1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN"[
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity contacting SYSTEM "contacting.sgml">
8 <!entity history SYSTEM "history.sgml">
9 <!entity copyright SYSTEM "copyright.sgml">
10 <!entity license SYSTEM "license.sgml">
11 <!entity p-version "3.0.27">
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 : $Source: /cvsroot/ijbswa/current/doc/source/faq.sgml,v $
27 This file belongs into
28 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
30 $Id: faq.sgml,v 2.135 2017/03/27 10:22:27 fabiankeil Exp $
32 Copyright (C) 2001-2014 Privoxy Developers https://www.privoxy.org/
35 Based partially on the Internet Junkbuster FAQ originally written by and
36 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
37 http://www.junkbusters.com/
39 <Qandaset defaultlabel='qanda'>
54 ========================================================================
55 NOTE: Please read developer-manual/documentation.html before touching
58 Please we keep the info in this file as version independent as possible
59 so we only have to maintain one FAQ. Where significant changes are
60 made to Privoxy configuration, please note the change in such a way that
61 it makes sense to both users of older and newer versions.
62 ========================================================================
68 <article id="index" class="faq">
70 <title>Privoxy Frequently Asked Questions</title>
74 <!-- Completely the wrong markup, but very little is allowed -->
75 <!-- in this part of an article. FIXME -->
76 <link linkend="copyright">Copyright</link> &my-copy; 2001-2016 by
77 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
81 <pubdate>$Id: faq.sgml,v 2.135 2017/03/27 10:22:27 fabiankeil Exp $</pubdate>
85 Note: this should generate a separate page, and a live link to it.
86 But it doesn't for some mysterious reason. Please leave commented
87 unless it can be fixed proper. For the time being, the copyright
88 statement will be in copyright.smgl.
92 <legalnotice id="legalnotice">
94 text goes here ........
104 <orgname>By: Privoxy Developers</orgname>
113 This is here to keep vim syntax file from breaking :/
114 If I knew enough to fix it, I would.
115 PLEASE DO NOT REMOVE! HB: hal@foobox.net
120 This FAQ gives quick answers to frequently asked questions about
121 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
122 It is not a substitute for the
123 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
125 This works, at least in some situtations:
126 Test: <ulink url="privoxy-user-manual.pdf"><citetitle>User Manual</citetitle></ulink>.
130 <!-- Include privoxy.sgml boilerplate: -->
131 <para>What is Privoxy?</para> &p-intro;
132 <!-- end boilerplate -->
135 Please note that this document is a work in progress. This copy represents
136 the state at the release of version &p-version;.
137 You can find the latest version of the document at <ulink
138 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
139 Please see the <link linkend="contact">Contact section</link> if you want to
140 contact the developers.
147 <!-- ~~~~~ New section ~~~~~ -->
149 <sect1 id="general"><title>General Information</title>
150 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
152 Anyone who is interested in security, privacy, or in
153 finer-grained control over their web and Internet experience.
157 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
160 &my-app; is certainly a good choice, especially for those who want more
161 control and security. Those with the willingness to read the documentation
162 and the ability to fine-tune their installation will benefit the most.
165 One of <application>Privoxy's</application>
166 strengths is that it is highly configurable giving you the ability to
167 completely personalize your installation. Being familiar with, or at least
168 having an interest in learning about <ulink
169 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
170 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
171 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
172 Expressions</quote></ulink>
173 will be a big plus and will help you get the most out of &my-app;.
174 A new installation just includes a very basic configuration. The user
175 should take this as a starting point only, and enhance it as he or she
176 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
180 Much of <application>Privoxy's</application> configuration can be done
181 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
182 But there are areas where configuration is done using a
183 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
184 to edit configuration files. Also note that the web-based action editor
185 doesn't use authentication and should only be enabled in environments
186 where all clients with access to &my-app; listening port can be trusted.
190 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
191 Privoxy work? </title>
193 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
194 is a service, based on a software such as &my-app;, that clients
195 (i.e. browsers) can use instead of connecting to web servers directly.
196 The clients then ask the proxy to request objects (web pages, images, movies etc)
197 on their behalf and to forward the data to the clients.
198 It is a <quote>go-between</quote>. For details, see
199 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
202 There are many reasons to use web proxies, such as security (firewalling),
203 efficiency (caching) and others, and there are any number of proxies
204 to accommodate those needs.
207 &my-app; is a proxy that is primarily focused on
208 privacy enhancement, ad and junk elimination and freeing the user from
209 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
210 it is in a perfect position to filter outbound personal information that your
211 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
212 this, all of which are under your complete control via the various configuration
213 files and options. Being a proxy also makes it easier to share
214 configurations among multiple browsers and/or users.
218 <sect2 renderas="sect3" id="otherstuff">
219 <title>Does Privoxy do anything more than ad blocking?</title>
221 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
222 can be used to sanitize and customize web browsing.
226 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
227 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
229 <!-- Include history.sgml -->
236 <sect2 renderas="sect3" id="whyprivoxy">
237 <title>Why <quote>Privoxy</quote>? Why change the name from
238 Junkbuster at all?</title>
240 Though outdated, Junkbusters Corporation continued to offer their original
241 version of the <application>Internet Junkbuster</application> for a while,
242 so publishing our <application> Junkbuster</application>-derived software
243 under the same name would have led to confusion.
246 There were also potential legal reasons not to use the
247 <application>Junkbuster</application> name, as it was (and maybe still is)
248 a registered trademark of Junkbusters Corporation.
249 There were, however, no objections from Junkbusters Corporation to the
250 <application>Privoxy</application> project itself, and they, in fact,
251 shared our ideals and goals.
254 The Privoxy developers also believed that there were so many improvements
255 over the original code, that it was time to make a clean break from the past
256 and make a name in their own right.
259 <application>Privoxy</application> is the
260 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
261 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
262 control, more freedom, and allows you to browse your personal and
263 <quote><emphasis>private</emphasis> edition</quote> of the web.
267 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
268 from the old Junkbuster?</title>
270 <application>Privoxy</application> picks up where
271 <application>Junkbuster</application> left off.
272 <application>Privoxy</application> still blocks ads and banners,
274 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
275 helps protect your privacy. But, most of these features have been enhanced,
276 and many new ones have been added, all in the same vein.
279 <application>Privoxy</application>'s new features include:
282 <!-- Include newfeatures.sgml: -->
288 <sect2 renderas="sect3" id="whatsanad">
289 <title>How does Privoxy know what is an ad, and what is not?</title>
291 <application>Privoxy</application>'s approach to blocking ads is twofold:
294 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
295 of banner images. This applies to both the path (you wouldn't guess how many
296 web sites serve their banners from a directory called <quote>banners</quote>!)
297 and the host (blocking the big banner hosting services like doublecklick.net
298 already helps a lot). <application>Privoxy</application> takes advantage of this
299 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
300 patterns</ulink> to sort out and block the requests for things that sound
301 like they would be ads or banners.
304 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
305 can't tell the size of an image by its URL without downloading it, and if you
306 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
307 also inspects the HTML sources of web pages while they are loaded, and replaces
308 references to images with standard banner sizes by dummy references, so that
309 your browser doesn't request them anymore in the first place.
312 Both of this involves a certain amount of guesswork and is, of course, freely
313 and readily configurable.
317 <sect2 renderas="sect3" id="mistakes">
318 <title>Can Privoxy make mistakes?
319 This does not sound very scientific.</title>
321 Actually, it's a black art ;-) And yes, it is always possible to have a broad
322 rule accidentally block or change something by mistake. You will almost surely
323 run into such situations at some point. It is tricky writing rules to
324 cover every conceivable possibility, and not occasionally get false positives.
328 But this should not be a big concern since the
329 <application>Privoxy</application> configuration is very flexible, and
330 includes tools to help identify these types of situations so they can be
331 addressed as needed, allowing you to customize your installation.
332 (<link linkend="badsite">See the Troubleshooting section below</link>.)
337 <sect2 renderas="sect3" id="configornot">
338 <title>Will I have to configure Privoxy
339 before I can use it?</title>
341 That depends on your expectations.
342 The default installation should give you a good starting
343 point, and block <emphasis>most</emphasis> ads and unwanted content,
344 but many of the more advanced features are off by default, and require
345 you to activate them.
348 You do have to set up your browser to use
349 <application>Privoxy</application> (see the <link
350 linkend="firststep">Installation section below</link>).
353 And you will certainly run into situations where there are false positives,
354 or ads not being blocked that you may not want to see. In these cases, you
355 would certainly benefit by customizing <application>Privoxy's</application>
356 configuration to more closely match your individual situation. And we
357 encourage you to do this. This is where the real power of
358 <application>Privoxy</application> lies!
363 <sect2 renderas="sect3" id="lan">
364 <title>Can Privoxy run as a server on a network?</title>
366 Yes, &my-app; runs as a server already, and can easily be configured to
367 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
368 How can I set up Privoxy to act as a proxy for my LAN</link> below.
372 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
373 Privoxy. Why should I use Privoxy at all?</title>
375 Modern browsers do indeed have <emphasis>some</emphasis> of the same
376 functionality as <application>Privoxy</application>. Maybe this is
377 adequate for you. But <application>Privoxy</application> is very
378 versatile and powerful, and can probably do a number of things
379 your browser just can't.
382 In addition, a proxy is good choice if you use multiple browsers, or
383 have a LAN with multiple computers since &my-app; can run as a server
384 application. This way all the configuration is in one place, and you don't
385 have to maintain a similar configuration for possibly many browsers or
389 Note, however, that it's recommended to leverage both your browser's
390 and <application>Privoxy's</application> privacy enhancing features
391 at the same time. While your browser probably lacks some features
392 &my-app; offers, it should also be able to do some things more
393 reliably, for example restricting and suppressing JavaScript.
397 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
399 The most important reason is because you have access to
400 <emphasis>everything</emphasis>, and you can control everything. You can
401 check every line of every configuration file yourself. You can check every
402 last bit of source code should you desire. And even if you can't read code,
403 there should be some comfort in knowing that <!-- thousands of -->other people can,
404 and do read it. You can build the software from scratch, if you want,
405 so that you know the executable is clean, and that it is
406 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
407 is one reason we use &my-app; ourselves.
411 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
412 warranty? Registration?</title>
414 <application>Privoxy</application> is free software and licensed under the <ulink
415 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
416 It is free to use, copy, modify or distribute as you wish under the terms of this
417 license. Please see the <link linkend="copyright">Copyright</link> section for more
418 information on the license and copyright. Or the <filename>LICENSE</filename> file
419 that should be included.
422 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
423 That is something that would cost real money ;-) There is no registration either.
428 <sect2 renderas="sect3" id="spyware">
429 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
431 No, at least not reliably enough to trust it. &my-app; is not designed to be
432 a malware removal tool and the default configuration doesn't even try to
433 filter out any malware.
436 &my-app; could help prevent contact from (known) sites that use such
437 tactics with appropriate configuration rules, and thus could conceivably
438 prevent contamination from such sites. However, keeping such a configuration
439 up to date would require a lot of time and effort that would be better spend
440 on keeping your software itself up to date so it doesn't have known
446 <sect2 renderas="sect3" id="otherads">
447 <title>Can I use Privoxy with other ad-blocking software?</title>
449 &my-app; should work fine with other proxies and other software in general.
452 But it is probably not necessary to use &my-app; in conjunction with other
453 ad-blocking products, and this could conceivably cause undesirable results.
454 It might be better to choose one software or the other and work a little to
455 tweak its configuration to your liking.
458 Note that this is an advice specific to ad blocking.
462 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
464 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
466 Well, we <emphasis>always</emphasis> need help. There is something for
467 everybody who wants to help us. We welcome new developers, packagers,
468 testers, documentation writers or really anyone with a desire to help in
469 any way. You <emphasis>DO NOT</emphasis> need to be a
470 <quote>programmer</quote>. There are many other tasks available. In fact,
471 the programmers often can't spend as much time programming because of some
472 of the other, more mundane things that need to be done, like checking the
473 Tracker feedback sections or responding to user questions on the mailing
477 So first thing, subscribe to the <ulink
478 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
479 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
480 Developers</ulink> mailing list, join the discussion, help out other users, provide general
481 feedback or report problems you noticed.
484 If you intend to help out with the trackers, you also might want to <ulink
485 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
486 so we don't confuse you with the other name-less users.
489 We also have a <ulink
490 url="../developer-manual/index.html">Developer's Manual</ulink>.
491 While it is partly out of date, it's still worth reading.
494 Our <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup">TODO list</ulink>
495 may be of interest to you as well.
496 Please let us know if you want to work on one of the items listed.
500 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
502 Donations are welcome. Our
503 <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup">TODO list</ulink>
504 is rather long and being able to pay one (or more) developers to work on Privoxy
505 would make a huge difference, even if it was only for a couple of weeks. Donations may
506 also be used for Privoxy-related travel expenses (for example to attend conferences),
507 for hardware used for Privoxy development and for hosting expenses etc.
511 <application>Privoxy</application> is an associated
512 project of <ulink url="https://www.spi-inc.org/">Software
513 in the Public Interest (SPI)</ulink>, which allows us to receive
514 tax-deductible donations in the United States.
515 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
516 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
517 For details, please have a look at
518 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
522 You can also donate to Privoxy using a bank account or a "Paypal" address:
525 Name on account: <ulink url="https://www.zwiebelfreunde.de/">Zwiebelfreunde e.V.</ulink>
526 IBAN: DE95430609671126825604
531 "Paypal" address: privoxy@zwiebelfreunde.de
534 Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany
535 and other countries that recognize German charitable clubs. Feel free to
536 use the Subject field to provide a name to be credited and a list of TODO
537 list items you are interested in the most. For example: Max Mustermann: #16, #1, #14.
541 Note that donations made through Zwiebelfreunde e.V. currently can't be checked
542 automatically so you may not get credited right away. The credits currently
543 reflect donations received before 2016-01-14.
547 If you have any questions regarding donations please mail to either the
548 public user mailing list or, if it's a private matter, to
549 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
554 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
556 We are currently offering the following sponsor levels as an experiment:
560 <term>Gold (10000 EUR/year)</term>
563 Logo shown at the bottom of the
564 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
565 Logo, link and self description on the
566 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
571 <term>Silver (1000 EUR/year)</term>
574 Logo shown randomly at the bottom of the
575 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
576 Logo, link and self description on the
577 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
582 <term>Bronze (500 EUR/year)</term>
585 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
591 The logo sizes depend on the sponsor level. Logos are served from
592 our server, no requests are made to the sponsor website unless
593 the links are being used.
596 The details may change over time but changes will only affect new sponsors
597 (or existing sponsors that explicitly agreed to the changes).
600 If you want to become a sponsor, please contact
601 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
602 New sponsors are only accepted if no developer objects.
610 <!-- ~~~~~ New section ~~~~~ -->
612 <sect1 id="installation"><title>Installation</title>
614 <sect2 renderas="sect3" id="whichbrowsers">
615 <title>Which browsers are supported by Privoxy?</title>
617 Any browser that can be configured to use a proxy, which
618 should be virtually all browsers, including
619 <application>Firefox</application>, <application>Internet
620 Explorer</application>, <application>Opera</application>, and
621 <application>Safari</application> among others.
622 Direct browser support is not an absolute requirement since
623 <application>Privoxy</application> runs as a separate application and talks
624 to the browser in the standardized HTTP protocol, just like a web server
629 <sect2 renderas="sect3" id="whichos">
630 <title>Which operating systems are supported?</title>
632 Include supported.sgml here:
637 <sect2 renderas="sect3" id="email-client">
638 <title>Can I use Privoxy with my email client?</title>
640 As long as there is some way to set a HTTP proxy for the client, then yes,
641 any application can be used, whether it is strictly speaking a
642 <quote>browser</quote> or not. Though this may not be the best approach for
643 dealing with some of the common abuses of HTML in email. See <link
644 linkend="outlook">How can I configure <application>Privoxy</application>
645 with <application>Outlook</application>?</link> below for more on
649 Be aware that HTML email presents a number of unique security and privacy
650 related issues, that can require advanced skills to overcome. The developers
651 recommend using email clients that can be configured to convert HTML to plain
652 text for these reasons.
656 <!-- Nobody is going to still be doing this!
657 <sect2 renderas="sect3" id="newinstall"><title>Can I install
658 Privoxy over Junkbuster?</title>
660 We recommend you un-install <application>Junkbuster</application>
661 first to minimize conflicts and confusion. You may want to
662 save your old configuration files for future reference. The configuration
663 files and syntax have substantially changed, so you will need to manually
664 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
665 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
666 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
670 Note: Some installers may automatically un-install
671 <application>Junkbuster</application>, if present!
677 <sect2 renderas="sect3" id="firststep">
678 <title>I just installed Privoxy. Is there anything
679 special I have to do now?</title>
682 All browsers should be told to use <application>Privoxy</application>
683 as a proxy by specifying the correct proxy address and port number
684 in the appropriate configuration area for the browser. It's possible
685 to combine &my-app; with a packet filter to intercept HTTP requests
686 even if the client isn't explicitly configured to use &my-app;,
687 but where possible, configuring the client is recommended. See
688 <ulink url="../user-manual/startup.html">the User Manual for more
689 details</ulink>. You should also flush your browser's memory and disk
690 cache to get rid of any cached junk items, and remove any stored
691 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
697 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
699 If you set up the <application>Privoxy</application> to run on
700 the computer you browse from (rather than your ISP's server or some
701 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
702 (sometimes referred to as <quote>localhost</quote>,
703 which is the special name used by every computer on the Internet to refer
704 to itself) and the port will be 8118 (unless you used the <ulink
705 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
706 config option to tell <application>Privoxy</application> to run on
710 When configuring your browser's proxy settings you typically enter
711 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
712 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
713 then the number <quote>8118</quote> for <quote>port</quote>.
714 This tells your browser to send all web requests to <application>Privoxy</application>
715 instead of directly to the Internet.
718 <application>Privoxy</application> can also be used to proxy for
719 a Local Area Network. In this case, your would enter either the IP
720 address of the LAN host where <application>Privoxy</application>
721 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
722 Port assignment would be same as above. Note that
723 <application>Privoxy</application> doesn't listen on any LAN interfaces by
727 <application>Privoxy</application> does not currently handle
728 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
732 <sect2 renderas="sect3" id="nothing">
733 <title>I just installed Privoxy, and nothing is happening.
734 All the ads are there. What's wrong?</title>
737 Did you configure your browser to use <application>Privoxy</application>
738 as a proxy? It does not sound like it. See above. You might also try flushing
739 the browser's caches to force a full re-reading of pages. You can verify
740 that <application>Privoxy</application> is running, and your browser
741 is correctly configured by entering the special URL:
742 <ulink url="http://p.p/">http://p.p/</ulink>.
743 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
744 of potential redirect caching problem (see next Q). -->
745 This should take you to a page titled <quote>This is Privoxy..</quote> with
746 access to <application>Privoxy's</application> internal configuration.
747 If you see this, then you are good to go. If you receive a page saying
748 <quote>Privoxy is not running</quote>, then the browser is not set up to use
749 your <application>Privoxy</application> installation.
750 If you receive anything else (probably nothing at all), it could either
751 be that the browser is not set up correctly, or that
752 <application>Privoxy</application> is not running at all. Check the <ulink
753 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
754 on starting <application>Privoxy</application> and browser configuration,
755 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
756 on starting <application>Privoxy</application></ulink> in the
757 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
762 <sect2 renderas="sect3" id="notused">
763 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
764 Privoxy is running and being used.</title>
767 First, make sure that Privoxy is <emphasis>really</emphasis> running and
768 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
769 should see the <application>Privoxy</application> main page. If not, see
770 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
771 on starting <application>Privoxy</application></ulink> in the
772 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
776 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
777 other parts of <application>Privoxy</application>'s web interface show
778 the dummy page, your browser has cached a redirection it encountered before
779 <application>Privoxy</application> was being used. You need to clear your
780 browser's cache. Note that shift-reloading the dummy page won't help, since
781 that'll only refresh the dummy page, not the redirection that lead you there.
785 The procedure for clearing the cache varies from browser to browser. For
786 example, <application>Mozilla/Netscape</application> users would click
787 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
788 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
789 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
790 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
791 In some <application>Firefox</application> versions it's
792 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
793 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
794 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
795 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
802 <!-- ~~~~~ New section ~~~~~ -->
804 <sect1 id="configuration"><title>Configuration</title>
805 <sect2 renderas="sect3" id="actionsfile">
806 <title>What exactly is an <quote>actions</quote> file?</title>
809 &my-app; utilizes the concept of <quote>
810 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
811 that are used to manipulate and control web page data.
812 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
813 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
814 that <application>Privoxy</application> could take while processing a certain
815 request, are configured. Typically, you would define a set of default actions
816 that apply globally to all URLs, then add exceptions to these defaults where needed.
817 There is a wide array of actions available that give the user a high degree
818 of control and flexibility on how to process each and every web page.
822 Actions can be defined on a <ulink
823 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
824 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
825 grouped together and then applied to requests matching one or more patterns.
826 There are many possible actions that might apply to any given site. As an example,
827 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
828 as one of your default actions, but need to accept cookies from a given site,
829 you would need to define an exception for this site in one of your actions
830 files, preferably in <filename>user.action</filename>.
835 <sect2 renderas="sect3" id="actionss">
836 <title>The <quote>actions</quote> concept confuses me. Please list
837 some of these <quote>actions</quote>.</title>
839 For a comprehensive discussion of the actions concept, please refer
840 to the <ulink url="../user-manual/actions-file.html">actions file
841 chapter</ulink> in the <ulink url="../user-manual/index.html">User
842 Manual</ulink>. It includes a <ulink
843 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
844 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
845 file tutorial</ulink> to get you started.
850 <sect2 renderas="sect3" id="actconfig">
851 <title>How are actions files configured? What is the easiest
852 way to do this?</title>
855 Actions files are just text files in a special syntax and can be edited
856 with a text editor. But probably the easiest way is to access
857 <application>Privoxy</application>'s user interface with your web browser
858 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
859 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
860 <quote><ulink url="http://config.privoxy.org/show-status">View &
861 change the current configuration</ulink></quote> from the menu. Note
862 that this feature must be explicitly enabled in the main config file
864 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
869 <sect2 renderas="sect3">
870 <title>There are several different <quote>actions</quote> files. What are
871 the differences?</title>
873 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
874 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
879 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
881 Based on your feedback and the continuing development, updates of
882 <filename>default.action</filename> will be
883 made available from time to time on the <ulink
884 url="https://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
885 our <ulink url="https://sourceforge.net/projects/ijbswa/">project page</ulink>.
889 If you wish to receive an email notification whenever we release updates of
890 <application>Privoxy</application> or the actions file, <ulink
891 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
892 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
897 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
899 The syntax and purpose of configuration files has remained roughly the
900 same throughout the 3.x series, but backwards compatibility is not guaranteed.
901 Also each release contains updated, <quote>improved</quote> versions and it is
902 therefore strongly recommended to install the newer configuration files
903 and merge back your modifications.
907 <sect2 renderas="sect3" id="difficult">
908 <title>Why is the configuration so complicated?</title>
910 <quote>Complicated</quote> is in the eye of the beholder.
913 Privoxy is currently mainly written by and for people who are already
914 familiar with the underlying concepts like regular expressions, HTTP and HTML,
915 or are willing to become familiar with them to be able to get the most
916 out of a powerful and flexible tool such as Privoxy.
919 While everybody is expected to be able to get a Privoxy default installation
920 up and running, fine-tuning requires a certain amount of background
921 information and Privoxy's documentation mainly concentrates on the
922 Privoxy-specific parts while only providing references to the rest.
925 If you or anyone you know has the skills, time and energy to
926 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
930 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
932 The default configuration shouldn't impact the usability of any of these services.
933 It may, however, make all <ulink
934 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
935 temporary, so that your browser will forget your
936 login credentials in between browser sessions. If you would like not to have to log
937 in manually each time you access those websites, simply turn off all cookie handling
938 for them in the <filename>user.action</filename> file. An example for yahoo might
942 <screen># Allow all cookies for Yahoo login:
944 { -<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> }
945 .login.yahoo.com</screen>
948 These kinds of sites are often quite complex and heavy with
949 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
950 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
952 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
956 <screen># Gmail is a _fragile_ site:
958 { <literal>fragile</literal> }
960 mail.google.com</screen>
963 Be sure to flush your browser's caches whenever making these kinds of
964 changes, just to make sure the changes <quote>take</quote>.
967 Make sure the domain, host and path are appropriate as well. Your browser can
968 tell you where you are specifically and you should use that information for
969 your configuration settings. Note that above it is not referenced as
970 <literal>gmail.com</literal>, which is a valid domain name.
975 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
976 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
978 Configuring <application>Privoxy</application> is not entirely trivial. To
979 help you get started, we provide you with three different default action
980 <quote>profiles</quote> in the web based actions file editor at <ulink
981 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
982 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
983 Manual</citetitle></ulink> for a list of actions, and how the default
988 Where the defaults are likely to break some sites, exceptions for
989 known popular <quote>problem</quote> sites are included, but in
990 general, the more aggressive your default settings are, the more exceptions
991 you will have to make later. New users are best to start off in
992 <quote>Cautious</quote> setting. This is safest and will have the fewest
993 problems. See the <ulink
994 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
995 for a more detailed discussion.
999 It should be noted that the <quote>Advanced</quote> profile (formerly known
1000 as the <quote>Adventuresome</quote> profile) is more
1001 aggressive, and will make use of some of
1002 <application>Privoxy's</application> advanced features. Use at your own risk!
1007 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
1008 with a browser? Does that not raise security issues?</title>
1010 It may seem strange that regular users can edit the config files with their
1011 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
1012 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
1015 When you use the browser-based editor, <application>Privoxy</application>
1016 itself is writing to the config files. Because
1017 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
1018 it can update its own config files.
1021 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
1022 a LAN) or aren't entirely in control of your own browser, you will probably want
1023 to make sure that the web-based editor and remote toggle features are
1024 <quote>off</quote> by setting <quote><literal><ulink
1025 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
1026 0</literal></quote> and <quote><literal><ulink
1027 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
1028 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
1031 As of &my-app; 3.0.7 these options are disabled by default.
1036 <sect2 renderas="sect3" id="filterfile">
1037 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
1039 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
1040 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1041 Filters are a special subset of actions that can be used to modify or
1042 remove web page content or headers on the fly. Content filters can
1043 be applied to <emphasis>anything</emphasis> in the page source,
1044 header filters can be applied to either server or client headers.
1045 Regular expressions are used to accomplish this.
1048 There are a number of pre-defined filters to deal with common annoyances. The
1049 filters are only defined here, to invoke them, you need to use the
1051 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1052 action</ulink> in one of the actions files. Content filtering is automatically
1053 disabled for inappropriate MIME types, but if you know better than Privoxy
1054 what should or should not be filtered you can filter any content you like.
1058 <emphasis>not</emphasis> be confused with <ulink
1059 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1060 is a completely different action, and is more typically used to block ads and
1065 If you are familiar with regular expressions, and HTML, you can look at
1066 the provided <filename>default.filter</filename> with a text editor and define
1067 your own filters. This is potentially a very powerful feature, but
1068 requires some expertise in both regular expressions and HTML/HTTP.
1069 <![%p-newstuff;[ You should
1070 place any modifications to the default filters, or any new ones you create
1071 in a separate file, such as <filename>user.filter</filename>, so they won't
1072 be overwritten during upgrades.
1073 The ability to define multiple filter files
1074 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1078 There is no GUI editor option for this part of the configuration,
1079 but you can disable/enable the various pre-defined filters of the included
1080 <filename>default.filter</filename> file with the <ulink
1081 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1082 Note that the custom actions editor must be explicitly enabled in
1083 the main config file (see <ulink
1084 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1088 If you intend to develop your own filters, you might want to have a look at
1090 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1095 <sect2 renderas="sect3" id="lanconfig">
1096 <title>How can I set up Privoxy to act as a proxy for my
1099 By default, <application>Privoxy</application> only responds to requests
1100 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1101 a network, this needs to be changed in the <ulink
1102 url="../user-manual/config.html">main configuration file</ulink>. Look for
1104 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1105 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1106 it is uncommented, and assign it the address of the LAN gateway interface,
1107 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1108 wish to run <application>Privoxy</application> on port 8118, this line
1114 listen-address 192.168.1.1:8118</screen>
1118 Save the file, and restart <application>Privoxy</application>. Configure
1119 all browsers on the network then to use this address and port number.
1123 Alternately, you can have <application>Privoxy</application> listen on
1124 all available interfaces:
1129 listen-address :8118</screen>
1133 And then use <application>Privoxy's</application>
1135 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1136 feature to limit connections. A firewall in this situation is recommended
1141 The above steps should be the same for any TCP network, regardless of
1146 If you run <application>Privoxy</application> on a LAN with untrusted users,
1147 we recommend that you double-check the <ulink
1148 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1155 <sect2 renderas="sect3" id="noseeum">
1156 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1158 The replacement for blocked images can be controlled with the <ulink
1159 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1160 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1161 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1162 Note that this choice only has effect for images which are blocked as images, i.e.
1163 whose URLs match both a <literal><ulink
1164 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1165 <emphasis>and</emphasis> <literal><ulink
1166 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1169 If you want to see nothing, then change the <ulink
1170 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1171 action</ulink> to <quote>blank</quote>. This can be done by editing the
1172 <filename>user.action</filename> file, or through the <ulink
1173 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1178 <sect2 renderas="sect3" id="whyseeum">
1179 <title>Why would anybody want to see a checkerboard pattern?</title>
1181 Remember that <link linkend="whatsanad">telling which image is an ad and which
1182 isn't</link>, is an educated guess. While we hope that the standard configuration
1183 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1184 decent, and it shows you where images have been blocked, which can be very
1185 helpful in case some navigation aid or otherwise innocent image was
1186 erroneously blocked. It is recommended for new users so they can
1187 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1188 many banners they <emphasis>don't</emphasis> have to see.
1193 <sect2 renderas="sect3" id="blockedbytext">
1194 <title>I see some images being replaced with text
1195 instead of the checkerboard image. Why and how do I get rid of this?</title>
1197 This happens when the banners are not embedded in the HTML code of the
1198 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1199 or (i)layers, and these external HTML documents are blocked. Being non-images
1200 they get replaced by a substitute HTML page rather than a substitute image,
1201 which wouldn't work out technically, since the browser expects and accepts
1202 only HTML when it has requested an HTML document.
1205 The substitute page adapts to the available space and shows itself as a
1206 miniature two-liner if loaded into small frames, or full-blown with a
1207 large red "BLOCKED" banner if space allows.
1210 If you prefer the banners to be blocked by images, you must see to it that
1211 the HTML documents in which they are embedded are not blocked. Clicking
1212 the <quote>See why</quote> link offered in the substitute page will show
1213 you which rule blocked the page. After changing the rule and un-blocking
1214 the HTML documents, the browser will try to load the actual banner images
1215 and the usual image blocking will (hopefully!) kick in.
1220 <sect2 renderas="sect3" id="srvany">
1221 <title>Can Privoxy run as a service
1222 on Win2K/NT/XP?</title>
1225 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1226 functionality. See <ulink url="../user-manual/installation.html#installation-pack-win">
1227 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1228 <application>Privoxy</application> as a service.
1231 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1232 See the discussion at <ulink
1233 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>,
1234 for details, and a sample configuration.
1239 <sect2 renderas="sect3" id="otherproxy">
1240 <title>How can I make Privoxy work with other proxies?</title>
1242 This can be done and is often useful to combine the benefits of
1243 <application>Privoxy</application> with those of a another proxy,
1244 for example to cache content.
1246 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1247 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1248 describes how to do this. If you intend to use Privoxy with Tor,
1249 please also have a look at
1250 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1254 <sect2 renderas="sect3" id="port-80">
1255 <title>Can I just set Privoxy to use port 80
1256 and thus avoid individual browser configuration?</title>
1259 No, its more complicated than that. This only works with special kinds
1260 of proxies known as <quote>intercepting</quote> proxies
1261 (<link linkend="INTERCEPTING">see below</link>).
1266 <sect2 renderas="sect3" id="transparent">
1267 <title>Can Privoxy run as a <quote>transparent
1268 </quote> proxy?</title>
1270 The whole idea of Privoxy is to modify client requests
1271 and server responses in all sorts of ways and therefore
1272 it's not a transparent proxy as described in
1273 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1276 However, some people say <quote>transparent proxy</quote> when they
1277 mean <quote>intercepting proxy</quote>. If you are one of them,
1278 please read the <link linkend="INTERCEPTING">next entry</link>.
1283 <sect2 renderas="sect3" id="intercepting">
1284 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1286 <application>Privoxy</application> can't intercept traffic itself,
1287 but it can handle requests that where intercepted and redirected
1288 with a packet filter (like <application>PF</application> or
1289 <application>iptables</application>), as long as the <literal>Host</literal>
1293 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1294 web sites rely on it anyway, this limitation shouldn't be a problem.
1297 Please refer to your packet filter's documentation to learn how to
1298 intercept and redirect traffic into <application>Privoxy</application>.
1299 Afterward you just have to configure <application>Privoxy</application> to
1300 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1301 intercepted requests</ulink>.
1306 <sect2 renderas="sect3" id="outlook">
1307 <title>How can I configure Privoxy for use with Outlook?</title>
1309 Versions of <application>Outlook</application> prior to Office 2007, use
1310 <application>Internet Explorer</application> components to both render HTML,
1311 and fetch any HTTP requests that may be embedded in an HTML email. So however
1312 you have <application>Privoxy</application> configured to work with IE, this
1313 configuration should automatically be shared, at least with older version of
1317 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1318 engine with Outlook. It is unknown whether this can be configured to use a
1320 <!-- FIXME HB 2009-02-15 -->
1324 <sect2 renderas="sect3" id="outlook-more">
1325 <title>How can I have separate rules just for HTML mail?</title>
1327 The short answer is, you can't. <application>Privoxy</application> has no way
1328 of knowing which particular application makes a request, so there is no way to
1329 distinguish between web pages and HTML mail.
1330 <application>Privoxy</application> just blindly proxies all requests. In the
1331 case of <application>Outlook Express</application> (see above), OE uses
1332 IE anyway, and there is no way for <application>Privoxy</application> to ever
1333 be able to distinguish between them (nor could any other proxy type application for
1337 For a good discussion of some of the issues involved (including privacy and
1338 security issues), see
1339 <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>.
1343 <sect2 renderas="sect3" id="sneaky-cookies">
1344 <title>I sometimes notice cookies sneaking through. How?</title>
1347 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1348 set in several ways. The classic method is via the
1349 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1350 easy one to manipulate, such as the &my-app; concept of
1351 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1352 There is also the possibility of using
1353 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1354 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1355 is trickier because the syntax can vary widely, and thus requires a certain
1356 amount of guesswork. It is not realistic to catch all of these short of
1357 disabling Javascript, which would break many sites. And lastly, if the
1358 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1359 <application>Privoxy's</application> reach.
1362 All in all, &my-app; can help manage cookies in general, can help minimize
1363 the loss of privacy posed by cookies, but can't realistically stop all
1368 <sect2 renderas="sect3" id="evil-cookies">
1369 <title>Are all cookies bad? Why?</title>
1371 No, in fact there are many beneficial uses of
1373 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1374 method that browsers can use to store data between pages, or between browser
1375 sessions. Sometimes there is a good reason for this, and the user's life is a
1376 bit easier as a result. But there is a long history of some websites taking
1377 advantage of this layer of trust, and using the data they glean from you and
1378 your browsing habits for their own purposes, and maybe to your potential
1379 detriment. Such sites are using you and storing their data on your system.
1380 That is why the privacy conscious watch from whom those cookies come, and why
1381 they really <emphasis>need</emphasis> to be there.
1385 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1386 definition</ulink> for more.
1390 <sect2 renderas="sect3" id="allow-cookies">
1391 <title>How can I allow permanent cookies for my trusted sites?</title>
1394 There are several actions that relate to cookies. The default behavior is to
1395 allow only <quote>session cookies</quote>, which means the cookies only last
1396 for the current browser session. This eliminates most kinds of abuse related
1397 to cookies. But there may be cases where you want cookies to last.
1400 To disable all cookie actions, so that cookies are allowed unrestricted,
1401 both in and out, for <literal>example.com</literal>:
1405 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1406 .example.com</screen>
1409 Place the above in <filename>user.action</filename>. Note that some of these may
1410 be off by default anyway, so this might be redundant, but there is no harm
1411 being explicit in what you want to happen. <filename>user.action</filename>
1412 includes an alias for this situation, called
1413 <literal>allow-all-cookies</literal>.
1417 <sect2 renderas="sect3" id="multiples">
1418 <title>Can I have separate configurations for different users?</title>
1420 Each instance of <application>Privoxy</application> has its own
1421 configuration, including such attributes as the TCP port that it listens on.
1422 What you can do is run multiple instances of <application>Privoxy</application>, each with
1424 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1425 configuration setting, and configuration path, and then
1426 each of these can have their own configurations. Think of it as per-port
1430 Simple enough for a few users, but for large installations, consider having
1431 groups of users that might share like configurations.
1435 <sect2 renderas="sect3" id="whitelists">
1436 <title>Can I set-up Privoxy as a whitelist of
1437 <quote>good</quote> sites?</title>
1439 Sure. There are a couple of things you can do for simple white-listing.
1440 Here's one real easy one:
1443 ############################################################
1445 ############################################################
1446 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1447 / # Block *all* URLs
1449 ############################################################
1451 ############################################################
1452 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1455 games.example.com</screen>
1457 This allows access to only those three sites by first blocking all URLs, and
1458 then subsequently allowing three specific exceptions.
1461 Another approach is <application>Privoxy's</application>
1462 <literal>trustfile</literal> concept, which incorporates the notion of
1463 <quote>trusted referrers</quote>. See the <ulink
1464 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1468 These are fairly simple approaches and are not completely foolproof. There
1469 are various other configuration options that should be disabled (described
1470 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1471 so that users can't modify their own configuration and easily circumvent the
1476 <sect2 renderas="sect3" id="no-adblock">
1477 <title>How can I turn off ad-blocking?</title>
1479 Ad blocking is achieved through a complex application of various &my-app;
1480 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1481 actions are deployed against simple images, banners, flash animations,
1482 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1483 just turning one or two actions off. The various actions that make up
1484 &my-app; ad blocking are hard-coded into the default configuration files. It
1485 has been assumed that everyone using &my-app; is interested in this
1489 If you want to do without this, there are several approaches you can take:
1490 You can manually undo the many block rules in
1491 <filename>default.action</filename>. Or even easier, just create your own
1492 <filename>default.action</filename> file from scratch without the many ad
1493 blocking rules, and corresponding exceptions. Or lastly, if you are not
1494 concerned about the additional blocks that are done for privacy reasons, you
1495 can very easily over-ride <emphasis>all</emphasis> blocking with the
1496 following very simple rule in your <filename>user.action</filename>:
1500 # Unblock everybody, everywhere
1501 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1502 / # UN-Block *all* URLs</screen>
1505 Or even a more comprehensive reversing of various ad related actions:
1509 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1510 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1511 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1512 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1513 <literal>allow-popups</literal> \
1515 / # UN-Block *all* URLs and allow ads</screen>
1518 This last <quote>action</quote> in this compound statement,
1519 <literal>allow-popups</literal>, is an <ulink
1520 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1521 various pop-up blocking features.
1525 <sect2 renderas="sect3" id="templates">
1526 <title>How can I have custom template pages, like the
1527 <emphasis>BLOCKED</emphasis> page?</title>
1529 &my-app; <quote>templates</quote> are specialized text files utilized by
1530 &my-app; for various purposes and can easily be modified using any text
1531 editor. All the template pages are installed in a sub-directory appropriately
1532 named: <filename>templates</filename>. Knowing something about HTML syntax
1533 will of course be helpful.
1536 Be forewarned that the default templates are subject to being overwritten
1537 during upgrades. You can, however, create completely new templates,
1538 place them in another directory and specify the alternate path in the main
1539 <filename>config</filename>. For details, have a look at the <ulink
1540 url="../user-manual/config.html#templdir">templdir</ulink> option.
1544 <sect2 renderas="sect3" id="blockall">
1545 <title>How can I remove the <quote>Go There Anyway</quote> link from
1546 the <emphasis>BLOCKED</emphasis> page?</title>
1548 There is more than one way to do it (although Perl is not involved).
1551 Editing the BLOCKED template page (see above) may dissuade some users, but
1552 this method is easily circumvented. Where you need this level of control, you
1553 might want to build &my-app; from source, and disable various features that are
1554 available as compile-time options. You should
1555 <command>configure</command> the sources as follows:
1559 ./configure --disable-toggle --disable-editor --disable-force</screen>
1562 This will create an executable with hard-coded security features so that
1563 &my-app; does not allow easy bypassing of blocked sites, or changing the
1564 current configuration via any connected user's web browser.
1567 Finally, all of these features can also be toggled on/off via options in
1568 <application>Privoxy's</application> main <ulink
1569 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1570 means you don't have to recompile anything.
1576 <!-- ~ End section ~ -->
1579 <!-- ~~~~~ New section ~~~~~ -->
1581 <sect1 id="misc"><title>Miscellaneous</title>
1583 <sect2 renderas="sect3" id="slowsme">
1584 <title>How much does Privoxy slow my browsing down? This
1585 has to add extra time to browsing.</title>
1587 How much of an impact depends on many things, including the CPU of the host
1588 system, how aggressive the configuration is, which specific actions are being triggered,
1589 the size of the page, the bandwidth of the connection, etc.
1592 Overall, it should not slow you down any in real terms, and may actually help
1593 speed things up since ads, banners and other junk are not typically being
1594 retrieved and displayed. The actual processing time required by
1595 <application>Privoxy</application> itself for each page, is relatively small
1596 in the overall scheme of things, and happens very quickly. This is typically
1597 more than offset by time saved not downloading and rendering ad images and
1598 other junk content (if ad blocking is being used).
1602 <quote>Filtering</quote> content via the <literal><ulink
1603 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1605 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1606 actions may cause a perceived slowdown, since the entire document
1607 needs to be buffered before displaying. And on very large documents,
1608 filtering may have some measurable impact. How much depends on the page size,
1609 the actual definition of the filter(s), etc. See below. Most other actions
1610 have little to no impact on speed.
1613 Also, when filtering is enabled but zlib support isn't available, compression
1614 is often disabled (see <ulink
1615 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1616 This can have an impact on speed as well, although it's probably smaller than
1617 you might think. Again, the page size, etc. will determine how much of an impact.
1623 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1624 delays in page requests. What's wrong?</title>
1626 If you use any <literal><ulink
1627 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1628 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1629 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1630 action, the entire document must be loaded into memory in order for the filtering
1631 mechanism to work, and nothing is sent to the browser during this time.
1634 The loading time typically does not really change much in real numbers, but
1635 the feeling is different, because most browsers are able to start rendering
1636 incomplete content, giving the user a feeling of "it works". This effect is
1637 more noticeable on slower dialup connections. Extremely large documents
1638 may have some impact on the time to load the page where there is filtering
1639 being done. But overall, the difference should be very minimal. If there is a
1640 big impact, then probably some other situation is contributing (like
1641 anti-virus software).
1644 Filtering is automatically disabled for inappropriate MIME types. But note
1645 that if the web server mis-reports the MIME type, then content that should
1646 not be filtered, could be. <application>Privoxy</application> only knows how
1647 to differentiate filterable content because of the MIME type as reported by
1648 the server, or because of some configuration setting that enables/disables
1653 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1654 "http://p.p/"?</title>
1656 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1657 address of <application>Privoxy</application>'s built-in user interface, and
1658 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1661 Since <application>Privoxy</application> sits between your web browser and the Internet,
1662 it can simply intercept requests for these addresses and answer them with its built-in
1663 <quote>web server</quote>.
1666 This also makes for a good test for your browser configuration: If entering the
1667 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1668 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1669 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1670 your browser didn't use <application>Privoxy</application> for the request,
1671 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1672 web site at config.privoxy.org.
1675 Note that config.privoxy.org resolves to a public IP address.
1676 If you use config.privoxy.org as ping or traceroute target you will
1677 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1678 If you want to ping the system Privoxy runs on,
1679 you should use its IP address or local DNS name (if it has got one).
1685 out of date 09/02/06 HB
1686 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1688 No. The patterns for blocking now reside (among other things) in the <ulink
1689 url="../user-manual/actions-file.html">actions files</ulink>, which are
1690 actively maintained instead. See next question ...
1694 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1697 Please see the <link linkend="contact">Contact section</link> for
1698 various ways to interact with the developers.
1703 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1704 they be included in future updates?</title>
1706 Whether such submissions are eventually included in the
1707 <filename>default.action</filename> configuration file depends on how
1708 significant the issue is. We of course want to address any potential
1709 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1710 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1711 has a good chance of being a candidate. But at the other end of the spectrum
1712 are any number of smaller, low-profile sites such as for local clubs or
1713 schools. Since their reach and impact are much less, they are best handled by
1714 inclusion in the user's <filename>user.action</filename>, and thus would be
1715 unlikely to be included.
1721 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1724 Rest assured that it has been read and considered. Why it is not answered,
1725 could be for various reasons, including no one has a good answer for it, no
1726 one has had time to yet investigate it thoroughly, it has been reported
1727 numerous times already, or because not enough information was provided to help
1728 us help you. Your efforts are not wasted, and we do appreciate them.
1734 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1736 If you run both the browser and &my-app; locally, you cannot hide your IP
1737 address with <application>Privoxy</application> or ultimately any other
1738 software alone. The server needs to know your IP address so that it knows
1739 where to send the responses back.
1742 There are many publicly usable "anonymous" proxies out there, which
1743 provide a further level of indirection between you and the web server.
1746 However, these proxies are called "anonymous" because you don't need
1747 to authenticate, not because they would offer any real anonymity.
1748 Most of them will log your IP address and make it available to the
1749 authorities in case you violate the law of the country they run in. In fact
1750 you can't even rule out that some of them only exist to *collect* information
1751 on (those suspicious) people with a more than average preference for privacy.
1754 If you want to hide your IP address from most adversaries,
1755 you should consider chaining <application>Privoxy</application>
1756 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1757 The configuration details can be found in
1758 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1759 with <application>Tor</application> section</ulink>
1764 <sect2 renderas="sect3" id="anonforsure">
1765 <title>Can Privoxy guarantee I am anonymous?</title>
1767 No. Your chances of remaining anonymous are improved, but unless you
1768 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1769 or a similar proxy and know what you're doing when it comes to configuring
1770 the rest of your system, you should assume that everything you do
1771 on the Web can be traced back to you.
1774 <application>Privoxy</application> can remove various information about you,
1775 and allows <emphasis>you</emphasis> more freedom to decide which sites
1776 you can trust, and what details you want to reveal. But it neither
1777 hides your IP address, nor can it guarantee that the rest of the system
1778 behaves correctly. There are several possibilities how a web sites can find
1779 out who you are, even if you are using a strict <application>Privoxy</application>
1780 configuration and chained it with <application>Tor</application>.
1783 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1784 by an insecure browser configuration, therefore you should use a browser that can
1785 be configured to only execute code from trusted sites, and be careful which sites you trust.
1786 For example there is no point in having <application>Privoxy</application>
1787 modify the User-Agent header, if websites can get all the information they want
1788 through JavaScript, ActiveX, Flash, Java etc.
1791 A few browsers disclose the user's email address in certain situations, such
1792 as when transferring a file by FTP. <application>Privoxy</application>
1793 does not filter FTP. If you need this feature, or are concerned about the
1794 mail handler of your browser disclosing your email address, you might
1795 consider products such as <application>NSClean</application>.
1798 Browsers available only as binaries could use non-standard headers to give
1799 out any information they can have access to: see the manufacturer's license
1800 agreement. It's impossible to anticipate and prevent every breach of privacy
1801 that might occur. The professionally paranoid prefer browsers available as
1802 source code, because anticipating their behavior is easier. Trust the source,
1808 <sect2 renderas="sect3" id="proxytest">
1809 <title>A test site says I am not using a Proxy.</title>
1811 Good! Actually, they are probably testing for some other kinds of proxies.
1812 Hiding yourself completely would require additional steps.
1816 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1817 together with Tor?</title>
1819 Before you configure <application>Privoxy</application> to use
1820 <ulink url="https://www.torproject.org/">Tor</ulink>,
1821 please follow the <citetitle>User Manual</citetitle> chapters
1822 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1823 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1824 <application>Privoxy</application> itself is setup correctly.
1827 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1828 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1829 and make sure <application>Tor</application>'s logfile says that
1830 <quote>Tor has successfully opened a circuit</quote> and it
1831 <quote>looks like client functionality is working</quote>.
1834 If either <application>Tor</application> or <application>Privoxy</application>
1835 isn't working, their combination most likely will neither. Testing them on their
1836 own will also help you to direct problem reports to the right audience.
1837 If <application>Privoxy</application> isn't working, don't bother the
1838 <application>Tor</application> developers. If <application>Tor</application>
1839 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1842 If you verified that <application>Privoxy</application> and <application>Tor</application>
1843 are working, it is time to connect them. As far as <application>Privoxy</application>
1844 is concerned, <application>Tor</application> is just another proxy that can be reached
1845 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1846 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1847 requests are done through <application>Tor</application> and thus invisible to your
1848 local network. Using socks4a would work too, but with socks5 you get more precise error
1853 <application>Privoxy's</application>
1854 <ulink url="../user-manual/config.html">main configuration file</ulink>
1855 is already prepared for <application>Tor</application>, if you are using a
1856 default <application>Tor</application> configuration and run it on the same
1857 system as &my-app;, you just have to edit the
1858 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1859 and uncomment the line:
1863 # forward-socks5t / 127.0.0.1:9050 .
1867 Note that if you got Tor through one of the bundles, you may
1868 have to change the port from 9050 to 9150 (or even another one).
1869 For details, please check the documentation on the
1870 <ulink url="https://torproject.org/">Tor website</ulink>.
1874 This is enough to reach the Internet, but additionally you might want to
1875 uncomment the following forward rules, to make sure your local network is still
1876 reachable through Privoxy:
1880 # forward 192.168.*.*/ .
1881 # forward 10.*.*.*/ .
1882 # forward 127.*.*.*/ .
1886 Unencrypted connections to systems in these address ranges will
1887 be as (un)secure as the local network is, but the alternative is
1888 that your browser can't reach the network at all. Then again,
1889 that may actually be desired and if you don't know for sure
1890 that your browser has to be able to reach the local network,
1891 there's no reason to allow it.
1894 If you want your browser to be able to reach servers in your local
1895 network by using their names, you will need additional exceptions
1896 that look like this:
1900 # forward localhost/ .
1904 Save the modified configuration file and open
1905 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1906 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1907 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1909 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1910 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1913 Afterward, please take the time to at least skim through the rest
1914 of <application>Tor's</application> documentation. Make sure you understand
1915 what <application>Tor</application> does, why it is no replacement for
1916 application level security, and why you probably don't want to
1917 use it for unencrypted logins.
1921 <sect2 renderas="sect3" id="sitebreak">
1922 <title>Might some things break because header information or
1923 content is being altered?</title>
1926 Definitely. It is common for sites to use browser type, browser version,
1927 HTTP header content, and various other techniques in order to dynamically
1928 decide what to display and how to display it. What you see, and what I see,
1929 might be very different. There are many, many ways that this can be handled,
1930 so having hard and fast rules, is tricky.
1934 The <quote>User-Agent</quote> is sometimes used in this way to identify
1935 the browser, and adjust content accordingly.
1939 Also, different browsers use different encodings of non-English
1940 characters, certain web servers convert pages on-the-fly according to the
1941 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1942 operating system or browser manufacturer causes some sites in these languages
1943 to be garbled; Surfers to Eastern European sites should change it to
1944 something closer. And then some page access counters work by looking at the
1945 <quote>Referer</quote> header; they may fail or break if unavailable. The
1946 weather maps of Intellicast have been blocked by their server when no
1947 <quote>Referer</quote> or cookie is provided, is another example. (But you
1948 can forge both headers without giving information away). There are
1949 many other ways things can go wrong when trying to fool a web server. The
1950 results of which could inadvertently cause pages to load incorrectly,
1951 partially, or even not at all. And there may be no obvious clues as to just
1952 what went wrong, or why. Nowhere will there be a message that says
1953 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1958 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1963 If you have problems with a site, you will have to adjust your configuration
1964 accordingly. Cookies are probably the most likely adjustment that may
1965 be required, but by no means the only one.
1971 <sect2 renderas="sect3" id="caching">
1972 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1973 speed up web browsing?</title>
1975 No, it does not have this ability at all. You want something like
1976 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1977 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1978 And, yes, before you ask, <application>Privoxy</application> can co-exist
1979 with other kinds of proxies like <application>Squid</application>.
1980 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1981 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1982 manual</ulink> for details.
1986 <sect2 renderas="sect3" id="firewall">
1987 <title>What about as a firewall? Can Privoxy protect me?</title>
1989 Not in the way you mean, or in the way some firewall vendors claim they can.
1990 <application>Privoxy</application> can help protect your privacy, but can't
1991 protect your system from intrusion attempts. It is, of course, perfectly possible
1992 to use <emphasis>both</emphasis>.
1996 <sect2 renderas="sect3" id="wasted">
1997 <title>I have large empty spaces / a checkerboard pattern now where
1998 ads used to be. Why?</title>
2000 It is technically possible to eliminate banners and ads in a way that frees
2001 their allocated page space. This could easily be done by blocking with
2002 <application>Privoxy's</application> filters,
2003 and eliminating the <emphasis>entire</emphasis> image references from the
2007 But, this would consume considerably more CPU resources (IOW, slow things
2008 down), would likely destroy the layout of some web pages which rely on the
2009 banners utilizing a certain amount of page space, and might fail in other
2010 cases, where the screen space is reserved (e.g. by HTML tables for instance).
2011 Also, making ads and banners disappear without any trace complicates
2012 troubleshooting, and would sooner or later be problematic.
2015 The better alternative is to instead let them stay, and block the resulting
2016 requests for the banners themselves as is now the case. This leaves either
2017 empty space, or the familiar checkerboard pattern.
2020 So the developers won't support this in the default configuration, but you
2021 can of course define appropriate filters yourself to achieve this.
2025 <sect2 renderas="sect3" id="ssl">
2026 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
2028 Since secure HTTP connections are encrypted SSL sessions between your browser
2029 and the secure site, and are meant to be reliably <emphasis>secure</emphasis>,
2030 there is little that <application>Privoxy</application> can do but hand the raw
2031 gibberish data though from one end to the other unprocessed.
2034 The only exception to this is blocking by host patterns, as the client needs
2035 to tell <application>Privoxy</application> the name of the remote server,
2036 so that <application>Privoxy</application> can establish the connection.
2037 If that name matches a host-only pattern, the connection will be blocked.
2040 As far as ad blocking is concerned, this is less of a restriction than it may
2041 seem, since ad sources are often identifiable by the host name, and often
2042 the banners to be placed in an encrypted page come unencrypted nonetheless
2043 for efficiency reasons, which exposes them to the full power of
2044 <application>Privoxy</application>'s ad blocking.
2047 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
2048 JS page content, see <literal><ulink
2049 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2050 in an SSL transaction will be impossible to block under these conditions.
2051 Fortunately, this does not seem to be a very common scenario since most
2052 cookies come by traditional means.
2057 <sect2 renderas="sect3" id="http2">
2058 <title>Does Privoxy support HTTP/2?</title>
2060 Privoxy currently doesn't parse HTTP/2 but applications
2061 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2062 to allow CONNECT requests (default) which are also used
2066 Adding HTTP/2 support is on the TODO list but currently
2067 nobody is known to work on it.
2071 <sect2 renderas="sect3" id="secure">
2072 <title>Privoxy runs as a <quote>server</quote>. How
2073 secure is it? Do I need to take any special precautions?</title>
2075 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2076 user, which is how we recommend it be run. Also, by default
2077 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2081 The server aspect of <application>Privoxy</application> is not itself directly
2082 exposed to the Internet in this configuration. If you want to have
2083 <application>Privoxy</application> serve as a LAN proxy, this will have to
2084 be opened up to allow for LAN requests. In this case, we'd recommend
2085 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2086 <application>Privoxy</application> configuration file and check all <ulink
2087 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2088 options</ulink>. All LAN hosts can then use this as their proxy address
2089 in the browser proxy configuration, but <application>Privoxy</application>
2090 will not listen on any external interfaces. ACLs can be defined in addition,
2091 and using a firewall is always good too. Better safe than sorry.
2096 <sect2 renderas="sect3" id="turnoff">
2097 <title>Can I temporarily disable Privoxy?</title>
2099 &my-app; doesn't have a transparent proxy mode,
2100 but you can toggle off blocking and content filtering.
2103 The easiest way to do that is to point your browser
2104 to the remote toggle URL: <ulink
2105 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2108 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2109 of the <citetitle>User Manual</citetitle> for an easy way to access this
2110 feature. Note that this is a feature that may need to be enabled in the main
2111 <filename>config</filename> file.
2116 <sect2 renderas="sect3" id="reallyoff">
2117 <title>When <quote>disabled</quote> is Privoxy totally
2118 out of the picture?</title>
2120 No, this just means all optional filtering and actions are disabled.
2121 <application>Privoxy</application> is still acting as a proxy, but just
2122 doing less of the things that <application>Privoxy</application> would
2123 normally be expected to do. It is still a <quote>middle-man</quote> in
2124 the interaction between your browser and web sites. See below to bypass
2129 <sect2 renderas="sect3" id="turnoff2">
2130 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2132 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2133 configuration issue, not a &my-app; issue. Modern browsers typically do have
2134 settings for not proxying certain sites. Check your browser's help files.
2139 <sect2 renderas="sect3" id="crunch">
2140 <title>My logs show Privoxy <quote>crunches</quote>
2141 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2143 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2144 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2145 banners, but <application>Privoxy</application> uses the same mechanism for
2146 trapping requests for its own internal pages. For instance, a request for
2147 <application>Privoxy's</application> configuration page at: <ulink
2148 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2149 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2150 configuration is returned to the browser, and the log consequently will show
2151 a <quote>crunch</quote>.
2154 Since version 3.0.7, Privoxy will also log the crunch reason.
2155 If you are using an older version you might want to upgrade.
2159 <sect2 renderas="sect3" id="downloads">
2160 <title>Can Privoxy affect files that I download
2161 from a webserver? FTP server?</title>
2163 From the webserver's perspective, there is no difference between
2164 viewing a document (i.e. a page), and downloading a file. The same is true of
2165 <application>Privoxy</application>. If there is a match for a <literal><ulink
2166 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2167 it will still be blocked, and of course this is obvious.
2170 Filtering is potentially more of a concern since the results are not always
2171 so obvious, and the effects of filtering are there whether the file is simply
2172 viewed, or downloaded. And potentially whether the content is some obnoxious
2173 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2174 one of these presumably is <quote>bad</quote> content that we don't want, and
2175 the other is <quote>good</quote> content that we do want.
2176 <application>Privoxy</application> is blind to the differences, and can only
2177 distinguish <quote>good from bad</quote> by the configuration parameters
2178 <emphasis>we</emphasis> give it.
2181 <application>Privoxy</application> knows the differences in files according
2182 to the <quote>Content Type</quote> as reported by the webserver. If this is
2183 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2184 then <application>Privoxy</application> knows to ignore these where
2185 appropriate. <application>Privoxy</application> potentially can filter HTML
2186 as well as plain text documents, subject to configuration parameters of
2187 course. Also, documents that are of an unknown type (generally assumed to be
2188 <quote>text/plain</quote>) can be filtered, as will those that might be
2189 incorrectly reported by the webserver. If such a file is a downloaded file
2190 that is intended to be saved to disk, then any content that might have been
2191 altered by filtering, will be saved too, for these (probably rare) cases.
2194 Note that versions later than 3.0.2 do NOT filter document types reported as
2195 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2196 did filter this document type.
2199 In short, filtering is <quote>ON</quote> if a) the content type as reported
2200 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2201 allows it (or at least does not disallow it). That's it. There is no magic
2202 cookie anywhere to say this is <quote>good</quote> and this is
2203 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2206 If you download text files, you probably do not want these to be filtered,
2207 particularly if the content is source code, or other critical content. Source
2208 code sometimes might be mistaken for Javascript (i.e. the kind that might
2209 open a pop-up window). It is recommended to turn off filtering for download
2210 sites (particularly if the content may be plain text files and you are using
2211 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2212 also, for any site or page where making <emphasis>any</emphasis> changes at
2213 all to the content is to be avoided.
2216 <application>Privoxy</application> does not do FTP at all, only HTTP
2217 and HTTPS (SSL) protocols.
2221 <sect2 renderas="sect3" id="downloads2">
2222 <title>I just downloaded a Perl script, and Privoxy
2223 altered it! Yikes, what is wrong!</title>
2229 <sect2 renderas="sect3" id="hostsfile">
2230 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2232 One time-tested technique to defeat common ads is to trick the local DNS
2233 system by giving a phony IP address for the ad generator in the local
2234 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2235 <literal>localhost</literal>. This effectively blocks the ad.
2238 There is no reason to use this technique in conjunction with
2239 <application>Privoxy</application>. <application>Privoxy</application>
2240 does essentially the same thing, much more elegantly and with much more
2241 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2242 duplicates effort, but may get in the way and seriously slow down your system.
2243 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2244 your hosts list is neglected by <application>Privoxy's </application>
2245 configuration, consider adding your list to your <filename>user.action</filename> file:
2252 ads.galore.example.com
2253 etc.example.com</screen>
2257 <sect2 renderas="sect3" id="seealso">
2258 <title>Where can I find more information about Privoxy
2259 and related issues?</title>
2260 <!-- Include seealso.sgml boilerplate: -->
2262 <!-- end boilerplate -->
2267 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2273 <sect2 renderas="sect3" id="microsuck">
2274 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2275 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2278 We're not. The text substitutions that you are seeing are disabled
2279 in the default configuration as shipped. You have either manually
2280 activated the <quote><literal>fun</literal></quote> filter which
2281 is clearly labeled <quote>Text replacements for subversive browsing
2282 fun!</quote> or you are using an older Privoxy version and have implicitly
2283 activated it by choosing the <quote>Advanced</quote> profile in the
2284 web-based editor. Please upgrade.
2288 <sect2 renderas="sect3" id="valid">
2289 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2292 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2293 whenever there are text substitutions via a &my-app; filter. While this
2294 should always conform to the HTML 4.01 specifications, it has not been
2295 validated against this or any other standard.
2299 <sect2 renderas="sect3" id="surprise-privoxy">
2300 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2303 We didn't. We make Privoxy available for download, but we don't go
2304 around installing it on other people's systems behind their back.
2305 If you discover Privoxy running on your system and are sure you didn't
2306 install it yourself, somebody else did. You may not even be running
2307 the real Privoxy, but maybe something else that only pretends to be
2308 Privoxy, or maybe something that is based on the real Privoxy,
2309 but has been modified.
2312 Lately there have been reports of problems with some kind of
2313 "parental control" software based on Privoxy that came preinstalled on
2314 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2315 The problems described are inconsistent with the behaviour of official
2316 Privoxy versions, which suggests that the preinstalled software may
2317 contain vendor modifications that we don't know about and thus can't debug.
2320 Privoxy's <link linkend="copyright">license</link> allows vendor
2321 modifications, but the vendor has to comply with the license,
2322 which involves informing the user about the changes and to make
2323 the changes available under the same license as Privoxy itself.
2326 If you are having trouble with a modified Privoxy version,
2327 please try to talk to whoever made the modifications before
2328 reporting the problem to us. Please also try to convince
2329 whoever made the modifications to talk to us. If you think
2330 somebody gave you a modified Privoxy version without complying
2331 to the license, please let us know.
2339 <!-- ~~~~~ New section ~~~~~ -->
2341 <sect1 id="trouble">
2342 <title>Troubleshooting</title>
2344 <sect2 renderas="sect3" id="refused">
2345 <title>I cannot connect to any websites. Or, I am getting
2346 <quote>connection refused</quote> message with every web page. Why?</title>
2348 There are several possibilities:
2353 <application>Privoxy</application> is not running. Solution: verify
2354 that &my-app; is installed correctly, has not crashed, and is indeed running.
2355 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2357 <listitem><para>Or your browser is configured for a different port than what
2358 <application>Privoxy</application> is using. Solution: verify that &my-app;
2359 and your browser are set to the same port (<literal>listen-address</literal>).
2361 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2362 problem with a host in the forwarding chain. Solution: temporarily alter your
2363 configuration and take the forwarders out of the equation.
2366 Or you have a firewall that is interfering and blocking you. Solution:
2367 try disabling or removing the firewall as a simple test.
2374 <!-- ~~~~~ New section ~~~~~ -->
2375 <sect2 renderas="sect3" id="error503">
2376 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2378 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2379 been reported to cause this symptom -- even if not running! The solution is
2380 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2381 something better behaved in its place. Other personal firewall type products
2382 may cause similar type problems if not configured correctly.
2386 <sect2 renderas="sect3" id="flushit">
2387 <title>I just added a new rule, but the steenkin ad is
2388 still getting through. How?</title>
2390 If the ad had been displayed before you added its URL, it will probably be
2391 held in the browser's cache for some time, so it will be displayed without
2392 the need for any request to the server, and <application>Privoxy</application>
2393 will not be involved. Flush the browser's caches, and then try again.
2397 If this doesn't help, you probably have an error in the rule you
2398 applied. Try pasting the full URL of the offending ad into <ulink
2399 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2400 and see if it really matches your new rule. Blocking ads is like blocking
2401 spam: a lot of tinkering is required to stay ahead of the game. And
2402 remember you need to block the URL of the ad in question, which may be
2403 entirely different from the site URL itself. Most ads are hosted on different
2404 servers than the main site itself. If you right-click on the ad, you should
2405 be able to get all the relevant information you need. Alternately, you can
2406 find the correct URL by looking at <application>Privoxy's</application> logs
2407 (you may need to enable logging in the main config file if its disabled).
2410 Below is a slightly modified real-life log snippet that originates with one
2411 requested URL: <literal>www.example.com</literal> (name of site was changed
2412 for this example, the number of requests is real). You can see in this the
2413 complexity of what goes into making up this one <quote>page</quote>. There
2414 are eight different domains involved here, with thirty two separate URLs
2415 requested in all, making up all manner of images, Shockwave Flash,
2416 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2417 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2418 Many of the more questionable looking requests, are going to outside domains
2419 that seem to be identifying themselves with suspicious looking names, making
2420 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2421 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2426 Request: www.example.com/
2427 Request: www.example.com/favicon.ico
2428 Request: img.example.com/main.css
2429 Request: img.example.com/sr.js
2430 Request: example.betamarker.com/example.html
2431 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2432 Request: img.example.com/pb.png
2433 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2434 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2435 Request: img.example.com/p.gif
2436 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2437 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2438 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2439 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2440 Request: www.adtrak.net/adx.js crunch! (Blocked)
2441 Request: img.example.com/hbg.gif
2442 Request: img.example.com/example.jpg
2443 Request: img.example.com/mt.png
2444 Request: img.example.com/mm.png
2445 Request: img.example.com/mb.png
2446 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2447 Request: www.example.com/tracker.js
2448 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2449 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2450 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2451 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2452 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2453 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2454 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2455 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2456 Request: 66.70.21.80/img/pixel.gif
2457 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2458 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2463 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2464 behave perfectly <quote>normal</quote> (minus some ads, of course).
2469 <sect2 renderas="sect3" id="badsite">
2470 <title>One of my favorite sites does not work with Privoxy.
2471 What can I do?</title>
2474 First verify that it is indeed a <application>Privoxy</application> problem,
2475 by toggling off <application>Privoxy</application> through <ulink
2476 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2477 (the toggle feature may need to be enabled in the main
2478 <filename>config</filename>),
2479 and then shift-reloading the problem page (i.e. holding down the shift key
2480 while clicking reload. Alternatively, flush your browser's disk and memory
2485 If the problem went away, we know we have a configuration related problem.
2487 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2488 and paste the full URL of the page in question into the prompt. See which
2489 actions are being applied to the URL, and which matches in which actions
2490 files are responsible for that. It might be helpful also to look at your logs
2491 for this site too, to see what else might be happening (note: logging may need
2492 to be enabled in the main config file). Many sites are
2493 complex and require a number of related pages to help present their content.
2494 Look at what else might be used by the page in question, and what of that
2495 might be <emphasis>required</emphasis>.
2496 Now, armed with this information, go to
2498 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2499 and select the appropriate actions files for editing. </para>
2501 You can now either look for a section which disables the actions that
2502 you suspect to cause the problem and add a pattern for your site there,
2503 or make up a completely new section for your site. In any case, the recommended
2504 way is to disable only the prime suspect, reload the problem page, and only
2505 if the problem persists, disable more and more actions until you have
2506 identified the culprit. You may or may not want to turn the other actions
2507 on again. Remember to flush your browser's caches in between any such changes!
2510 Alternately, if you are comfortable with a text editor, you can accomplish
2511 the same thing by editing the appropriate actions file. Probably the easiest
2512 way to deal with such problems when editing by hand is to add your
2513 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2514 which is an alias that turns off most <quote>dangerous</quote>
2515 actions, but is also likely to turn off more actions then needed, and thus lower
2516 your privacy and protection more than necessary,
2519 Troubleshooting actions is discussed in more detail in the <ulink
2520 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2521 Troubleshooting: the Anatomy of an Action</ulink>.
2522 There is also an <ulink
2523 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2524 with general configuration information and examples.
2527 As a last resort, you can always see if your browser has a setting that will
2528 bypass the proxy setting for selective sites. Modern browsers can do this.
2534 <!-- ~~~~~ New section ~~~~~ -->
2535 <sect2 id="dun" renderas="sect3">
2536 <title>After installing Privoxy, I have to log in
2537 every time I start IE. What gives?</title>
2540 This is a quirk that affects the installation of
2541 <application>Privoxy</application>, in conjunction with Internet Explorer and
2542 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2543 appear to be corrupted or invalid DUN settings, or passwords.
2547 When setting up an NT based Windows system with
2548 <application>Privoxy</application> you may find that things do not seem to be
2549 doing what you expect. When you set your system up you will probably have set
2550 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2551 logged in with administrator privileges. You will probably have made this DUN
2552 connection available to other accounts that you may have set-up on your
2553 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2554 configured for the kids.
2558 When setting up <application>Privoxy</application> in this environment you
2559 will have to alter the proxy set-up of Internet Explorer (IE) for the
2560 specific DUN connection on which you wish to use
2561 <application>Privoxy</application>. When you do this the ICS DUN set-up
2562 becomes user specific. In this instance you will see no difference if you
2563 change the DUN connection under the account used to set-up the connection.
2564 However when you do this from another user you will notice that the DUN
2565 connection changes to make available to "Me only". You will also find that
2566 you have to store the password under each different user!
2570 The reason for this is that each user's set-up for IE is user specific. Each
2571 set-up DUN connection and each LAN connection in IE store the settings for
2572 each user individually. As such this enforces individual configurations
2573 rather than common ones. Hence the first time you use a DUN connection after
2574 re-booting your system it may not perform as you expect, and prompt you for
2575 the password. Just set and save the password again and all should be OK.
2579 [Thanks to Ray Griffith for this submission.]
2584 <!-- ~~~~~ New section ~~~~~ -->
2585 <sect2 id="ftp" renderas="sect3">
2586 <title>I cannot connect to any FTP sites. Privoxy
2587 is blocking me.</title>
2589 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2590 so do not configure your browser to use <application>Privoxy</application>
2591 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2592 or HTTPS (SSL)</emphasis>.
2595 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2596 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2597 an FTP connection, and not a HTTP connection. So while your browser may
2598 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2602 To complicate matters, some systems may have a generic <quote>proxy</quote>
2603 setting, which will enable various protocols, including
2604 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2605 accidentally enable FTP proxying in these cases. And of course, if this
2606 happens, <application>Privoxy</application> will indeed cause problems since
2607 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2608 message if a FTP connection is attempted.]]> Just disable the FTP setting
2609 and all will be well again.
2612 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2613 There just is not much reason, and the work to make this happen is more than
2618 <!-- ~~~~~ New section ~~~~~ -->
2619 <sect2 id="macosxie" renderas="sect3">
2620 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2621 Privoxy as the HTTP proxy.</title>
2623 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2624 network settings. In order to change the HTTP proxy, open System
2625 Preferences, and click on the Network icon. In the settings pane that
2626 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2627 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2628 Enter <literal>8118</literal> in the Port field. The next time you start
2629 IE, it should reflect these values.
2633 <!-- ~~~~~ New section ~~~~~ -->
2634 <sect2 renderas="sect3" id="macosxuninstall">
2635 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2636 uninstall it. Now the finder tells me I don't have sufficient privileges to
2637 empty the trash.</title>
2639 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2642 Just dragging the <application>Privoxy</application> folder to the trash is
2643 not enough to delete it. <application>Privoxy</application> supplies an
2644 <application>uninstall.command</application> file that takes care of
2645 these details. Open the trash, drag the <application>uninstall.command</application>
2646 file out of the trash and double-click on it. You will be prompted for
2647 confirmation and the administration password.
2650 The trash may still appear full after this command; emptying the trash
2651 from the desktop should make it appear empty again.
2655 <!-- ~~~~~ New section ~~~~~ -->
2656 <sect2 renderas="sect3" id="macosximages">
2657 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2658 experience random delays in page loading. I'm using
2659 <literal>localhost</literal> as my browser's proxy setting.</title>
2661 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2662 understand the issue yet. In any case, changing the proxy setting to
2663 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2664 works around the problem.
2668 <!-- ~~~~~ New section ~~~~~ -->
2669 <sect2 renderas="sect3" id="macosxaccountdeletion">
2670 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2673 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2674 X deletes all user accounts that are either not part of OS X itself or are
2675 not interactive user accounts (ones you log in with). Since, for the sake of
2676 security, &my-app; runs as a non-privileged user that is created by its
2677 installer (_privoxy), it can no longer start up once that account gets deleted.
2678 The solution is to perform a complete uninstall using the supplied
2679 <application>uninstall.command</application> script (either back up your
2680 configuration files or select to not have the uninstaller remove them when it
2681 prompts you) and then reinstall &my-app; using the installer package and merge
2682 in your configuration.
2686 <sect2 renderas="sect3" id="nohostname">
2687 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2690 <application>Privoxy</application> tries to get the hostname of the system
2691 its running on from the IP address of the system interface it is bound to
2692 (from the <filename>config</filename> file
2693 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2694 this information, <application>Privoxy</application> logs this condition.
2697 Typically, this would be considered a minor system configuration error. It is
2698 not a fatal error to <application>Privoxy</application> however, but may
2699 result in a much slower response from <application>Privoxy</application> on
2700 some platforms due to DNS timeouts.
2703 This can be caused by a problem with the local <filename>hosts</filename>
2704 file. If this file has been changed from the original, try reverting it to
2705 see if that helps. Make sure whatever name(s) are used for the local system,
2706 that they resolve both ways.
2709 You should also be able to work around the problem with the
2710 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2714 <sect2 renderas="sect3" id="inuse">
2715 <title>When I try to launch Privoxy, I get an
2716 error message <quote>port 8118 is already in use</quote> (or similar wording).
2719 Port 8118 is <application>Privoxy's</application> default TCP
2720 <quote>listening</quote> port. Typically this message would mean that there
2721 is already one instance of <application>Privoxy</application> running, and
2722 your system is actually trying to start a second
2723 <application>Privoxy</application> on the same port, which will not work.
2724 (You can have multiple instances but they must be assigned different ports.)
2725 How and why this might happen varies from platform to platform, but you need
2726 to check your installation and start-up procedures.
2730 <sect2 renderas="sect3" id="demoronizer">
2732 Pages with UTF-8 fonts are garbled.
2735 This may be the result of an overly aggressive filter. The filters that
2736 are enabled in the default configuration aren't expected to cause problems
2737 like this. If you enabled the <quote>demoronizer</quote> filter, please
2738 try temporarily disabling it.
2741 If that doesn't help, temporarily disable all filters to see if another
2742 filter could be the culprit. If the problem disappears, enable the filters
2743 one by one, until the problem reappears and the offending filter is found.
2746 Once the problem-causing filter is known, it can be fixed or disabled.
2749 Upgrading <application>Privoxy</application>, or going to the most recent
2750 <filename>default.action</filename> file available from <ulink
2751 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2752 might be worth a try, too.
2756 <sect2 renderas="sect3" id="demoronizer2">
2758 Why are binary files (such as images) corrupted when Privoxy
2762 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2763 filter</link> in conjunction with a web server that is misreporting the content
2764 type. By default binary files are exempted from
2765 <application>Privoxy's</application> filtering
2766 (unless the web server by mistake says the file is something else).
2770 <sect2 renderas="sect3" id="demoronizer3">
2772 What is the <quote>demoronizer</quote> and why is it there?
2775 The original demoronizer was a Perl script that cleaned up HTML pages which
2776 were created with certain Microsoft products. MS has used proprietary extensions
2777 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2778 that are viewed with non-Microsoft products (and are expecting to see a
2779 standard set of fonts). The demoronizer corrected these errors so the pages
2780 displayed correctly. <application>Privoxy</application> borrowed from this
2781 script, introducing a filter based on the original demoronizer, which in turn could
2782 correct these errors on the fly.
2785 But this is only needed in some situations, and will cause serious problems in some
2789 If you are using Microsoft products, you do not need it. If you need to view
2790 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2791 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2794 On the other hand, if you use non-Microsoft products, and you occasionally
2795 notice weird characters on pages, you might want to try it.
2799 <sect2 renderas="sect3" id="windowopen">
2801 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2804 <application>Privoxy</application> is attempting to disable malicious
2805 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2806 in this case, with the <literal>unsolicited-popups</literal>
2807 filter. <application>Privoxy</application> cannot tell very well
2808 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2811 If you see this in HTML source, and the page displays without problems, then
2812 this is good, and likely some pop-up window was disabled. If you see this
2813 where it is causing a problem, such as a downloaded program source code file,
2814 then you should set an exception for this site or page such that the
2815 integrity of the page stays in tact by disabling all filtering.
2819 <sect2 renderas="sect3" id="dnserrors">
2821 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2822 can't Privoxy do this better?
2825 There are potentially several factors here. First of all, the DNS resolution
2826 is done by the underlying operating system -- not
2827 <application>Privoxy</application> itself. <application>Privoxy</application>
2828 merely initiates the process and hands it off, and then later reports
2829 whatever the outcome was and tries to give a coherent message if there seems
2830 to be a problem. In some cases, this might otherwise be mitigated by the
2831 browser itself which might try some work-arounds and alternate approaches (e.g
2832 adding <quote>www.</quote> to the URL).
2835 In other cases, if <application>Privoxy</application> is being chained
2836 with another proxy, this could complicate the issue, and cause undue
2837 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2838 server handles all the DNS. <application>Privoxy</application> would just be
2839 the <quote>messenger</quote> which is reporting whatever problem occurred
2840 downstream, and not the root cause of the error.
2844 In any case, versions newer than 3.0.3 include various improvements to help
2845 <application>Privoxy</application> better handle these cases.
2849 <sect2 renderas="sect3" id="allcpu">
2851 At one site Privoxy just hangs, and starts taking
2852 all CPU. Why is this?
2855 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2856 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2857 are in the raw HTML source of the page, and the browser just ignores them. But the
2858 pattern matching in <application>Privoxy's</application> page filtering
2859 mechanism is trying to match against absurdly long strings and this becomes
2860 very CPU-intensive, taking a long, long time to complete.
2863 Until a better solution comes along, disable filtering on these pages,
2864 particularly the <literal>js-annoyances</literal> and
2865 <literal>unsolicited-popups</literal> filters. If you run into this problem
2866 with a recent &my-app; version, please send a problem report.
2870 <sect2 renderas="sect3" id="slowcrawl">
2871 <title>I just installed Privoxy, and all my
2872 browsing has slowed to a crawl. What gives? </title>
2874 This should not happen, and for the overwhelming number of users world-wide,
2875 it does not happen. I would suspect some inadvertent interaction of software
2876 components such as anti-virus software, spyware protectors, personal
2877 firewalls or similar components. Try disabling (or uninstalling) these one
2878 at a time and see if that helps. Either way, if you are using a
2879 recent &my-app; version, please report the problem.
2883 <sect2 renderas="sect3" id="preventcomp">
2884 <title>Why do my filters work on some sites but not on others? </title>
2886 It's probably due to compression. It is a common practice for web servers to
2887 send their content <quote>compressed</quote> in order to speed things up, and
2888 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2889 &my-app; can decompress content before filtering, otherwise you may want to enable
2891 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2894 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2899 <sect2 renderas="sect3" id="ssl-warnings">
2900 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2901 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2902 What's going on?</title>
2904 Probably the browser is requesting ads through HTTPS and &my-app;
2905 is blocking the requests. Privoxy's error messages are delivered
2906 unencrypted and while it's obvious for the browser that the HTTPS
2907 request is already blocked by the proxy, some warn about unauthenticated
2911 To work around the problem you can redirect those requests to an invalid
2912 local address instead of blocking them. While the redirects aren't
2913 encrypted either, many browsers don't care. They simply follow the
2914 redirect, fail to reach a server and display an error message instead
2918 To do that, enable logging to figure out which requests get blocked by
2919 &my-app; and add the hosts (no path patterns) to a section like this:
2924 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2930 Additionally you have to configure your browser to contact
2931 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2934 To add a proxy exception in <application>Mozilla Firefox</application>
2935 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2936 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2937 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2943 <sect2 renderas="sect3" id="se-linux">
2944 <title>I get selinux error messages. How can I fix this?</title>
2946 Please report the problem to the creator of your selinux policies.
2949 The problem is that some selinux policy writers aren't familiar
2950 with the application they are trying to <quote>secure</quote> and
2951 thus create policies that make no sense.
2954 In <application>Privoxy's</application> case the problem usually
2955 is that the policy only allows outgoing connections for certain
2956 destination ports (e.g. 80 and 443). While this may cover the
2957 standard ports, websites occasionally use other ports as well.
2958 This isn't a security problem and therefore <application>Privoxy's</application>
2959 default configuration doesn't block these requests.
2962 If you really want to block these ports (and don't be able
2963 to load websites that don't use standard ports), you should
2964 configure Privoxy to block these ports as well, so it doesn't
2965 trigger the selinux warnings.
2970 <sect2 renderas="sect3" id="gentoo-ricers">
2971 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2973 Probably you unintentionally compiled &my-app; without threading support
2974 in which case requests have to be serialized and only one can be served
2978 Check your <quote>USE</quote> flags and make sure they include
2979 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2982 If you compiled &my-app; with threading support (on POSIX-based systems),
2983 the <quote>Conditional #defines</quote> section on <ulink
2984 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2985 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2989 <sect2 renderas="sect3" id="tainted-sockets">
2990 <title>What are tainted sockets and how do I prevent them?</title>
2992 &my-app; marks sockets as tainted when it can't use them to
2993 serve additional requests.
2994 This does not necessarily mean that something went wrong and
2995 information about tainted sockets is only logged if connection
2996 debugging is enabled (debug 2).
2999 For example server sockets that were used for CONNECT requests
3000 (which are used to tunnel https:// requests) are considered tainted
3001 once the client closed its connection to &my-app;.
3002 Technically &my-app; could keep the connection to the server open,
3003 but the server would not accept requests that do not belong to the
3004 previous TLS/SSL session (and the client may even have terminated
3008 Server sockets are also marked tainted when a client requests a
3009 resource, but closes the connection before &my-app; has completely
3010 received (and forwarded) the resource to the client.
3011 In this case the server would (probably) accept additional requests,
3012 but &my-app; could not get the response without completely reading
3013 the leftovers from the previous response.
3016 These are just two examples, there are currently a bit more than
3017 25 scenarios in which a socket is considered tainted.
3020 While sockets can also be marked tainted as a result of a technical
3021 problem that may be worth fixing, the problem will be explicitly
3026 <sect2 renderas="sect3" id="pcre-stack-limit">
3027 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
3029 This can happen if your custom filters require more memory than &my-app;
3031 Usually the problem is that the operating system enforces a stack size limit
3032 that isn't sufficient.
3035 Unless the problem occurs with the filters available in the default configuration,
3036 this is not considered a Privoxy bug.
3039 To prevent the crashes you can rewrite your filter to use less ressources,
3040 increase the relevant memory limit or recompile pcre to use less stack space.
3041 For details please see the
3042 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3043 and the documentation of your operating system.
3049 <!-- ~~~~~ New section ~~~~~ -->
3050 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3051 <!-- Include contacting.sgml -->
3053 <!-- end contacting -->
3056 <!-- ~~~~~ New section ~~~~~ -->
3057 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3059 <!-- Include copyright.sgml -->
3065 Portions of this document are <quote>borrowed</quote> from the original
3066 <application>Junkbuster</application> (tm) FAQ, and modified as
3067 appropriate for <application>Privoxy</application>.
3070 <!-- ~~~~~ New section ~~~~~ -->
3071 <sect2><title>License</title>
3072 <!-- Include copyright.sgml: -->
3074 <!-- end copyright -->
3076 <!-- ~ End section ~ -->
3078 <!-- ~~~~~ New section ~~~~~ -->
3079 <sect2><title>History</title>
3080 <!-- Include history.sgml -->
3086 <!-- ~ End section ~ -->
3089 <!-- ~~~~~ New section ~~~~~ -->
3091 <sect1 id="seealso"><title>See also</title>
3093 <!-- Include seealso.sgml -->
3103 This program is free software; you can redistribute it
3104 and/or modify it under the terms of the GNU General
3105 Public License as published by the Free Software
3106 Foundation; either version 2 of the License, or (at
3107 your option) any later version.
3109 This program is distributed in the hope that it will
3110 be useful, but WITHOUT ANY WARRANTY; without even the
3111 implied warranty of MERCHANTABILITY or FITNESS FOR A
3112 PARTICULAR PURPOSE. See the GNU General Public
3113 License for more details.
3115 The GNU General Public License should be included with
3116 this file. If not, you can view it at
3117 http://www.gnu.org/copyleft/gpl.html
3118 or write to the Free Software Foundation, Inc.,
3119 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA