system, you should assume that everything you do
1719 on the Web can be traced back to you.
1722 <application>Privoxy</application> can remove various information about you,
1723 and allows <emphasis>you</emphasis> more freedom to decide which sites
1724 you can trust, and what details you want to reveal. But it neither
1725 hides your IP address, nor can it guarantee that the rest of the system
1726 behaves correctly. There are several possibilities how a web sites can find
1727 out who you are, even if you are using a strict <application>Privoxy</application>
1728 configuration and chained it with <application>Tor</application>.
1731 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1732 by an insecure browser configuration, therefore you should use a browser that can
1733 be configured to only execute code from trusted sites, and be careful which sites you trust.
1734 For example there is no point in having <application>Privoxy</application>
1735 modify the User-Agent header, if websites can get all the information they want
1736 through JavaScript, ActiveX, Flash, Java etc.
1739 A few browsers disclose the user's email address in certain situations, such
1740 as when transferring a file by FTP. <application>Privoxy</application>
1741 does not filter FTP. If you need this feature, or are concerned about the
1742 mail handler of your browser disclosing your email address, you might
1743 consider products such as <application>NSClean</application>.
1746 Browsers available only as binaries could use non-standard headers to give
1747 out any information they can have access to: see the manufacturer's license
1748 agreement. It's impossible to anticipate and prevent every breach of privacy
1749 that might occur. The professionally paranoid prefer browsers available as
1750 source code, because anticipating their behavior is easier. Trust the source,
1756 <sect2 renderas="sect3" id="proxytest">
1757 <title>A test site says I am not using a Proxy.</title>
1759 Good! Actually, they are probably testing for some other kinds of proxies.
1760 Hiding yourself completely would require additional steps.
1764 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1765 together with Tor?</title>
1767 Before you configure <application>Privoxy</application> to use
1768 <ulink url="https://www.torproject.org/">Tor</ulink>,
1769 please follow the <citetitle>User Manual</citetitle> chapters
1770 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1771 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1772 <application>Privoxy</application> itself is setup correctly.
1775 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1776 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1777 and make sure <application>Tor</application>'s logfile says that
1778 <quote>Tor has successfully opened a circuit</quote> and it
1779 <quote>looks like client functionality is working</quote>.
1782 If either <application>Tor</application> or <application>Privoxy</application>
1783 isn't working, their combination most likely will neither. Testing them on their
1784 own will also help you to direct problem reports to the right audience.
1785 If <application>Privoxy</application> isn't working, don't bother the
1786 <application>Tor</application> developers. If <application>Tor</application>
1787 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1790 If you verified that <application>Privoxy</application> and <application>Tor</application>
1791 are working, it is time to connect them. As far as <application>Privoxy</application>
1792 is concerned, <application>Tor</application> is just another proxy that can be reached
1793 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1794 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1795 requests are done through <application>Tor</application> and thus invisible to your
1796 local network. Using socks4a would work too, but with socks5 you get more precise error
1801 <application>Privoxy's</application>
1802 <ulink url="../user-manual/config.html">main configuration file</ulink>
1803 is already prepared for <application>Tor</application>, if you are using a
1804 default <application>Tor</application> configuration and run it on the same
1805 system as &my-app;, you just have to edit the
1806 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1807 and uncomment the line:
1810 # forward-socks5t / 127.0.0.1:9050 .
1813 Note that if you got Tor through one of the bundles, you may
1814 have to change the port from 9050 to 9150 (or even another one).
1815 For details, please check the documentation on the
1816 <ulink url="https://torproject.org/">Tor website</ulink>.
1820 This is enough to reach the Internet, but additionally you might want to
1821 uncomment the following forward rules, to make sure your local network is still
1822 reachable through Privoxy:
1825 # forward 192.168.*.*/ .
1826 # forward 10.*.*.*/ .
1827 # forward 127.*.*.*/ .
1830 Unencrypted connections to systems in these address ranges will
1831 be as (un)secure as the local network is, but the alternative is
1832 that your browser can't reach the network at all. Then again,
1833 that may actually be desired and if you don't know for sure
1834 that your browser has to be able to reach the local network,
1835 there's no reason to allow it.
1838 If you want your browser to be able to reach servers in your local
1839 network by using their names, you will need additional exceptions
1840 that look like this:
1843 # forward localhost/ .
1846 Save the modified configuration file and open
1847 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1848 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1849 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1851 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1852 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1855 Afterward, please take the time to at least skim through the rest
1856 of <application>Tor's</application> documentation. Make sure you understand
1857 what <application>Tor</application> does, why it is no replacement for
1858 application level security, and why you probably don't want to
1859 use it for unencrypted logins.
1863 <sect2 renderas="sect3" id="sitebreak">
1864 <title>Might some things break because header information or
1865 content is being altered?</title>
1868 Definitely. It is common for sites to use browser type, browser version,
1869 HTTP header content, and various other techniques in order to dynamically
1870 decide what to display and how to display it. What you see, and what I see,
1871 might be very different. There are many, many ways that this can be handled,
1872 so having hard and fast rules, is tricky.
1876 The <quote>User-Agent</quote> is sometimes used in this way to identify
1877 the browser, and adjust content accordingly.
1881 Also, different browsers use different encodings of non-English
1882 characters, certain web servers convert pages on-the-fly according to the
1883 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1884 operating system or browser manufacturer causes some sites in these languages
1885 to be garbled; Surfers to Eastern European sites should change it to
1886 something closer. And then some page access counters work by looking at the
1887 <quote>Referer</quote> header; they may fail or break if unavailable. The
1888 weather maps of Intellicast have been blocked by their server when no
1889 <quote>Referer</quote> or cookie is provided, is another example. (But you
1890 can forge both headers without giving information away). There are
1891 many other ways things can go wrong when trying to fool a web server. The
1892 results of which could inadvertently cause pages to load incorrectly,
1893 partially, or even not at all. And there may be no obvious clues as to just
1894 what went wrong, or why. Nowhere will there be a message that says
1895 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1900 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1905 If you have problems with a site, you will have to adjust your configuration
1906 accordingly. Cookies are probably the most likely adjustment that may
1907 be required, but by no means the only one.
1913 <sect2 renderas="sect3" id="caching">
1914 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1915 speed up web browsing?</title>
1917 No, it does not have this ability at all. You want something like
1918 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1919 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1920 And, yes, before you ask, <application>Privoxy</application> can co-exist
1921 with other kinds of proxies like <application>Squid</application>.
1922 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1923 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1924 manual</ulink> for details.
1928 <sect2 renderas="sect3" id="firewall">
1929 <title>What about as a firewall? Can Privoxy protect me?</title>
1931 Not in the way you mean, or in the way some firewall vendors claim they can.
1932 <application>Privoxy</application> can help protect your privacy, but can't
1933 protect your system from intrusion attempts. It is, of course, perfectly possible
1934 to use <emphasis>both</emphasis>.
1938 <sect2 renderas="sect3" id="wasted">
1939 <title>I have large empty spaces / a checkerboard pattern now where
1940 ads used to be. Why?</title>
1942 It is technically possible to eliminate banners and ads in a way that frees
1943 their allocated page space. This could easily be done by blocking with
1944 <application>Privoxy's</application> filters,
1945 and eliminating the <emphasis>entire</emphasis> image references from the
1949 But, this would consume considerably more CPU resources (IOW, slow things
1950 down), would likely destroy the layout of some web pages which rely on the
1951 banners utilizing a certain amount of page space, and might fail in other
1952 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1953 Also, making ads and banners disappear without any trace complicates
1954 troubleshooting, and would sooner or later be problematic.
1957 The better alternative is to instead let them stay, and block the resulting
1958 requests for the banners themselves as is now the case. This leaves either
1959 empty space, or the familiar checkerboard pattern.
1962 So the developers won't support this in the default configuration, but you
1963 can of course define appropriate filters yourself to achieve this.
1967 <sect2 renderas="sect3" id="ssl">
1968 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1971 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1972 <application>Privoxy</application> will impersonate the destination
1973 server and can thus filter encrypted requests and responses as well.
1977 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1978 secure HTTP connections are encrypted SSL sessions between your
1979 browser and the secure site, and there is little
1980 that <application>Privoxy</application> can do but hand the raw
1981 gibberish data though from one end to the other unprocessed.
1984 The only exception to this is blocking by host patterns, as the client needs
1985 to tell <application>Privoxy</application> the name of the remote server,
1986 so that <application>Privoxy</application> can establish the connection.
1987 If that name matches a host-only pattern, the connection will be blocked.
1990 As far as ad blocking is concerned, this is less of a restriction than it may
1991 seem, since ad sources are often identifiable by the host name, and often
1992 the banners to be placed in an encrypted page come unencrypted nonetheless
1993 for efficiency reasons, which exposes them to the full power of
1994 <application>Privoxy</application>'s ad blocking.
1997 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
1998 JS page content, see <literal><ulink
1999 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2000 in an SSL transaction will be impossible to block under these conditions.
2001 Fortunately, this does not seem to be a very common scenario since most
2002 cookies come by traditional means.
2007 <sect2 renderas="sect3" id="http2">
2008 <title>Does Privoxy support HTTP/2?</title>
2010 Privoxy currently doesn't parse HTTP/2 but applications
2011 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2012 to allow CONNECT requests (default) which are also used
2016 Adding HTTP/2 support is on the
2017 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2018 list but currently nobody is known to work on it.
2022 <sect2 renderas="sect3" id="secure">
2023 <title>Privoxy runs as a <quote>server</quote>. How
2024 secure is it? Do I need to take any special precautions?</title>
2026 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2027 user, which is how we recommend it be run. Also, by default
2028 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2032 The server aspect of <application>Privoxy</application> is not itself directly
2033 exposed to the Internet in this configuration. If you want to have
2034 <application>Privoxy</application> serve as a LAN proxy, this will have to
2035 be opened up to allow for LAN requests. In this case, we'd recommend
2036 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2037 <application>Privoxy</application> configuration file and check all <ulink
2038 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2039 options</ulink>. All LAN hosts can then use this as their proxy address
2040 in the browser proxy configuration, but <application>Privoxy</application>
2041 will not listen on any external interfaces. ACLs can be defined in addition,
2042 and using a firewall is always good too. Better safe than sorry.
2047 <sect2 renderas="sect3" id="turnoff">
2048 <title>Can I temporarily disable Privoxy?</title>
2050 &my-app; doesn't have a transparent proxy mode,
2051 but you can toggle off blocking and content filtering.
2054 The easiest way to do that is to point your browser
2055 to the remote toggle URL: <ulink
2056 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2059 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2060 of the <citetitle>User Manual</citetitle> for an easy way to access this
2061 feature. Note that this is a feature that may need to be enabled in the main
2062 <filename>config</filename> file.
2067 <sect2 renderas="sect3" id="reallyoff">
2068 <title>When <quote>disabled</quote> is Privoxy totally
2069 out of the picture?</title>
2071 No, this just means all optional filtering and actions are disabled.
2072 <application>Privoxy</application> is still acting as a proxy, but just
2073 doing less of the things that <application>Privoxy</application> would
2074 normally be expected to do. It is still a <quote>middle-man</quote> in
2075 the interaction between your browser and web sites. See below to bypass
2080 <sect2 renderas="sect3" id="turnoff2">
2081 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2083 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2084 configuration issue, not a &my-app; issue. Modern browsers typically do have
2085 settings for not proxying certain sites. Check your browser's help files.
2090 <sect2 renderas="sect3" id="crunch">
2091 <title>My logs show Privoxy <quote>crunches</quote>
2092 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2094 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2095 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2096 banners, but <application>Privoxy</application> uses the same mechanism for
2097 trapping requests for its own internal pages. For instance, a request for
2098 <application>Privoxy's</application> configuration page at: <ulink
2099 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2100 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2101 configuration is returned to the browser, and the log consequently will show
2102 a <quote>crunch</quote>.
2105 Since version 3.0.7, Privoxy will also log the crunch reason.
2106 If you are using an older version you might want to upgrade.
2110 <sect2 renderas="sect3" id="downloads">
2111 <title>Can Privoxy affect files that I download
2112 from a webserver? FTP server?</title>
2114 From the webserver's perspective, there is no difference between
2115 viewing a document (i.e. a page), and downloading a file. The same is true of
2116 <application>Privoxy</application>. If there is a match for a <literal><ulink
2117 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2118 it will still be blocked, and of course this is obvious.
2121 Filtering is potentially more of a concern since the results are not always
2122 so obvious, and the effects of filtering are there whether the file is simply
2123 viewed, or downloaded. And potentially whether the content is some obnoxious
2124 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2125 one of these presumably is <quote>bad</quote> content that we don't want, and
2126 the other is <quote>good</quote> content that we do want.
2127 <application>Privoxy</application> is blind to the differences, and can only
2128 distinguish <quote>good from bad</quote> by the configuration parameters
2129 <emphasis>we</emphasis> give it.
2132 <application>Privoxy</application> knows the differences in files according
2133 to the <quote>Content Type</quote> as reported by the webserver. If this is
2134 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2135 then <application>Privoxy</application> knows to ignore these where
2136 appropriate. <application>Privoxy</application> potentially can filter HTML
2137 as well as plain text documents, subject to configuration parameters of
2138 course. Also, documents that are of an unknown type (generally assumed to be
2139 <quote>text/plain</quote>) can be filtered, as will those that might be
2140 incorrectly reported by the webserver. If such a file is a downloaded file
2141 that is intended to be saved to disk, then any content that might have been
2142 altered by filtering, will be saved too, for these (probably rare) cases.
2145 Note that versions later than 3.0.2 do NOT filter document types reported as
2146 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2147 did filter this document type.
2150 In short, filtering is <quote>ON</quote> if a) the content type as reported
2151 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2152 allows it (or at least does not disallow it). That's it. There is no magic
2153 cookie anywhere to say this is <quote>good</quote> and this is
2154 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2157 If you download text files, you probably do not want these to be filtered,
2158 particularly if the content is source code, or other critical content. Source
2159 code sometimes might be mistaken for Javascript (i.e. the kind that might
2160 open a pop-up window). It is recommended to turn off filtering for download
2161 sites (particularly if the content may be plain text files and you are using
2162 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2163 also, for any site or page where making <emphasis>any</emphasis> changes at
2164 all to the content is to be avoided.
2167 <application>Privoxy</application> does not do FTP at all, only HTTP
2168 and HTTPS (SSL) protocols.
2172 <sect2 renderas="sect3" id="downloads2">
2173 <title>I just downloaded a Perl script, and Privoxy
2174 altered it! Yikes, what is wrong!</title>
2180 <sect2 renderas="sect3" id="hostsfile">
2181 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2183 One time-tested technique to defeat common ads is to trick the local DNS
2184 system by giving a phony IP address for the ad generator in the local
2185 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2186 <literal>localhost</literal>. This effectively blocks the ad.
2189 There is no reason to use this technique in conjunction with
2190 <application>Privoxy</application>. <application>Privoxy</application>
2191 does essentially the same thing, much more elegantly and with much more
2192 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2193 duplicates effort, but may get in the way and seriously slow down your system.
2194 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2195 your hosts list is neglected by <application>Privoxy's </application>
2196 configuration, consider adding your list to your <filename>user.action</filename> file:
2202 ads.galore.example.com
2203 etc.example.com</screen>
2206 <sect2 renderas="sect3" id="seealso">
2207 <title>Where can I find more information about Privoxy
2208 and related issues?</title>
2209 <!-- Include seealso.sgml boilerplate: -->
2211 <!-- end boilerplate -->
2216 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2222 <sect2 renderas="sect3" id="microsuck">
2223 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2224 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2227 We're not. The text substitutions that you are seeing are disabled
2228 in the default configuration as shipped. You have either manually
2229 activated the <quote><literal>fun</literal></quote> filter which
2230 is clearly labeled <quote>Text replacements for subversive browsing
2231 fun!</quote> or you are using an older Privoxy version and have implicitly
2232 activated it by choosing the <quote>Advanced</quote> profile in the
2233 web-based editor. Please upgrade.
2237 <sect2 renderas="sect3" id="valid">
2238 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2241 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2242 whenever there are text substitutions via a &my-app; filter. While this
2243 should always conform to the HTML 4.01 specifications, it has not been
2244 validated against this or any other standard.
2248 <sect2 renderas="sect3" id="surprise-privoxy">
2249 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2252 We didn't. We make Privoxy available for download, but we don't go
2253 around installing it on other people's systems behind their back.
2254 If you discover Privoxy running on your system and are sure you didn't
2255 install it yourself, somebody else did. You may not even be running
2256 the real Privoxy, but maybe something else that only pretends to be
2257 Privoxy, or maybe something that is based on the real Privoxy,
2258 but has been modified.
2261 Lately there have been reports of problems with some kind of
2262 "parental control" software based on Privoxy that came preinstalled on
2263 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2264 The problems described are inconsistent with the behaviour of official
2265 Privoxy versions, which suggests that the preinstalled software may
2266 contain vendor modifications that we don't know about and thus can't debug.
2269 Privoxy's <link linkend="copyright">license</link> allows vendor
2270 modifications, but the vendor has to comply with the license,
2271 which involves informing the user about the changes and to make
2272 the changes available under the same license as Privoxy itself.
2275 If you are having trouble with a modified Privoxy version,
2276 please try to talk to whoever made the modifications before
2277 reporting the problem to us. Please also try to convince
2278 whoever made the modifications to talk to us. If you think
2279 somebody gave you a modified Privoxy version without complying
2280 to the license, please let us know.
2288 <!-- ~~~~~ New section ~~~~~ -->
2290 <sect1 id="trouble">
2291 <title>Troubleshooting</title>
2293 <sect2 renderas="sect3" id="refused">
2294 <title>I cannot connect to any websites. Or, I am getting
2295 <quote>connection refused</quote> message with every web page. Why?</title>
2297 There are several possibilities:
2301 <application>Privoxy</application> is not running. Solution: verify
2302 that &my-app; is installed correctly, has not crashed, and is indeed running.
2303 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2305 <listitem><para>Or your browser is configured for a different port than what
2306 <application>Privoxy</application> is using. Solution: verify that &my-app;
2307 and your browser are set to the same port (<literal>listen-address</literal>).
2309 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2310 problem with a host in the forwarding chain. Solution: temporarily alter your
2311 configuration and take the forwarders out of the equation.
2314 Or you have a firewall that is interfering and blocking you. Solution:
2315 try disabling or removing the firewall as a simple test.
2321 <!-- ~~~~~ New section ~~~~~ -->
2322 <sect2 renderas="sect3" id="error503">
2323 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2325 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2326 been reported to cause this symptom -- even if not running! The solution is
2327 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2328 something better behaved in its place. Other personal firewall type products
2329 may cause similar type problems if not configured correctly.
2333 <sect2 renderas="sect3" id="flushit">
2334 <title>I just added a new rule, but the steenkin ad is
2335 still getting through. How?</title>
2337 If the ad had been displayed before you added its URL, it will probably be
2338 held in the browser's cache for some time, so it will be displayed without
2339 the need for any request to the server, and <application>Privoxy</application>
2340 will not be involved. Flush the browser's caches, and then try again.
2344 If this doesn't help, you probably have an error in the rule you
2345 applied. Try pasting the full URL of the offending ad into <ulink
2346 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2347 and see if it really matches your new rule. Blocking ads is like blocking
2348 spam: a lot of tinkering is required to stay ahead of the game. And
2349 remember you need to block the URL of the ad in question, which may be
2350 entirely different from the site URL itself. Most ads are hosted on different
2351 servers than the main site itself. If you right-click on the ad, you should
2352 be able to get all the relevant information you need. Alternately, you can
2353 find the correct URL by looking at <application>Privoxy's</application> logs
2354 (you may need to enable logging in the main config file if its disabled).
2357 Below is a slightly modified real-life log snippet that originates with one
2358 requested URL: <literal>www.example.com</literal> (name of site was changed
2359 for this example, the number of requests is real). You can see in this the
2360 complexity of what goes into making up this one <quote>page</quote>. There
2361 are eight different domains involved here, with thirty two separate URLs
2362 requested in all, making up all manner of images, Shockwave Flash,
2363 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2364 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2365 Many of the more questionable looking requests, are going to outside domains
2366 that seem to be identifying themselves with suspicious looking names, making
2367 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2368 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2372 Request: www.example.com/
2373 Request: www.example.com/favicon.ico
2374 Request: img.example.com/main.css
2375 Request: img.example.com/sr.js
2376 Request: example.betamarker.com/example.html
2377 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2378 Request: img.example.com/pb.png
2379 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2380 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2381 Request: img.example.com/p.gif
2382 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2383 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2384 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2385 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2386 Request: www.adtrak.net/adx.js crunch! (Blocked)
2387 Request: img.example.com/hbg.gif
2388 Request: img.example.com/example.jpg
2389 Request: img.example.com/mt.png
2390 Request: img.example.com/mm.png
2391 Request: img.example.com/mb.png
2392 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2393 Request: www.example.com/tracker.js
2394 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2395 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2396 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2397 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2398 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2399 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2400 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2401 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2402 Request: 66.70.21.80/img/pixel.gif
2403 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2404 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2408 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2409 behave perfectly <quote>normal</quote> (minus some ads, of course).
2414 <sect2 renderas="sect3" id="badsite">
2415 <title>One of my favorite sites does not work with Privoxy.
2416 What can I do?</title>
2419 First verify that it is indeed a <application>Privoxy</application> problem,
2420 by toggling off <application>Privoxy</application> through <ulink
2421 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2422 (the toggle feature may need to be enabled in the main
2423 <filename>config</filename>),
2424 and then shift-reloading the problem page (i.e. holding down the shift key
2425 while clicking reload. Alternatively, flush your browser's disk and memory
2430 If the problem went away, we know we have a configuration related problem.
2432 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2433 and paste the full URL of the page in question into the prompt. See which
2434 actions are being applied to the URL, and which matches in which actions
2435 files are responsible for that. It might be helpful also to look at your logs
2436 for this site too, to see what else might be happening (note: logging may need
2437 to be enabled in the main config file). Many sites are
2438 complex and require a number of related pages to help present their content.
2439 Look at what else might be used by the page in question, and what of that
2440 might be <emphasis>required</emphasis>.
2441 Now, armed with this information, go to
2443 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2444 and select the appropriate actions files for editing. </para>
2446 You can now either look for a section which disables the actions that
2447 you suspect to cause the problem and add a pattern for your site there,
2448 or make up a completely new section for your site. In any case, the recommended
2449 way is to disable only the prime suspect, reload the problem page, and only
2450 if the problem persists, disable more and more actions until you have
2451 identified the culprit. You may or may not want to turn the other actions
2452 on again. Remember to flush your browser's caches in between any such changes!
2455 Alternately, if you are comfortable with a text editor, you can accomplish
2456 the same thing by editing the appropriate actions file. Probably the easiest
2457 way to deal with such problems when editing by hand is to add your
2458 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2459 which is an alias that turns off most <quote>dangerous</quote>
2460 actions, but is also likely to turn off more actions then needed, and thus lower
2461 your privacy and protection more than necessary,
2464 Troubleshooting actions is discussed in more detail in the <ulink
2465 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2466 Troubleshooting: the Anatomy of an Action</ulink>.
2467 There is also an <ulink
2468 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2469 with general configuration information and examples.
2472 As a last resort, you can always see if your browser has a setting that will
2473 bypass the proxy setting for selective sites. Modern browsers can do this.
2479 <!-- ~~~~~ New section ~~~~~ -->
2480 <sect2 id="dun" renderas="sect3">
2481 <title>After installing Privoxy, I have to log in
2482 every time I start IE. What gives?</title>
2485 This is a quirk that affects the installation of
2486 <application>Privoxy</application>, in conjunction with Internet Explorer and
2487 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2488 appear to be corrupted or invalid DUN settings, or passwords.
2492 When setting up an NT based Windows system with
2493 <application>Privoxy</application> you may find that things do not seem to be
2494 doing what you expect. When you set your system up you will probably have set
2495 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2496 logged in with administrator privileges. You will probably have made this DUN
2497 connection available to other accounts that you may have set-up on your
2498 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2499 configured for the kids.
2503 When setting up <application>Privoxy</application> in this environment you
2504 will have to alter the proxy set-up of Internet Explorer (IE) for the
2505 specific DUN connection on which you wish to use
2506 <application>Privoxy</application>. When you do this the ICS DUN set-up
2507 becomes user specific. In this instance you will see no difference if you
2508 change the DUN connection under the account used to set-up the connection.
2509 However when you do this from another user you will notice that the DUN
2510 connection changes to make available to "Me only". You will also find that
2511 you have to store the password under each different user!
2515 The reason for this is that each user's set-up for IE is user specific. Each
2516 set-up DUN connection and each LAN connection in IE store the settings for
2517 each user individually. As such this enforces individual configurations
2518 rather than common ones. Hence the first time you use a DUN connection after
2519 re-booting your system it may not perform as you expect, and prompt you for
2520 the password. Just set and save the password again and all should be OK.
2524 [Thanks to Ray Griffith for this submission.]
2529 <!-- ~~~~~ New section ~~~~~ -->
2530 <sect2 id="ftp" renderas="sect3">
2531 <title>I cannot connect to any FTP sites. Privoxy
2532 is blocking me.</title>
2534 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2535 so do not configure your browser to use <application>Privoxy</application>
2536 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2537 or HTTPS (SSL)</emphasis>.
2540 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2541 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2542 an FTP connection, and not a HTTP connection. So while your browser may
2543 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2547 To complicate matters, some systems may have a generic <quote>proxy</quote>
2548 setting, which will enable various protocols, including
2549 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2550 accidentally enable FTP proxying in these cases. And of course, if this
2551 happens, <application>Privoxy</application> will indeed cause problems since
2552 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2553 message if a FTP connection is attempted.]]> Just disable the FTP setting
2554 and all will be well again.
2557 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2558 There just is not much reason, and the work to make this happen is more than
2563 <!-- ~~~~~ New section ~~~~~ -->
2564 <sect2 id="macosxie" renderas="sect3">
2565 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2566 Privoxy as the HTTP proxy.</title>
2568 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2569 network settings. In order to change the HTTP proxy, open System
2570 Preferences, and click on the Network icon. In the settings pane that
2571 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2572 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2573 Enter <literal>8118</literal> in the Port field. The next time you start
2574 IE, it should reflect these values.
2578 <!-- ~~~~~ New section ~~~~~ -->
2579 <sect2 renderas="sect3" id="macosxuninstall">
2580 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2581 uninstall it. Now the finder tells me I don't have sufficient privileges to
2582 empty the trash.</title>
2584 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2587 Just dragging the <application>Privoxy</application> folder to the trash is
2588 not enough to delete it. <application>Privoxy</application> supplies an
2589 <application>uninstall.command</application> file that takes care of
2590 these details. Open the trash, drag the <application>uninstall.command</application>
2591 file out of the trash and double-click on it. You will be prompted for
2592 confirmation and the administration password.
2595 The trash may still appear full after this command; emptying the trash
2596 from the desktop should make it appear empty again.
2600 <!-- ~~~~~ New section ~~~~~ -->
2601 <sect2 renderas="sect3" id="macosximages">
2602 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2603 experience random delays in page loading. I'm using
2604 <literal>localhost</literal> as my browser's proxy setting.</title>
2606 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2607 understand the issue yet. In any case, changing the proxy setting to
2608 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2609 works around the problem.
2613 <!-- ~~~~~ New section ~~~~~ -->
2614 <sect2 renderas="sect3" id="macosxaccountdeletion">
2615 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2618 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2619 X deletes all user accounts that are either not part of OS X itself or are
2620 not interactive user accounts (ones you log in with). Since, for the sake of
2621 security, &my-app; runs as a non-privileged user that is created by its
2622 installer (_privoxy), it can no longer start up once that account gets deleted.
2623 The solution is to perform a complete uninstall using the supplied
2624 <application>uninstall.command</application> script (either back up your
2625 configuration files or select to not have the uninstaller remove them when it
2626 prompts you) and then reinstall &my-app; using the installer package and merge
2627 in your configuration.
2631 <sect2 renderas="sect3" id="nohostname">
2632 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2635 <application>Privoxy</application> tries to get the hostname of the system
2636 its running on from the IP address of the system interface it is bound to
2637 (from the <filename>config</filename> file
2638 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2639 this information, <application>Privoxy</application> logs this condition.
2642 Typically, this would be considered a minor system configuration error. It is
2643 not a fatal error to <application>Privoxy</application> however, but may
2644 result in a much slower response from <application>Privoxy</application> on
2645 some platforms due to DNS timeouts.
2648 This can be caused by a problem with the local <filename>hosts</filename>
2649 file. If this file has been changed from the original, try reverting it to
2650 see if that helps. Make sure whatever name(s) are used for the local system,
2651 that they resolve both ways.
2654 You should also be able to work around the problem with the
2655 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2659 <sect2 renderas="sect3" id="inuse">
2660 <title>When I try to launch Privoxy, I get an
2661 error message <quote>port 8118 is already in use</quote> (or similar wording).
2664 Port 8118 is <application>Privoxy's</application> default TCP
2665 <quote>listening</quote> port. Typically this message would mean that there
2666 is already one instance of <application>Privoxy</application> running, and
2667 your system is actually trying to start a second
2668 <application>Privoxy</application> on the same port, which will not work.
2669 (You can have multiple instances but they must be assigned different ports.)
2670 How and why this might happen varies from platform to platform, but you need
2671 to check your installation and start-up procedures.
2675 <sect2 renderas="sect3" id="demoronizer">
2677 Pages with UTF-8 fonts are garbled.
2680 This may be the result of an overly aggressive filter. The filters that
2681 are enabled in the default configuration aren't expected to cause problems
2682 like this. If you enabled the <quote>demoronizer</quote> filter, please
2683 try temporarily disabling it.
2686 If that doesn't help, temporarily disable all filters to see if another
2687 filter could be the culprit. If the problem disappears, enable the filters
2688 one by one, until the problem reappears and the offending filter is found.
2691 Once the problem-causing filter is known, it can be fixed or disabled.
2694 Upgrading <application>Privoxy</application>, or going to the most recent
2695 <filename>default.action</filename> file available from <ulink
2696 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2697 might be worth a try, too.
2701 <sect2 renderas="sect3" id="demoronizer2">
2703 Why are binary files (such as images) corrupted when Privoxy
2707 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2708 filter</link> in conjunction with a web server that is misreporting the content
2709 type. By default binary files are exempted from
2710 <application>Privoxy's</application> filtering
2711 (unless the web server by mistake says the file is something else).
2715 <sect2 renderas="sect3" id="demoronizer3">
2717 What is the <quote>demoronizer</quote> and why is it there?
2720 The original demoronizer was a Perl script that cleaned up HTML pages which
2721 were created with certain Microsoft products. MS has used proprietary extensions
2722 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2723 that are viewed with non-Microsoft products (and are expecting to see a
2724 standard set of fonts). The demoronizer corrected these errors so the pages
2725 displayed correctly. <application>Privoxy</application> borrowed from this
2726 script, introducing a filter based on the original demoronizer, which in turn could
2727 correct these errors on the fly.
2730 But this is only needed in some situations, and will cause serious problems in some
2734 If you are using Microsoft products, you do not need it. If you need to view
2735 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2736 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2739 On the other hand, if you use non-Microsoft products, and you occasionally
2740 notice weird characters on pages, you might want to try it.
2744 <sect2 renderas="sect3" id="windowopen">
2746 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2749 <application>Privoxy</application> is attempting to disable malicious
2750 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2751 in this case, with the <literal>unsolicited-popups</literal>
2752 filter. <application>Privoxy</application> cannot tell very well
2753 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2756 If you see this in HTML source, and the page displays without problems, then
2757 this is good, and likely some pop-up window was disabled. If you see this
2758 where it is causing a problem, such as a downloaded program source code file,
2759 then you should set an exception for this site or page such that the
2760 integrity of the page stays in tact by disabling all filtering.
2764 <sect2 renderas="sect3" id="dnserrors">
2766 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2767 can't Privoxy do this better?
2770 There are potentially several factors here. First of all, the DNS resolution
2771 is done by the underlying operating system -- not
2772 <application>Privoxy</application> itself. <application>Privoxy</application>
2773 merely initiates the process and hands it off, and then later reports
2774 whatever the outcome was and tries to give a coherent message if there seems
2775 to be a problem. In some cases, this might otherwise be mitigated by the
2776 browser itself which might try some work-arounds and alternate approaches (e.g
2777 adding <quote>www.</quote> to the URL).
2780 In other cases, if <application>Privoxy</application> is being chained
2781 with another proxy, this could complicate the issue, and cause undue
2782 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2783 server handles all the DNS. <application>Privoxy</application> would just be
2784 the <quote>messenger</quote> which is reporting whatever problem occurred
2785 downstream, and not the root cause of the error.
2789 In any case, versions newer than 3.0.3 include various improvements to help
2790 <application>Privoxy</application> better handle these cases.
2794 <sect2 renderas="sect3" id="allcpu">
2796 At one site Privoxy just hangs, and starts taking
2797 all CPU. Why is this?
2800 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2801 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2802 are in the raw HTML source of the page, and the browser just ignores them. But the
2803 pattern matching in <application>Privoxy's</application> page filtering
2804 mechanism is trying to match against absurdly long strings and this becomes
2805 very CPU-intensive, taking a long, long time to complete.
2808 Until a better solution comes along, disable filtering on these pages,
2809 particularly the <literal>js-annoyances</literal> and
2810 <literal>unsolicited-popups</literal> filters. If you run into this problem
2811 with a recent &my-app; version, please send a problem report.
2815 <sect2 renderas="sect3" id="slowcrawl">
2816 <title>I just installed Privoxy, and all my
2817 browsing has slowed to a crawl. What gives? </title>
2819 This should not happen, and for the overwhelming number of users world-wide,
2820 it does not happen. I would suspect some inadvertent interaction of software
2821 components such as anti-virus software, spyware protectors, personal
2822 firewalls or similar components. Try disabling (or uninstalling) these one
2823 at a time and see if that helps. Either way, if you are using a
2824 recent &my-app; version, please report the problem.
2828 <sect2 renderas="sect3" id="preventcomp">
2829 <title>Why do my filters work on some sites but not on others? </title>
2831 It's probably due to compression. It is a common practice for web servers to
2832 send their content <quote>compressed</quote> in order to speed things up, and
2833 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2834 &my-app; can decompress content before filtering, otherwise you may want to enable
2836 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2839 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2844 <sect2 renderas="sect3" id="ssl-warnings">
2845 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2846 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2847 What's going on?</title>
2849 Probably the browser is requesting ads through HTTPS and &my-app;
2850 is blocking the requests. Privoxy's error messages are delivered
2851 unencrypted and while it's obvious for the browser that the HTTPS
2852 request is already blocked by the proxy, some warn about unauthenticated
2856 To work around the problem you can redirect those requests to an invalid
2857 local address instead of blocking them. While the redirects aren't
2858 encrypted either, many browsers don't care. They simply follow the
2859 redirect, fail to reach a server and display an error message instead
2863 To do that, enable logging to figure out which requests get blocked by
2864 &my-app; and add the hosts (no path patterns) to a section like this:
2868 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2873 Additionally you have to configure your browser to contact
2874 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2877 To add a proxy exception in <application>Mozilla Firefox</application>
2878 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2879 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2880 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2886 <sect2 renderas="sect3" id="se-linux">
2887 <title>I get selinux error messages. How can I fix this?</title>
2889 Please report the problem to the creator of your selinux policies.
2892 The problem is that some selinux policy writers aren't familiar
2893 with the application they are trying to <quote>secure</quote> and
2894 thus create policies that make no sense.
2897 In <application>Privoxy's</application> case the problem usually
2898 is that the policy only allows outgoing connections for certain
2899 destination ports (e.g. 80 and 443). While this may cover the
2900 standard ports, websites occasionally use other ports as well.
2901 This isn't a security problem and therefore <application>Privoxy's</application>
2902 default configuration doesn't block these requests.
2905 If you really want to block these ports (and don't be able
2906 to load websites that don't use standard ports), you should
2907 configure Privoxy to block these ports as well, so it doesn't
2908 trigger the selinux warnings.
2913 <sect2 renderas="sect3" id="gentoo-ricers">
2914 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2916 Probably you unintentionally compiled &my-app; without threading support
2917 in which case requests have to be serialized and only one can be served
2921 Check your <quote>USE</quote> flags and make sure they include
2922 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2925 If you compiled &my-app; with threading support (on POSIX-based systems),
2926 the <quote>Conditional #defines</quote> section on <ulink
2927 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2928 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2932 <sect2 renderas="sect3" id="tainted-sockets">
2933 <title>What are tainted sockets and how do I prevent them?</title>
2935 &my-app; marks sockets as tainted when it can't use them to
2936 serve additional requests.
2937 This does not necessarily mean that something went wrong and
2938 information about tainted sockets is only logged if connection
2939 debugging is enabled (debug 2).
2942 For example server sockets that were used for CONNECT requests
2943 (which are used to tunnel https:// requests) are considered tainted
2944 once the client closed its connection to &my-app;.
2945 Technically &my-app; could keep the connection to the server open,
2946 but the server would not accept requests that do not belong to the
2947 previous TLS/SSL session (and the client may even have terminated
2951 Server sockets are also marked tainted when a client requests a
2952 resource, but closes the connection before &my-app; has completely
2953 received (and forwarded) the resource to the client.
2954 In this case the server would (probably) accept additional requests,
2955 but &my-app; could not get the response without completely reading
2956 the leftovers from the previous response.
2959 These are just two examples, there are currently a bit more than
2960 25 scenarios in which a socket is considered tainted.
2963 While sockets can also be marked tainted as a result of a technical
2964 problem that may be worth fixing, the problem will be explicitly
2969 <sect2 renderas="sect3" id="pcre-stack-limit">
2970 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2972 This can happen if your custom filters require more memory than &my-app;
2974 Usually the problem is that the operating system enforces a stack size limit
2975 that isn't sufficient.
2978 Unless the problem occurs with the filters available in the default configuration,
2979 this is not considered a Privoxy bug.
2982 To prevent the crashes you can rewrite your filter to use less resources,
2983 increase the relevant memory limit or recompile pcre to use less stack space.
2984 For details please see the
2985 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
2986 and the documentation of your operating system.
2990 <sect2 renderas="sect3" id="file-permissions">
2991 <title>What to do if editing the config file of privoxy is access denied?</title>
2993 Your userid probably isn't allowed to edit the file.
2994 <!-- show how to check permissions? -->
2995 On Windows you can use the windows equivalent of sudo:
2997 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
3000 or fix the file permissions:
3002 <screen>C:\Privoxy>icacls config.txt
3003 config.txt BUILTIN\Administrators:(I)(F)
3004 NT AUTHORITY\SYSTEM:(I)(F)
3005 BUILTIN\Users:(I)(RX)
3006 NT AUTHORITY\Authenticated Users:(I)(M)
3008 Successfully processed 1 files; Failed processing 0 files
3010 C:\Privoxy>icacls config.txt /grant Lee:F
3011 processed file: config.txt
3012 Successfully processed 1 files; Failed processing 0 files
3014 C:\Privoxy>icacls config.txt
3015 config.txt I3668\Lee:(F)
3016 BUILTIN\Administrators:(I)(F)
3017 NT AUTHORITY\SYSTEM:(I)(F)
3018 BUILTIN\Users:(I)(RX)
3019 NT AUTHORITY\Authenticated Users:(I)(M)
3021 Successfully processed 1 files; Failed processing 0 files
3023 C:\Privoxy></screen>
3026 or try to point-n-click your way through adjusting the file
3027 permissions in windows explorer.
3033 <!-- ~~~~~ New section ~~~~~ -->
3034 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3035 <!-- Include contacting.sgml -->
3037 <!-- end contacting -->
3040 <!-- ~~~~~ New section ~~~~~ -->
3041 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3043 <!-- Include copyright.sgml -->
3049 Portions of this document are <quote>borrowed</quote> from the original
3050 <application>Junkbuster</application> (tm) FAQ, and modified as
3051 appropriate for <application>Privoxy</application>.
3054 <!-- ~~~~~ New section ~~~~~ -->
3055 <sect2><title>License</title>
3056 <!-- Include copyright.sgml: -->
3058 <!-- end copyright -->
3060 <!-- ~ End section ~ -->
3062 <!-- ~~~~~ New section ~~~~~ -->
3063 <sect2><title>History</title>
3064 <!-- Include history.sgml -->
3070 <!-- ~ End section ~ -->
3073 <!-- ~~~~~ New section ~~~~~ -->
3075 <sect1 id="seealso"><title>See also</title>
3077 <!-- Include seealso.sgml -->
3087 This program is free software; you can redistribute it
3088 and/or modify it under the terms of the GNU General
3089 Public License as published by the Free Software
3090 Foundation; either version 2 of the License, or (at
3091 your option) any later version.
3093 This program is distributed in the hope that it will
3094 be useful, but WITHOUT ANY WARRANTY; without even the
3095 implied warranty of MERCHANTABILITY or FITNESS FOR A
3096 PARTICULAR PURPOSE. See the GNU General Public
3097 License for more details.
3099 The GNU General Public License should be included with
3100 this file. If not, you can view it at
3101 http://www.gnu.org/copyleft/gpl.html
3102 or write to the Free Software Foundation, Inc.,
3103 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA