1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN"[
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3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity contacting SYSTEM "contacting.sgml">
8 <!entity history SYSTEM "history.sgml">
9 <!entity copyright SYSTEM "copyright.sgml">
10 <!entity license SYSTEM "license.sgml">
11 <!entity p-version "3.0.29">
12 <!entity p-status "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) 2001-2020 Privoxy Developers https://www.privoxy.org/
31 Based partially on the Internet Junkbuster FAQ originally written by and
32 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
33 http://www.junkbusters.com/
35 <Qandaset defaultlabel='qanda'>
50 ========================================================================
51 NOTE: Please read developer-manual/documentation.html before touching
54 Please we keep the info in this file as version independent as possible
55 so we only have to maintain one FAQ. Where significant changes are
56 made to Privoxy configuration, please note the change in such a way that
57 it makes sense to both users of older and newer versions.
58 ========================================================================
64 <article id="index" class="faq">
66 <title>Privoxy Frequently Asked Questions</title>
70 <!-- Completely the wrong markup, but very little is allowed -->
71 <!-- in this part of an article. FIXME -->
72 <link linkend="copyright">Copyright</link> &my-copy; 2001-2020 by
73 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
79 Note: this should generate a separate page, and a live link to it.
80 But it doesn't for some mysterious reason. Please leave commented
81 unless it can be fixed proper. For the time being, the copyright
82 statement will be in copyright.smgl.
86 <legalnotice id="legalnotice">
88 text goes here ........
98 <orgname>By: Privoxy Developers</orgname>
107 This is here to keep vim syntax file from breaking :/
108 If I knew enough to fix it, I would.
109 PLEASE DO NOT REMOVE! HB: hal@foobox.net
114 This FAQ gives quick answers to frequently asked questions about
115 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
116 It is not a substitute for the
117 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
120 <!-- Include privoxy.sgml boilerplate: -->
121 <para>What is Privoxy?</para> &p-intro;
122 <!-- end boilerplate -->
125 Please note that this document is a work in progress. This copy represents
126 the state at the release of version &p-version;.
127 You can find the latest version of the document at <ulink
128 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
129 Please see the <link linkend="contact">Contact section</link> if you want to
130 contact the developers.
137 <!-- ~~~~~ New section ~~~~~ -->
139 <sect1 id="general"><title>General Information</title>
140 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
142 Anyone who is interested in security, privacy, or in
143 finer-grained control over their web and Internet experience.
147 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
150 &my-app; is certainly a good choice, especially for those who want more
151 control and security. Those with the willingness to read the documentation
152 and the ability to fine-tune their installation will benefit the most.
155 One of <application>Privoxy's</application>
156 strengths is that it is highly configurable giving you the ability to
157 completely personalize your installation. Being familiar with, or at least
158 having an interest in learning about <ulink
159 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
160 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
161 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
162 Expressions</quote></ulink>
163 will be a big plus and will help you get the most out of &my-app;.
164 A new installation just includes a very basic configuration. The user
165 should take this as a starting point only, and enhance it as he or she
166 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
170 Much of <application>Privoxy's</application> configuration can be done
171 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
172 But there are areas where configuration is done using a
173 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
174 to edit configuration files. Also note that the web-based action editor
175 doesn't use authentication and should only be enabled in environments
176 where all clients with access to &my-app; listening port can be trusted.
180 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
181 Privoxy work? </title>
183 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
184 is a service, based on a software such as &my-app;, that clients
185 (i.e. browsers) can use instead of connecting to web servers directly.
186 The clients then ask the proxy to request objects (web pages, images, movies etc)
187 on their behalf and to forward the data to the clients.
188 It is a <quote>go-between</quote>. For details, see
189 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
192 There are many reasons to use web proxies, such as security (firewalling),
193 efficiency (caching) and others, and there are any number of proxies
194 to accommodate those needs.
197 &my-app; is a proxy that is primarily focused on
198 privacy enhancement, ad and junk elimination and freeing the user from
199 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
200 it is in a perfect position to filter outbound personal information that your
201 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
202 this, all of which are under your complete control via the various configuration
203 files and options. Being a proxy also makes it easier to share
204 configurations among multiple browsers and/or users.
208 <sect2 renderas="sect3" id="otherstuff">
209 <title>Does Privoxy do anything more than ad blocking?</title>
211 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
212 can be used to sanitize and customize web browsing.
216 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
217 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
219 <!-- Include history.sgml -->
226 <sect2 renderas="sect3" id="whyprivoxy">
227 <title>Why <quote>Privoxy</quote>? Why change the name from
228 Junkbuster at all?</title>
230 Though outdated, Junkbusters Corporation continued to offer their original
231 version of the <application>Internet Junkbuster</application> for a while,
232 so publishing our <application> Junkbuster</application>-derived software
233 under the same name would have led to confusion.
236 There were also potential legal reasons not to use the
237 <application>Junkbuster</application> name, as it was (and maybe still is)
238 a registered trademark of Junkbusters Corporation.
239 There were, however, no objections from Junkbusters Corporation to the
240 <application>Privoxy</application> project itself, and they, in fact,
241 shared our ideals and goals.
244 The Privoxy developers also believed that there were so many improvements
245 over the original code, that it was time to make a clean break from the past
246 and make a name in their own right.
249 <application>Privoxy</application> is the
250 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
251 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
252 control, more freedom, and allows you to browse your personal and
253 <quote><emphasis>private</emphasis> edition</quote> of the web.
257 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
258 from the old Junkbuster?</title>
260 <application>Privoxy</application> picks up where
261 <application>Junkbuster</application> left off.
262 <application>Privoxy</application> still blocks ads and banners,
264 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
265 helps protect your privacy. But, most of these features have been enhanced,
266 and many new ones have been added, all in the same vein.
269 <application>Privoxy</application>'s new features include:
272 <!-- Include newfeatures.sgml: -->
278 <sect2 renderas="sect3" id="whatsanad">
279 <title>How does Privoxy know what is an ad, and what is not?</title>
281 <application>Privoxy</application>'s approach to blocking ads is twofold:
284 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
285 of banner images. This applies to both the path (you wouldn't guess how many
286 web sites serve their banners from a directory called <quote>banners</quote>!)
287 and the host (blocking the big banner hosting services like doublecklick.net
288 already helps a lot). <application>Privoxy</application> takes advantage of this
289 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
290 patterns</ulink> to sort out and block the requests for things that sound
291 like they would be ads or banners.
294 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
295 can't tell the size of an image by its URL without downloading it, and if you
296 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
297 also inspects the HTML sources of web pages while they are loaded, and replaces
298 references to images with standard banner sizes by dummy references, so that
299 your browser doesn't request them anymore in the first place.
302 Both of this involves a certain amount of guesswork and is, of course, freely
303 and readily configurable.
307 <sect2 renderas="sect3" id="mistakes">
308 <title>Can Privoxy make mistakes?
309 This does not sound very scientific.</title>
311 Actually, it's a black art ;-) And yes, it is always possible to have a broad
312 rule accidentally block or change something by mistake. You will almost surely
313 run into such situations at some point. It is tricky writing rules to
314 cover every conceivable possibility, and not occasionally get false positives.
318 But this should not be a big concern since the
319 <application>Privoxy</application> configuration is very flexible, and
320 includes tools to help identify these types of situations so they can be
321 addressed as needed, allowing you to customize your installation.
322 (<link linkend="badsite">See the Troubleshooting section below</link>.)
327 <sect2 renderas="sect3" id="configornot">
328 <title>Will I have to configure Privoxy
329 before I can use it?</title>
331 That depends on your expectations.
332 The default installation should give you a good starting
333 point, and block <emphasis>most</emphasis> ads and unwanted content,
334 but many of the more advanced features are off by default, and require
335 you to activate them.
338 You do have to set up your browser to use
339 <application>Privoxy</application> (see the <link
340 linkend="firststep">Installation section below</link>).
343 And you will certainly run into situations where there are false positives,
344 or ads not being blocked that you may not want to see. In these cases, you
345 would certainly benefit by customizing <application>Privoxy's</application>
346 configuration to more closely match your individual situation. And we
347 encourage you to do this. This is where the real power of
348 <application>Privoxy</application> lies!
353 <sect2 renderas="sect3" id="lan">
354 <title>Can Privoxy run as a server on a network?</title>
356 Yes, &my-app; runs as a server already, and can easily be configured to
357 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
358 How can I set up Privoxy to act as a proxy for my LAN</link> below.
362 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
363 Privoxy. Why should I use Privoxy at all?</title>
365 Modern browsers do indeed have <emphasis>some</emphasis> of the same
366 functionality as <application>Privoxy</application>. Maybe this is
367 adequate for you. But <application>Privoxy</application> is very
368 versatile and powerful, and can probably do a number of things
369 your browser just can't.
372 In addition, a proxy is good choice if you use multiple browsers, or
373 have a LAN with multiple computers since &my-app; can run as a server
374 application. This way all the configuration is in one place, and you don't
375 have to maintain a similar configuration for possibly many browsers or
379 Note, however, that it's recommended to leverage both your browser's
380 and <application>Privoxy's</application> privacy enhancing features
381 at the same time. While your browser probably lacks some features
382 &my-app; offers, it should also be able to do some things more
383 reliably, for example restricting and suppressing JavaScript.
387 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
389 The most important reason is because you have access to
390 <emphasis>everything</emphasis>, and you can control everything. You can
391 check every line of every configuration file yourself. You can check every
392 last bit of source code should you desire. And even if you can't read code,
393 there should be some comfort in knowing that <!-- thousands of -->other people can,
394 and do read it. You can build the software from scratch, if you want,
395 so that you know the executable is clean, and that it is
396 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
397 is one reason we use &my-app; ourselves.
401 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
402 warranty? Registration?</title>
404 <application>Privoxy</application> is free software and licensed under the <ulink
405 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
406 It is free to use, copy, modify or distribute as you wish under the terms of this
407 license. Please see the <link linkend="copyright">Copyright</link> section for more
408 information on the license and copyright. Or the <filename>LICENSE</filename> file
409 that should be included.
412 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
413 That is something that would cost real money ;-) There is no registration either.
418 <sect2 renderas="sect3" id="spyware">
419 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
421 No, at least not reliably enough to trust it. &my-app; is not designed to be
422 a malware removal tool and the default configuration doesn't even try to
423 filter out any malware.
426 &my-app; could help prevent contact from (known) sites that use such
427 tactics with appropriate configuration rules, and thus could conceivably
428 prevent contamination from such sites. However, keeping such a configuration
429 up to date would require a lot of time and effort that would be better spend
430 on keeping your software itself up to date so it doesn't have known
436 <sect2 renderas="sect3" id="otherads">
437 <title>Can I use Privoxy with other ad-blocking software?</title>
439 &my-app; should work fine with other proxies and other software in general.
442 But it is probably not necessary to use &my-app; in conjunction with other
443 ad-blocking products, and this could conceivably cause undesirable results.
444 It might be better to choose one software or the other and work a little to
445 tweak its configuration to your liking.
448 Note that this is an advice specific to ad blocking.
452 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
454 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
456 Well, we <emphasis>always</emphasis> need help. There is something for
457 everybody who wants to help us. We welcome new developers, packagers,
458 testers, documentation writers or really anyone with a desire to help in
459 any way. You <emphasis>DO NOT</emphasis> need to be a
460 <quote>programmer</quote>. There are many other tasks available. In fact,
461 the programmers often can't spend as much time programming because of some
462 of the other, more mundane things that need to be done, like checking the
463 Tracker feedback sections or responding to user questions on the mailing
467 So first thing, subscribe to the <ulink
468 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
469 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
470 Developers</ulink> mailing list, join the discussion, help out other users, provide general
471 feedback or report problems you noticed.
474 If you intend to help out with the trackers, you also might want to <ulink
475 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
476 so we don't confuse you with the other name-less users.
479 We also have a <ulink
480 url="../developer-manual/index.html">Developer's Manual</ulink>.
481 While it is partly out of date, it's still worth reading.
484 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
485 may be of interest to you as well.
486 Please let us know if you want to work on one of the items listed.
490 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
492 Donations are welcome. Our
493 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
494 is rather long and being able to pay one (or more) developers to work on Privoxy
495 would make a huge difference, even if it was only for a couple of weeks. Donations may
496 also be used for Privoxy-related travel expenses (for example to attend conferences),
497 for hardware used for Privoxy development and for hosting expenses etc.
501 <application>Privoxy</application> is an associated
502 project of <ulink url="https://www.spi-inc.org/">Software
503 in the Public Interest (SPI)</ulink>, which allows us to receive
504 tax-deductible donations in the United States.
505 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
506 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
507 For details, please have a look at
508 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
512 You can also donate to Privoxy using a bank account or a "Paypal" address:
515 Name on account: <ulink url="https://www.zwiebelfreunde.de/">Zwiebelfreunde e.V.</ulink>
516 IBAN: DE95430609671126825604
521 "Paypal" address: privoxy@zwiebelfreunde.de
524 Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany
525 and other countries that recognize German charitable clubs. Feel free to
526 use the Subject field to provide a name to be credited and a list of TODO
527 list items you are interested in the most. For example: Max Mustermann: #16, #1, #14.
531 Note that donations made through Zwiebelfreunde e.V. currently can't be checked
532 automatically so you may not get credited right away. The credits currently
533 reflect donations received before 2016-01-14.
537 If you have any questions regarding donations please mail to either the
538 public user mailing list or, if it's a private matter, to
539 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
544 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
546 We are currently offering the following sponsor levels as an experiment:
550 <term>Gold (12000 USD/year)</term>
553 Logo shown at the bottom of the
554 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
555 Logo, link and self description on the
556 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
561 <term>Silver (1200 USD/year)</term>
564 Logo shown randomly at the bottom of the
565 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
566 Logo, link and self description on the
567 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
572 <term>Bronze (600 USD/year)</term>
575 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
581 The logo sizes depend on the sponsor level. Logos are served from
582 our server, no requests are made to the sponsor website unless
583 the links are being used.
586 The details may change over time but changes will only affect new sponsors
587 (or existing sponsors that explicitly agreed to the changes).
590 If you want to become a sponsor, please contact
591 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
592 New sponsors are only accepted if no developer objects.
600 <!-- ~~~~~ New section ~~~~~ -->
602 <sect1 id="installation"><title>Installation</title>
604 <sect2 renderas="sect3" id="whichbrowsers">
605 <title>Which browsers are supported by Privoxy?</title>
607 Any browser that can be configured to use a proxy, which
608 should be virtually all browsers, including
609 <application>Firefox</application>, <application>Internet
610 Explorer</application>, <application>Opera</application>, and
611 <application>Safari</application> among others.
612 Direct browser support is not an absolute requirement since
613 <application>Privoxy</application> runs as a separate application and talks
614 to the browser in the standardized HTTP protocol, just like a web server
619 <sect2 renderas="sect3" id="whichos">
620 <title>Which operating systems are supported?</title>
622 Include supported.sgml here:
627 <sect2 renderas="sect3" id="email-client">
628 <title>Can I use Privoxy with my email client?</title>
630 As long as there is some way to set a HTTP proxy for the client, then yes,
631 any application can be used, whether it is strictly speaking a
632 <quote>browser</quote> or not. Though this may not be the best approach for
633 dealing with some of the common abuses of HTML in email. See <link
634 linkend="outlook">How can I configure <application>Privoxy</application>
635 with <application>Outlook</application>?</link> below for more on
639 Be aware that HTML email presents a number of unique security and privacy
640 related issues, that can require advanced skills to overcome. The developers
641 recommend using email clients that can be configured to convert HTML to plain
642 text for these reasons.
646 <!-- Nobody is going to still be doing this!
647 <sect2 renderas="sect3" id="newinstall"><title>Can I install
648 Privoxy over Junkbuster?</title>
650 We recommend you un-install <application>Junkbuster</application>
651 first to minimize conflicts and confusion. You may want to
652 save your old configuration files for future reference. The configuration
653 files and syntax have substantially changed, so you will need to manually
654 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
655 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
656 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
660 Note: Some installers may automatically un-install
661 <application>Junkbuster</application>, if present!
667 <sect2 renderas="sect3" id="firststep">
668 <title>I just installed Privoxy. Is there anything
669 special I have to do now?</title>
672 All browsers should be told to use <application>Privoxy</application>
673 as a proxy by specifying the correct proxy address and port number
674 in the appropriate configuration area for the browser. It's possible
675 to combine &my-app; with a packet filter to intercept HTTP requests
676 even if the client isn't explicitly configured to use &my-app;,
677 but where possible, configuring the client is recommended. See
678 <ulink url="../user-manual/startup.html">the User Manual for more
679 details</ulink>. You should also flush your browser's memory and disk
680 cache to get rid of any cached junk items, and remove any stored
681 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
686 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
688 If you set up the <application>Privoxy</application> to run on
689 the computer you browse from (rather than your ISP's server or some
690 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
691 (sometimes referred to as <quote>localhost</quote>,
692 which is the special name used by every computer on the Internet to refer
693 to itself) and the port will be 8118 (unless you used the <ulink
694 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
695 config option to tell <application>Privoxy</application> to run on
699 When configuring your browser's proxy settings you typically enter
700 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
701 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
702 then the number <quote>8118</quote> for <quote>port</quote>.
703 This tells your browser to send all web requests to <application>Privoxy</application>
704 instead of directly to the Internet.
707 <application>Privoxy</application> can also be used to proxy for
708 a Local Area Network. In this case, your would enter either the IP
709 address of the LAN host where <application>Privoxy</application>
710 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
711 Port assignment would be same as above. Note that
712 <application>Privoxy</application> doesn't listen on any LAN interfaces by
716 <application>Privoxy</application> does not currently handle
717 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
721 <sect2 renderas="sect3" id="nothing">
722 <title>I just installed Privoxy, and nothing is happening.
723 All the ads are there. What's wrong?</title>
726 Did you configure your browser to use <application>Privoxy</application>
727 as a proxy? It does not sound like it. See above. You might also try flushing
728 the browser's caches to force a full re-reading of pages. You can verify
729 that <application>Privoxy</application> is running, and your browser
730 is correctly configured by entering the special URL:
731 <ulink url="http://p.p/">http://p.p/</ulink>.
732 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
733 of potential redirect caching problem (see next Q). -->
734 This should take you to a page titled <quote>This is Privoxy..</quote> with
735 access to <application>Privoxy's</application> internal configuration.
736 If you see this, then you are good to go. If you receive a page saying
737 <quote>Privoxy is not running</quote>, then the browser is not set up to use
738 your <application>Privoxy</application> installation.
739 If you receive anything else (probably nothing at all), it could either
740 be that the browser is not set up correctly, or that
741 <application>Privoxy</application> is not running at all. Check the <ulink
742 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
743 on starting <application>Privoxy</application> and browser configuration,
744 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
745 on starting <application>Privoxy</application></ulink> in the
746 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
751 <sect2 renderas="sect3" id="notused">
752 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
753 Privoxy is running and being used.</title>
756 First, make sure that Privoxy is <emphasis>really</emphasis> running and
757 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
758 should see the <application>Privoxy</application> main page. If not, see
759 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
760 on starting <application>Privoxy</application></ulink> in the
761 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
765 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
766 other parts of <application>Privoxy</application>'s web interface show
767 the dummy page, your browser has cached a redirection it encountered before
768 <application>Privoxy</application> was being used. You need to clear your
769 browser's cache. Note that shift-reloading the dummy page won't help, since
770 that'll only refresh the dummy page, not the redirection that lead you there.
774 The procedure for clearing the cache varies from browser to browser. For
775 example, <application>Mozilla/Netscape</application> users would click
776 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
777 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
778 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
779 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
780 In some <application>Firefox</application> versions it's
781 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
782 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
783 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
784 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
791 <!-- ~~~~~ New section ~~~~~ -->
793 <sect1 id="configuration"><title>Configuration</title>
794 <sect2 renderas="sect3" id="actionsfile">
795 <title>What exactly is an <quote>actions</quote> file?</title>
798 &my-app; utilizes the concept of <quote>
799 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
800 that are used to manipulate and control web page data.
801 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
802 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
803 that <application>Privoxy</application> could take while processing a certain
804 request, are configured. Typically, you would define a set of default actions
805 that apply globally to all URLs, then add exceptions to these defaults where needed.
806 There is a wide array of actions available that give the user a high degree
807 of control and flexibility on how to process each and every web page.
811 Actions can be defined on a <ulink
812 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
813 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
814 grouped together and then applied to requests matching one or more patterns.
815 There are many possible actions that might apply to any given site. As an example,
816 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
817 as one of your default actions, but need to accept cookies from a given site,
818 you would need to define an exception for this site in one of your actions
819 files, preferably in <filename>user.action</filename>.
824 <sect2 renderas="sect3" id="actionss">
825 <title>The <quote>actions</quote> concept confuses me. Please list
826 some of these <quote>actions</quote>.</title>
828 For a comprehensive discussion of the actions concept, please refer
829 to the <ulink url="../user-manual/actions-file.html">actions file
830 chapter</ulink> in the <ulink url="../user-manual/index.html">User
831 Manual</ulink>. It includes a <ulink
832 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
833 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
834 file tutorial</ulink> to get you started.
839 <sect2 renderas="sect3" id="actconfig">
840 <title>How are actions files configured? What is the easiest
841 way to do this?</title>
844 Actions files are just text files in a special syntax and can be edited
845 with a text editor. But probably the easiest way is to access
846 <application>Privoxy</application>'s user interface with your web browser
847 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
848 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
849 <quote><ulink url="http://config.privoxy.org/show-status">View &
850 change the current configuration</ulink></quote> from the menu. Note
851 that this feature must be explicitly enabled in the main config file
853 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
858 <sect2 renderas="sect3">
859 <title>There are several different <quote>actions</quote> files. What are
860 the differences?</title>
862 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
863 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
868 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
870 Based on your feedback and the continuing development, updates of
871 <filename>default.action</filename> will be
872 made available from time to time on the <ulink
873 url="https://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
874 our <ulink url="https://sourceforge.net/projects/ijbswa/">project page</ulink>.
878 If you wish to receive an email notification whenever we release updates of
879 <application>Privoxy</application> or the actions file, <ulink
880 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
881 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
886 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
888 The syntax and purpose of configuration files has remained roughly the
889 same throughout the 3.x series, but backwards compatibility is not guaranteed.
890 Also each release contains updated, <quote>improved</quote> versions and it is
891 therefore strongly recommended to install the newer configuration files
892 and merge back your modifications.
896 <sect2 renderas="sect3" id="difficult">
897 <title>Why is the configuration so complicated?</title>
899 <quote>Complicated</quote> is in the eye of the beholder.
902 Privoxy is currently mainly written by and for people who are already
903 familiar with the underlying concepts like regular expressions, HTTP and HTML,
904 or are willing to become familiar with them to be able to get the most
905 out of a powerful and flexible tool such as Privoxy.
908 While everybody is expected to be able to get a Privoxy default installation
909 up and running, fine-tuning requires a certain amount of background
910 information and Privoxy's documentation mainly concentrates on the
911 Privoxy-specific parts while only providing references to the rest.
914 If you or anyone you know has the skills, time and energy to
915 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
919 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
921 The default configuration shouldn't impact the usability of any of these services.
922 It may, however, make all <ulink
923 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
924 temporary, so that your browser will forget your
925 login credentials in between browser sessions. If you would like not to have to log
926 in manually each time you access those websites, simply turn off all cookie handling
927 for them in the <filename>user.action</filename> file. An example for yahoo might
930 <screen># Allow all cookies for Yahoo login:
932 { -<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> }
933 .login.yahoo.com</screen>
935 These kinds of sites are often quite complex and heavy with
936 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
937 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
939 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
942 <screen># Gmail is a _fragile_ site:
944 { <literal>fragile</literal> }
946 mail.google.com</screen>
948 Be sure to flush your browser's caches whenever making these kinds of
949 changes, just to make sure the changes <quote>take</quote>.
952 Make sure the domain, host and path are appropriate as well. Your browser can
953 tell you where you are specifically and you should use that information for
954 your configuration settings. Note that above it is not referenced as
955 <literal>gmail.com</literal>, which is a valid domain name.
960 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
961 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
963 Configuring <application>Privoxy</application> is not entirely trivial. To
964 help you get started, we provide you with three different default action
965 <quote>profiles</quote> in the web based actions file editor at <ulink
966 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
967 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
968 Manual</citetitle></ulink> for a list of actions, and how the default
973 Where the defaults are likely to break some sites, exceptions for
974 known popular <quote>problem</quote> sites are included, but in
975 general, the more aggressive your default settings are, the more exceptions
976 you will have to make later. New users are best to start off in
977 <quote>Cautious</quote> setting. This is safest and will have the fewest
978 problems. See the <ulink
979 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
980 for a more detailed discussion.
984 It should be noted that the <quote>Advanced</quote> profile (formerly known
985 as the <quote>Adventuresome</quote> profile) is more
986 aggressive, and will make use of some of
987 <application>Privoxy's</application> advanced features. Use at your own risk!
992 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
993 with a browser? Does that not raise security issues?</title>
995 It may seem strange that regular users can edit the config files with their
996 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
997 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
1000 When you use the browser-based editor, <application>Privoxy</application>
1001 itself is writing to the config files. Because
1002 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
1003 it can update its own config files.
1006 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
1007 a LAN) or aren't entirely in control of your own browser, you will probably want
1008 to make sure that the web-based editor and remote toggle features are
1009 <quote>off</quote> by setting <quote><literal><ulink
1010 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
1011 0</literal></quote> and <quote><literal><ulink
1012 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
1013 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
1016 As of &my-app; 3.0.7 these options are disabled by default.
1021 <sect2 renderas="sect3" id="filterfile">
1022 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
1024 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
1025 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1026 Filters are a special subset of actions that can be used to modify or
1027 remove web page content or headers on the fly. Content filters can
1028 be applied to <emphasis>anything</emphasis> in the page source,
1029 header filters can be applied to either server or client headers.
1030 Regular expressions are used to accomplish this.
1033 There are a number of pre-defined filters to deal with common annoyances. The
1034 filters are only defined here, to invoke them, you need to use the
1036 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1037 action</ulink> in one of the actions files. Content filtering is automatically
1038 disabled for inappropriate MIME types, but if you know better than Privoxy
1039 what should or should not be filtered you can filter any content you like.
1043 <emphasis>not</emphasis> be confused with <ulink
1044 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1045 is a completely different action, and is more typically used to block ads and
1050 If you are familiar with regular expressions, and HTML, you can look at
1051 the provided <filename>default.filter</filename> with a text editor and define
1052 your own filters. This is potentially a very powerful feature, but
1053 requires some expertise in both regular expressions and HTML/HTTP.
1054 <![%p-newstuff;[ You should
1055 place any modifications to the default filters, or any new ones you create
1056 in a separate file, such as <filename>user.filter</filename>, so they won't
1057 be overwritten during upgrades.
1058 The ability to define multiple filter files
1059 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1063 There is no GUI editor option for this part of the configuration,
1064 but you can disable/enable the various pre-defined filters of the included
1065 <filename>default.filter</filename> file with the <ulink
1066 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1067 Note that the custom actions editor must be explicitly enabled in
1068 the main config file (see <ulink
1069 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1073 If you intend to develop your own filters, you might want to have a look at
1075 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1080 <sect2 renderas="sect3" id="lanconfig">
1081 <title>How can I set up Privoxy to act as a proxy for my
1084 By default, <application>Privoxy</application> only responds to requests
1085 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1086 a network, this needs to be changed in the <ulink
1087 url="../user-manual/config.html">main configuration file</ulink>. Look for
1089 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1090 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1091 it is uncommented, and assign it the address of the LAN gateway interface,
1092 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1093 wish to run <application>Privoxy</application> on port 8118, this line
1098 listen-address 192.168.1.1:8118</screen>
1101 Save the file, and restart <application>Privoxy</application>. Configure
1102 all browsers on the network then to use this address and port number.
1106 Alternately, you can have <application>Privoxy</application> listen on
1107 all available interfaces:
1111 listen-address :8118</screen>
1114 And then use <application>Privoxy's</application>
1116 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1117 feature to limit connections. A firewall in this situation is recommended
1122 The above steps should be the same for any TCP network, regardless of
1127 If you run <application>Privoxy</application> on a LAN with untrusted users,
1128 we recommend that you double-check the <ulink
1129 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1136 <sect2 renderas="sect3" id="noseeum">
1137 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1139 The replacement for blocked images can be controlled with the <ulink
1140 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1141 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1142 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1143 Note that this choice only has effect for images which are blocked as images, i.e.
1144 whose URLs match both a <literal><ulink
1145 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1146 <emphasis>and</emphasis> <literal><ulink
1147 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1150 If you want to see nothing, then change the <ulink
1151 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1152 action</ulink> to <quote>blank</quote>. This can be done by editing the
1153 <filename>user.action</filename> file, or through the <ulink
1154 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1159 <sect2 renderas="sect3" id="whyseeum">
1160 <title>Why would anybody want to see a checkerboard pattern?</title>
1162 Remember that <link linkend="whatsanad">telling which image is an ad and which
1163 isn't</link>, is an educated guess. While we hope that the standard configuration
1164 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1165 decent, and it shows you where images have been blocked, which can be very
1166 helpful in case some navigation aid or otherwise innocent image was
1167 erroneously blocked. It is recommended for new users so they can
1168 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1169 many banners they <emphasis>don't</emphasis> have to see.
1174 <sect2 renderas="sect3" id="blockedbytext">
1175 <title>I see some images being replaced with text
1176 instead of the checkerboard image. Why and how do I get rid of this?</title>
1178 This happens when the banners are not embedded in the HTML code of the
1179 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1180 or (i)layers, and these external HTML documents are blocked. Being non-images
1181 they get replaced by a substitute HTML page rather than a substitute image,
1182 which wouldn't work out technically, since the browser expects and accepts
1183 only HTML when it has requested an HTML document.
1186 The substitute page adapts to the available space and shows itself as a
1187 miniature two-liner if loaded into small frames, or full-blown with a
1188 large red "BLOCKED" banner if space allows.
1191 If you prefer the banners to be blocked by images, you must see to it that
1192 the HTML documents in which they are embedded are not blocked. Clicking
1193 the <quote>See why</quote> link offered in the substitute page will show
1194 you which rule blocked the page. After changing the rule and un-blocking
1195 the HTML documents, the browser will try to load the actual banner images
1196 and the usual image blocking will (hopefully!) kick in.
1201 <sect2 renderas="sect3" id="srvany">
1202 <title>Can Privoxy run as a service
1203 on Win2K/NT/XP?</title>
1206 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1207 functionality. See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1208 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1209 <application>Privoxy</application> as a service.
1212 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1213 See the discussion at <ulink
1214 url="https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</ulink>,
1215 for details, and a sample configuration.
1220 <sect2 renderas="sect3" id="otherproxy">
1221 <title>How can I make Privoxy work with other proxies?</title>
1223 This can be done and is often useful to combine the benefits of
1224 <application>Privoxy</application> with those of a another proxy,
1225 for example to cache content.
1227 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1228 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1229 describes how to do this. If you intend to use Privoxy with Tor,
1230 please also have a look at
1231 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1235 <sect2 renderas="sect3" id="port-80">
1236 <title>Can I just set Privoxy to use port 80
1237 and thus avoid individual browser configuration?</title>
1240 No, its more complicated than that. This only works with special kinds
1241 of proxies known as <quote>intercepting</quote> proxies
1242 (<link linkend="INTERCEPTING">see below</link>).
1247 <sect2 renderas="sect3" id="transparent">
1248 <title>Can Privoxy run as a <quote>transparent
1249 </quote> proxy?</title>
1251 The whole idea of Privoxy is to modify client requests
1252 and server responses in all sorts of ways and therefore
1253 it's not a transparent proxy as described in
1254 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1257 However, some people say <quote>transparent proxy</quote> when they
1258 mean <quote>intercepting proxy</quote>. If you are one of them,
1259 please read the <link linkend="INTERCEPTING">next entry</link>.
1264 <sect2 renderas="sect3" id="intercepting">
1265 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1267 <application>Privoxy</application> can't intercept traffic itself,
1268 but it can handle requests that where intercepted and redirected
1269 with a packet filter (like <application>PF</application> or
1270 <application>iptables</application>), as long as the <literal>Host</literal>
1274 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1275 web sites rely on it anyway, this limitation shouldn't be a problem.
1278 Please refer to your packet filter's documentation to learn how to
1279 intercept and redirect traffic into <application>Privoxy</application>.
1280 Afterward you just have to configure <application>Privoxy</application> to
1281 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1282 intercepted requests</ulink>.
1287 <sect2 renderas="sect3" id="outlook">
1288 <title>How can I configure Privoxy for use with Outlook?</title>
1290 Versions of <application>Outlook</application> prior to Office 2007, use
1291 <application>Internet Explorer</application> components to both render HTML,
1292 and fetch any HTTP requests that may be embedded in an HTML email. So however
1293 you have <application>Privoxy</application> configured to work with IE, this
1294 configuration should automatically be shared, at least with older version of
1298 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1299 engine with Outlook. It is unknown whether this can be configured to use a
1301 <!-- FIXME HB 2009-02-15 -->
1305 <sect2 renderas="sect3" id="outlook-more">
1306 <title>How can I have separate rules just for HTML mail?</title>
1308 The short answer is, you can't. <application>Privoxy</application> has no way
1309 of knowing which particular application makes a request, so there is no way to
1310 distinguish between web pages and HTML mail.
1311 <application>Privoxy</application> just blindly proxies all requests. In the
1312 case of <application>Outlook Express</application> (see above), OE uses
1313 IE anyway, and there is no way for <application>Privoxy</application> to ever
1314 be able to distinguish between them (nor could any other proxy type application for
1318 For a good discussion of some of the issues involved (including privacy and
1319 security issues), see
1320 <ulink url="https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1324 <sect2 renderas="sect3" id="sneaky-cookies">
1325 <title>I sometimes notice cookies sneaking through. How?</title>
1328 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1329 set in several ways. The classic method is via the
1330 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1331 easy one to manipulate, such as the &my-app; concept of
1332 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1333 There is also the possibility of using
1334 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1335 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1336 is trickier because the syntax can vary widely, and thus requires a certain
1337 amount of guesswork. It is not realistic to catch all of these short of
1338 disabling Javascript, which would break many sites. And lastly, if the
1339 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1340 <application>Privoxy's</application> reach unless you enable
1341 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1344 All in all, &my-app; can help manage cookies in general, can help minimize
1345 the loss of privacy posed by cookies, but can't realistically stop all
1350 <sect2 renderas="sect3" id="evil-cookies">
1351 <title>Are all cookies bad? Why?</title>
1353 No, in fact there are many beneficial uses of
1355 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1356 method that browsers can use to store data between pages, or between browser
1357 sessions. Sometimes there is a good reason for this, and the user's life is a
1358 bit easier as a result. But there is a long history of some websites taking
1359 advantage of this layer of trust, and using the data they glean from you and
1360 your browsing habits for their own purposes, and maybe to your potential
1361 detriment. Such sites are using you and storing their data on your system.
1362 That is why the privacy conscious watch from whom those cookies come, and why
1363 they really <emphasis>need</emphasis> to be there.
1367 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1368 definition</ulink> for more.
1372 <sect2 renderas="sect3" id="allow-cookies">
1373 <title>How can I allow permanent cookies for my trusted sites?</title>
1376 There are several actions that relate to cookies. The default behavior is to
1377 allow only <quote>session cookies</quote>, which means the cookies only last
1378 for the current browser session. This eliminates most kinds of abuse related
1379 to cookies. But there may be cases where you want cookies to last.
1382 To disable all cookie actions, so that cookies are allowed unrestricted,
1383 both in and out, for <literal>example.com</literal>:
1386 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1387 .example.com</screen>
1389 Place the above in <filename>user.action</filename>. Note that some of these may
1390 be off by default anyway, so this might be redundant, but there is no harm
1391 being explicit in what you want to happen. <filename>user.action</filename>
1392 includes an alias for this situation, called
1393 <literal>allow-all-cookies</literal>.
1397 <sect2 renderas="sect3" id="multiples">
1398 <title>Can I have separate configurations for different users?</title>
1400 Each instance of <application>Privoxy</application> has its own
1401 configuration, including such attributes as the TCP port that it listens on.
1402 What you can do is run multiple instances of <application>Privoxy</application>, each with
1404 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1405 configuration setting, and configuration path, and then
1406 each of these can have their own configurations. Think of it as per-port
1410 Simple enough for a few users, but for large installations, consider having
1411 groups of users that might share like configurations.
1415 <sect2 renderas="sect3" id="whitelists">
1416 <title>Can I set-up Privoxy as a whitelist of
1417 <quote>good</quote> sites?</title>
1419 Sure. There are a couple of things you can do for simple white-listing.
1420 Here's one real easy one:
1423 ############################################################
1425 ############################################################
1426 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1427 / # Block *all* URLs
1429 ############################################################
1431 ############################################################
1432 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1435 games.example.com</screen>
1437 This allows access to only those three sites by first blocking all URLs, and
1438 then subsequently allowing three specific exceptions.
1441 Another approach is <application>Privoxy's</application>
1442 <literal>trustfile</literal> concept, which incorporates the notion of
1443 <quote>trusted referrers</quote>. See the <ulink
1444 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1448 These are fairly simple approaches and are not completely foolproof. There
1449 are various other configuration options that should be disabled (described
1450 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1451 so that users can't modify their own configuration and easily circumvent the
1456 <sect2 renderas="sect3" id="no-adblock">
1457 <title>How can I turn off ad-blocking?</title>
1459 Ad blocking is achieved through a complex application of various &my-app;
1460 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1461 actions are deployed against simple images, banners, flash animations,
1462 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1463 just turning one or two actions off. The various actions that make up
1464 &my-app; ad blocking are hard-coded into the default configuration files. It
1465 has been assumed that everyone using &my-app; is interested in this
1469 If you want to do without this, there are several approaches you can take:
1470 You can manually undo the many block rules in
1471 <filename>default.action</filename>. Or even easier, just create your own
1472 <filename>default.action</filename> file from scratch without the many ad
1473 blocking rules, and corresponding exceptions. Or lastly, if you are not
1474 concerned about the additional blocks that are done for privacy reasons, you
1475 can very easily over-ride <emphasis>all</emphasis> blocking with the
1476 following very simple rule in your <filename>user.action</filename>:
1479 # Unblock everybody, everywhere
1480 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1481 / # UN-Block *all* URLs</screen>
1483 Or even a more comprehensive reversing of various ad related actions:
1486 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1487 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1488 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1489 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1490 <literal>allow-popups</literal> \
1492 / # UN-Block *all* URLs and allow ads</screen>
1494 This last <quote>action</quote> in this compound statement,
1495 <literal>allow-popups</literal>, is an <ulink
1496 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1497 various pop-up blocking features.
1501 <sect2 renderas="sect3" id="templates">
1502 <title>How can I have custom template pages, like the
1503 <emphasis>BLOCKED</emphasis> page?</title>
1505 &my-app; <quote>templates</quote> are specialized text files utilized by
1506 &my-app; for various purposes and can easily be modified using any text
1507 editor. All the template pages are installed in a sub-directory appropriately
1508 named: <filename>templates</filename>. Knowing something about HTML syntax
1509 will of course be helpful.
1512 Be forewarned that the default templates are subject to being overwritten
1513 during upgrades. You can, however, create completely new templates,
1514 place them in another directory and specify the alternate path in the main
1515 <filename>config</filename>. For details, have a look at the <ulink
1516 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1520 <sect2 renderas="sect3" id="blockall">
1521 <title>How can I remove the <quote>Go There Anyway</quote> link from
1522 the <emphasis>BLOCKED</emphasis> page?</title>
1524 There is more than one way to do it (although Perl is not involved).
1527 Editing the BLOCKED template page (see above) may dissuade some users, but
1528 this method is easily circumvented. Where you need this level of control, you
1529 might want to build &my-app; from source, and disable various features that are
1530 available as compile-time options. You should
1531 <command>configure</command> the sources as follows:
1534 ./configure --disable-toggle --disable-editor --disable-force</screen>
1536 This will create an executable with hard-coded security features so that
1537 &my-app; does not allow easy bypassing of blocked sites, or changing the
1538 current configuration via any connected user's web browser.
1541 Finally, all of these features can also be toggled on/off via options in
1542 <application>Privoxy's</application> main <ulink
1543 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1544 means you don't have to recompile anything.
1550 <!-- ~ End section ~ -->
1553 <!-- ~~~~~ New section ~~~~~ -->
1555 <sect1 id="misc"><title>Miscellaneous</title>
1557 <sect2 renderas="sect3" id="slowsme">
1558 <title>How much does Privoxy slow my browsing down? This
1559 has to add extra time to browsing.</title>
1561 How much of an impact depends on many things, including the CPU of the host
1562 system, how aggressive the configuration is, which specific actions are being triggered,
1563 the size of the page, the bandwidth of the connection, etc.
1566 Overall, it should not slow you down any in real terms, and may actually help
1567 speed things up since ads, banners and other junk are not typically being
1568 retrieved and displayed. The actual processing time required by
1569 <application>Privoxy</application> itself for each page, is relatively small
1570 in the overall scheme of things, and happens very quickly. This is typically
1571 more than offset by time saved not downloading and rendering ad images and
1572 other junk content (if ad blocking is being used).
1576 <quote>Filtering</quote> content via the <literal><ulink
1577 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1579 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1580 actions may cause a perceived slowdown, since the entire document
1581 needs to be buffered before displaying. And on very large documents,
1582 filtering may have some measurable impact. How much depends on the page size,
1583 the actual definition of the filter(s), etc. See below. Most other actions
1584 have little to no impact on speed.
1587 Also, when filtering is enabled but zlib support isn't available, compression
1588 is often disabled (see <ulink
1589 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1590 This can have an impact on speed as well, although it's probably smaller than
1591 you might think. Again, the page size, etc. will determine how much of an impact.
1597 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1598 delays in page requests. What's wrong?</title>
1600 If you use any <literal><ulink
1601 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1602 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1603 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1604 action, the entire document must be loaded into memory in order for the filtering
1605 mechanism to work, and nothing is sent to the browser during this time.
1608 The loading time typically does not really change much in real numbers, but
1609 the feeling is different, because most browsers are able to start rendering
1610 incomplete content, giving the user a feeling of "it works". This effect is
1611 more noticeable on slower dialup connections. Extremely large documents
1612 may have some impact on the time to load the page where there is filtering
1613 being done. But overall, the difference should be very minimal. If there is a
1614 big impact, then probably some other situation is contributing (like
1615 anti-virus software).
1618 Filtering is automatically disabled for inappropriate MIME types. But note
1619 that if the web server mis-reports the MIME type, then content that should
1620 not be filtered, could be. <application>Privoxy</application> only knows how
1621 to differentiate filterable content because of the MIME type as reported by
1622 the server, or because of some configuration setting that enables/disables
1627 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1628 "http://p.p/"?</title>
1630 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1631 address of <application>Privoxy</application>'s built-in user interface, and
1632 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1635 Since <application>Privoxy</application> sits between your web browser and the Internet,
1636 it can simply intercept requests for these addresses and answer them with its built-in
1637 <quote>web server</quote>.
1640 This also makes for a good test for your browser configuration: If entering the
1641 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1642 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1643 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1644 your browser didn't use <application>Privoxy</application> for the request,
1645 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1646 web site at config.privoxy.org.
1649 Note that config.privoxy.org resolves to a public IP address.
1650 If you use config.privoxy.org as ping or traceroute target you will
1651 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1652 If you want to ping the system Privoxy runs on,
1653 you should use its IP address or local DNS name (if it has got one).
1659 out of date 09/02/06 HB
1660 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1662 No. The patterns for blocking now reside (among other things) in the <ulink
1663 url="../user-manual/actions-file.html">actions files</ulink>, which are
1664 actively maintained instead. See next question ...
1668 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1671 Please see the <link linkend="contact">Contact section</link> for
1672 various ways to interact with the developers.
1677 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1678 they be included in future updates?</title>
1680 Whether such submissions are eventually included in the
1681 <filename>default.action</filename> configuration file depends on how
1682 significant the issue is. We of course want to address any potential
1683 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1684 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1685 has a good chance of being a candidate. But at the other end of the spectrum
1686 are any number of smaller, low-profile sites such as for local clubs or
1687 schools. Since their reach and impact are much less, they are best handled by
1688 inclusion in the user's <filename>user.action</filename>, and thus would be
1689 unlikely to be included.
1695 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1698 Rest assured that it has been read and considered. Why it is not answered,
1699 could be for various reasons, including no one has a good answer for it, no
1700 one has had time to yet investigate it thoroughly, it has been reported
1701 numerous times already, or because not enough information was provided to help
1702 us help you. Your efforts are not wasted, and we do appreciate them.
1708 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1710 If you run both the browser and &my-app; locally, you cannot hide your IP
1711 address with <application>Privoxy</application> or ultimately any other
1712 software alone. The server needs to know your IP address so that it knows
1713 where to send the responses back.
1716 There are many publicly usable "anonymous" proxies out there, which
1717 provide a further level of indirection between you and the web server.
1720 However, these proxies are called "anonymous" because you don't need
1721 to authenticate, not because they would offer any real anonymity.
1722 Most of them will log your IP address and make it available to the
1723 authorities in case you violate the law of the country they run in. In fact
1724 you can't even rule out that some of them only exist to *collect* information
1725 on (those suspicious) people with a more than average preference for privacy.
1728 If you want to hide your IP address from most adversaries,
1729 you should consider chaining <application>Privoxy</application>
1730 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1731 The configuration details can be found in
1732 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1733 with <application>Tor</application> section</ulink>
1738 <sect2 renderas="sect3" id="anonforsure">
1739 <title>Can Privoxy guarantee I am anonymous?</title>
1741 No. Your chances of remaining anonymous are improved, but unless you
1742 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1743 or a similar proxy and know what you're doing when it comes to configuring
1744 the rest of your system, you should assume that everything you do
1745 on the Web can be traced back to you.
1748 <application>Privoxy</application> can remove various information about you,
1749 and allows <emphasis>you</emphasis> more freedom to decide which sites
1750 you can trust, and what details you want to reveal. But it neither
1751 hides your IP address, nor can it guarantee that the rest of the system
1752 behaves correctly. There are several possibilities how a web sites can find
1753 out who you are, even if you are using a strict <application>Privoxy</application>
1754 configuration and chained it with <application>Tor</application>.
1757 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1758 by an insecure browser configuration, therefore you should use a browser that can
1759 be configured to only execute code from trusted sites, and be careful which sites you trust.
1760 For example there is no point in having <application>Privoxy</application>
1761 modify the User-Agent header, if websites can get all the information they want
1762 through JavaScript, ActiveX, Flash, Java etc.
1765 A few browsers disclose the user's email address in certain situations, such
1766 as when transferring a file by FTP. <application>Privoxy</application>
1767 does not filter FTP. If you need this feature, or are concerned about the
1768 mail handler of your browser disclosing your email address, you might
1769 consider products such as <application>NSClean</application>.
1772 Browsers available only as binaries could use non-standard headers to give
1773 out any information they can have access to: see the manufacturer's license
1774 agreement. It's impossible to anticipate and prevent every breach of privacy
1775 that might occur. The professionally paranoid prefer browsers available as
1776 source code, because anticipating their behavior is easier. Trust the source,
1782 <sect2 renderas="sect3" id="proxytest">
1783 <title>A test site says I am not using a Proxy.</title>
1785 Good! Actually, they are probably testing for some other kinds of proxies.
1786 Hiding yourself completely would require additional steps.
1790 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1791 together with Tor?</title>
1793 Before you configure <application>Privoxy</application> to use
1794 <ulink url="https://www.torproject.org/">Tor</ulink>,
1795 please follow the <citetitle>User Manual</citetitle> chapters
1796 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1797 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1798 <application>Privoxy</application> itself is setup correctly.
1801 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1802 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1803 and make sure <application>Tor</application>'s logfile says that
1804 <quote>Tor has successfully opened a circuit</quote> and it
1805 <quote>looks like client functionality is working</quote>.
1808 If either <application>Tor</application> or <application>Privoxy</application>
1809 isn't working, their combination most likely will neither. Testing them on their
1810 own will also help you to direct problem reports to the right audience.
1811 If <application>Privoxy</application> isn't working, don't bother the
1812 <application>Tor</application> developers. If <application>Tor</application>
1813 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1816 If you verified that <application>Privoxy</application> and <application>Tor</application>
1817 are working, it is time to connect them. As far as <application>Privoxy</application>
1818 is concerned, <application>Tor</application> is just another proxy that can be reached
1819 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1820 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1821 requests are done through <application>Tor</application> and thus invisible to your
1822 local network. Using socks4a would work too, but with socks5 you get more precise error
1827 <application>Privoxy's</application>
1828 <ulink url="../user-manual/config.html">main configuration file</ulink>
1829 is already prepared for <application>Tor</application>, if you are using a
1830 default <application>Tor</application> configuration and run it on the same
1831 system as &my-app;, you just have to edit the
1832 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1833 and uncomment the line:
1836 # forward-socks5t / 127.0.0.1:9050 .
1839 Note that if you got Tor through one of the bundles, you may
1840 have to change the port from 9050 to 9150 (or even another one).
1841 For details, please check the documentation on the
1842 <ulink url="https://torproject.org/">Tor website</ulink>.
1846 This is enough to reach the Internet, but additionally you might want to
1847 uncomment the following forward rules, to make sure your local network is still
1848 reachable through Privoxy:
1851 # forward 192.168.*.*/ .
1852 # forward 10.*.*.*/ .
1853 # forward 127.*.*.*/ .
1856 Unencrypted connections to systems in these address ranges will
1857 be as (un)secure as the local network is, but the alternative is
1858 that your browser can't reach the network at all. Then again,
1859 that may actually be desired and if you don't know for sure
1860 that your browser has to be able to reach the local network,
1861 there's no reason to allow it.
1864 If you want your browser to be able to reach servers in your local
1865 network by using their names, you will need additional exceptions
1866 that look like this:
1869 # forward localhost/ .
1872 Save the modified configuration file and open
1873 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1874 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1875 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1877 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1878 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1881 Afterward, please take the time to at least skim through the rest
1882 of <application>Tor's</application> documentation. Make sure you understand
1883 what <application>Tor</application> does, why it is no replacement for
1884 application level security, and why you probably don't want to
1885 use it for unencrypted logins.
1889 <sect2 renderas="sect3" id="sitebreak">
1890 <title>Might some things break because header information or
1891 content is being altered?</title>
1894 Definitely. It is common for sites to use browser type, browser version,
1895 HTTP header content, and various other techniques in order to dynamically
1896 decide what to display and how to display it. What you see, and what I see,
1897 might be very different. There are many, many ways that this can be handled,
1898 so having hard and fast rules, is tricky.
1902 The <quote>User-Agent</quote> is sometimes used in this way to identify
1903 the browser, and adjust content accordingly.
1907 Also, different browsers use different encodings of non-English
1908 characters, certain web servers convert pages on-the-fly according to the
1909 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1910 operating system or browser manufacturer causes some sites in these languages
1911 to be garbled; Surfers to Eastern European sites should change it to
1912 something closer. And then some page access counters work by looking at the
1913 <quote>Referer</quote> header; they may fail or break if unavailable. The
1914 weather maps of Intellicast have been blocked by their server when no
1915 <quote>Referer</quote> or cookie is provided, is another example. (But you
1916 can forge both headers without giving information away). There are
1917 many other ways things can go wrong when trying to fool a web server. The
1918 results of which could inadvertently cause pages to load incorrectly,
1919 partially, or even not at all. And there may be no obvious clues as to just
1920 what went wrong, or why. Nowhere will there be a message that says
1921 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1926 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1931 If you have problems with a site, you will have to adjust your configuration
1932 accordingly. Cookies are probably the most likely adjustment that may
1933 be required, but by no means the only one.
1939 <sect2 renderas="sect3" id="caching">
1940 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1941 speed up web browsing?</title>
1943 No, it does not have this ability at all. You want something like
1944 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1945 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1946 And, yes, before you ask, <application>Privoxy</application> can co-exist
1947 with other kinds of proxies like <application>Squid</application>.
1948 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1949 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1950 manual</ulink> for details.
1954 <sect2 renderas="sect3" id="firewall">
1955 <title>What about as a firewall? Can Privoxy protect me?</title>
1957 Not in the way you mean, or in the way some firewall vendors claim they can.
1958 <application>Privoxy</application> can help protect your privacy, but can't
1959 protect your system from intrusion attempts. It is, of course, perfectly possible
1960 to use <emphasis>both</emphasis>.
1964 <sect2 renderas="sect3" id="wasted">
1965 <title>I have large empty spaces / a checkerboard pattern now where
1966 ads used to be. Why?</title>
1968 It is technically possible to eliminate banners and ads in a way that frees
1969 their allocated page space. This could easily be done by blocking with
1970 <application>Privoxy's</application> filters,
1971 and eliminating the <emphasis>entire</emphasis> image references from the
1975 But, this would consume considerably more CPU resources (IOW, slow things
1976 down), would likely destroy the layout of some web pages which rely on the
1977 banners utilizing a certain amount of page space, and might fail in other
1978 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1979 Also, making ads and banners disappear without any trace complicates
1980 troubleshooting, and would sooner or later be problematic.
1983 The better alternative is to instead let them stay, and block the resulting
1984 requests for the banners themselves as is now the case. This leaves either
1985 empty space, or the familiar checkerboard pattern.
1988 So the developers won't support this in the default configuration, but you
1989 can of course define appropriate filters yourself to achieve this.
1993 <sect2 renderas="sect3" id="ssl">
1994 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1997 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1998 <application>Privoxy</application> will impersonate the destination
1999 server and can thus filter encrypted requests and responses as well.
2003 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
2004 secure HTTP connections are encrypted SSL sessions between your
2005 browser and the secure site, and there is little
2006 that <application>Privoxy</application> can do but hand the raw
2007 gibberish data though from one end to the other unprocessed.
2010 The only exception to this is blocking by host patterns, as the client needs
2011 to tell <application>Privoxy</application> the name of the remote server,
2012 so that <application>Privoxy</application> can establish the connection.
2013 If that name matches a host-only pattern, the connection will be blocked.
2016 As far as ad blocking is concerned, this is less of a restriction than it may
2017 seem, since ad sources are often identifiable by the host name, and often
2018 the banners to be placed in an encrypted page come unencrypted nonetheless
2019 for efficiency reasons, which exposes them to the full power of
2020 <application>Privoxy</application>'s ad blocking.
2023 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
2024 JS page content, see <literal><ulink
2025 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2026 in an SSL transaction will be impossible to block under these conditions.
2027 Fortunately, this does not seem to be a very common scenario since most
2028 cookies come by traditional means.
2033 <sect2 renderas="sect3" id="http2">
2034 <title>Does Privoxy support HTTP/2?</title>
2036 Privoxy currently doesn't parse HTTP/2 but applications
2037 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2038 to allow CONNECT requests (default) which are also used
2042 Adding HTTP/2 support is on the
2043 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2044 list but currently nobody is known to work on it.
2048 <sect2 renderas="sect3" id="secure">
2049 <title>Privoxy runs as a <quote>server</quote>. How
2050 secure is it? Do I need to take any special precautions?</title>
2052 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2053 user, which is how we recommend it be run. Also, by default
2054 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2058 The server aspect of <application>Privoxy</application> is not itself directly
2059 exposed to the Internet in this configuration. If you want to have
2060 <application>Privoxy</application> serve as a LAN proxy, this will have to
2061 be opened up to allow for LAN requests. In this case, we'd recommend
2062 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2063 <application>Privoxy</application> configuration file and check all <ulink
2064 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2065 options</ulink>. All LAN hosts can then use this as their proxy address
2066 in the browser proxy configuration, but <application>Privoxy</application>
2067 will not listen on any external interfaces. ACLs can be defined in addition,
2068 and using a firewall is always good too. Better safe than sorry.
2073 <sect2 renderas="sect3" id="turnoff">
2074 <title>Can I temporarily disable Privoxy?</title>
2076 &my-app; doesn't have a transparent proxy mode,
2077 but you can toggle off blocking and content filtering.
2080 The easiest way to do that is to point your browser
2081 to the remote toggle URL: <ulink
2082 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2085 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2086 of the <citetitle>User Manual</citetitle> for an easy way to access this
2087 feature. Note that this is a feature that may need to be enabled in the main
2088 <filename>config</filename> file.
2093 <sect2 renderas="sect3" id="reallyoff">
2094 <title>When <quote>disabled</quote> is Privoxy totally
2095 out of the picture?</title>
2097 No, this just means all optional filtering and actions are disabled.
2098 <application>Privoxy</application> is still acting as a proxy, but just
2099 doing less of the things that <application>Privoxy</application> would
2100 normally be expected to do. It is still a <quote>middle-man</quote> in
2101 the interaction between your browser and web sites. See below to bypass
2106 <sect2 renderas="sect3" id="turnoff2">
2107 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2109 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2110 configuration issue, not a &my-app; issue. Modern browsers typically do have
2111 settings for not proxying certain sites. Check your browser's help files.
2116 <sect2 renderas="sect3" id="crunch">
2117 <title>My logs show Privoxy <quote>crunches</quote>
2118 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2120 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2121 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2122 banners, but <application>Privoxy</application> uses the same mechanism for
2123 trapping requests for its own internal pages. For instance, a request for
2124 <application>Privoxy's</application> configuration page at: <ulink
2125 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2126 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2127 configuration is returned to the browser, and the log consequently will show
2128 a <quote>crunch</quote>.
2131 Since version 3.0.7, Privoxy will also log the crunch reason.
2132 If you are using an older version you might want to upgrade.
2136 <sect2 renderas="sect3" id="downloads">
2137 <title>Can Privoxy affect files that I download
2138 from a webserver? FTP server?</title>
2140 From the webserver's perspective, there is no difference between
2141 viewing a document (i.e. a page), and downloading a file. The same is true of
2142 <application>Privoxy</application>. If there is a match for a <literal><ulink
2143 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2144 it will still be blocked, and of course this is obvious.
2147 Filtering is potentially more of a concern since the results are not always
2148 so obvious, and the effects of filtering are there whether the file is simply
2149 viewed, or downloaded. And potentially whether the content is some obnoxious
2150 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2151 one of these presumably is <quote>bad</quote> content that we don't want, and
2152 the other is <quote>good</quote> content that we do want.
2153 <application>Privoxy</application> is blind to the differences, and can only
2154 distinguish <quote>good from bad</quote> by the configuration parameters
2155 <emphasis>we</emphasis> give it.
2158 <application>Privoxy</application> knows the differences in files according
2159 to the <quote>Content Type</quote> as reported by the webserver. If this is
2160 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2161 then <application>Privoxy</application> knows to ignore these where
2162 appropriate. <application>Privoxy</application> potentially can filter HTML
2163 as well as plain text documents, subject to configuration parameters of
2164 course. Also, documents that are of an unknown type (generally assumed to be
2165 <quote>text/plain</quote>) can be filtered, as will those that might be
2166 incorrectly reported by the webserver. If such a file is a downloaded file
2167 that is intended to be saved to disk, then any content that might have been
2168 altered by filtering, will be saved too, for these (probably rare) cases.
2171 Note that versions later than 3.0.2 do NOT filter document types reported as
2172 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2173 did filter this document type.
2176 In short, filtering is <quote>ON</quote> if a) the content type as reported
2177 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2178 allows it (or at least does not disallow it). That's it. There is no magic
2179 cookie anywhere to say this is <quote>good</quote> and this is
2180 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2183 If you download text files, you probably do not want these to be filtered,
2184 particularly if the content is source code, or other critical content. Source
2185 code sometimes might be mistaken for Javascript (i.e. the kind that might
2186 open a pop-up window). It is recommended to turn off filtering for download
2187 sites (particularly if the content may be plain text files and you are using
2188 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2189 also, for any site or page where making <emphasis>any</emphasis> changes at
2190 all to the content is to be avoided.
2193 <application>Privoxy</application> does not do FTP at all, only HTTP
2194 and HTTPS (SSL) protocols.
2198 <sect2 renderas="sect3" id="downloads2">
2199 <title>I just downloaded a Perl script, and Privoxy
2200 altered it! Yikes, what is wrong!</title>
2206 <sect2 renderas="sect3" id="hostsfile">
2207 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2209 One time-tested technique to defeat common ads is to trick the local DNS
2210 system by giving a phony IP address for the ad generator in the local
2211 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2212 <literal>localhost</literal>. This effectively blocks the ad.
2215 There is no reason to use this technique in conjunction with
2216 <application>Privoxy</application>. <application>Privoxy</application>
2217 does essentially the same thing, much more elegantly and with much more
2218 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2219 duplicates effort, but may get in the way and seriously slow down your system.
2220 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2221 your hosts list is neglected by <application>Privoxy's </application>
2222 configuration, consider adding your list to your <filename>user.action</filename> file:
2228 ads.galore.example.com
2229 etc.example.com</screen>
2232 <sect2 renderas="sect3" id="seealso">
2233 <title>Where can I find more information about Privoxy
2234 and related issues?</title>
2235 <!-- Include seealso.sgml boilerplate: -->
2237 <!-- end boilerplate -->
2242 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2248 <sect2 renderas="sect3" id="microsuck">
2249 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2250 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2253 We're not. The text substitutions that you are seeing are disabled
2254 in the default configuration as shipped. You have either manually
2255 activated the <quote><literal>fun</literal></quote> filter which
2256 is clearly labeled <quote>Text replacements for subversive browsing
2257 fun!</quote> or you are using an older Privoxy version and have implicitly
2258 activated it by choosing the <quote>Advanced</quote> profile in the
2259 web-based editor. Please upgrade.
2263 <sect2 renderas="sect3" id="valid">
2264 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2267 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2268 whenever there are text substitutions via a &my-app; filter. While this
2269 should always conform to the HTML 4.01 specifications, it has not been
2270 validated against this or any other standard.
2274 <sect2 renderas="sect3" id="surprise-privoxy">
2275 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2278 We didn't. We make Privoxy available for download, but we don't go
2279 around installing it on other people's systems behind their back.
2280 If you discover Privoxy running on your system and are sure you didn't
2281 install it yourself, somebody else did. You may not even be running
2282 the real Privoxy, but maybe something else that only pretends to be
2283 Privoxy, or maybe something that is based on the real Privoxy,
2284 but has been modified.
2287 Lately there have been reports of problems with some kind of
2288 "parental control" software based on Privoxy that came preinstalled on
2289 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2290 The problems described are inconsistent with the behaviour of official
2291 Privoxy versions, which suggests that the preinstalled software may
2292 contain vendor modifications that we don't know about and thus can't debug.
2295 Privoxy's <link linkend="copyright">license</link> allows vendor
2296 modifications, but the vendor has to comply with the license,
2297 which involves informing the user about the changes and to make
2298 the changes available under the same license as Privoxy itself.
2301 If you are having trouble with a modified Privoxy version,
2302 please try to talk to whoever made the modifications before
2303 reporting the problem to us. Please also try to convince
2304 whoever made the modifications to talk to us. If you think
2305 somebody gave you a modified Privoxy version without complying
2306 to the license, please let us know.
2314 <!-- ~~~~~ New section ~~~~~ -->
2316 <sect1 id="trouble">
2317 <title>Troubleshooting</title>
2319 <sect2 renderas="sect3" id="refused">
2320 <title>I cannot connect to any websites. Or, I am getting
2321 <quote>connection refused</quote> message with every web page. Why?</title>
2323 There are several possibilities:
2327 <application>Privoxy</application> is not running. Solution: verify
2328 that &my-app; is installed correctly, has not crashed, and is indeed running.
2329 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2331 <listitem><para>Or your browser is configured for a different port than what
2332 <application>Privoxy</application> is using. Solution: verify that &my-app;
2333 and your browser are set to the same port (<literal>listen-address</literal>).
2335 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2336 problem with a host in the forwarding chain. Solution: temporarily alter your
2337 configuration and take the forwarders out of the equation.
2340 Or you have a firewall that is interfering and blocking you. Solution:
2341 try disabling or removing the firewall as a simple test.
2347 <!-- ~~~~~ New section ~~~~~ -->
2348 <sect2 renderas="sect3" id="error503">
2349 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2351 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2352 been reported to cause this symptom -- even if not running! The solution is
2353 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2354 something better behaved in its place. Other personal firewall type products
2355 may cause similar type problems if not configured correctly.
2359 <sect2 renderas="sect3" id="flushit">
2360 <title>I just added a new rule, but the steenkin ad is
2361 still getting through. How?</title>
2363 If the ad had been displayed before you added its URL, it will probably be
2364 held in the browser's cache for some time, so it will be displayed without
2365 the need for any request to the server, and <application>Privoxy</application>
2366 will not be involved. Flush the browser's caches, and then try again.
2370 If this doesn't help, you probably have an error in the rule you
2371 applied. Try pasting the full URL of the offending ad into <ulink
2372 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2373 and see if it really matches your new rule. Blocking ads is like blocking
2374 spam: a lot of tinkering is required to stay ahead of the game. And
2375 remember you need to block the URL of the ad in question, which may be
2376 entirely different from the site URL itself. Most ads are hosted on different
2377 servers than the main site itself. If you right-click on the ad, you should
2378 be able to get all the relevant information you need. Alternately, you can
2379 find the correct URL by looking at <application>Privoxy's</application> logs
2380 (you may need to enable logging in the main config file if its disabled).
2383 Below is a slightly modified real-life log snippet that originates with one
2384 requested URL: <literal>www.example.com</literal> (name of site was changed
2385 for this example, the number of requests is real). You can see in this the
2386 complexity of what goes into making up this one <quote>page</quote>. There
2387 are eight different domains involved here, with thirty two separate URLs
2388 requested in all, making up all manner of images, Shockwave Flash,
2389 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2390 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2391 Many of the more questionable looking requests, are going to outside domains
2392 that seem to be identifying themselves with suspicious looking names, making
2393 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2394 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2398 Request: www.example.com/
2399 Request: www.example.com/favicon.ico
2400 Request: img.example.com/main.css
2401 Request: img.example.com/sr.js
2402 Request: example.betamarker.com/example.html
2403 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2404 Request: img.example.com/pb.png
2405 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2406 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2407 Request: img.example.com/p.gif
2408 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2409 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2410 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2411 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2412 Request: www.adtrak.net/adx.js crunch! (Blocked)
2413 Request: img.example.com/hbg.gif
2414 Request: img.example.com/example.jpg
2415 Request: img.example.com/mt.png
2416 Request: img.example.com/mm.png
2417 Request: img.example.com/mb.png
2418 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2419 Request: www.example.com/tracker.js
2420 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2421 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2422 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2423 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2424 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2425 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2426 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2427 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2428 Request: 66.70.21.80/img/pixel.gif
2429 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2430 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2434 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2435 behave perfectly <quote>normal</quote> (minus some ads, of course).
2440 <sect2 renderas="sect3" id="badsite">
2441 <title>One of my favorite sites does not work with Privoxy.
2442 What can I do?</title>
2445 First verify that it is indeed a <application>Privoxy</application> problem,
2446 by toggling off <application>Privoxy</application> through <ulink
2447 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2448 (the toggle feature may need to be enabled in the main
2449 <filename>config</filename>),
2450 and then shift-reloading the problem page (i.e. holding down the shift key
2451 while clicking reload. Alternatively, flush your browser's disk and memory
2456 If the problem went away, we know we have a configuration related problem.
2458 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2459 and paste the full URL of the page in question into the prompt. See which
2460 actions are being applied to the URL, and which matches in which actions
2461 files are responsible for that. It might be helpful also to look at your logs
2462 for this site too, to see what else might be happening (note: logging may need
2463 to be enabled in the main config file). Many sites are
2464 complex and require a number of related pages to help present their content.
2465 Look at what else might be used by the page in question, and what of that
2466 might be <emphasis>required</emphasis>.
2467 Now, armed with this information, go to
2469 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2470 and select the appropriate actions files for editing. </para>
2472 You can now either look for a section which disables the actions that
2473 you suspect to cause the problem and add a pattern for your site there,
2474 or make up a completely new section for your site. In any case, the recommended
2475 way is to disable only the prime suspect, reload the problem page, and only
2476 if the problem persists, disable more and more actions until you have
2477 identified the culprit. You may or may not want to turn the other actions
2478 on again. Remember to flush your browser's caches in between any such changes!
2481 Alternately, if you are comfortable with a text editor, you can accomplish
2482 the same thing by editing the appropriate actions file. Probably the easiest
2483 way to deal with such problems when editing by hand is to add your
2484 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2485 which is an alias that turns off most <quote>dangerous</quote>
2486 actions, but is also likely to turn off more actions then needed, and thus lower
2487 your privacy and protection more than necessary,
2490 Troubleshooting actions is discussed in more detail in the <ulink
2491 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2492 Troubleshooting: the Anatomy of an Action</ulink>.
2493 There is also an <ulink
2494 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2495 with general configuration information and examples.
2498 As a last resort, you can always see if your browser has a setting that will
2499 bypass the proxy setting for selective sites. Modern browsers can do this.
2505 <!-- ~~~~~ New section ~~~~~ -->
2506 <sect2 id="dun" renderas="sect3">
2507 <title>After installing Privoxy, I have to log in
2508 every time I start IE. What gives?</title>
2511 This is a quirk that affects the installation of
2512 <application>Privoxy</application>, in conjunction with Internet Explorer and
2513 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2514 appear to be corrupted or invalid DUN settings, or passwords.
2518 When setting up an NT based Windows system with
2519 <application>Privoxy</application> you may find that things do not seem to be
2520 doing what you expect. When you set your system up you will probably have set
2521 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2522 logged in with administrator privileges. You will probably have made this DUN
2523 connection available to other accounts that you may have set-up on your
2524 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2525 configured for the kids.
2529 When setting up <application>Privoxy</application> in this environment you
2530 will have to alter the proxy set-up of Internet Explorer (IE) for the
2531 specific DUN connection on which you wish to use
2532 <application>Privoxy</application>. When you do this the ICS DUN set-up
2533 becomes user specific. In this instance you will see no difference if you
2534 change the DUN connection under the account used to set-up the connection.
2535 However when you do this from another user you will notice that the DUN
2536 connection changes to make available to "Me only". You will also find that
2537 you have to store the password under each different user!
2541 The reason for this is that each user's set-up for IE is user specific. Each
2542 set-up DUN connection and each LAN connection in IE store the settings for
2543 each user individually. As such this enforces individual configurations
2544 rather than common ones. Hence the first time you use a DUN connection after
2545 re-booting your system it may not perform as you expect, and prompt you for
2546 the password. Just set and save the password again and all should be OK.
2550 [Thanks to Ray Griffith for this submission.]
2555 <!-- ~~~~~ New section ~~~~~ -->
2556 <sect2 id="ftp" renderas="sect3">
2557 <title>I cannot connect to any FTP sites. Privoxy
2558 is blocking me.</title>
2560 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2561 so do not configure your browser to use <application>Privoxy</application>
2562 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2563 or HTTPS (SSL)</emphasis>.
2566 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2567 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2568 an FTP connection, and not a HTTP connection. So while your browser may
2569 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2573 To complicate matters, some systems may have a generic <quote>proxy</quote>
2574 setting, which will enable various protocols, including
2575 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2576 accidentally enable FTP proxying in these cases. And of course, if this
2577 happens, <application>Privoxy</application> will indeed cause problems since
2578 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2579 message if a FTP connection is attempted.]]> Just disable the FTP setting
2580 and all will be well again.
2583 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2584 There just is not much reason, and the work to make this happen is more than
2589 <!-- ~~~~~ New section ~~~~~ -->
2590 <sect2 id="macosxie" renderas="sect3">
2591 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2592 Privoxy as the HTTP proxy.</title>
2594 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2595 network settings. In order to change the HTTP proxy, open System
2596 Preferences, and click on the Network icon. In the settings pane that
2597 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2598 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2599 Enter <literal>8118</literal> in the Port field. The next time you start
2600 IE, it should reflect these values.
2604 <!-- ~~~~~ New section ~~~~~ -->
2605 <sect2 renderas="sect3" id="macosxuninstall">
2606 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2607 uninstall it. Now the finder tells me I don't have sufficient privileges to
2608 empty the trash.</title>
2610 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2613 Just dragging the <application>Privoxy</application> folder to the trash is
2614 not enough to delete it. <application>Privoxy</application> supplies an
2615 <application>uninstall.command</application> file that takes care of
2616 these details. Open the trash, drag the <application>uninstall.command</application>
2617 file out of the trash and double-click on it. You will be prompted for
2618 confirmation and the administration password.
2621 The trash may still appear full after this command; emptying the trash
2622 from the desktop should make it appear empty again.
2626 <!-- ~~~~~ New section ~~~~~ -->
2627 <sect2 renderas="sect3" id="macosximages">
2628 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2629 experience random delays in page loading. I'm using
2630 <literal>localhost</literal> as my browser's proxy setting.</title>
2632 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2633 understand the issue yet. In any case, changing the proxy setting to
2634 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2635 works around the problem.
2639 <!-- ~~~~~ New section ~~~~~ -->
2640 <sect2 renderas="sect3" id="macosxaccountdeletion">
2641 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2644 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2645 X deletes all user accounts that are either not part of OS X itself or are
2646 not interactive user accounts (ones you log in with). Since, for the sake of
2647 security, &my-app; runs as a non-privileged user that is created by its
2648 installer (_privoxy), it can no longer start up once that account gets deleted.
2649 The solution is to perform a complete uninstall using the supplied
2650 <application>uninstall.command</application> script (either back up your
2651 configuration files or select to not have the uninstaller remove them when it
2652 prompts you) and then reinstall &my-app; using the installer package and merge
2653 in your configuration.
2657 <sect2 renderas="sect3" id="nohostname">
2658 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2661 <application>Privoxy</application> tries to get the hostname of the system
2662 its running on from the IP address of the system interface it is bound to
2663 (from the <filename>config</filename> file
2664 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2665 this information, <application>Privoxy</application> logs this condition.
2668 Typically, this would be considered a minor system configuration error. It is
2669 not a fatal error to <application>Privoxy</application> however, but may
2670 result in a much slower response from <application>Privoxy</application> on
2671 some platforms due to DNS timeouts.
2674 This can be caused by a problem with the local <filename>hosts</filename>
2675 file. If this file has been changed from the original, try reverting it to
2676 see if that helps. Make sure whatever name(s) are used for the local system,
2677 that they resolve both ways.
2680 You should also be able to work around the problem with the
2681 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2685 <sect2 renderas="sect3" id="inuse">
2686 <title>When I try to launch Privoxy, I get an
2687 error message <quote>port 8118 is already in use</quote> (or similar wording).
2690 Port 8118 is <application>Privoxy's</application> default TCP
2691 <quote>listening</quote> port. Typically this message would mean that there
2692 is already one instance of <application>Privoxy</application> running, and
2693 your system is actually trying to start a second
2694 <application>Privoxy</application> on the same port, which will not work.
2695 (You can have multiple instances but they must be assigned different ports.)
2696 How and why this might happen varies from platform to platform, but you need
2697 to check your installation and start-up procedures.
2701 <sect2 renderas="sect3" id="demoronizer">
2703 Pages with UTF-8 fonts are garbled.
2706 This may be the result of an overly aggressive filter. The filters that
2707 are enabled in the default configuration aren't expected to cause problems
2708 like this. If you enabled the <quote>demoronizer</quote> filter, please
2709 try temporarily disabling it.
2712 If that doesn't help, temporarily disable all filters to see if another
2713 filter could be the culprit. If the problem disappears, enable the filters
2714 one by one, until the problem reappears and the offending filter is found.
2717 Once the problem-causing filter is known, it can be fixed or disabled.
2720 Upgrading <application>Privoxy</application>, or going to the most recent
2721 <filename>default.action</filename> file available from <ulink
2722 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2723 might be worth a try, too.
2727 <sect2 renderas="sect3" id="demoronizer2">
2729 Why are binary files (such as images) corrupted when Privoxy
2733 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2734 filter</link> in conjunction with a web server that is misreporting the content
2735 type. By default binary files are exempted from
2736 <application>Privoxy's</application> filtering
2737 (unless the web server by mistake says the file is something else).
2741 <sect2 renderas="sect3" id="demoronizer3">
2743 What is the <quote>demoronizer</quote> and why is it there?
2746 The original demoronizer was a Perl script that cleaned up HTML pages which
2747 were created with certain Microsoft products. MS has used proprietary extensions
2748 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2749 that are viewed with non-Microsoft products (and are expecting to see a
2750 standard set of fonts). The demoronizer corrected these errors so the pages
2751 displayed correctly. <application>Privoxy</application> borrowed from this
2752 script, introducing a filter based on the original demoronizer, which in turn could
2753 correct these errors on the fly.
2756 But this is only needed in some situations, and will cause serious problems in some
2760 If you are using Microsoft products, you do not need it. If you need to view
2761 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2762 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2765 On the other hand, if you use non-Microsoft products, and you occasionally
2766 notice weird characters on pages, you might want to try it.
2770 <sect2 renderas="sect3" id="windowopen">
2772 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2775 <application>Privoxy</application> is attempting to disable malicious
2776 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2777 in this case, with the <literal>unsolicited-popups</literal>
2778 filter. <application>Privoxy</application> cannot tell very well
2779 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2782 If you see this in HTML source, and the page displays without problems, then
2783 this is good, and likely some pop-up window was disabled. If you see this
2784 where it is causing a problem, such as a downloaded program source code file,
2785 then you should set an exception for this site or page such that the
2786 integrity of the page stays in tact by disabling all filtering.
2790 <sect2 renderas="sect3" id="dnserrors">
2792 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2793 can't Privoxy do this better?
2796 There are potentially several factors here. First of all, the DNS resolution
2797 is done by the underlying operating system -- not
2798 <application>Privoxy</application> itself. <application>Privoxy</application>
2799 merely initiates the process and hands it off, and then later reports
2800 whatever the outcome was and tries to give a coherent message if there seems
2801 to be a problem. In some cases, this might otherwise be mitigated by the
2802 browser itself which might try some work-arounds and alternate approaches (e.g
2803 adding <quote>www.</quote> to the URL).
2806 In other cases, if <application>Privoxy</application> is being chained
2807 with another proxy, this could complicate the issue, and cause undue
2808 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2809 server handles all the DNS. <application>Privoxy</application> would just be
2810 the <quote>messenger</quote> which is reporting whatever problem occurred
2811 downstream, and not the root cause of the error.
2815 In any case, versions newer than 3.0.3 include various improvements to help
2816 <application>Privoxy</application> better handle these cases.
2820 <sect2 renderas="sect3" id="allcpu">
2822 At one site Privoxy just hangs, and starts taking
2823 all CPU. Why is this?
2826 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2827 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2828 are in the raw HTML source of the page, and the browser just ignores them. But the
2829 pattern matching in <application>Privoxy's</application> page filtering
2830 mechanism is trying to match against absurdly long strings and this becomes
2831 very CPU-intensive, taking a long, long time to complete.
2834 Until a better solution comes along, disable filtering on these pages,
2835 particularly the <literal>js-annoyances</literal> and
2836 <literal>unsolicited-popups</literal> filters. If you run into this problem
2837 with a recent &my-app; version, please send a problem report.
2841 <sect2 renderas="sect3" id="slowcrawl">
2842 <title>I just installed Privoxy, and all my
2843 browsing has slowed to a crawl. What gives? </title>
2845 This should not happen, and for the overwhelming number of users world-wide,
2846 it does not happen. I would suspect some inadvertent interaction of software
2847 components such as anti-virus software, spyware protectors, personal
2848 firewalls or similar components. Try disabling (or uninstalling) these one
2849 at a time and see if that helps. Either way, if you are using a
2850 recent &my-app; version, please report the problem.
2854 <sect2 renderas="sect3" id="preventcomp">
2855 <title>Why do my filters work on some sites but not on others? </title>
2857 It's probably due to compression. It is a common practice for web servers to
2858 send their content <quote>compressed</quote> in order to speed things up, and
2859 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2860 &my-app; can decompress content before filtering, otherwise you may want to enable
2862 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2865 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2870 <sect2 renderas="sect3" id="ssl-warnings">
2871 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2872 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2873 What's going on?</title>
2875 Probably the browser is requesting ads through HTTPS and &my-app;
2876 is blocking the requests. Privoxy's error messages are delivered
2877 unencrypted and while it's obvious for the browser that the HTTPS
2878 request is already blocked by the proxy, some warn about unauthenticated
2882 To work around the problem you can redirect those requests to an invalid
2883 local address instead of blocking them. While the redirects aren't
2884 encrypted either, many browsers don't care. They simply follow the
2885 redirect, fail to reach a server and display an error message instead
2889 To do that, enable logging to figure out which requests get blocked by
2890 &my-app; and add the hosts (no path patterns) to a section like this:
2894 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2899 Additionally you have to configure your browser to contact
2900 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2903 To add a proxy exception in <application>Mozilla Firefox</application>
2904 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2905 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2906 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2912 <sect2 renderas="sect3" id="se-linux">
2913 <title>I get selinux error messages. How can I fix this?</title>
2915 Please report the problem to the creator of your selinux policies.
2918 The problem is that some selinux policy writers aren't familiar
2919 with the application they are trying to <quote>secure</quote> and
2920 thus create policies that make no sense.
2923 In <application>Privoxy's</application> case the problem usually
2924 is that the policy only allows outgoing connections for certain
2925 destination ports (e.g. 80 and 443). While this may cover the
2926 standard ports, websites occasionally use other ports as well.
2927 This isn't a security problem and therefore <application>Privoxy's</application>
2928 default configuration doesn't block these requests.
2931 If you really want to block these ports (and don't be able
2932 to load websites that don't use standard ports), you should
2933 configure Privoxy to block these ports as well, so it doesn't
2934 trigger the selinux warnings.
2939 <sect2 renderas="sect3" id="gentoo-ricers">
2940 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2942 Probably you unintentionally compiled &my-app; without threading support
2943 in which case requests have to be serialized and only one can be served
2947 Check your <quote>USE</quote> flags and make sure they include
2948 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2951 If you compiled &my-app; with threading support (on POSIX-based systems),
2952 the <quote>Conditional #defines</quote> section on <ulink
2953 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2954 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2958 <sect2 renderas="sect3" id="tainted-sockets">
2959 <title>What are tainted sockets and how do I prevent them?</title>
2961 &my-app; marks sockets as tainted when it can't use them to
2962 serve additional requests.
2963 This does not necessarily mean that something went wrong and
2964 information about tainted sockets is only logged if connection
2965 debugging is enabled (debug 2).
2968 For example server sockets that were used for CONNECT requests
2969 (which are used to tunnel https:// requests) are considered tainted
2970 once the client closed its connection to &my-app;.
2971 Technically &my-app; could keep the connection to the server open,
2972 but the server would not accept requests that do not belong to the
2973 previous TLS/SSL session (and the client may even have terminated
2977 Server sockets are also marked tainted when a client requests a
2978 resource, but closes the connection before &my-app; has completely
2979 received (and forwarded) the resource to the client.
2980 In this case the server would (probably) accept additional requests,
2981 but &my-app; could not get the response without completely reading
2982 the leftovers from the previous response.
2985 These are just two examples, there are currently a bit more than
2986 25 scenarios in which a socket is considered tainted.
2989 While sockets can also be marked tainted as a result of a technical
2990 problem that may be worth fixing, the problem will be explicitly
2995 <sect2 renderas="sect3" id="pcre-stack-limit">
2996 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2998 This can happen if your custom filters require more memory than &my-app;
3000 Usually the problem is that the operating system enforces a stack size limit
3001 that isn't sufficient.
3004 Unless the problem occurs with the filters available in the default configuration,
3005 this is not considered a Privoxy bug.
3008 To prevent the crashes you can rewrite your filter to use less resources,
3009 increase the relevant memory limit or recompile pcre to use less stack space.
3010 For details please see the
3011 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3012 and the documentation of your operating system.
3016 <sect2 renderas="sect3" id="file-permissions">
3017 <title>What to do if editing the config file of privoxy is access denied?</title>
3019 Your userid probably isn't allowed to edit the file.
3020 <!-- show how to check permissions? -->
3021 On Windows you can use the windows equivalent of sudo:
3023 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
3026 or fix the file permissions:
3028 <screen>C:\Privoxy>icacls config.txt
3029 config.txt BUILTIN\Administrators:(I)(F)
3030 NT AUTHORITY\SYSTEM:(I)(F)
3031 BUILTIN\Users:(I)(RX)
3032 NT AUTHORITY\Authenticated Users:(I)(M)
3034 Successfully processed 1 files; Failed processing 0 files
3036 C:\Privoxy>icacls config.txt /grant Lee:F
3037 processed file: config.txt
3038 Successfully processed 1 files; Failed processing 0 files
3040 C:\Privoxy>icacls config.txt
3041 config.txt I3668\Lee:(F)
3042 BUILTIN\Administrators:(I)(F)
3043 NT AUTHORITY\SYSTEM:(I)(F)
3044 BUILTIN\Users:(I)(RX)
3045 NT AUTHORITY\Authenticated Users:(I)(M)
3047 Successfully processed 1 files; Failed processing 0 files
3049 C:\Privoxy></screen>
3052 or try to point-n-click your way through adjusting the file
3053 permissions in windows explorer.
3059 <!-- ~~~~~ New section ~~~~~ -->
3060 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3061 <!-- Include contacting.sgml -->
3063 <!-- end contacting -->
3066 <!-- ~~~~~ New section ~~~~~ -->
3067 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3069 <!-- Include copyright.sgml -->
3075 Portions of this document are <quote>borrowed</quote> from the original
3076 <application>Junkbuster</application> (tm) FAQ, and modified as
3077 appropriate for <application>Privoxy</application>.
3080 <!-- ~~~~~ New section ~~~~~ -->
3081 <sect2><title>License</title>
3082 <!-- Include copyright.sgml: -->
3084 <!-- end copyright -->
3086 <!-- ~ End section ~ -->
3088 <!-- ~~~~~ New section ~~~~~ -->
3089 <sect2><title>History</title>
3090 <!-- Include history.sgml -->
3096 <!-- ~ End section ~ -->
3099 <!-- ~~~~~ New section ~~~~~ -->
3101 <sect1 id="seealso"><title>See also</title>
3103 <!-- Include seealso.sgml -->
3113 This program is free software; you can redistribute it
3114 and/or modify it under the terms of the GNU General
3115 Public License as published by the Free Software
3116 Foundation; either version 2 of the License, or (at
3117 your option) any later version.
3119 This program is distributed in the hope that it will
3120 be useful, but WITHOUT ANY WARRANTY; without even the
3121 implied warranty of MERCHANTABILITY or FITNESS FOR A
3122 PARTICULAR PURPOSE. See the GNU General Public
3123 License for more details.
3125 The GNU General Public License should be included with
3126 this file. If not, you can view it at
3127 http://www.gnu.org/copyleft/gpl.html
3128 or write to the Free Software Foundation, Inc.,
3129 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA