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 "3.0.34">
12 <!entity p-status "UNRELEASED">
13 <!entity % p-not-stable "INCLUDE">
14 <!entity % p-stable "IGNORE">
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) 2001-2021 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; 2001-2021 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="https://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
160 protocols, <ulink url="https://en.wikipedia.org/wiki/Html">HTML</ulink>, and
161 <ulink url="https://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="https://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
172 But there are areas where configuration is done using a
173 <ulink url="https://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="https://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="https://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="https://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.
405 It is free to use, copy, modify or distribute as you wish under the terms of its
407 Please see the <link linkend="copyright">Copyright</link> section for more
408 information on the license and copyright.
411 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
412 That is something that would cost real money ;-) There is no registration either.
417 <sect2 renderas="sect3" id="spyware">
418 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
420 No, at least not reliably enough to trust it. &my-app; is not designed to be
421 a malware removal tool and the default configuration doesn't even try to
422 filter out any malware.
425 &my-app; could help prevent contact from (known) sites that use such
426 tactics with appropriate configuration rules, and thus could conceivably
427 prevent contamination from such sites. However, keeping such a configuration
428 up to date would require a lot of time and effort that would be better spend
429 on keeping your software itself up to date so it doesn't have known
435 <sect2 renderas="sect3" id="otherads">
436 <title>Can I use Privoxy with other ad-blocking software?</title>
438 &my-app; should work fine with other proxies and other software in general.
441 But it is probably not necessary to use &my-app; in conjunction with other
442 ad-blocking products, and this could conceivably cause undesirable results.
443 It might be better to choose one software or the other and work a little to
444 tweak its configuration to your liking.
447 Note that this is an advice specific to ad blocking.
451 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
453 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
455 Well, we <emphasis>always</emphasis> need help. There is something for
456 everybody who wants to help us. We welcome new developers, packagers,
457 testers, documentation writers or really anyone with a desire to help in
458 any way. You <emphasis>DO NOT</emphasis> need to be a
459 <quote>programmer</quote>. There are many other tasks available. In fact,
460 the programmers often can't spend as much time programming because of some
461 of the other, more mundane things that need to be done, like checking the
462 Tracker feedback sections or responding to user questions on the mailing
466 So first thing, subscribe to the <ulink
467 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
468 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
469 Developers</ulink> mailing list, join the discussion, help out other users, provide general
470 feedback or report problems you noticed.
473 If you intend to help out with the trackers, you also might want to <ulink
474 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
475 so we don't confuse you with the other name-less users.
478 We also have a <ulink
479 url="../developer-manual/index.html">Developer's Manual</ulink>.
480 While it is partly out of date, it's still worth reading.
483 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
484 may be of interest to you as well.
485 Please let us know if you want to work on one of the items listed.
489 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
491 Donations are welcome. Our
492 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
493 is rather long and being able to pay one (or more) developers to work on Privoxy
494 would make a huge difference, even if it was only for a couple of weeks. Donations may
495 also be used for Privoxy-related travel expenses (for example to attend conferences),
496 for hardware used for Privoxy development and for hosting expenses etc.
500 <application>Privoxy</application> is an associated
501 project of <ulink url="https://www.spi-inc.org/">Software
502 in the Public Interest (SPI)</ulink>, which allows us to receive
503 tax-deductible donations in the United States.
504 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
505 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
506 For details, please have a look at
507 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
511 If you have any questions regarding donations please mail to either the
512 public user mailing list or, if it's a private matter, to
513 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
518 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
520 We are currently offering the following sponsor levels as an experiment:
524 <term>Gold (12000 USD/year)</term>
527 Logo or text link shown at the bottom of the
528 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
529 Logo, link and self description on the
530 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
535 <term>Silver (1200 USD/year)</term>
538 Logo or text link shown at the bottom of the
539 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
540 Logo, link and self description on the
541 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
546 <term>Bronze (600 USD/year)</term>
549 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
555 The logo sizes depend on the sponsor level. Logos are served from
556 our server, no requests are made to the sponsor website unless
557 the links are being used. Note that Privoxy comes with a
558 <ulink url="https://www.privoxy.org/user-manual/actions-file.html#HIDE-REFERRER">hide-referrer</ulink>
559 action so Privoxy users following links to sponsor websites
560 may not necessarily send requests with a Referer header set.
563 Link targets are without path (<quote>https://www.example.org/</quote>
564 not <quote>https://www.example.org/seo/keyword/spam/</quote>).
567 The details may change over time but changes will only affect new sponsors
568 (or existing sponsors that explicitly agreed to the changes).
571 Thanks to <ulink url="https://www.spi-inc.org/">Software in the Public Interest (SPI)</ulink>
572 <application>Privoxy</application> sponsors can get a proper invoice.
575 If you want to become a sponsor, please contact
576 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>
577 and include the link target in the mail.
578 New sponsors are only accepted if no
579 <ulink url="../user-manual/copyright.html#AUTHORS">Privoxy team</ulink>
588 <!-- ~~~~~ New section ~~~~~ -->
590 <sect1 id="installation"><title>Installation</title>
592 <sect2 renderas="sect3" id="whichbrowsers">
593 <title>Which browsers are supported by Privoxy?</title>
595 Any browser that can be configured to use a proxy, which
596 should be virtually all browsers, including
597 <application>Firefox</application>, <application>Internet
598 Explorer</application>, <application>Opera</application>, and
599 <application>Safari</application> among others.
600 Direct browser support is not an absolute requirement since
601 <application>Privoxy</application> runs as a separate application and talks
602 to the browser in the standardized HTTP protocol, just like a web server
607 <sect2 renderas="sect3" id="whichos">
608 <title>Which operating systems are supported?</title>
610 Include supported.sgml here:
615 <sect2 renderas="sect3" id="email-client">
616 <title>Can I use Privoxy with my email client?</title>
618 As long as there is some way to set a HTTP proxy for the client, then yes,
619 any application can be used, whether it is strictly speaking a
620 <quote>browser</quote> or not. Though this may not be the best approach for
621 dealing with some of the common abuses of HTML in email. See <link
622 linkend="outlook">How can I configure <application>Privoxy</application>
623 with <application>Outlook</application>?</link> below for more on
627 Be aware that HTML email presents a number of unique security and privacy
628 related issues, that can require advanced skills to overcome. The developers
629 recommend using email clients that can be configured to convert HTML to plain
630 text for these reasons.
634 <!-- Nobody is going to still be doing this!
635 <sect2 renderas="sect3" id="newinstall"><title>Can I install
636 Privoxy over Junkbuster?</title>
638 We recommend you un-install <application>Junkbuster</application>
639 first to minimize conflicts and confusion. You may want to
640 save your old configuration files for future reference. The configuration
641 files and syntax have substantially changed, so you will need to manually
642 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
643 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
644 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
648 Note: Some installers may automatically un-install
649 <application>Junkbuster</application>, if present!
655 <sect2 renderas="sect3" id="firststep">
656 <title>I just installed Privoxy. Is there anything
657 special I have to do now?</title>
660 All browsers should be told to use <application>Privoxy</application>
661 as a proxy by specifying the correct proxy address and port number
662 in the appropriate configuration area for the browser. It's possible
663 to combine &my-app; with a packet filter to intercept HTTP requests
664 even if the client isn't explicitly configured to use &my-app;,
665 but where possible, configuring the client is recommended. See
666 <ulink url="../user-manual/startup.html">the User Manual for more
667 details</ulink>. You should also flush your browser's memory and disk
668 cache to get rid of any cached junk items, and remove any stored
669 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
674 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
676 If you set up the <application>Privoxy</application> to run on
677 the computer you browse from (rather than your ISP's server or some
678 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
679 (sometimes referred to as <quote>localhost</quote>,
680 which is the special name used by every computer on the Internet to refer
681 to itself) and the port will be 8118 (unless you used the <ulink
682 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
683 config option to tell <application>Privoxy</application> to run on
687 When configuring your browser's proxy settings you typically enter
688 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
689 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
690 then the number <quote>8118</quote> for <quote>port</quote>.
691 This tells your browser to send all web requests to <application>Privoxy</application>
692 instead of directly to the Internet.
695 <application>Privoxy</application> can also be used to proxy for
696 a Local Area Network. In this case, your would enter either the IP
697 address of the LAN host where <application>Privoxy</application>
698 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
699 Port assignment would be same as above. Note that
700 <application>Privoxy</application> doesn't listen on any LAN interfaces by
704 <application>Privoxy</application> does not currently handle
705 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
709 <sect2 renderas="sect3" id="nothing">
710 <title>I just installed Privoxy, and nothing is happening.
711 All the ads are there. What's wrong?</title>
714 Did you configure your browser to use <application>Privoxy</application>
715 as a proxy? It does not sound like it. See above. You might also try flushing
716 the browser's caches to force a full re-reading of pages. You can verify
717 that <application>Privoxy</application> is running, and your browser
718 is correctly configured by entering the special URL:
719 <ulink url="http://p.p/">http://p.p/</ulink>.
720 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
721 of potential redirect caching problem (see next Q). -->
722 This should take you to a page titled <quote>This is Privoxy..</quote> with
723 access to <application>Privoxy's</application> internal configuration.
724 If you see this, then you are good to go. If you receive a page saying
725 <quote>Privoxy is not running</quote>, then the browser is not set up to use
726 your <application>Privoxy</application> installation.
727 If you receive anything else (probably nothing at all), it could either
728 be that the browser is not set up correctly, or that
729 <application>Privoxy</application> is not running at all. Check the <ulink
730 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
731 on starting <application>Privoxy</application> and browser configuration,
732 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
733 on starting <application>Privoxy</application></ulink> in the
734 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
739 <sect2 renderas="sect3" id="notused">
740 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
741 Privoxy is running and being used.</title>
744 First, make sure that Privoxy is <emphasis>really</emphasis> running and
745 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
746 should see the <application>Privoxy</application> main page. If not, see
747 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
748 on starting <application>Privoxy</application></ulink> in the
749 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
753 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
754 other parts of <application>Privoxy</application>'s web interface show
755 the dummy page, your browser has cached a redirection it encountered before
756 <application>Privoxy</application> was being used. You need to clear your
757 browser's cache. Note that shift-reloading the dummy page won't help, since
758 that'll only refresh the dummy page, not the redirection that lead you there.
762 The procedure for clearing the cache varies from browser to browser. For
763 example, <application>Mozilla/Netscape</application> users would click
764 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
765 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
766 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
767 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
768 In some <application>Firefox</application> versions it's
769 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
770 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
771 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
772 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
779 <!-- ~~~~~ New section ~~~~~ -->
781 <sect1 id="configuration"><title>Configuration</title>
782 <sect2 renderas="sect3" id="actionsfile">
783 <title>What exactly is an <quote>actions</quote> file?</title>
786 &my-app; utilizes the concept of <quote>
787 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
788 that are used to manipulate and control web page data.
789 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
790 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
791 that <application>Privoxy</application> could take while processing a certain
792 request, are configured. Typically, you would define a set of default actions
793 that apply globally to all URLs, then add exceptions to these defaults where needed.
794 There is a wide array of actions available that give the user a high degree
795 of control and flexibility on how to process each and every web page.
799 Actions can be defined on a <ulink
800 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
801 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
802 grouped together and then applied to requests matching one or more patterns.
803 There are many possible actions that might apply to any given site. As an example,
804 if you are blocking <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
805 as one of your default actions, but need to accept cookies from a given site,
806 you would need to define an exception for this site in one of your actions
807 files, preferably in <filename>user.action</filename>.
812 <sect2 renderas="sect3" id="actionss">
813 <title>The <quote>actions</quote> concept confuses me. Please list
814 some of these <quote>actions</quote>.</title>
816 For a comprehensive discussion of the actions concept, please refer
817 to the <ulink url="../user-manual/actions-file.html">actions file
818 chapter</ulink> in the <ulink url="../user-manual/index.html">User
819 Manual</ulink>. It includes a <ulink
820 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
821 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
822 file tutorial</ulink> to get you started.
827 <sect2 renderas="sect3" id="actconfig">
828 <title>How are actions files configured? What is the easiest
829 way to do this?</title>
832 Actions files are just text files in a special syntax and can be edited
833 with a text editor. But probably the easiest way is to access
834 <application>Privoxy</application>'s user interface with your web browser
835 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
836 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
837 <quote><ulink url="http://config.privoxy.org/show-status">View &
838 change the current configuration</ulink></quote> from the menu. Note
839 that this feature must be explicitly enabled in the main config file
841 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
846 <sect2 renderas="sect3" id="actionfile-differences">
847 <title>There are several different <quote>actions</quote> files. What are
848 the differences?</title>
850 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
851 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
856 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
858 Based on your feedback and the continuing development, updates of
859 <filename>default.action</filename> are available from
861 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>.
865 If you wish to receive an email notification whenever we release updates of
866 <application>Privoxy</application> or the actions file, <ulink
867 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
868 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
873 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
875 The syntax and purpose of configuration files has remained roughly the
876 same throughout the 3.x series, but backwards compatibility is not guaranteed.
877 Also each release contains updated, <quote>improved</quote> versions and it is
878 therefore strongly recommended to install the newer configuration files
879 and merge back your modifications.
883 <sect2 renderas="sect3" id="difficult">
884 <title>Why is the configuration so complicated?</title>
886 <quote>Complicated</quote> is in the eye of the beholder.
889 Privoxy is currently mainly written by and for people who are already
890 familiar with the underlying concepts like regular expressions, HTTP and HTML,
891 or are willing to become familiar with them to be able to get the most
892 out of a powerful and flexible tool such as Privoxy.
895 While everybody is expected to be able to get a Privoxy default installation
896 up and running, fine-tuning requires a certain amount of background
897 information and Privoxy's documentation mainly concentrates on the
898 Privoxy-specific parts while only providing references to the rest.
901 If you or anyone you know has the skills, time and energy to
902 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
906 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
908 The default configuration shouldn't impact the usability of any of these services.
909 It may, however, make all <ulink
910 url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
911 temporary, so that your browser will forget your
912 login credentials in between browser sessions. If you would like not to have to log
913 in manually each time you access those websites, simply turn off all cookie handling
914 for them in the <filename>user.action</filename> file. An example for yahoo might
917 <screen># Allow all cookies for Yahoo login:
919 { -<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> }
920 .login.yahoo.com</screen>
922 These kinds of sites are often quite complex and heavy with
923 <ulink url="https://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
924 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
926 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
930 # Gmail is a _fragile_ site:
932 { <literal>fragile</literal> }
937 Be sure to flush your browser's caches whenever making these kinds of
938 changes, just to make sure the changes <quote>take</quote>.
941 Make sure the domain, host and path are appropriate as well. Your browser can
942 tell you where you are specifically and you should use that information for
943 your configuration settings. Note that above it is not referenced as
944 <literal>gmail.com</literal>, which is a valid domain name.
949 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
950 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
952 Configuring <application>Privoxy</application> is not entirely trivial. To
953 help you get started, we provide you with three different default action
954 <quote>profiles</quote> in the web based actions file editor at <ulink
955 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
956 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
957 Manual</citetitle></ulink> for a list of actions, and how the default
962 Where the defaults are likely to break some sites, exceptions for
963 known popular <quote>problem</quote> sites are included, but in
964 general, the more aggressive your default settings are, the more exceptions
965 you will have to make later. New users are best to start off in
966 <quote>Cautious</quote> setting. This is safest and will have the fewest
967 problems. See the <ulink
968 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
969 for a more detailed discussion.
973 It should be noted that the <quote>Advanced</quote> profile (formerly known
974 as the <quote>Adventuresome</quote> profile) is more
975 aggressive, and will make use of some of
976 <application>Privoxy's</application> advanced features. Use at your own risk!
981 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
982 with a browser? Does that not raise security issues?</title>
984 It may seem strange that regular users can edit the config files with their
985 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
986 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
989 When you use the browser-based editor, <application>Privoxy</application>
990 itself is writing to the config files. Because
991 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
992 it can update its own config files.
995 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
996 a LAN) or aren't entirely in control of your own browser, you will probably want
997 to make sure that the web-based editor and remote toggle features are
998 <quote>off</quote> by setting <quote><literal><ulink
999 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
1000 0</literal></quote> and <quote><literal><ulink
1001 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
1002 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
1005 As of &my-app; 3.0.7 these options are disabled by default.
1010 <sect2 renderas="sect3" id="filterfile">
1011 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
1013 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
1014 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1015 Filters are a special subset of actions that can be used to modify or
1016 remove web page content or headers on the fly. Content filters can
1017 be applied to <emphasis>anything</emphasis> in the page source,
1018 header filters can be applied to either server or client headers.
1019 Regular expressions are used to accomplish this.
1022 There are a number of pre-defined filters to deal with common annoyances. The
1023 filters are only defined here, to invoke them, you need to use the
1025 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1026 action</ulink> in one of the actions files. Content filtering is automatically
1027 disabled for inappropriate MIME types, but if you know better than Privoxy
1028 what should or should not be filtered you can filter any content you like.
1032 <emphasis>not</emphasis> be confused with <ulink
1033 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1034 is a completely different action, and is more typically used to block ads and
1039 If you are familiar with regular expressions, and HTML, you can look at
1040 the provided <filename>default.filter</filename> with a text editor and define
1041 your own filters. This is potentially a very powerful feature, but
1042 requires some expertise in both regular expressions and HTML/HTTP.
1043 <![%p-newstuff;[ You should
1044 place any modifications to the default filters, or any new ones you create
1045 in a separate file, such as <filename>user.filter</filename>, so they won't
1046 be overwritten during upgrades.
1047 The ability to define multiple filter files
1048 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1052 There is no GUI editor option for this part of the configuration,
1053 but you can disable/enable the various pre-defined filters of the included
1054 <filename>default.filter</filename> file with the <ulink
1055 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1056 Note that the custom actions editor must be explicitly enabled in
1057 the main config file (see <ulink
1058 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1062 If you intend to develop your own filters, you might want to have a look at
1064 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1069 <sect2 renderas="sect3" id="lanconfig">
1070 <title>How can I set up Privoxy to act as a proxy for my
1073 By default, <application>Privoxy</application> only responds to requests
1074 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1075 a network, this needs to be changed in the <ulink
1076 url="../user-manual/config.html">main configuration file</ulink>. Look for
1078 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1079 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1080 it is uncommented, and assign it the address of the LAN gateway interface,
1081 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1082 wish to run <application>Privoxy</application> on port 8118, this line
1087 listen-address 192.168.1.1:8118</screen>
1090 Save the file, and restart <application>Privoxy</application>. Configure
1091 all browsers on the network then to use this address and port number.
1095 Alternately, you can have <application>Privoxy</application> listen on
1096 all available interfaces:
1100 listen-address :8118</screen>
1103 And then use <application>Privoxy's</application>
1105 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1106 feature to limit connections. A firewall in this situation is recommended
1111 The above steps should be the same for any TCP network, regardless of
1116 If you run <application>Privoxy</application> on a LAN with untrusted users,
1117 we recommend that you double-check the <ulink
1118 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1125 <sect2 renderas="sect3" id="noseeum">
1126 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1128 The replacement for blocked images can be controlled with the <ulink
1129 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1130 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1131 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1132 Note that this choice only has effect for images which are blocked as images, i.e.
1133 whose URLs match both a <literal><ulink
1134 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1135 <emphasis>and</emphasis> <literal><ulink
1136 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1139 If you want to see nothing, then change the <ulink
1140 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1141 action</ulink> to <quote>blank</quote>. This can be done by editing the
1142 <filename>user.action</filename> file, or through the <ulink
1143 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1148 <sect2 renderas="sect3" id="whyseeum">
1149 <title>Why would anybody want to see a checkerboard pattern?</title>
1151 Remember that <link linkend="whatsanad">telling which image is an ad and which
1152 isn't</link>, is an educated guess. While we hope that the standard configuration
1153 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1154 decent, and it shows you where images have been blocked, which can be very
1155 helpful in case some navigation aid or otherwise innocent image was
1156 erroneously blocked. It is recommended for new users so they can
1157 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1158 many banners they <emphasis>don't</emphasis> have to see.
1163 <sect2 renderas="sect3" id="blockedbytext">
1164 <title>I see some images being replaced with text
1165 instead of the checkerboard image. Why and how do I get rid of this?</title>
1167 This happens when the banners are not embedded in the HTML code of the
1168 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1169 or (i)layers, and these external HTML documents are blocked. Being non-images
1170 they get replaced by a substitute HTML page rather than a substitute image,
1171 which wouldn't work out technically, since the browser expects and accepts
1172 only HTML when it has requested an HTML document.
1175 The substitute page adapts to the available space and shows itself as a
1176 miniature two-liner if loaded into small frames, or full-blown with a
1177 large red "BLOCKED" banner if space allows.
1180 If you prefer the banners to be blocked by images, you must see to it that
1181 the HTML documents in which they are embedded are not blocked. Clicking
1182 the <quote>See why</quote> link offered in the substitute page will show
1183 you which rule blocked the page. After changing the rule and un-blocking
1184 the HTML documents, the browser will try to load the actual banner images
1185 and the usual image blocking will (hopefully!) kick in.
1190 <sect2 renderas="sect3" id="srvany">
1191 <title>Can Privoxy run as a service
1192 on Win2K/NT/XP?</title>
1194 Yes. Full <application>Windows</application> service
1195 functionality was introduced in <application>Privoxy</application> 3.0.5.
1196 See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1197 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1198 <application>Privoxy</application> as a service.
1203 <sect2 renderas="sect3" id="otherproxy">
1204 <title>How can I make Privoxy work with other proxies?</title>
1206 This can be done and is often useful to combine the benefits of
1207 <application>Privoxy</application> with those of a another proxy,
1208 for example to cache content.
1210 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1211 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1212 describes how to do this. If you intend to use Privoxy with Tor,
1213 please also have a look at
1214 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1218 <sect2 renderas="sect3" id="port-80">
1219 <title>Can I just set Privoxy to use port 80
1220 and thus avoid individual browser configuration?</title>
1223 No, its more complicated than that. This only works with special kinds
1224 of proxies known as <quote>intercepting</quote> proxies
1225 (<link linkend="INTERCEPTING">see below</link>).
1230 <sect2 renderas="sect3" id="transparent">
1231 <title>Can Privoxy run as a <quote>transparent
1232 </quote> proxy?</title>
1234 The whole idea of Privoxy is to modify client requests
1235 and server responses in all sorts of ways and therefore
1236 it's not a transparent proxy as described in
1237 <ulink url="https://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1240 However, some people say <quote>transparent proxy</quote> when they
1241 mean <quote>intercepting proxy</quote>. If you are one of them,
1242 please read the <link linkend="INTERCEPTING">next entry</link>.
1247 <sect2 renderas="sect3" id="intercepting">
1248 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1250 <application>Privoxy</application> can't intercept traffic itself,
1251 but it can handle requests that where intercepted and redirected
1252 with a packet filter (like <application>PF</application> or
1253 <application>iptables</application>), as long as the <literal>Host</literal>
1257 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1258 web sites rely on it anyway, this limitation shouldn't be a problem.
1261 Please refer to your packet filter's documentation to learn how to
1262 intercept and redirect traffic into <application>Privoxy</application>.
1263 Afterward you just have to configure <application>Privoxy</application> to
1264 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1265 intercepted requests</ulink>.
1270 <sect2 renderas="sect3" id="outlook">
1271 <title>How can I configure Privoxy for use with Outlook?</title>
1273 Versions of <application>Outlook</application> prior to Office 2007, use
1274 <application>Internet Explorer</application> components to both render HTML,
1275 and fetch any HTTP requests that may be embedded in an HTML email. So however
1276 you have <application>Privoxy</application> configured to work with IE, this
1277 configuration should automatically be shared, at least with older version of
1281 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1282 engine with Outlook. It is unknown whether this can be configured to use a
1284 <!-- FIXME HB 2009-02-15 -->
1288 <sect2 renderas="sect3" id="outlook-more">
1289 <title>How can I have separate rules just for HTML mail?</title>
1291 The short answer is, you can't. <application>Privoxy</application> has no way
1292 of knowing which particular application makes a request, so there is no way to
1293 distinguish between web pages and HTML mail.
1294 <application>Privoxy</application> just blindly proxies all requests. In the
1295 case of <application>Outlook Express</application> (see above), OE uses
1296 IE anyway, and there is no way for <application>Privoxy</application> to ever
1297 be able to distinguish between them (nor could any other proxy type application for
1301 For a good discussion of some of the issues involved (including privacy and
1302 security issues), see
1303 <ulink url="https://sourceforge.net/p/ijbswa/support-requests/107/"
1304 >https://sourceforge.net/p/ijbswa/support-requests/107/</ulink>.
1308 <sect2 renderas="sect3" id="sneaky-cookies">
1309 <title>I sometimes notice cookies sneaking through. How?</title>
1312 url="https://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1313 set in several ways. The classic method is via the
1314 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1315 easy one to manipulate, such as the &my-app; concept of
1316 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1317 There is also the possibility of using
1318 <ulink url="https://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1319 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1320 is trickier because the syntax can vary widely, and thus requires a certain
1321 amount of guesswork. It is not realistic to catch all of these short of
1322 disabling Javascript, which would break many sites. And lastly, if the
1323 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1324 <application>Privoxy's</application> reach unless you enable
1325 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1328 All in all, &my-app; can help manage cookies in general, can help minimize
1329 the loss of privacy posed by cookies, but can't realistically stop all
1334 <sect2 renderas="sect3" id="evil-cookies">
1335 <title>Are all cookies bad? Why?</title>
1337 No, in fact there are many beneficial uses of
1339 url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1340 method that browsers can use to store data between pages, or between browser
1341 sessions. Sometimes there is a good reason for this, and the user's life is a
1342 bit easier as a result. But there is a long history of some websites taking
1343 advantage of this layer of trust, and using the data they glean from you and
1344 your browsing habits for their own purposes, and maybe to your potential
1345 detriment. Such sites are using you and storing their data on your system.
1346 That is why the privacy conscious watch from whom those cookies come, and why
1347 they really <emphasis>need</emphasis> to be there.
1351 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1352 definition</ulink> for more.
1356 <sect2 renderas="sect3" id="allow-cookies">
1357 <title>How can I allow permanent cookies for my trusted sites?</title>
1360 There are several actions that relate to cookies. The default behavior is to
1361 allow only <quote>session cookies</quote>, which means the cookies only last
1362 for the current browser session. This eliminates most kinds of abuse related
1363 to cookies. But there may be cases where you want cookies to last.
1366 To disable all cookie actions, so that cookies are allowed unrestricted,
1367 both in and out, for <literal>example.com</literal>:
1370 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1374 Place the above in <filename>user.action</filename>. Note that some of these may
1375 be off by default anyway, so this might be redundant, but there is no harm
1376 being explicit in what you want to happen. <filename>user.action</filename>
1377 includes an alias for this situation, called
1378 <literal>allow-all-cookies</literal>.
1382 <sect2 renderas="sect3" id="multiples">
1383 <title>Can I have separate configurations for different users?</title>
1385 Each instance of <application>Privoxy</application> has its own
1386 configuration, including such attributes as the TCP port that it listens on.
1387 What you can do is run multiple instances of <application>Privoxy</application>, each with
1389 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1390 configuration setting, and configuration path, and then
1391 each of these can have their own configurations. Think of it as per-port
1395 Simple enough for a few users, but for large installations, consider having
1396 groups of users that might share like configurations.
1400 <sect2 renderas="sect3" id="whitelists">
1401 <title>Can I set-up Privoxy as a whitelist of
1402 <quote>good</quote> sites?</title>
1404 Sure. There are a couple of things you can do for simple white-listing.
1405 Here's one real easy one:
1408 ############################################################
1410 ############################################################
1411 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1412 / # Block *all* URLs
1414 ############################################################
1416 ############################################################
1417 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1423 This allows access to only those three sites by first blocking all URLs, and
1424 then subsequently allowing three specific exceptions.
1427 Another approach is <application>Privoxy's</application>
1428 <literal>trustfile</literal> concept, which incorporates the notion of
1429 <quote>trusted referrers</quote>. See the <ulink
1430 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1434 These are fairly simple approaches and are not completely foolproof. There
1435 are various other configuration options that should be disabled (described
1436 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1437 so that users can't modify their own configuration and easily circumvent the
1442 <sect2 renderas="sect3" id="no-adblock">
1443 <title>How can I turn off ad-blocking?</title>
1445 Ad blocking is achieved through a complex application of various &my-app;
1446 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1447 actions are deployed against simple images, banners, flash animations,
1448 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1449 just turning one or two actions off. The various actions that make up
1450 &my-app; ad blocking are hard-coded into the default configuration files. It
1451 has been assumed that everyone using &my-app; is interested in this
1455 If you want to do without this, there are several approaches you can take:
1456 You can manually undo the many block rules in
1457 <filename>default.action</filename>. Or even easier, just create your own
1458 <filename>default.action</filename> file from scratch without the many ad
1459 blocking rules, and corresponding exceptions. Or lastly, if you are not
1460 concerned about the additional blocks that are done for privacy reasons, you
1461 can very easily over-ride <emphasis>all</emphasis> blocking with the
1462 following very simple rule in your <filename>user.action</filename>:
1465 # Unblock everybody, everywhere
1466 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1467 / # UN-Block *all* URLs
1470 Or even a more comprehensive reversing of various ad related actions:
1473 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1474 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1475 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1476 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1477 <literal>allow-popups</literal> \
1479 / # UN-Block *all* URLs and allow ads
1482 This last <quote>action</quote> in this compound statement,
1483 <literal>allow-popups</literal>, is an <ulink
1484 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1485 various pop-up blocking features.
1489 <sect2 renderas="sect3" id="templates">
1490 <title>How can I have custom template pages, like the
1491 <emphasis>BLOCKED</emphasis> page?</title>
1493 &my-app; <quote>templates</quote> are specialized text files utilized by
1494 &my-app; for various purposes and can easily be modified using any text
1495 editor. All the template pages are installed in a sub-directory appropriately
1496 named: <filename>templates</filename>. Knowing something about HTML syntax
1497 will of course be helpful.
1500 Be forewarned that the default templates are subject to being overwritten
1501 during upgrades. You can, however, create completely new templates,
1502 place them in another directory and specify the alternate path in the main
1503 <filename>config</filename>. For details, have a look at the <ulink
1504 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1508 <sect2 renderas="sect3" id="blockall">
1509 <title>How can I remove the <quote>Go There Anyway</quote> link from
1510 the <emphasis>BLOCKED</emphasis> page?</title>
1512 There is more than one way to do it (although Perl is not involved).
1515 Editing the BLOCKED template page (see above) may dissuade some users, but
1516 this method is easily circumvented. Where you need this level of control, you
1517 might want to build &my-app; from source, and disable various features that are
1518 available as compile-time options. You should
1519 <command>configure</command> the sources as follows:
1522 ./configure --disable-toggle --disable-editor --disable-force
1525 This will create an executable with hard-coded security features so that
1526 &my-app; does not allow easy bypassing of blocked sites, or changing the
1527 current configuration via any connected user's web browser.
1530 Finally, all of these features can also be toggled on/off via options in
1531 <application>Privoxy's</application> main <ulink
1532 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1533 means you don't have to recompile anything.
1539 <!-- ~ End section ~ -->
1542 <!-- ~~~~~ New section ~~~~~ -->
1544 <sect1 id="misc"><title>Miscellaneous</title>
1546 <sect2 renderas="sect3" id="slowsme">
1547 <title>How much does Privoxy slow my browsing down? This
1548 has to add extra time to browsing.</title>
1550 How much of an impact depends on many things, including the CPU of the host
1551 system, how aggressive the configuration is, which specific actions are being triggered,
1552 the size of the page, the bandwidth of the connection, etc.
1555 Overall, it should not slow you down any in real terms, and may actually help
1556 speed things up since ads, banners and other junk are not typically being
1557 retrieved and displayed. The actual processing time required by
1558 <application>Privoxy</application> itself for each page, is relatively small
1559 in the overall scheme of things, and happens very quickly. This is typically
1560 more than offset by time saved not downloading and rendering ad images and
1561 other junk content (if ad blocking is being used).
1565 <quote>Filtering</quote> content via the <literal><ulink
1566 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1568 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1569 actions may cause a perceived slowdown, since the entire document
1570 needs to be buffered before displaying. And on very large documents,
1571 filtering may have some measurable impact. How much depends on the page size,
1572 the actual definition of the filter(s), etc. See below. Most other actions
1573 have little to no impact on speed.
1576 Also, when filtering is enabled but zlib support isn't available, compression
1577 is often disabled (see <ulink
1578 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1579 This can have an impact on speed as well, although it's probably smaller than
1580 you might think. Again, the page size, etc. will determine how much of an impact.
1586 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1587 delays in page requests. What's wrong?</title>
1589 If you use any <literal><ulink
1590 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1591 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1592 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1593 action, the entire document must be loaded into memory in order for the filtering
1594 mechanism to work, and nothing is sent to the browser during this time.
1597 The loading time typically does not really change much in real numbers, but
1598 the feeling is different, because most browsers are able to start rendering
1599 incomplete content, giving the user a feeling of "it works". This effect is
1600 more noticeable on slower dialup connections. Extremely large documents
1601 may have some impact on the time to load the page where there is filtering
1602 being done. But overall, the difference should be very minimal. If there is a
1603 big impact, then probably some other situation is contributing (like
1604 anti-virus software).
1607 Filtering is automatically disabled for inappropriate MIME types. But note
1608 that if the web server mis-reports the MIME type, then content that should
1609 not be filtered, could be. <application>Privoxy</application> only knows how
1610 to differentiate filterable content because of the MIME type as reported by
1611 the server, or because of some configuration setting that enables/disables
1616 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1617 "http://p.p/"?</title>
1619 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1620 address of <application>Privoxy</application>'s built-in user interface, and
1621 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1624 Since <application>Privoxy</application> sits between your web browser and the Internet,
1625 it can simply intercept requests for these addresses and answer them with its built-in
1626 <quote>web server</quote>.
1629 This also makes for a good test for your browser configuration: If entering the
1630 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1631 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1632 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1633 your browser didn't use <application>Privoxy</application> for the request,
1634 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1635 web site at config.privoxy.org.
1638 Note that config.privoxy.org resolves to a public IP address.
1639 If you use config.privoxy.org as ping or traceroute target you will
1640 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1641 If you want to ping the system Privoxy runs on,
1642 you should use its IP address or local DNS name (if it has got one).
1648 out of date 09/02/06 HB
1649 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1651 No. The patterns for blocking now reside (among other things) in the <ulink
1652 url="../user-manual/actions-file.html">actions files</ulink>, which are
1653 actively maintained instead. See next question ...
1657 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1660 Please see the <link linkend="contact">Contact section</link> for
1661 various ways to interact with the developers.
1666 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1667 they be included in future updates?</title>
1669 Whether such submissions are eventually included in the
1670 <filename>default.action</filename> configuration file depends on how
1671 significant the issue is. We of course want to address any potential
1672 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1673 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1674 has a good chance of being a candidate. But at the other end of the spectrum
1675 are any number of smaller, low-profile sites such as for local clubs or
1676 schools. Since their reach and impact are much less, they are best handled by
1677 inclusion in the user's <filename>user.action</filename>, and thus would be
1678 unlikely to be included.
1684 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1687 Rest assured that it has been read and considered. Why it is not answered,
1688 could be for various reasons, including no one has a good answer for it, no
1689 one has had time to yet investigate it thoroughly, it has been reported
1690 numerous times already, or because not enough information was provided to help
1691 us help you. Your efforts are not wasted, and we do appreciate them.
1697 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1699 If you run both the browser and &my-app; locally, you cannot hide your IP
1700 address with <application>Privoxy</application> or ultimately any other
1701 software alone. The server needs to know your IP address so that it knows
1702 where to send the responses back.
1705 There are many publicly usable "anonymous" proxies out there, which
1706 provide a further level of indirection between you and the web server.
1709 However, these proxies are called "anonymous" because you don't need
1710 to authenticate, not because they would offer any real anonymity.
1711 Most of them will log your IP address and make it available to the
1712 authorities in case you violate the law of the country they run in. In fact
1713 you can't even rule out that some of them only exist to *collect* information
1714 on (those suspicious) people with a more than average preference for privacy.
1717 If you want to hide your IP address from most adversaries,
1718 you should consider chaining <application>Privoxy</application>
1719 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1720 The configuration details can be found in
1721 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1722 with <application>Tor</application> section</ulink>
1727 <sect2 renderas="sect3" id="anonforsure">
1728 <title>Can Privoxy guarantee I am anonymous?</title>
1730 No. Your chances of remaining anonymous are improved, but unless you
1731 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1732 or a similar proxy and know what you're doing when it comes to configuring
1733 the rest of your system, you should assume that everything you do
1734 on the Web can be traced back to you.
1737 <application>Privoxy</application> can remove various information about you,
1738 and allows <emphasis>you</emphasis> more freedom to decide which sites
1739 you can trust, and what details you want to reveal. But it neither
1740 hides your IP address, nor can it guarantee that the rest of the system
1741 behaves correctly. There are several possibilities how a web sites can find
1742 out who you are, even if you are using a strict <application>Privoxy</application>
1743 configuration and chained it with <application>Tor</application>.
1746 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1747 by an insecure browser configuration, therefore you should use a browser that can
1748 be configured to only execute code from trusted sites, and be careful which sites you trust.
1749 For example there is no point in having <application>Privoxy</application>
1750 modify the User-Agent header, if websites can get all the information they want
1751 through JavaScript, ActiveX, Flash, Java etc.
1754 A few browsers disclose the user's email address in certain situations, such
1755 as when transferring a file by FTP. <application>Privoxy</application>
1756 does not filter FTP. If you need this feature, or are concerned about the
1757 mail handler of your browser disclosing your email address, you might
1758 consider products such as <application>NSClean</application>.
1761 Browsers available only as binaries could use non-standard headers to give
1762 out any information they can have access to: see the manufacturer's license
1763 agreement. It's impossible to anticipate and prevent every breach of privacy
1764 that might occur. The professionally paranoid prefer browsers available as
1765 source code, because anticipating their behavior is easier. Trust the source,
1771 <sect2 renderas="sect3" id="proxytest">
1772 <title>A test site says I am not using a Proxy.</title>
1774 Good! Actually, they are probably testing for some other kinds of proxies.
1775 Hiding yourself completely would require additional steps.
1779 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1780 together with Tor?</title>
1782 Before you configure <application>Privoxy</application> to use
1783 <ulink url="https://www.torproject.org/">Tor</ulink>,
1784 please follow the <citetitle>User Manual</citetitle> chapters
1785 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1786 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1787 <application>Privoxy</application> itself is setup correctly.
1790 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1791 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1792 and make sure <application>Tor</application>'s logfile says that
1793 <quote>Tor has successfully opened a circuit</quote> and it
1794 <quote>looks like client functionality is working</quote>.
1797 If either <application>Tor</application> or <application>Privoxy</application>
1798 isn't working, their combination most likely will neither. Testing them on their
1799 own will also help you to direct problem reports to the right audience.
1800 If <application>Privoxy</application> isn't working, don't bother the
1801 <application>Tor</application> developers. If <application>Tor</application>
1802 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1805 If you verified that <application>Privoxy</application> and <application>Tor</application>
1806 are working, it is time to connect them. As far as <application>Privoxy</application>
1807 is concerned, <application>Tor</application> is just another proxy that can be reached
1808 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1809 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1810 requests are done through <application>Tor</application> and thus invisible to your
1811 local network. Using socks4a would work too, but with socks5 you get more precise error
1816 <application>Privoxy's</application>
1817 <ulink url="../user-manual/config.html">main configuration file</ulink>
1818 is already prepared for <application>Tor</application>, if you are using a
1819 default <application>Tor</application> configuration and run it on the same
1820 system as &my-app;, you just have to edit the
1821 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1822 and uncomment the line:
1825 # forward-socks5t / 127.0.0.1:9050 .
1828 Note that if you got Tor through one of the bundles, you may
1829 have to change the port from 9050 to 9150 (or even another one).
1830 For details, please check the documentation on the
1831 <ulink url="https://torproject.org/">Tor website</ulink>.
1835 This is enough to reach the Internet, but additionally you might want to
1836 uncomment the following forward rules, to make sure your local network is still
1837 reachable through Privoxy:
1840 # forward 192.168.*.*/ .
1841 # forward 10.*.*.*/ .
1842 # forward 127.*.*.*/ .
1845 Unencrypted connections to systems in these address ranges will
1846 be as (un)secure as the local network is, but the alternative is
1847 that your browser can't reach the network at all. Then again,
1848 that may actually be desired and if you don't know for sure
1849 that your browser has to be able to reach the local network,
1850 there's no reason to allow it.
1853 If you want your browser to be able to reach servers in your local
1854 network by using their names, you will need additional exceptions
1855 that look like this:
1858 # forward localhost/ .
1861 Save the modified configuration file and open
1862 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1863 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1864 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1866 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1867 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1870 Afterward, please take the time to at least skim through the rest
1871 of <application>Tor's</application> documentation. Make sure you understand
1872 what <application>Tor</application> does, why it is no replacement for
1873 application level security, and why you probably don't want to
1874 use it for unencrypted logins.
1878 <sect2 renderas="sect3" id="sitebreak">
1879 <title>Might some things break because header information or
1880 content is being altered?</title>
1883 Definitely. It is common for sites to use browser type, browser version,
1884 HTTP header content, and various other techniques in order to dynamically
1885 decide what to display and how to display it. What you see, and what I see,
1886 might be very different. There are many, many ways that this can be handled,
1887 so having hard and fast rules, is tricky.
1891 The <quote>User-Agent</quote> is sometimes used in this way to identify
1892 the browser, and adjust content accordingly.
1896 Also, different browsers use different encodings of non-English
1897 characters, certain web servers convert pages on-the-fly according to the
1898 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1899 operating system or browser manufacturer causes some sites in these languages
1900 to be garbled; Surfers to Eastern European sites should change it to
1901 something closer. And then some page access counters work by looking at the
1902 <quote>Referer</quote> header; they may fail or break if unavailable. The
1903 weather maps of Intellicast have been blocked by their server when no
1904 <quote>Referer</quote> or cookie is provided, is another example. (But you
1905 can forge both headers without giving information away). There are
1906 many other ways things can go wrong when trying to fool a web server. The
1907 results of which could inadvertently cause pages to load incorrectly,
1908 partially, or even not at all. And there may be no obvious clues as to just
1909 what went wrong, or why. Nowhere will there be a message that says
1910 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1915 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1920 If you have problems with a site, you will have to adjust your configuration
1921 accordingly. Cookies are probably the most likely adjustment that may
1922 be required, but by no means the only one.
1928 <sect2 renderas="sect3" id="caching">
1929 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1930 speed up web browsing?</title>
1932 No, it does not have this ability at all. You want something like
1933 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1934 <ulink url="https://www.irif.fr/~jch//software/polipo/">Polipo</ulink> for this.
1935 And, yes, before you ask, <application>Privoxy</application> can co-exist
1936 with other kinds of proxies like <application>Squid</application>.
1937 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1938 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1939 manual</ulink> for details.
1943 <sect2 renderas="sect3" id="firewall">
1944 <title>What about as a firewall? Can Privoxy protect me?</title>
1946 Not in the way you mean, or in the way some firewall vendors claim they can.
1947 <application>Privoxy</application> can help protect your privacy, but can't
1948 protect your system from intrusion attempts. It is, of course, perfectly possible
1949 to use <emphasis>both</emphasis>.
1953 <sect2 renderas="sect3" id="wasted">
1954 <title>I have large empty spaces / a checkerboard pattern now where
1955 ads used to be. Why?</title>
1957 It is technically possible to eliminate banners and ads in a way that frees
1958 their allocated page space. This could easily be done by blocking with
1959 <application>Privoxy's</application> filters,
1960 and eliminating the <emphasis>entire</emphasis> image references from the
1964 But, this would consume considerably more CPU resources (IOW, slow things
1965 down), would likely destroy the layout of some web pages which rely on the
1966 banners utilizing a certain amount of page space, and might fail in other
1967 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1968 Also, making ads and banners disappear without any trace complicates
1969 troubleshooting, and would sooner or later be problematic.
1972 The better alternative is to instead let them stay, and block the resulting
1973 requests for the banners themselves as is now the case. This leaves either
1974 empty space, or the familiar checkerboard pattern.
1977 So the developers won't support this in the default configuration, but you
1978 can of course define appropriate filters yourself to achieve this.
1982 <sect2 renderas="sect3" id="ssl">
1983 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1986 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1987 <application>Privoxy</application> will impersonate the destination
1988 server and can thus filter encrypted requests and responses as well.
1992 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1993 secure HTTP connections are encrypted SSL sessions between your
1994 browser and the secure site, and there is little
1995 that <application>Privoxy</application> can do but hand the raw
1996 gibberish data though from one end to the other unprocessed.
1999 The only exception to this is blocking by host patterns, as the client needs
2000 to tell <application>Privoxy</application> the name of the remote server,
2001 so that <application>Privoxy</application> can establish the connection.
2002 If that name matches a host-only pattern, the connection will be blocked.
2005 As far as ad blocking is concerned, this is less of a restriction than it may
2006 seem, since ad sources are often identifiable by the host name, and often
2007 the banners to be placed in an encrypted page come unencrypted nonetheless
2008 for efficiency reasons, which exposes them to the full power of
2009 <application>Privoxy</application>'s ad blocking.
2012 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
2013 JS page content, see <literal><ulink
2014 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2015 in an SSL transaction will be impossible to block under these conditions.
2016 Fortunately, this does not seem to be a very common scenario since most
2017 cookies come by traditional means.
2022 <sect2 renderas="sect3" id="http2">
2023 <title>Does Privoxy support HTTP/2?</title>
2025 Privoxy currently doesn't parse HTTP/2 but applications
2026 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2027 to allow CONNECT requests (default) which are also used
2031 Adding HTTP/2 support is on the
2032 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2033 list but currently nobody is known to work on it.
2037 <sect2 renderas="sect3" id="secure">
2038 <title>Privoxy runs as a <quote>server</quote>. How
2039 secure is it? Do I need to take any special precautions?</title>
2041 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2042 user, which is how we recommend it be run. Also, by default
2043 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2047 The server aspect of <application>Privoxy</application> is not itself directly
2048 exposed to the Internet in this configuration. If you want to have
2049 <application>Privoxy</application> serve as a LAN proxy, this will have to
2050 be opened up to allow for LAN requests. In this case, we'd recommend
2051 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2052 <application>Privoxy</application> configuration file and check all <ulink
2053 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2054 options</ulink>. All LAN hosts can then use this as their proxy address
2055 in the browser proxy configuration, but <application>Privoxy</application>
2056 will not listen on any external interfaces. ACLs can be defined in addition,
2057 and using a firewall is always good too. Better safe than sorry.
2062 <sect2 renderas="sect3" id="turnoff">
2063 <title>Can I temporarily disable Privoxy?</title>
2065 &my-app; doesn't have a transparent proxy mode,
2066 but you can toggle off blocking and content filtering.
2069 The easiest way to do that is to point your browser
2070 to the remote toggle URL: <ulink
2071 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2074 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2075 of the <citetitle>User Manual</citetitle> for an easy way to access this
2076 feature. Note that this is a feature that may need to be enabled in the main
2077 <filename>config</filename> file.
2082 <sect2 renderas="sect3" id="reallyoff">
2083 <title>When <quote>disabled</quote> is Privoxy totally
2084 out of the picture?</title>
2086 No, this just means all optional filtering and actions are disabled.
2087 <application>Privoxy</application> is still acting as a proxy, but just
2088 doing less of the things that <application>Privoxy</application> would
2089 normally be expected to do. It is still a <quote>middle-man</quote> in
2090 the interaction between your browser and web sites. See below to bypass
2095 <sect2 renderas="sect3" id="turnoff2">
2096 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2098 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2099 configuration issue, not a &my-app; issue. Modern browsers typically do have
2100 settings for not proxying certain sites. Check your browser's help files.
2105 <sect2 renderas="sect3" id="crunch">
2106 <title>My logs show Privoxy <quote>crunches</quote>
2107 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2109 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2110 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2111 banners, but <application>Privoxy</application> uses the same mechanism for
2112 trapping requests for its own internal pages. For instance, a request for
2113 <application>Privoxy's</application> configuration page at: <ulink
2114 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2115 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2116 configuration is returned to the browser, and the log consequently will show
2117 a <quote>crunch</quote>.
2120 Since version 3.0.7, Privoxy will also log the crunch reason.
2121 If you are using an older version you might want to upgrade.
2125 <sect2 renderas="sect3" id="downloads">
2126 <title>Can Privoxy affect files that I download
2127 from a webserver? FTP server?</title>
2129 From the webserver's perspective, there is no difference between
2130 viewing a document (i.e. a page), and downloading a file. The same is true of
2131 <application>Privoxy</application>. If there is a match for a <literal><ulink
2132 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2133 it will still be blocked, and of course this is obvious.
2136 Filtering is potentially more of a concern since the results are not always
2137 so obvious, and the effects of filtering are there whether the file is simply
2138 viewed, or downloaded. And potentially whether the content is some obnoxious
2139 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2140 one of these presumably is <quote>bad</quote> content that we don't want, and
2141 the other is <quote>good</quote> content that we do want.
2142 <application>Privoxy</application> is blind to the differences, and can only
2143 distinguish <quote>good from bad</quote> by the configuration parameters
2144 <emphasis>we</emphasis> give it.
2147 <application>Privoxy</application> knows the differences in files according
2148 to the <quote>Content Type</quote> as reported by the webserver. If this is
2149 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2150 then <application>Privoxy</application> knows to ignore these where
2151 appropriate. <application>Privoxy</application> potentially can filter HTML
2152 as well as plain text documents, subject to configuration parameters of
2153 course. Also, documents that are of an unknown type (generally assumed to be
2154 <quote>text/plain</quote>) can be filtered, as will those that might be
2155 incorrectly reported by the webserver. If such a file is a downloaded file
2156 that is intended to be saved to disk, then any content that might have been
2157 altered by filtering, will be saved too, for these (probably rare) cases.
2160 Note that versions later than 3.0.2 do NOT filter document types reported as
2161 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2162 did filter this document type.
2165 In short, filtering is <quote>ON</quote> if a) the content type as reported
2166 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2167 allows it (or at least does not disallow it). That's it. There is no magic
2168 cookie anywhere to say this is <quote>good</quote> and this is
2169 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2172 If you download text files, you probably do not want these to be filtered,
2173 particularly if the content is source code, or other critical content. Source
2174 code sometimes might be mistaken for Javascript (i.e. the kind that might
2175 open a pop-up window). It is recommended to turn off filtering for download
2176 sites (particularly if the content may be plain text files and you are using
2177 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2178 also, for any site or page where making <emphasis>any</emphasis> changes at
2179 all to the content is to be avoided.
2182 <application>Privoxy</application> does not do FTP at all, only HTTP
2183 and HTTPS (SSL) protocols.
2187 <sect2 renderas="sect3" id="downloads2">
2188 <title>I just downloaded a Perl script, and Privoxy
2189 altered it! Yikes, what is wrong!</title>
2195 <sect2 renderas="sect3" id="hostsfile">
2196 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2198 One time-tested technique to defeat common ads is to trick the local DNS
2199 system by giving a phony IP address for the ad generator in the local
2200 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2201 <literal>localhost</literal>. This effectively blocks the ad.
2204 There is no reason to use this technique in conjunction with
2205 <application>Privoxy</application>. <application>Privoxy</application>
2206 does essentially the same thing, much more elegantly and with much more
2207 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2208 duplicates effort, but may get in the way and seriously slow down your system.
2209 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2210 your hosts list is neglected by <application>Privoxy's </application>
2211 configuration, consider adding your list to your <filename>user.action</filename> file:
2217 ads.galore.example.com
2222 <sect2 renderas="sect3" id="seealso">
2223 <title>Where can I find more information about Privoxy
2224 and related issues?</title>
2225 <!-- Include seealso.sgml boilerplate: -->
2227 <!-- end boilerplate -->
2232 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2238 <sect2 renderas="sect3" id="microsuck">
2239 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2240 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2243 We're not. The text substitutions that you are seeing are disabled
2244 in the default configuration as shipped. You have either manually
2245 activated the <quote><literal>fun</literal></quote> filter which
2246 is clearly labeled <quote>Text replacements for subversive browsing
2247 fun!</quote> or you are using an older Privoxy version and have implicitly
2248 activated it by choosing the <quote>Advanced</quote> profile in the
2249 web-based editor. Please upgrade.
2253 <sect2 renderas="sect3" id="valid">
2254 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2257 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2258 whenever there are text substitutions via a &my-app; filter. While this
2259 should always conform to the HTML 4.01 specifications, it has not been
2260 validated against this or any other standard.
2264 <sect2 renderas="sect3" id="surprise-privoxy">
2265 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2268 We didn't. We make Privoxy available for download, but we don't go
2269 around installing it on other people's systems behind their back.
2270 If you discover Privoxy running on your system and are sure you didn't
2271 install it yourself, somebody else did. You may not even be running
2272 the real Privoxy, but maybe something else that only pretends to be
2273 Privoxy, or maybe something that is based on the real Privoxy,
2274 but has been modified.
2277 Lately there have been reports of problems with some kind of
2278 "parental control" software based on Privoxy that came preinstalled on
2279 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2280 The problems described are inconsistent with the behaviour of official
2281 Privoxy versions, which suggests that the preinstalled software may
2282 contain vendor modifications that we don't know about and thus can't debug.
2285 Privoxy's <link linkend="copyright">license</link> allows vendor
2286 modifications, but the vendor has to comply with the license,
2287 which involves informing the user about the changes and to make
2288 the changes available under the same license as Privoxy itself.
2291 If you are having trouble with a modified Privoxy version,
2292 please try to talk to whoever made the modifications before
2293 reporting the problem to us. Please also try to convince
2294 whoever made the modifications to talk to us. If you think
2295 somebody gave you a modified Privoxy version without complying
2296 to the license, please let us know.
2304 <!-- ~~~~~ New section ~~~~~ -->
2306 <sect1 id="trouble">
2307 <title>Troubleshooting</title>
2309 <sect2 renderas="sect3" id="refused">
2310 <title>I cannot connect to any websites. Or, I am getting
2311 <quote>connection refused</quote> message with every web page. Why?</title>
2313 There are several possibilities:
2317 <application>Privoxy</application> is not running. Solution: verify
2318 that &my-app; is installed correctly, has not crashed, and is indeed running.
2319 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2321 <listitem><para>Or your browser is configured for a different port than what
2322 <application>Privoxy</application> is using. Solution: verify that &my-app;
2323 and your browser are set to the same port (<literal>listen-address</literal>).
2325 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2326 problem with a host in the forwarding chain. Solution: temporarily alter your
2327 configuration and take the forwarders out of the equation.
2330 Or you have a firewall that is interfering and blocking you. Solution:
2331 try disabling or removing the firewall as a simple test.
2337 <!-- ~~~~~ New section ~~~~~ -->
2338 <sect2 renderas="sect3" id="error503">
2339 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2341 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2342 been reported to cause this symptom -- even if not running! The solution is
2343 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2344 something better behaved in its place. Other personal firewall type products
2345 may cause similar type problems if not configured correctly.
2349 <sect2 renderas="sect3" id="flushit">
2350 <title>I just added a new rule, but the steenkin ad is
2351 still getting through. How?</title>
2353 If the ad had been displayed before you added its URL, it will probably be
2354 held in the browser's cache for some time, so it will be displayed without
2355 the need for any request to the server, and <application>Privoxy</application>
2356 will not be involved. Flush the browser's caches, and then try again.
2360 If this doesn't help, you probably have an error in the rule you
2361 applied. Try pasting the full URL of the offending ad into <ulink
2362 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2363 and see if it really matches your new rule. Blocking ads is like blocking
2364 spam: a lot of tinkering is required to stay ahead of the game. And
2365 remember you need to block the URL of the ad in question, which may be
2366 entirely different from the site URL itself. Most ads are hosted on different
2367 servers than the main site itself. If you right-click on the ad, you should
2368 be able to get all the relevant information you need. Alternately, you can
2369 find the correct URL by looking at <application>Privoxy's</application> logs
2370 (you may need to enable logging in the main config file if its disabled).
2373 Below is a slightly modified real-life log snippet that originates with one
2374 requested URL: <literal>www.example.com</literal> (name of site was changed
2375 for this example, the number of requests is real). You can see in this the
2376 complexity of what goes into making up this one <quote>page</quote>. There
2377 are eight different domains involved here, with thirty two separate URLs
2378 requested in all, making up all manner of images, Shockwave Flash,
2379 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2380 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2381 Many of the more questionable looking requests, are going to outside domains
2382 that seem to be identifying themselves with suspicious looking names, making
2383 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2384 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2388 Request: www.example.com/
2389 Request: www.example.com/favicon.ico
2390 Request: img.example.com/main.css
2391 Request: img.example.com/sr.js
2392 Request: example.betamarker.com/example.html
2393 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2394 Request: img.example.com/pb.png
2395 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2396 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2397 Request: img.example.com/p.gif
2398 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2399 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2400 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2401 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2402 Request: www.adtrak.net/adx.js crunch! (Blocked)
2403 Request: img.example.com/hbg.gif
2404 Request: img.example.com/example.jpg
2405 Request: img.example.com/mt.png
2406 Request: img.example.com/mm.png
2407 Request: img.example.com/mb.png
2408 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2409 Request: www.example.com/tracker.js
2410 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2411 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2412 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2413 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2414 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2415 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2416 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2417 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2418 Request: 66.70.21.80/img/pixel.gif
2419 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2420 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2424 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2425 behave perfectly <quote>normal</quote> (minus some ads, of course).
2430 <sect2 renderas="sect3" id="badsite">
2431 <title>One of my favorite sites does not work with Privoxy.
2432 What can I do?</title>
2435 First verify that it is indeed a <application>Privoxy</application> problem,
2436 by toggling off <application>Privoxy</application> through <ulink
2437 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2438 (the toggle feature may need to be enabled in the main
2439 <filename>config</filename>),
2440 and then shift-reloading the problem page (i.e. holding down the shift key
2441 while clicking reload. Alternatively, flush your browser's disk and memory
2446 If the problem went away, we know we have a configuration related problem.
2448 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2449 and paste the full URL of the page in question into the prompt. See which
2450 actions are being applied to the URL, and which matches in which actions
2451 files are responsible for that. It might be helpful also to look at your logs
2452 for this site too, to see what else might be happening (note: logging may need
2453 to be enabled in the main config file). Many sites are
2454 complex and require a number of related pages to help present their content.
2455 Look at what else might be used by the page in question, and what of that
2456 might be <emphasis>required</emphasis>.
2457 Now, armed with this information, go to
2459 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2460 and select the appropriate actions files for editing. </para>
2462 You can now either look for a section which disables the actions that
2463 you suspect to cause the problem and add a pattern for your site there,
2464 or make up a completely new section for your site. In any case, the recommended
2465 way is to disable only the prime suspect, reload the problem page, and only
2466 if the problem persists, disable more and more actions until you have
2467 identified the culprit. You may or may not want to turn the other actions
2468 on again. Remember to flush your browser's caches in between any such changes!
2471 Alternately, if you are comfortable with a text editor, you can accomplish
2472 the same thing by editing the appropriate actions file. Probably the easiest
2473 way to deal with such problems when editing by hand is to add your
2474 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2475 which is an alias that turns off most <quote>dangerous</quote>
2476 actions, but is also likely to turn off more actions then needed, and thus lower
2477 your privacy and protection more than necessary,
2480 Troubleshooting actions is discussed in more detail in the <ulink
2481 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2482 Troubleshooting: the Anatomy of an Action</ulink>.
2483 There is also an <ulink
2484 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2485 with general configuration information and examples.
2488 As a last resort, you can always see if your browser has a setting that will
2489 bypass the proxy setting for selective sites. Modern browsers can do this.
2495 <!-- ~~~~~ New section ~~~~~ -->
2496 <sect2 id="dun" renderas="sect3">
2497 <title>After installing Privoxy, I have to log in
2498 every time I start IE. What gives?</title>
2501 This is a quirk that affects the installation of
2502 <application>Privoxy</application>, in conjunction with Internet Explorer and
2503 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2504 appear to be corrupted or invalid DUN settings, or passwords.
2508 When setting up an NT based Windows system with
2509 <application>Privoxy</application> you may find that things do not seem to be
2510 doing what you expect. When you set your system up you will probably have set
2511 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2512 logged in with administrator privileges. You will probably have made this DUN
2513 connection available to other accounts that you may have set-up on your
2514 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2515 configured for the kids.
2519 When setting up <application>Privoxy</application> in this environment you
2520 will have to alter the proxy set-up of Internet Explorer (IE) for the
2521 specific DUN connection on which you wish to use
2522 <application>Privoxy</application>. When you do this the ICS DUN set-up
2523 becomes user specific. In this instance you will see no difference if you
2524 change the DUN connection under the account used to set-up the connection.
2525 However when you do this from another user you will notice that the DUN
2526 connection changes to make available to "Me only". You will also find that
2527 you have to store the password under each different user!
2531 The reason for this is that each user's set-up for IE is user specific. Each
2532 set-up DUN connection and each LAN connection in IE store the settings for
2533 each user individually. As such this enforces individual configurations
2534 rather than common ones. Hence the first time you use a DUN connection after
2535 re-booting your system it may not perform as you expect, and prompt you for
2536 the password. Just set and save the password again and all should be OK.
2540 [Thanks to Ray Griffith for this submission.]
2545 <!-- ~~~~~ New section ~~~~~ -->
2546 <sect2 id="ftp" renderas="sect3">
2547 <title>I cannot connect to any FTP sites. Privoxy
2548 is blocking me.</title>
2550 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2551 so do not configure your browser to use <application>Privoxy</application>
2552 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2553 or HTTPS (SSL)</emphasis>.
2556 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2557 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2558 an FTP connection, and not a HTTP connection. So while your browser may
2559 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2563 To complicate matters, some systems may have a generic <quote>proxy</quote>
2564 setting, which will enable various protocols, including
2565 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2566 accidentally enable FTP proxying in these cases. And of course, if this
2567 happens, <application>Privoxy</application> will indeed cause problems since
2568 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2569 message if a FTP connection is attempted.]]> Just disable the FTP setting
2570 and all will be well again.
2573 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2574 There just is not much reason, and the work to make this happen is more than
2579 <!-- ~~~~~ New section ~~~~~ -->
2580 <sect2 id="macosxie" renderas="sect3">
2581 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2582 Privoxy as the HTTP proxy.</title>
2584 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2585 network settings. In order to change the HTTP proxy, open System
2586 Preferences, and click on the Network icon. In the settings pane that
2587 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2588 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2589 Enter <literal>8118</literal> in the Port field. The next time you start
2590 IE, it should reflect these values.
2594 <!-- ~~~~~ New section ~~~~~ -->
2595 <sect2 renderas="sect3" id="macosxuninstall">
2596 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2597 uninstall it. Now the finder tells me I don't have sufficient privileges to
2598 empty the trash.</title>
2600 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2603 Just dragging the <application>Privoxy</application> folder to the trash is
2604 not enough to delete it. <application>Privoxy</application> supplies an
2605 <application>uninstall.command</application> file that takes care of
2606 these details. Open the trash, drag the <application>uninstall.command</application>
2607 file out of the trash and double-click on it. You will be prompted for
2608 confirmation and the administration password.
2611 The trash may still appear full after this command; emptying the trash
2612 from the desktop should make it appear empty again.
2616 <!-- ~~~~~ New section ~~~~~ -->
2617 <sect2 renderas="sect3" id="macosximages">
2618 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2619 experience random delays in page loading. I'm using
2620 <literal>localhost</literal> as my browser's proxy setting.</title>
2622 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2623 understand the issue yet. In any case, changing the proxy setting to
2624 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2625 works around the problem.
2629 <!-- ~~~~~ New section ~~~~~ -->
2630 <sect2 renderas="sect3" id="macosxaccountdeletion">
2631 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2634 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2635 X deletes all user accounts that are either not part of OS X itself or are
2636 not interactive user accounts (ones you log in with). Since, for the sake of
2637 security, &my-app; runs as a non-privileged user that is created by its
2638 installer (_privoxy), it can no longer start up once that account gets deleted.
2639 The solution is to perform a complete uninstall using the supplied
2640 <application>uninstall.command</application> script (either back up your
2641 configuration files or select to not have the uninstaller remove them when it
2642 prompts you) and then reinstall &my-app; using the installer package and merge
2643 in your configuration.
2647 <sect2 renderas="sect3" id="nohostname">
2648 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2651 <application>Privoxy</application> tries to get the hostname of the system
2652 its running on from the IP address of the system interface it is bound to
2653 (from the <filename>config</filename> file
2654 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2655 this information, <application>Privoxy</application> logs this condition.
2658 Typically, this would be considered a minor system configuration error. It is
2659 not a fatal error to <application>Privoxy</application> however, but may
2660 result in a much slower response from <application>Privoxy</application> on
2661 some platforms due to DNS timeouts.
2664 This can be caused by a problem with the local <filename>hosts</filename>
2665 file. If this file has been changed from the original, try reverting it to
2666 see if that helps. Make sure whatever name(s) are used for the local system,
2667 that they resolve both ways.
2670 You should also be able to work around the problem with the
2671 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2675 <sect2 renderas="sect3" id="inuse">
2676 <title>When I try to launch Privoxy, I get an
2677 error message <quote>port 8118 is already in use</quote> (or similar wording).
2680 Port 8118 is <application>Privoxy's</application> default TCP
2681 <quote>listening</quote> port. Typically this message would mean that there
2682 is already one instance of <application>Privoxy</application> running, and
2683 your system is actually trying to start a second
2684 <application>Privoxy</application> on the same port, which will not work.
2685 (You can have multiple instances but they must be assigned different ports.)
2686 How and why this might happen varies from platform to platform, but you need
2687 to check your installation and start-up procedures.
2691 <sect2 renderas="sect3" id="demoronizer">
2693 Pages with UTF-8 fonts are garbled.
2696 This may be the result of an overly aggressive filter. The filters that
2697 are enabled in the default configuration aren't expected to cause problems
2698 like this. If you enabled the <quote>demoronizer</quote> filter, please
2699 try temporarily disabling it.
2702 If that doesn't help, temporarily disable all filters to see if another
2703 filter could be the culprit. If the problem disappears, enable the filters
2704 one by one, until the problem reappears and the offending filter is found.
2707 Once the problem-causing filter is known, it can be fixed or disabled.
2710 Upgrading <application>Privoxy</application>, or going to the most recent
2711 <filename>default.action</filename> file available from <ulink
2712 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>
2713 might be worth a try, too.
2717 <sect2 renderas="sect3" id="demoronizer2">
2719 Why are binary files (such as images) corrupted when Privoxy
2723 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2724 filter</link> in conjunction with a web server that is misreporting the content
2725 type. By default binary files are exempted from
2726 <application>Privoxy's</application> filtering
2727 (unless the web server by mistake says the file is something else).
2731 <sect2 renderas="sect3" id="demoronizer3">
2733 What is the <quote>demoronizer</quote> and why is it there?
2736 The original demoronizer was a Perl script that cleaned up HTML pages which
2737 were created with certain Microsoft products. MS has used proprietary extensions
2738 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2739 that are viewed with non-Microsoft products (and are expecting to see a
2740 standard set of fonts). The demoronizer corrected these errors so the pages
2741 displayed correctly. <application>Privoxy</application> borrowed from this
2742 script, introducing a filter based on the original demoronizer, which in turn could
2743 correct these errors on the fly.
2746 But this is only needed in some situations, and will cause serious problems in some
2750 If you are using Microsoft products, you do not need it. If you need to view
2751 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2752 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2755 On the other hand, if you use non-Microsoft products, and you occasionally
2756 notice weird characters on pages, you might want to try it.
2760 <sect2 renderas="sect3" id="windowopen">
2762 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2765 <application>Privoxy</application> is attempting to disable malicious
2766 <ulink url="https://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2767 in this case, with the <literal>unsolicited-popups</literal>
2768 filter. <application>Privoxy</application> cannot tell very well
2769 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2772 If you see this in HTML source, and the page displays without problems, then
2773 this is good, and likely some pop-up window was disabled. If you see this
2774 where it is causing a problem, such as a downloaded program source code file,
2775 then you should set an exception for this site or page such that the
2776 integrity of the page stays in tact by disabling all filtering.
2780 <sect2 renderas="sect3" id="dnserrors">
2782 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2783 can't Privoxy do this better?
2786 There are potentially several factors here. First of all, the DNS resolution
2787 is done by the underlying operating system -- not
2788 <application>Privoxy</application> itself. <application>Privoxy</application>
2789 merely initiates the process and hands it off, and then later reports
2790 whatever the outcome was and tries to give a coherent message if there seems
2791 to be a problem. In some cases, this might otherwise be mitigated by the
2792 browser itself which might try some work-arounds and alternate approaches (e.g
2793 adding <quote>www.</quote> to the URL).
2796 In other cases, if <application>Privoxy</application> is being chained
2797 with another proxy, this could complicate the issue, and cause undue
2798 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2799 server handles all the DNS. <application>Privoxy</application> would just be
2800 the <quote>messenger</quote> which is reporting whatever problem occurred
2801 downstream, and not the root cause of the error.
2805 In any case, versions newer than 3.0.3 include various improvements to help
2806 <application>Privoxy</application> better handle these cases.
2810 <sect2 renderas="sect3" id="allcpu">
2812 At one site Privoxy just hangs, and starts taking
2813 all CPU. Why is this?
2816 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2817 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2818 are in the raw HTML source of the page, and the browser just ignores them. But the
2819 pattern matching in <application>Privoxy's</application> page filtering
2820 mechanism is trying to match against absurdly long strings and this becomes
2821 very CPU-intensive, taking a long, long time to complete.
2824 Until a better solution comes along, disable filtering on these pages,
2825 particularly the <literal>js-annoyances</literal> and
2826 <literal>unsolicited-popups</literal> filters. If you run into this problem
2827 with a recent &my-app; version, please send a problem report.
2831 <sect2 renderas="sect3" id="slowcrawl">
2832 <title>I just installed Privoxy, and all my
2833 browsing has slowed to a crawl. What gives? </title>
2835 This should not happen, and for the overwhelming number of users world-wide,
2836 it does not happen. I would suspect some inadvertent interaction of software
2837 components such as anti-virus software, spyware protectors, personal
2838 firewalls or similar components. Try disabling (or uninstalling) these one
2839 at a time and see if that helps. Either way, if you are using a
2840 recent &my-app; version, please report the problem.
2844 <sect2 renderas="sect3" id="preventcomp">
2845 <title>Why do my filters work on some sites but not on others? </title>
2847 It's probably due to compression. It is a common practice for web servers to
2848 send their content <quote>compressed</quote> in order to speed things up, and
2849 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2850 &my-app; can decompress content before filtering, otherwise you may want to enable
2852 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2855 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2860 <sect2 renderas="sect3" id="ssl-warnings">
2861 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2862 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2863 What's going on?</title>
2865 Probably the browser is requesting ads through HTTPS and &my-app;
2866 is blocking the requests. Privoxy's error messages are delivered
2867 unencrypted and while it's obvious for the browser that the HTTPS
2868 request is already blocked by the proxy, some warn about unauthenticated
2872 To work around the problem you can redirect those requests to an invalid
2873 local address instead of blocking them. While the redirects aren't
2874 encrypted either, many browsers don't care. They simply follow the
2875 redirect, fail to reach a server and display an error message instead
2879 To do that, enable logging to figure out which requests get blocked by
2880 &my-app; and add the hosts (no path patterns) to a section like this:
2884 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2889 Additionally you have to configure your browser to contact
2890 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2893 To add a proxy exception in <application>Mozilla Firefox</application>
2894 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2895 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2896 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2900 You can also prevent the problem by enabling
2901 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
2902 in which case Privoxy's error messages are delivered encrypted.
2907 <sect2 renderas="sect3" id="se-linux">
2908 <title>I get selinux error messages. How can I fix this?</title>
2910 Please report the problem to the creator of your selinux policies.
2913 The problem is that some selinux policy writers aren't familiar
2914 with the application they are trying to <quote>secure</quote> and
2915 thus create policies that make no sense.
2918 In <application>Privoxy's</application> case the problem usually
2919 is that the policy only allows outgoing connections for certain
2920 destination ports (e.g. 80 and 443). While this may cover the
2921 standard ports, websites occasionally use other ports as well.
2922 This isn't a security problem and therefore <application>Privoxy's</application>
2923 default configuration doesn't block these requests.
2926 If you really want to block these ports (and don't be able
2927 to load websites that don't use standard ports), you should
2928 configure Privoxy to block these ports as well, so it doesn't
2929 trigger the selinux warnings.
2934 <sect2 renderas="sect3" id="gentoo-ricers">
2935 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2937 Probably you unintentionally compiled &my-app; without threading support
2938 in which case requests have to be serialized and only one can be served
2942 Check your <quote>USE</quote> flags and make sure they include
2943 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2946 If you compiled &my-app; with threading support (on POSIX-based systems),
2947 the <quote>Conditional #defines</quote> section on <ulink
2948 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2949 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2953 <sect2 renderas="sect3" id="tainted-sockets">
2954 <title>What are tainted sockets and how do I prevent them?</title>
2956 &my-app; marks sockets as tainted when it can't use them to
2957 serve additional requests.
2958 This does not necessarily mean that something went wrong and
2959 information about tainted sockets is only logged if connection
2960 debugging is enabled (debug 2).
2963 For example server sockets that were used for CONNECT requests
2964 (which are used to tunnel https:// requests) are considered tainted
2965 once the client closed its connection to &my-app;.
2966 Technically &my-app; could keep the connection to the server open,
2967 but the server would not accept requests that do not belong to the
2968 previous TLS/SSL session (and the client may even have terminated
2972 Server sockets are also marked tainted when a client requests a
2973 resource, but closes the connection before &my-app; has completely
2974 received (and forwarded) the resource to the client.
2975 In this case the server would (probably) accept additional requests,
2976 but &my-app; could not get the response without completely reading
2977 the leftovers from the previous response.
2980 These are just two examples, there are currently a bit more than
2981 25 scenarios in which a socket is considered tainted.
2984 While sockets can also be marked tainted as a result of a technical
2985 problem that may be worth fixing, the problem will be explicitly
2990 <sect2 renderas="sect3" id="pcre-stack-limit">
2991 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2993 This can happen if your custom filters require more memory than &my-app;
2995 Usually the problem is that the operating system enforces a stack size limit
2996 that isn't sufficient.
2999 Unless the problem occurs with the filters available in the default configuration,
3000 this is not considered a Privoxy bug.
3003 To prevent the crashes you can rewrite your filter to use less resources,
3004 increase the relevant memory limit or recompile pcre to use less stack space.
3005 For details please see the
3006 <ulink url="https://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3007 and the documentation of your operating system.
3011 <sect2 renderas="sect3" id="file-permissions">
3012 <title>What to do if editing the config file of privoxy is access denied?</title>
3014 Your userid probably isn't allowed to edit the file.
3015 <!-- show how to check permissions? -->
3016 On Windows you can use the windows equivalent of sudo:
3018 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
3021 or fix the file permissions:
3023 <screen>C:\Privoxy>icacls config.txt
3024 config.txt BUILTIN\Administrators:(I)(F)
3025 NT AUTHORITY\SYSTEM:(I)(F)
3026 BUILTIN\Users:(I)(RX)
3027 NT AUTHORITY\Authenticated Users:(I)(M)
3029 Successfully processed 1 files; Failed processing 0 files
3031 C:\Privoxy>icacls config.txt /grant Lee:F
3032 processed file: config.txt
3033 Successfully processed 1 files; Failed processing 0 files
3035 C:\Privoxy>icacls config.txt
3036 config.txt I3668\Lee:(F)
3037 BUILTIN\Administrators:(I)(F)
3038 NT AUTHORITY\SYSTEM:(I)(F)
3039 BUILTIN\Users:(I)(RX)
3040 NT AUTHORITY\Authenticated Users:(I)(M)
3042 Successfully processed 1 files; Failed processing 0 files
3044 C:\Privoxy></screen>
3047 or try to point-n-click your way through adjusting the file
3048 permissions in windows explorer.
3054 <!-- ~~~~~ New section ~~~~~ -->
3055 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3056 <!-- Include contacting.sgml -->
3058 <!-- end contacting -->
3061 <!-- ~~~~~ New section ~~~~~ -->
3062 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3064 <!-- Include copyright.sgml -->
3070 Portions of this document are <quote>borrowed</quote> from the original
3071 <application>Junkbuster</application> (tm) FAQ, and modified as
3072 appropriate for <application>Privoxy</application>.
3075 <!-- ~~~~~ New section ~~~~~ -->
3076 <sect2 id="privoxy-license"><title>License</title>
3077 <!-- Include copyright.sgml: -->
3079 <!-- end copyright -->
3081 <!-- ~ End section ~ -->
3083 <!-- ~~~~~ New section ~~~~~ -->
3084 <sect2 id="history"><title>History</title>
3085 <!-- Include history.sgml -->
3091 <!-- ~ End section ~ -->
3094 <!-- ~~~~~ New section ~~~~~ -->
3096 <sect1 id="seealso"><title>See also</title>
3098 <!-- Include seealso.sgml -->
3108 This program is free software; you can redistribute it
3109 and/or modify it under the terms of the GNU General
3110 Public License as published by the Free Software
3111 Foundation; either version 2 of the License, or (at
3112 your option) any later version.
3114 This program is distributed in the hope that it will
3115 be useful, but WITHOUT ANY WARRANTY; without even the
3116 implied warranty of MERCHANTABILITY or FITNESS FOR A
3117 PARTICULAR PURPOSE. See the GNU General Public
3118 License for more details.
3120 The GNU General Public License should be included with
3121 this file. If not, you can view it at
3122 http://www.gnu.org/copyleft/gpl.html
3123 or write to the Free Software Foundation, Inc.,
3124 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA