1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN"[
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity contacting SYSTEM "contacting.sgml">
8 <!entity history SYSTEM "history.sgml">
9 <!entity copyright SYSTEM "copyright.sgml">
10 <!entity license SYSTEM "license.sgml">
11 <!entity p-version "3.0.29">
12 <!entity p-status "stable">
13 <!entity % p-not-stable "IGNORE">
14 <!entity % p-stable "INCLUDE">
15 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
16 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
17 <!entity % p-supp-userman "INCLUDE"> <!-- Include all from supported.sgml -->
18 <!entity my-copy "©"> <!-- kludge for docbook2man -->
19 <!entity % p-newstuff "INCLUDE"> <!-- exclude stuff from devel versions -->
20 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
21 <!entity my-app "<application>Privoxy</application>">
24 File : doc/source/faq.sgml
28 Copyright (C) 2001-2020 Privoxy Developers https://www.privoxy.org/
31 Based partially on the Internet Junkbuster FAQ originally written by and
32 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
33 http://www.junkbusters.com/
35 <Qandaset defaultlabel='qanda'>
50 ========================================================================
51 NOTE: Please read developer-manual/documentation.html before touching
54 Please we keep the info in this file as version independent as possible
55 so we only have to maintain one FAQ. Where significant changes are
56 made to Privoxy configuration, please note the change in such a way that
57 it makes sense to both users of older and newer versions.
58 ========================================================================
64 <article id="index" class="faq">
66 <title>Privoxy Frequently Asked Questions</title>
70 <!-- Completely the wrong markup, but very little is allowed -->
71 <!-- in this part of an article. FIXME -->
72 <link linkend="copyright">Copyright</link> &my-copy; 2001-2020 by
73 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
79 Note: this should generate a separate page, and a live link to it.
80 But it doesn't for some mysterious reason. Please leave commented
81 unless it can be fixed proper. For the time being, the copyright
82 statement will be in copyright.smgl.
86 <legalnotice id="legalnotice">
88 text goes here ........
98 <orgname>By: Privoxy Developers</orgname>
107 This is here to keep vim syntax file from breaking :/
108 If I knew enough to fix it, I would.
109 PLEASE DO NOT REMOVE! HB: hal@foobox.net
114 This FAQ gives quick answers to frequently asked questions about
115 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
116 It is not a substitute for the
117 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
120 <!-- Include privoxy.sgml boilerplate: -->
121 <para>What is Privoxy?</para> &p-intro;
122 <!-- end boilerplate -->
125 Please note that this document is a work in progress. This copy represents
126 the state at the release of version &p-version;.
127 You can find the latest version of the document at <ulink
128 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
129 Please see the <link linkend="contact">Contact section</link> if you want to
130 contact the developers.
137 <!-- ~~~~~ New section ~~~~~ -->
139 <sect1 id="general"><title>General Information</title>
140 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
142 Anyone who is interested in security, privacy, or in
143 finer-grained control over their web and Internet experience.
147 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
150 &my-app; is certainly a good choice, especially for those who want more
151 control and security. Those with the willingness to read the documentation
152 and the ability to fine-tune their installation will benefit the most.
155 One of <application>Privoxy's</application>
156 strengths is that it is highly configurable giving you the ability to
157 completely personalize your installation. Being familiar with, or at least
158 having an interest in learning about <ulink
159 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
160 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
161 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
162 Expressions</quote></ulink>
163 will be a big plus and will help you get the most out of &my-app;.
164 A new installation just includes a very basic configuration. The user
165 should take this as a starting point only, and enhance it as he or she
166 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
170 Much of <application>Privoxy's</application> configuration can be done
171 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
172 But there are areas where configuration is done using a
173 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
174 to edit configuration files. Also note that the web-based action editor
175 doesn't use authentication and should only be enabled in environments
176 where all clients with access to &my-app; listening port can be trusted.
180 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
181 Privoxy work? </title>
183 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
184 is a service, based on a software such as &my-app;, that clients
185 (i.e. browsers) can use instead of connecting to web servers directly.
186 The clients then ask the proxy to request objects (web pages, images, movies etc)
187 on their behalf and to forward the data to the clients.
188 It is a <quote>go-between</quote>. For details, see
189 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
192 There are many reasons to use web proxies, such as security (firewalling),
193 efficiency (caching) and others, and there are any number of proxies
194 to accommodate those needs.
197 &my-app; is a proxy that is primarily focused on
198 privacy enhancement, ad and junk elimination and freeing the user from
199 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
200 it is in a perfect position to filter outbound personal information that your
201 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
202 this, all of which are under your complete control via the various configuration
203 files and options. Being a proxy also makes it easier to share
204 configurations among multiple browsers and/or users.
208 <sect2 renderas="sect3" id="otherstuff">
209 <title>Does Privoxy do anything more than ad blocking?</title>
211 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
212 can be used to sanitize and customize web browsing.
216 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
217 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
219 <!-- Include history.sgml -->
226 <sect2 renderas="sect3" id="whyprivoxy">
227 <title>Why <quote>Privoxy</quote>? Why change the name from
228 Junkbuster at all?</title>
230 Though outdated, Junkbusters Corporation continued to offer their original
231 version of the <application>Internet Junkbuster</application> for a while,
232 so publishing our <application> Junkbuster</application>-derived software
233 under the same name would have led to confusion.
236 There were also potential legal reasons not to use the
237 <application>Junkbuster</application> name, as it was (and maybe still is)
238 a registered trademark of Junkbusters Corporation.
239 There were, however, no objections from Junkbusters Corporation to the
240 <application>Privoxy</application> project itself, and they, in fact,
241 shared our ideals and goals.
244 The Privoxy developers also believed that there were so many improvements
245 over the original code, that it was time to make a clean break from the past
246 and make a name in their own right.
249 <application>Privoxy</application> is the
250 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
251 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
252 control, more freedom, and allows you to browse your personal and
253 <quote><emphasis>private</emphasis> edition</quote> of the web.
257 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
258 from the old Junkbuster?</title>
260 <application>Privoxy</application> picks up where
261 <application>Junkbuster</application> left off.
262 <application>Privoxy</application> still blocks ads and banners,
264 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
265 helps protect your privacy. But, most of these features have been enhanced,
266 and many new ones have been added, all in the same vein.
269 <application>Privoxy</application>'s new features include:
272 <!-- Include newfeatures.sgml: -->
278 <sect2 renderas="sect3" id="whatsanad">
279 <title>How does Privoxy know what is an ad, and what is not?</title>
281 <application>Privoxy</application>'s approach to blocking ads is twofold:
284 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
285 of banner images. This applies to both the path (you wouldn't guess how many
286 web sites serve their banners from a directory called <quote>banners</quote>!)
287 and the host (blocking the big banner hosting services like doublecklick.net
288 already helps a lot). <application>Privoxy</application> takes advantage of this
289 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
290 patterns</ulink> to sort out and block the requests for things that sound
291 like they would be ads or banners.
294 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
295 can't tell the size of an image by its URL without downloading it, and if you
296 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
297 also inspects the HTML sources of web pages while they are loaded, and replaces
298 references to images with standard banner sizes by dummy references, so that
299 your browser doesn't request them anymore in the first place.
302 Both of this involves a certain amount of guesswork and is, of course, freely
303 and readily configurable.
307 <sect2 renderas="sect3" id="mistakes">
308 <title>Can Privoxy make mistakes?
309 This does not sound very scientific.</title>
311 Actually, it's a black art ;-) And yes, it is always possible to have a broad
312 rule accidentally block or change something by mistake. You will almost surely
313 run into such situations at some point. It is tricky writing rules to
314 cover every conceivable possibility, and not occasionally get false positives.
318 But this should not be a big concern since the
319 <application>Privoxy</application> configuration is very flexible, and
320 includes tools to help identify these types of situations so they can be
321 addressed as needed, allowing you to customize your installation.
322 (<link linkend="badsite">See the Troubleshooting section below</link>.)
327 <sect2 renderas="sect3" id="configornot">
328 <title>Will I have to configure Privoxy
329 before I can use it?</title>
331 That depends on your expectations.
332 The default installation should give you a good starting
333 point, and block <emphasis>most</emphasis> ads and unwanted content,
334 but many of the more advanced features are off by default, and require
335 you to activate them.
338 You do have to set up your browser to use
339 <application>Privoxy</application> (see the <link
340 linkend="firststep">Installation section below</link>).
343 And you will certainly run into situations where there are false positives,
344 or ads not being blocked that you may not want to see. In these cases, you
345 would certainly benefit by customizing <application>Privoxy's</application>
346 configuration to more closely match your individual situation. And we
347 encourage you to do this. This is where the real power of
348 <application>Privoxy</application> lies!
353 <sect2 renderas="sect3" id="lan">
354 <title>Can Privoxy run as a server on a network?</title>
356 Yes, &my-app; runs as a server already, and can easily be configured to
357 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
358 How can I set up Privoxy to act as a proxy for my LAN</link> below.
362 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
363 Privoxy. Why should I use Privoxy at all?</title>
365 Modern browsers do indeed have <emphasis>some</emphasis> of the same
366 functionality as <application>Privoxy</application>. Maybe this is
367 adequate for you. But <application>Privoxy</application> is very
368 versatile and powerful, and can probably do a number of things
369 your browser just can't.
372 In addition, a proxy is good choice if you use multiple browsers, or
373 have a LAN with multiple computers since &my-app; can run as a server
374 application. This way all the configuration is in one place, and you don't
375 have to maintain a similar configuration for possibly many browsers or
379 Note, however, that it's recommended to leverage both your browser's
380 and <application>Privoxy's</application> privacy enhancing features
381 at the same time. While your browser probably lacks some features
382 &my-app; offers, it should also be able to do some things more
383 reliably, for example restricting and suppressing JavaScript.
387 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
389 The most important reason is because you have access to
390 <emphasis>everything</emphasis>, and you can control everything. You can
391 check every line of every configuration file yourself. You can check every
392 last bit of source code should you desire. And even if you can't read code,
393 there should be some comfort in knowing that <!-- thousands of -->other people can,
394 and do read it. You can build the software from scratch, if you want,
395 so that you know the executable is clean, and that it is
396 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
397 is one reason we use &my-app; ourselves.
401 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
402 warranty? Registration?</title>
404 <application>Privoxy</application> is free software and licensed under the <ulink
405 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
406 It is free to use, copy, modify or distribute as you wish under the terms of this
407 license. Please see the <link linkend="copyright">Copyright</link> section for more
408 information on the license and copyright. Or the <filename>LICENSE</filename> file
409 that should be included.
412 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
413 That is something that would cost real money ;-) There is no registration either.
418 <sect2 renderas="sect3" id="spyware">
419 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
421 No, at least not reliably enough to trust it. &my-app; is not designed to be
422 a malware removal tool and the default configuration doesn't even try to
423 filter out any malware.
426 &my-app; could help prevent contact from (known) sites that use such
427 tactics with appropriate configuration rules, and thus could conceivably
428 prevent contamination from such sites. However, keeping such a configuration
429 up to date would require a lot of time and effort that would be better spend
430 on keeping your software itself up to date so it doesn't have known
436 <sect2 renderas="sect3" id="otherads">
437 <title>Can I use Privoxy with other ad-blocking software?</title>
439 &my-app; should work fine with other proxies and other software in general.
442 But it is probably not necessary to use &my-app; in conjunction with other
443 ad-blocking products, and this could conceivably cause undesirable results.
444 It might be better to choose one software or the other and work a little to
445 tweak its configuration to your liking.
448 Note that this is an advice specific to ad blocking.
452 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
454 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
456 Well, we <emphasis>always</emphasis> need help. There is something for
457 everybody who wants to help us. We welcome new developers, packagers,
458 testers, documentation writers or really anyone with a desire to help in
459 any way. You <emphasis>DO NOT</emphasis> need to be a
460 <quote>programmer</quote>. There are many other tasks available. In fact,
461 the programmers often can't spend as much time programming because of some
462 of the other, more mundane things that need to be done, like checking the
463 Tracker feedback sections or responding to user questions on the mailing
467 So first thing, subscribe to the <ulink
468 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
469 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
470 Developers</ulink> mailing list, join the discussion, help out other users, provide general
471 feedback or report problems you noticed.
474 If you intend to help out with the trackers, you also might want to <ulink
475 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
476 so we don't confuse you with the other name-less users.
479 We also have a <ulink
480 url="../developer-manual/index.html">Developer's Manual</ulink>.
481 While it is partly out of date, it's still worth reading.
484 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
485 may be of interest to you as well.
486 Please let us know if you want to work on one of the items listed.
490 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
492 Donations are welcome. Our
493 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
494 is rather long and being able to pay one (or more) developers to work on Privoxy
495 would make a huge difference, even if it was only for a couple of weeks. Donations may
496 also be used for Privoxy-related travel expenses (for example to attend conferences),
497 for hardware used for Privoxy development and for hosting expenses etc.
501 <application>Privoxy</application> is an associated
502 project of <ulink url="https://www.spi-inc.org/">Software
503 in the Public Interest (SPI)</ulink>, which allows us to receive
504 tax-deductible donations in the United States.
505 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
506 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
507 For details, please have a look at
508 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
512 If you have any questions regarding donations please mail to either the
513 public user mailing list or, if it's a private matter, to
514 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
519 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
521 We are currently offering the following sponsor levels as an experiment:
525 <term>Gold (12000 USD/year)</term>
528 Logo or text link shown at the bottom of the
529 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
530 Logo, link and self description on the
531 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
536 <term>Silver (1200 USD/year)</term>
539 Logo or text link shown at the bottom of the
540 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
541 Logo, link and self description on the
542 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
547 <term>Bronze (600 USD/year)</term>
550 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
556 The logo sizes depend on the sponsor level. Logos are served from
557 our server, no requests are made to the sponsor website unless
558 the links are being used.
561 Link targets are without path (<quote>https://www.example.org/</quote>
562 not <quote>https://www.example.org/seo/keyword/spam/</quote>).
565 The details may change over time but changes will only affect new sponsors
566 (or existing sponsors that explicitly agreed to the changes).
569 If you want to become a sponsor, please contact
570 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
571 New sponsors are only accepted if no developer objects.
579 <!-- ~~~~~ New section ~~~~~ -->
581 <sect1 id="installation"><title>Installation</title>
583 <sect2 renderas="sect3" id="whichbrowsers">
584 <title>Which browsers are supported by Privoxy?</title>
586 Any browser that can be configured to use a proxy, which
587 should be virtually all browsers, including
588 <application>Firefox</application>, <application>Internet
589 Explorer</application>, <application>Opera</application>, and
590 <application>Safari</application> among others.
591 Direct browser support is not an absolute requirement since
592 <application>Privoxy</application> runs as a separate application and talks
593 to the browser in the standardized HTTP protocol, just like a web server
598 <sect2 renderas="sect3" id="whichos">
599 <title>Which operating systems are supported?</title>
601 Include supported.sgml here:
606 <sect2 renderas="sect3" id="email-client">
607 <title>Can I use Privoxy with my email client?</title>
609 As long as there is some way to set a HTTP proxy for the client, then yes,
610 any application can be used, whether it is strictly speaking a
611 <quote>browser</quote> or not. Though this may not be the best approach for
612 dealing with some of the common abuses of HTML in email. See <link
613 linkend="outlook">How can I configure <application>Privoxy</application>
614 with <application>Outlook</application>?</link> below for more on
618 Be aware that HTML email presents a number of unique security and privacy
619 related issues, that can require advanced skills to overcome. The developers
620 recommend using email clients that can be configured to convert HTML to plain
621 text for these reasons.
625 <!-- Nobody is going to still be doing this!
626 <sect2 renderas="sect3" id="newinstall"><title>Can I install
627 Privoxy over Junkbuster?</title>
629 We recommend you un-install <application>Junkbuster</application>
630 first to minimize conflicts and confusion. You may want to
631 save your old configuration files for future reference. The configuration
632 files and syntax have substantially changed, so you will need to manually
633 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
634 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
635 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
639 Note: Some installers may automatically un-install
640 <application>Junkbuster</application>, if present!
646 <sect2 renderas="sect3" id="firststep">
647 <title>I just installed Privoxy. Is there anything
648 special I have to do now?</title>
651 All browsers should be told to use <application>Privoxy</application>
652 as a proxy by specifying the correct proxy address and port number
653 in the appropriate configuration area for the browser. It's possible
654 to combine &my-app; with a packet filter to intercept HTTP requests
655 even if the client isn't explicitly configured to use &my-app;,
656 but where possible, configuring the client is recommended. See
657 <ulink url="../user-manual/startup.html">the User Manual for more
658 details</ulink>. You should also flush your browser's memory and disk
659 cache to get rid of any cached junk items, and remove any stored
660 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
665 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
667 If you set up the <application>Privoxy</application> to run on
668 the computer you browse from (rather than your ISP's server or some
669 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
670 (sometimes referred to as <quote>localhost</quote>,
671 which is the special name used by every computer on the Internet to refer
672 to itself) and the port will be 8118 (unless you used the <ulink
673 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
674 config option to tell <application>Privoxy</application> to run on
678 When configuring your browser's proxy settings you typically enter
679 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
680 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
681 then the number <quote>8118</quote> for <quote>port</quote>.
682 This tells your browser to send all web requests to <application>Privoxy</application>
683 instead of directly to the Internet.
686 <application>Privoxy</application> can also be used to proxy for
687 a Local Area Network. In this case, your would enter either the IP
688 address of the LAN host where <application>Privoxy</application>
689 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
690 Port assignment would be same as above. Note that
691 <application>Privoxy</application> doesn't listen on any LAN interfaces by
695 <application>Privoxy</application> does not currently handle
696 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
700 <sect2 renderas="sect3" id="nothing">
701 <title>I just installed Privoxy, and nothing is happening.
702 All the ads are there. What's wrong?</title>
705 Did you configure your browser to use <application>Privoxy</application>
706 as a proxy? It does not sound like it. See above. You might also try flushing
707 the browser's caches to force a full re-reading of pages. You can verify
708 that <application>Privoxy</application> is running, and your browser
709 is correctly configured by entering the special URL:
710 <ulink url="http://p.p/">http://p.p/</ulink>.
711 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
712 of potential redirect caching problem (see next Q). -->
713 This should take you to a page titled <quote>This is Privoxy..</quote> with
714 access to <application>Privoxy's</application> internal configuration.
715 If you see this, then you are good to go. If you receive a page saying
716 <quote>Privoxy is not running</quote>, then the browser is not set up to use
717 your <application>Privoxy</application> installation.
718 If you receive anything else (probably nothing at all), it could either
719 be that the browser is not set up correctly, or that
720 <application>Privoxy</application> is not running at all. Check the <ulink
721 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
722 on starting <application>Privoxy</application> and browser configuration,
723 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
724 on starting <application>Privoxy</application></ulink> in the
725 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
730 <sect2 renderas="sect3" id="notused">
731 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
732 Privoxy is running and being used.</title>
735 First, make sure that Privoxy is <emphasis>really</emphasis> running and
736 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
737 should see the <application>Privoxy</application> main page. If not, see
738 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
739 on starting <application>Privoxy</application></ulink> in the
740 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
744 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
745 other parts of <application>Privoxy</application>'s web interface show
746 the dummy page, your browser has cached a redirection it encountered before
747 <application>Privoxy</application> was being used. You need to clear your
748 browser's cache. Note that shift-reloading the dummy page won't help, since
749 that'll only refresh the dummy page, not the redirection that lead you there.
753 The procedure for clearing the cache varies from browser to browser. For
754 example, <application>Mozilla/Netscape</application> users would click
755 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
756 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
757 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
758 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
759 In some <application>Firefox</application> versions it's
760 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
761 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
762 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
763 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
770 <!-- ~~~~~ New section ~~~~~ -->
772 <sect1 id="configuration"><title>Configuration</title>
773 <sect2 renderas="sect3" id="actionsfile">
774 <title>What exactly is an <quote>actions</quote> file?</title>
777 &my-app; utilizes the concept of <quote>
778 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
779 that are used to manipulate and control web page data.
780 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
781 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
782 that <application>Privoxy</application> could take while processing a certain
783 request, are configured. Typically, you would define a set of default actions
784 that apply globally to all URLs, then add exceptions to these defaults where needed.
785 There is a wide array of actions available that give the user a high degree
786 of control and flexibility on how to process each and every web page.
790 Actions can be defined on a <ulink
791 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
792 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
793 grouped together and then applied to requests matching one or more patterns.
794 There are many possible actions that might apply to any given site. As an example,
795 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
796 as one of your default actions, but need to accept cookies from a given site,
797 you would need to define an exception for this site in one of your actions
798 files, preferably in <filename>user.action</filename>.
803 <sect2 renderas="sect3" id="actionss">
804 <title>The <quote>actions</quote> concept confuses me. Please list
805 some of these <quote>actions</quote>.</title>
807 For a comprehensive discussion of the actions concept, please refer
808 to the <ulink url="../user-manual/actions-file.html">actions file
809 chapter</ulink> in the <ulink url="../user-manual/index.html">User
810 Manual</ulink>. It includes a <ulink
811 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
812 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
813 file tutorial</ulink> to get you started.
818 <sect2 renderas="sect3" id="actconfig">
819 <title>How are actions files configured? What is the easiest
820 way to do this?</title>
823 Actions files are just text files in a special syntax and can be edited
824 with a text editor. But probably the easiest way is to access
825 <application>Privoxy</application>'s user interface with your web browser
826 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
827 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
828 <quote><ulink url="http://config.privoxy.org/show-status">View &
829 change the current configuration</ulink></quote> from the menu. Note
830 that this feature must be explicitly enabled in the main config file
832 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
837 <sect2 renderas="sect3">
838 <title>There are several different <quote>actions</quote> files. What are
839 the differences?</title>
841 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
842 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
847 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
849 Based on your feedback and the continuing development, updates of
850 <filename>default.action</filename> are available from
852 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>.
856 If you wish to receive an email notification whenever we release updates of
857 <application>Privoxy</application> or the actions file, <ulink
858 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
859 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
864 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
866 The syntax and purpose of configuration files has remained roughly the
867 same throughout the 3.x series, but backwards compatibility is not guaranteed.
868 Also each release contains updated, <quote>improved</quote> versions and it is
869 therefore strongly recommended to install the newer configuration files
870 and merge back your modifications.
874 <sect2 renderas="sect3" id="difficult">
875 <title>Why is the configuration so complicated?</title>
877 <quote>Complicated</quote> is in the eye of the beholder.
880 Privoxy is currently mainly written by and for people who are already
881 familiar with the underlying concepts like regular expressions, HTTP and HTML,
882 or are willing to become familiar with them to be able to get the most
883 out of a powerful and flexible tool such as Privoxy.
886 While everybody is expected to be able to get a Privoxy default installation
887 up and running, fine-tuning requires a certain amount of background
888 information and Privoxy's documentation mainly concentrates on the
889 Privoxy-specific parts while only providing references to the rest.
892 If you or anyone you know has the skills, time and energy to
893 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
897 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
899 The default configuration shouldn't impact the usability of any of these services.
900 It may, however, make all <ulink
901 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
902 temporary, so that your browser will forget your
903 login credentials in between browser sessions. If you would like not to have to log
904 in manually each time you access those websites, simply turn off all cookie handling
905 for them in the <filename>user.action</filename> file. An example for yahoo might
908 <screen># Allow all cookies for Yahoo login:
910 { -<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> }
911 .login.yahoo.com</screen>
913 These kinds of sites are often quite complex and heavy with
914 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
915 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
917 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
920 <screen># Gmail is a _fragile_ site:
922 { <literal>fragile</literal> }
924 mail.google.com</screen>
926 Be sure to flush your browser's caches whenever making these kinds of
927 changes, just to make sure the changes <quote>take</quote>.
930 Make sure the domain, host and path are appropriate as well. Your browser can
931 tell you where you are specifically and you should use that information for
932 your configuration settings. Note that above it is not referenced as
933 <literal>gmail.com</literal>, which is a valid domain name.
938 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
939 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
941 Configuring <application>Privoxy</application> is not entirely trivial. To
942 help you get started, we provide you with three different default action
943 <quote>profiles</quote> in the web based actions file editor at <ulink
944 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
945 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
946 Manual</citetitle></ulink> for a list of actions, and how the default
951 Where the defaults are likely to break some sites, exceptions for
952 known popular <quote>problem</quote> sites are included, but in
953 general, the more aggressive your default settings are, the more exceptions
954 you will have to make later. New users are best to start off in
955 <quote>Cautious</quote> setting. This is safest and will have the fewest
956 problems. See the <ulink
957 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
958 for a more detailed discussion.
962 It should be noted that the <quote>Advanced</quote> profile (formerly known
963 as the <quote>Adventuresome</quote> profile) is more
964 aggressive, and will make use of some of
965 <application>Privoxy's</application> advanced features. Use at your own risk!
970 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
971 with a browser? Does that not raise security issues?</title>
973 It may seem strange that regular users can edit the config files with their
974 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
975 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
978 When you use the browser-based editor, <application>Privoxy</application>
979 itself is writing to the config files. Because
980 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
981 it can update its own config files.
984 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
985 a LAN) or aren't entirely in control of your own browser, you will probably want
986 to make sure that the web-based editor and remote toggle features are
987 <quote>off</quote> by setting <quote><literal><ulink
988 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
989 0</literal></quote> and <quote><literal><ulink
990 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
991 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
994 As of &my-app; 3.0.7 these options are disabled by default.
999 <sect2 renderas="sect3" id="filterfile">
1000 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
1002 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
1003 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1004 Filters are a special subset of actions that can be used to modify or
1005 remove web page content or headers on the fly. Content filters can
1006 be applied to <emphasis>anything</emphasis> in the page source,
1007 header filters can be applied to either server or client headers.
1008 Regular expressions are used to accomplish this.
1011 There are a number of pre-defined filters to deal with common annoyances. The
1012 filters are only defined here, to invoke them, you need to use the
1014 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1015 action</ulink> in one of the actions files. Content filtering is automatically
1016 disabled for inappropriate MIME types, but if you know better than Privoxy
1017 what should or should not be filtered you can filter any content you like.
1021 <emphasis>not</emphasis> be confused with <ulink
1022 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1023 is a completely different action, and is more typically used to block ads and
1028 If you are familiar with regular expressions, and HTML, you can look at
1029 the provided <filename>default.filter</filename> with a text editor and define
1030 your own filters. This is potentially a very powerful feature, but
1031 requires some expertise in both regular expressions and HTML/HTTP.
1032 <![%p-newstuff;[ You should
1033 place any modifications to the default filters, or any new ones you create
1034 in a separate file, such as <filename>user.filter</filename>, so they won't
1035 be overwritten during upgrades.
1036 The ability to define multiple filter files
1037 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1041 There is no GUI editor option for this part of the configuration,
1042 but you can disable/enable the various pre-defined filters of the included
1043 <filename>default.filter</filename> file with the <ulink
1044 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1045 Note that the custom actions editor must be explicitly enabled in
1046 the main config file (see <ulink
1047 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1051 If you intend to develop your own filters, you might want to have a look at
1053 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1058 <sect2 renderas="sect3" id="lanconfig">
1059 <title>How can I set up Privoxy to act as a proxy for my
1062 By default, <application>Privoxy</application> only responds to requests
1063 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1064 a network, this needs to be changed in the <ulink
1065 url="../user-manual/config.html">main configuration file</ulink>. Look for
1067 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1068 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1069 it is uncommented, and assign it the address of the LAN gateway interface,
1070 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1071 wish to run <application>Privoxy</application> on port 8118, this line
1076 listen-address 192.168.1.1:8118</screen>
1079 Save the file, and restart <application>Privoxy</application>. Configure
1080 all browsers on the network then to use this address and port number.
1084 Alternately, you can have <application>Privoxy</application> listen on
1085 all available interfaces:
1089 listen-address :8118</screen>
1092 And then use <application>Privoxy's</application>
1094 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1095 feature to limit connections. A firewall in this situation is recommended
1100 The above steps should be the same for any TCP network, regardless of
1105 If you run <application>Privoxy</application> on a LAN with untrusted users,
1106 we recommend that you double-check the <ulink
1107 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1114 <sect2 renderas="sect3" id="noseeum">
1115 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1117 The replacement for blocked images can be controlled with the <ulink
1118 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1119 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1120 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1121 Note that this choice only has effect for images which are blocked as images, i.e.
1122 whose URLs match both a <literal><ulink
1123 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1124 <emphasis>and</emphasis> <literal><ulink
1125 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1128 If you want to see nothing, then change the <ulink
1129 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1130 action</ulink> to <quote>blank</quote>. This can be done by editing the
1131 <filename>user.action</filename> file, or through the <ulink
1132 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1137 <sect2 renderas="sect3" id="whyseeum">
1138 <title>Why would anybody want to see a checkerboard pattern?</title>
1140 Remember that <link linkend="whatsanad">telling which image is an ad and which
1141 isn't</link>, is an educated guess. While we hope that the standard configuration
1142 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1143 decent, and it shows you where images have been blocked, which can be very
1144 helpful in case some navigation aid or otherwise innocent image was
1145 erroneously blocked. It is recommended for new users so they can
1146 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1147 many banners they <emphasis>don't</emphasis> have to see.
1152 <sect2 renderas="sect3" id="blockedbytext">
1153 <title>I see some images being replaced with text
1154 instead of the checkerboard image. Why and how do I get rid of this?</title>
1156 This happens when the banners are not embedded in the HTML code of the
1157 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1158 or (i)layers, and these external HTML documents are blocked. Being non-images
1159 they get replaced by a substitute HTML page rather than a substitute image,
1160 which wouldn't work out technically, since the browser expects and accepts
1161 only HTML when it has requested an HTML document.
1164 The substitute page adapts to the available space and shows itself as a
1165 miniature two-liner if loaded into small frames, or full-blown with a
1166 large red "BLOCKED" banner if space allows.
1169 If you prefer the banners to be blocked by images, you must see to it that
1170 the HTML documents in which they are embedded are not blocked. Clicking
1171 the <quote>See why</quote> link offered in the substitute page will show
1172 you which rule blocked the page. After changing the rule and un-blocking
1173 the HTML documents, the browser will try to load the actual banner images
1174 and the usual image blocking will (hopefully!) kick in.
1179 <sect2 renderas="sect3" id="srvany">
1180 <title>Can Privoxy run as a service
1181 on Win2K/NT/XP?</title>
1183 Yes. Full <application>Windows</application> service
1184 functionality was introduced in <application>Privoxy</application> 3.0.5.
1185 See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1186 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1187 <application>Privoxy</application> as a service.
1192 <sect2 renderas="sect3" id="otherproxy">
1193 <title>How can I make Privoxy work with other proxies?</title>
1195 This can be done and is often useful to combine the benefits of
1196 <application>Privoxy</application> with those of a another proxy,
1197 for example to cache content.
1199 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1200 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1201 describes how to do this. If you intend to use Privoxy with Tor,
1202 please also have a look at
1203 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1207 <sect2 renderas="sect3" id="port-80">
1208 <title>Can I just set Privoxy to use port 80
1209 and thus avoid individual browser configuration?</title>
1212 No, its more complicated than that. This only works with special kinds
1213 of proxies known as <quote>intercepting</quote> proxies
1214 (<link linkend="INTERCEPTING">see below</link>).
1219 <sect2 renderas="sect3" id="transparent">
1220 <title>Can Privoxy run as a <quote>transparent
1221 </quote> proxy?</title>
1223 The whole idea of Privoxy is to modify client requests
1224 and server responses in all sorts of ways and therefore
1225 it's not a transparent proxy as described in
1226 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1229 However, some people say <quote>transparent proxy</quote> when they
1230 mean <quote>intercepting proxy</quote>. If you are one of them,
1231 please read the <link linkend="INTERCEPTING">next entry</link>.
1236 <sect2 renderas="sect3" id="intercepting">
1237 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1239 <application>Privoxy</application> can't intercept traffic itself,
1240 but it can handle requests that where intercepted and redirected
1241 with a packet filter (like <application>PF</application> or
1242 <application>iptables</application>), as long as the <literal>Host</literal>
1246 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1247 web sites rely on it anyway, this limitation shouldn't be a problem.
1250 Please refer to your packet filter's documentation to learn how to
1251 intercept and redirect traffic into <application>Privoxy</application>.
1252 Afterward you just have to configure <application>Privoxy</application> to
1253 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1254 intercepted requests</ulink>.
1259 <sect2 renderas="sect3" id="outlook">
1260 <title>How can I configure Privoxy for use with Outlook?</title>
1262 Versions of <application>Outlook</application> prior to Office 2007, use
1263 <application>Internet Explorer</application> components to both render HTML,
1264 and fetch any HTTP requests that may be embedded in an HTML email. So however
1265 you have <application>Privoxy</application> configured to work with IE, this
1266 configuration should automatically be shared, at least with older version of
1270 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1271 engine with Outlook. It is unknown whether this can be configured to use a
1273 <!-- FIXME HB 2009-02-15 -->
1277 <sect2 renderas="sect3" id="outlook-more">
1278 <title>How can I have separate rules just for HTML mail?</title>
1280 The short answer is, you can't. <application>Privoxy</application> has no way
1281 of knowing which particular application makes a request, so there is no way to
1282 distinguish between web pages and HTML mail.
1283 <application>Privoxy</application> just blindly proxies all requests. In the
1284 case of <application>Outlook Express</application> (see above), OE uses
1285 IE anyway, and there is no way for <application>Privoxy</application> to ever
1286 be able to distinguish between them (nor could any other proxy type application for
1290 For a good discussion of some of the issues involved (including privacy and
1291 security issues), see
1292 <ulink url="https://sourceforge.net/p/ijbswa/support-requests/107/"
1293 >https://sourceforge.net/p/ijbswa/support-requests/107/</ulink>.
1297 <sect2 renderas="sect3" id="sneaky-cookies">
1298 <title>I sometimes notice cookies sneaking through. How?</title>
1301 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1302 set in several ways. The classic method is via the
1303 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1304 easy one to manipulate, such as the &my-app; concept of
1305 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1306 There is also the possibility of using
1307 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1308 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1309 is trickier because the syntax can vary widely, and thus requires a certain
1310 amount of guesswork. It is not realistic to catch all of these short of
1311 disabling Javascript, which would break many sites. And lastly, if the
1312 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1313 <application>Privoxy's</application> reach unless you enable
1314 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1317 All in all, &my-app; can help manage cookies in general, can help minimize
1318 the loss of privacy posed by cookies, but can't realistically stop all
1323 <sect2 renderas="sect3" id="evil-cookies">
1324 <title>Are all cookies bad? Why?</title>
1326 No, in fact there are many beneficial uses of
1328 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1329 method that browsers can use to store data between pages, or between browser
1330 sessions. Sometimes there is a good reason for this, and the user's life is a
1331 bit easier as a result. But there is a long history of some websites taking
1332 advantage of this layer of trust, and using the data they glean from you and
1333 your browsing habits for their own purposes, and maybe to your potential
1334 detriment. Such sites are using you and storing their data on your system.
1335 That is why the privacy conscious watch from whom those cookies come, and why
1336 they really <emphasis>need</emphasis> to be there.
1340 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1341 definition</ulink> for more.
1345 <sect2 renderas="sect3" id="allow-cookies">
1346 <title>How can I allow permanent cookies for my trusted sites?</title>
1349 There are several actions that relate to cookies. The default behavior is to
1350 allow only <quote>session cookies</quote>, which means the cookies only last
1351 for the current browser session. This eliminates most kinds of abuse related
1352 to cookies. But there may be cases where you want cookies to last.
1355 To disable all cookie actions, so that cookies are allowed unrestricted,
1356 both in and out, for <literal>example.com</literal>:
1359 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1360 .example.com</screen>
1362 Place the above in <filename>user.action</filename>. Note that some of these may
1363 be off by default anyway, so this might be redundant, but there is no harm
1364 being explicit in what you want to happen. <filename>user.action</filename>
1365 includes an alias for this situation, called
1366 <literal>allow-all-cookies</literal>.
1370 <sect2 renderas="sect3" id="multiples">
1371 <title>Can I have separate configurations for different users?</title>
1373 Each instance of <application>Privoxy</application> has its own
1374 configuration, including such attributes as the TCP port that it listens on.
1375 What you can do is run multiple instances of <application>Privoxy</application>, each with
1377 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1378 configuration setting, and configuration path, and then
1379 each of these can have their own configurations. Think of it as per-port
1383 Simple enough for a few users, but for large installations, consider having
1384 groups of users that might share like configurations.
1388 <sect2 renderas="sect3" id="whitelists">
1389 <title>Can I set-up Privoxy as a whitelist of
1390 <quote>good</quote> sites?</title>
1392 Sure. There are a couple of things you can do for simple white-listing.
1393 Here's one real easy one:
1396 ############################################################
1398 ############################################################
1399 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1400 / # Block *all* URLs
1402 ############################################################
1404 ############################################################
1405 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1408 games.example.com</screen>
1410 This allows access to only those three sites by first blocking all URLs, and
1411 then subsequently allowing three specific exceptions.
1414 Another approach is <application>Privoxy's</application>
1415 <literal>trustfile</literal> concept, which incorporates the notion of
1416 <quote>trusted referrers</quote>. See the <ulink
1417 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1421 These are fairly simple approaches and are not completely foolproof. There
1422 are various other configuration options that should be disabled (described
1423 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1424 so that users can't modify their own configuration and easily circumvent the
1429 <sect2 renderas="sect3" id="no-adblock">
1430 <title>How can I turn off ad-blocking?</title>
1432 Ad blocking is achieved through a complex application of various &my-app;
1433 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1434 actions are deployed against simple images, banners, flash animations,
1435 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1436 just turning one or two actions off. The various actions that make up
1437 &my-app; ad blocking are hard-coded into the default configuration files. It
1438 has been assumed that everyone using &my-app; is interested in this
1442 If you want to do without this, there are several approaches you can take:
1443 You can manually undo the many block rules in
1444 <filename>default.action</filename>. Or even easier, just create your own
1445 <filename>default.action</filename> file from scratch without the many ad
1446 blocking rules, and corresponding exceptions. Or lastly, if you are not
1447 concerned about the additional blocks that are done for privacy reasons, you
1448 can very easily over-ride <emphasis>all</emphasis> blocking with the
1449 following very simple rule in your <filename>user.action</filename>:
1452 # Unblock everybody, everywhere
1453 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1454 / # UN-Block *all* URLs</screen>
1456 Or even a more comprehensive reversing of various ad related actions:
1459 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1460 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1461 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1462 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1463 <literal>allow-popups</literal> \
1465 / # UN-Block *all* URLs and allow ads</screen>
1467 This last <quote>action</quote> in this compound statement,
1468 <literal>allow-popups</literal>, is an <ulink
1469 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1470 various pop-up blocking features.
1474 <sect2 renderas="sect3" id="templates">
1475 <title>How can I have custom template pages, like the
1476 <emphasis>BLOCKED</emphasis> page?</title>
1478 &my-app; <quote>templates</quote> are specialized text files utilized by
1479 &my-app; for various purposes and can easily be modified using any text
1480 editor. All the template pages are installed in a sub-directory appropriately
1481 named: <filename>templates</filename>. Knowing something about HTML syntax
1482 will of course be helpful.
1485 Be forewarned that the default templates are subject to being overwritten
1486 during upgrades. You can, however, create completely new templates,
1487 place them in another directory and specify the alternate path in the main
1488 <filename>config</filename>. For details, have a look at the <ulink
1489 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1493 <sect2 renderas="sect3" id="blockall">
1494 <title>How can I remove the <quote>Go There Anyway</quote> link from
1495 the <emphasis>BLOCKED</emphasis> page?</title>
1497 There is more than one way to do it (although Perl is not involved).
1500 Editing the BLOCKED template page (see above) may dissuade some users, but
1501 this method is easily circumvented. Where you need this level of control, you
1502 might want to build &my-app; from source, and disable various features that are
1503 available as compile-time options. You should
1504 <command>configure</command> the sources as follows:
1507 ./configure --disable-toggle --disable-editor --disable-force</screen>
1509 This will create an executable with hard-coded security features so that
1510 &my-app; does not allow easy bypassing of blocked sites, or changing the
1511 current configuration via any connected user's web browser.
1514 Finally, all of these features can also be toggled on/off via options in
1515 <application>Privoxy's</application> main <ulink
1516 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1517 means you don't have to recompile anything.
1523 <!-- ~ End section ~ -->
1526 <!-- ~~~~~ New section ~~~~~ -->
1528 <sect1 id="misc"><title>Miscellaneous</title>
1530 <sect2 renderas="sect3" id="slowsme">
1531 <title>How much does Privoxy slow my browsing down? This
1532 has to add extra time to browsing.</title>
1534 How much of an impact depends on many things, including the CPU of the host
1535 system, how aggressive the configuration is, which specific actions are being triggered,
1536 the size of the page, the bandwidth of the connection, etc.
1539 Overall, it should not slow you down any in real terms, and may actually help
1540 speed things up since ads, banners and other junk are not typically being
1541 retrieved and displayed. The actual processing time required by
1542 <application>Privoxy</application> itself for each page, is relatively small
1543 in the overall scheme of things, and happens very quickly. This is typically
1544 more than offset by time saved not downloading and rendering ad images and
1545 other junk content (if ad blocking is being used).
1549 <quote>Filtering</quote> content via the <literal><ulink
1550 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1552 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1553 actions may cause a perceived slowdown, since the entire document
1554 needs to be buffered before displaying. And on very large documents,
1555 filtering may have some measurable impact. How much depends on the page size,
1556 the actual definition of the filter(s), etc. See below. Most other actions
1557 have little to no impact on speed.
1560 Also, when filtering is enabled but zlib support isn't available, compression
1561 is often disabled (see <ulink
1562 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1563 This can have an impact on speed as well, although it's probably smaller than
1564 you might think. Again, the page size, etc. will determine how much of an impact.
1570 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1571 delays in page requests. What's wrong?</title>
1573 If you use any <literal><ulink
1574 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1575 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1576 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1577 action, the entire document must be loaded into memory in order for the filtering
1578 mechanism to work, and nothing is sent to the browser during this time.
1581 The loading time typically does not really change much in real numbers, but
1582 the feeling is different, because most browsers are able to start rendering
1583 incomplete content, giving the user a feeling of "it works". This effect is
1584 more noticeable on slower dialup connections. Extremely large documents
1585 may have some impact on the time to load the page where there is filtering
1586 being done. But overall, the difference should be very minimal. If there is a
1587 big impact, then probably some other situation is contributing (like
1588 anti-virus software).
1591 Filtering is automatically disabled for inappropriate MIME types. But note
1592 that if the web server mis-reports the MIME type, then content that should
1593 not be filtered, could be. <application>Privoxy</application> only knows how
1594 to differentiate filterable content because of the MIME type as reported by
1595 the server, or because of some configuration setting that enables/disables
1600 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1601 "http://p.p/"?</title>
1603 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1604 address of <application>Privoxy</application>'s built-in user interface, and
1605 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1608 Since <application>Privoxy</application> sits between your web browser and the Internet,
1609 it can simply intercept requests for these addresses and answer them with its built-in
1610 <quote>web server</quote>.
1613 This also makes for a good test for your browser configuration: If entering the
1614 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1615 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1616 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1617 your browser didn't use <application>Privoxy</application> for the request,
1618 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1619 web site at config.privoxy.org.
1622 Note that config.privoxy.org resolves to a public IP address.
1623 If you use config.privoxy.org as ping or traceroute target you will
1624 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1625 If you want to ping the system Privoxy runs on,
1626 you should use its IP address or local DNS name (if it has got one).
1632 out of date 09/02/06 HB
1633 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1635 No. The patterns for blocking now reside (among other things) in the <ulink
1636 url="../user-manual/actions-file.html">actions files</ulink>, which are
1637 actively maintained instead. See next question ...
1641 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1644 Please see the <link linkend="contact">Contact section</link> for
1645 various ways to interact with the developers.
1650 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1651 they be included in future updates?</title>
1653 Whether such submissions are eventually included in the
1654 <filename>default.action</filename> configuration file depends on how
1655 significant the issue is. We of course want to address any potential
1656 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1657 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1658 has a good chance of being a candidate. But at the other end of the spectrum
1659 are any number of smaller, low-profile sites such as for local clubs or
1660 schools. Since their reach and impact are much less, they are best handled by
1661 inclusion in the user's <filename>user.action</filename>, and thus would be
1662 unlikely to be included.
1668 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1671 Rest assured that it has been read and considered. Why it is not answered,
1672 could be for various reasons, including no one has a good answer for it, no
1673 one has had time to yet investigate it thoroughly, it has been reported
1674 numerous times already, or because not enough information was provided to help
1675 us help you. Your efforts are not wasted, and we do appreciate them.
1681 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1683 If you run both the browser and &my-app; locally, you cannot hide your IP
1684 address with <application>Privoxy</application> or ultimately any other
1685 software alone. The server needs to know your IP address so that it knows
1686 where to send the responses back.
1689 There are many publicly usable "anonymous" proxies out there, which
1690 provide a further level of indirection between you and the web server.
1693 However, these proxies are called "anonymous" because you don't need
1694 to authenticate, not because they would offer any real anonymity.
1695 Most of them will log your IP address and make it available to the
1696 authorities in case you violate the law of the country they run in. In fact
1697 you can't even rule out that some of them only exist to *collect* information
1698 on (those suspicious) people with a more than average preference for privacy.
1701 If you want to hide your IP address from most adversaries,
1702 you should consider chaining <application>Privoxy</application>
1703 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1704 The configuration details can be found in
1705 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1706 with <application>Tor</application> section</ulink>
1711 <sect2 renderas="sect3" id="anonforsure">
1712 <title>Can Privoxy guarantee I am anonymous?</title>
1714 No. Your chances of remaining anonymous are improved, but unless you
1715 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1716 or a similar proxy and know what you're doing when it comes to configuring
1717 the rest of your system, you should assume that everything you do
1718 on the Web can be traced back to you.
1721 <application>Privoxy</application> can remove various information about you,
1722 and allows <emphasis>you</emphasis> more freedom to decide which sites
1723 you can trust, and what details you want to reveal. But it neither
1724 hides your IP address, nor can it guarantee that the rest of the system
1725 behaves correctly. There are several possibilities how a web sites can find
1726 out who you are, even if you are using a strict <application>Privoxy</application>
1727 configuration and chained it with <application>Tor</application>.
1730 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1731 by an insecure browser configuration, therefore you should use a browser that can
1732 be configured to only execute code from trusted sites, and be careful which sites you trust.
1733 For example there is no point in having <application>Privoxy</application>
1734 modify the User-Agent header, if websites can get all the information they want
1735 through JavaScript, ActiveX, Flash, Java etc.
1738 A few browsers disclose the user's email address in certain situations, such
1739 as when transferring a file by FTP. <application>Privoxy</application>
1740 does not filter FTP. If you need this feature, or are concerned about the
1741 mail handler of your browser disclosing your email address, you might
1742 consider products such as <application>NSClean</application>.
1745 Browsers available only as binaries could use non-standard headers to give
1746 out any information they can have access to: see the manufacturer's license
1747 agreement. It's impossible to anticipate and prevent every breach of privacy
1748 that might occur. The professionally paranoid prefer browsers available as
1749 source code, because anticipating their behavior is easier. Trust the source,
1755 <sect2 renderas="sect3" id="proxytest">
1756 <title>A test site says I am not using a Proxy.</title>
1758 Good! Actually, they are probably testing for some other kinds of proxies.
1759 Hiding yourself completely would require additional steps.
1763 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1764 together with Tor?</title>
1766 Before you configure <application>Privoxy</application> to use
1767 <ulink url="https://www.torproject.org/">Tor</ulink>,
1768 please follow the <citetitle>User Manual</citetitle> chapters
1769 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1770 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1771 <application>Privoxy</application> itself is setup correctly.
1774 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1775 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1776 and make sure <application>Tor</application>'s logfile says that
1777 <quote>Tor has successfully opened a circuit</quote> and it
1778 <quote>looks like client functionality is working</quote>.
1781 If either <application>Tor</application> or <application>Privoxy</application>
1782 isn't working, their combination most likely will neither. Testing them on their
1783 own will also help you to direct problem reports to the right audience.
1784 If <application>Privoxy</application> isn't working, don't bother the
1785 <application>Tor</application> developers. If <application>Tor</application>
1786 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1789 If you verified that <application>Privoxy</application> and <application>Tor</application>
1790 are working, it is time to connect them. As far as <application>Privoxy</application>
1791 is concerned, <application>Tor</application> is just another proxy that can be reached
1792 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1793 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1794 requests are done through <application>Tor</application> and thus invisible to your
1795 local network. Using socks4a would work too, but with socks5 you get more precise error
1800 <application>Privoxy's</application>
1801 <ulink url="../user-manual/config.html">main configuration file</ulink>
1802 is already prepared for <application>Tor</application>, if you are using a
1803 default <application>Tor</application> configuration and run it on the same
1804 system as &my-app;, you just have to edit the
1805 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1806 and uncomment the line:
1809 # forward-socks5t / 127.0.0.1:9050 .
1812 Note that if you got Tor through one of the bundles, you may
1813 have to change the port from 9050 to 9150 (or even another one).
1814 For details, please check the documentation on the
1815 <ulink url="https://torproject.org/">Tor website</ulink>.
1819 This is enough to reach the Internet, but additionally you might want to
1820 uncomment the following forward rules, to make sure your local network is still
1821 reachable through Privoxy:
1824 # forward 192.168.*.*/ .
1825 # forward 10.*.*.*/ .
1826 # forward 127.*.*.*/ .
1829 Unencrypted connections to systems in these address ranges will
1830 be as (un)secure as the local network is, but the alternative is
1831 that your browser can't reach the network at all. Then again,
1832 that may actually be desired and if you don't know for sure
1833 that your browser has to be able to reach the local network,
1834 there's no reason to allow it.
1837 If you want your browser to be able to reach servers in your local
1838 network by using their names, you will need additional exceptions
1839 that look like this:
1842 # forward localhost/ .
1845 Save the modified configuration file and open
1846 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1847 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1848 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1850 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1851 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1854 Afterward, please take the time to at least skim through the rest
1855 of <application>Tor's</application> documentation. Make sure you understand
1856 what <application>Tor</application> does, why it is no replacement for
1857 application level security, and why you probably don't want to
1858 use it for unencrypted logins.
1862 <sect2 renderas="sect3" id="sitebreak">
1863 <title>Might some things break because header information or
1864 content is being altered?</title>
1867 Definitely. It is common for sites to use browser type, browser version,
1868 HTTP header content, and various other techniques in order to dynamically
1869 decide what to display and how to display it. What you see, and what I see,
1870 might be very different. There are many, many ways that this can be handled,
1871 so having hard and fast rules, is tricky.
1875 The <quote>User-Agent</quote> is sometimes used in this way to identify
1876 the browser, and adjust content accordingly.
1880 Also, different browsers use different encodings of non-English
1881 characters, certain web servers convert pages on-the-fly according to the
1882 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1883 operating system or browser manufacturer causes some sites in these languages
1884 to be garbled; Surfers to Eastern European sites should change it to
1885 something closer. And then some page access counters work by looking at the
1886 <quote>Referer</quote> header; they may fail or break if unavailable. The
1887 weather maps of Intellicast have been blocked by their server when no
1888 <quote>Referer</quote> or cookie is provided, is another example. (But you
1889 can forge both headers without giving information away). There are
1890 many other ways things can go wrong when trying to fool a web server. The
1891 results of which could inadvertently cause pages to load incorrectly,
1892 partially, or even not at all. And there may be no obvious clues as to just
1893 what went wrong, or why. Nowhere will there be a message that says
1894 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1899 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1904 If you have problems with a site, you will have to adjust your configuration
1905 accordingly. Cookies are probably the most likely adjustment that may
1906 be required, but by no means the only one.
1912 <sect2 renderas="sect3" id="caching">
1913 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1914 speed up web browsing?</title>
1916 No, it does not have this ability at all. You want something like
1917 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1918 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1919 And, yes, before you ask, <application>Privoxy</application> can co-exist
1920 with other kinds of proxies like <application>Squid</application>.
1921 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1922 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1923 manual</ulink> for details.
1927 <sect2 renderas="sect3" id="firewall">
1928 <title>What about as a firewall? Can Privoxy protect me?</title>
1930 Not in the way you mean, or in the way some firewall vendors claim they can.
1931 <application>Privoxy</application> can help protect your privacy, but can't
1932 protect your system from intrusion attempts. It is, of course, perfectly possible
1933 to use <emphasis>both</emphasis>.
1937 <sect2 renderas="sect3" id="wasted">
1938 <title>I have large empty spaces / a checkerboard pattern now where
1939 ads used to be. Why?</title>
1941 It is technically possible to eliminate banners and ads in a way that frees
1942 their allocated page space. This could easily be done by blocking with
1943 <application>Privoxy's</application> filters,
1944 and eliminating the <emphasis>entire</emphasis> image references from the
1948 But, this would consume considerably more CPU resources (IOW, slow things
1949 down), would likely destroy the layout of some web pages which rely on the
1950 banners utilizing a certain amount of page space, and might fail in other
1951 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1952 Also, making ads and banners disappear without any trace complicates
1953 troubleshooting, and would sooner or later be problematic.
1956 The better alternative is to instead let them stay, and block the resulting
1957 requests for the banners themselves as is now the case. This leaves either
1958 empty space, or the familiar checkerboard pattern.
1961 So the developers won't support this in the default configuration, but you
1962 can of course define appropriate filters yourself to achieve this.
1966 <sect2 renderas="sect3" id="ssl">
1967 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1970 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1971 <application>Privoxy</application> will impersonate the destination
1972 server and can thus filter encrypted requests and responses as well.
1976 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1977 secure HTTP connections are encrypted SSL sessions between your
1978 browser and the secure site, and there is little
1979 that <application>Privoxy</application> can do but hand the raw
1980 gibberish data though from one end to the other unprocessed.
1983 The only exception to this is blocking by host patterns, as the client needs
1984 to tell <application>Privoxy</application> the name of the remote server,
1985 so that <application>Privoxy</application> can establish the connection.
1986 If that name matches a host-only pattern, the connection will be blocked.
1989 As far as ad blocking is concerned, this is less of a restriction than it may
1990 seem, since ad sources are often identifiable by the host name, and often
1991 the banners to be placed in an encrypted page come unencrypted nonetheless
1992 for efficiency reasons, which exposes them to the full power of
1993 <application>Privoxy</application>'s ad blocking.
1996 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
1997 JS page content, see <literal><ulink
1998 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
1999 in an SSL transaction will be impossible to block under these conditions.
2000 Fortunately, this does not seem to be a very common scenario since most
2001 cookies come by traditional means.
2006 <sect2 renderas="sect3" id="http2">
2007 <title>Does Privoxy support HTTP/2?</title>
2009 Privoxy currently doesn't parse HTTP/2 but applications
2010 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2011 to allow CONNECT requests (default) which are also used
2015 Adding HTTP/2 support is on the
2016 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2017 list but currently nobody is known to work on it.
2021 <sect2 renderas="sect3" id="secure">
2022 <title>Privoxy runs as a <quote>server</quote>. How
2023 secure is it? Do I need to take any special precautions?</title>
2025 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2026 user, which is how we recommend it be run. Also, by default
2027 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2031 The server aspect of <application>Privoxy</application> is not itself directly
2032 exposed to the Internet in this configuration. If you want to have
2033 <application>Privoxy</application> serve as a LAN proxy, this will have to
2034 be opened up to allow for LAN requests. In this case, we'd recommend
2035 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2036 <application>Privoxy</application> configuration file and check all <ulink
2037 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2038 options</ulink>. All LAN hosts can then use this as their proxy address
2039 in the browser proxy configuration, but <application>Privoxy</application>
2040 will not listen on any external interfaces. ACLs can be defined in addition,
2041 and using a firewall is always good too. Better safe than sorry.
2046 <sect2 renderas="sect3" id="turnoff">
2047 <title>Can I temporarily disable Privoxy?</title>
2049 &my-app; doesn't have a transparent proxy mode,
2050 but you can toggle off blocking and content filtering.
2053 The easiest way to do that is to point your browser
2054 to the remote toggle URL: <ulink
2055 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2058 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2059 of the <citetitle>User Manual</citetitle> for an easy way to access this
2060 feature. Note that this is a feature that may need to be enabled in the main
2061 <filename>config</filename> file.
2066 <sect2 renderas="sect3" id="reallyoff">
2067 <title>When <quote>disabled</quote> is Privoxy totally
2068 out of the picture?</title>
2070 No, this just means all optional filtering and actions are disabled.
2071 <application>Privoxy</application> is still acting as a proxy, but just
2072 doing less of the things that <application>Privoxy</application> would
2073 normally be expected to do. It is still a <quote>middle-man</quote> in
2074 the interaction between your browser and web sites. See below to bypass
2079 <sect2 renderas="sect3" id="turnoff2">
2080 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2082 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2083 configuration issue, not a &my-app; issue. Modern browsers typically do have
2084 settings for not proxying certain sites. Check your browser's help files.
2089 <sect2 renderas="sect3" id="crunch">
2090 <title>My logs show Privoxy <quote>crunches</quote>
2091 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2093 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2094 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2095 banners, but <application>Privoxy</application> uses the same mechanism for
2096 trapping requests for its own internal pages. For instance, a request for
2097 <application>Privoxy's</application> configuration page at: <ulink
2098 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2099 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2100 configuration is returned to the browser, and the log consequently will show
2101 a <quote>crunch</quote>.
2104 Since version 3.0.7, Privoxy will also log the crunch reason.
2105 If you are using an older version you might want to upgrade.
2109 <sect2 renderas="sect3" id="downloads">
2110 <title>Can Privoxy affect files that I download
2111 from a webserver? FTP server?</title>
2113 From the webserver's perspective, there is no difference between
2114 viewing a document (i.e. a page), and downloading a file. The same is true of
2115 <application>Privoxy</application>. If there is a match for a <literal><ulink
2116 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2117 it will still be blocked, and of course this is obvious.
2120 Filtering is potentially more of a concern since the results are not always
2121 so obvious, and the effects of filtering are there whether the file is simply
2122 viewed, or downloaded. And potentially whether the content is some obnoxious
2123 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2124 one of these presumably is <quote>bad</quote> content that we don't want, and
2125 the other is <quote>good</quote> content that we do want.
2126 <application>Privoxy</application> is blind to the differences, and can only
2127 distinguish <quote>good from bad</quote> by the configuration parameters
2128 <emphasis>we</emphasis> give it.
2131 <application>Privoxy</application> knows the differences in files according
2132 to the <quote>Content Type</quote> as reported by the webserver. If this is
2133 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2134 then <application>Privoxy</application> knows to ignore these where
2135 appropriate. <application>Privoxy</application> potentially can filter HTML
2136 as well as plain text documents, subject to configuration parameters of
2137 course. Also, documents that are of an unknown type (generally assumed to be
2138 <quote>text/plain</quote>) can be filtered, as will those that might be
2139 incorrectly reported by the webserver. If such a file is a downloaded file
2140 that is intended to be saved to disk, then any content that might have been
2141 altered by filtering, will be saved too, for these (probably rare) cases.
2144 Note that versions later than 3.0.2 do NOT filter document types reported as
2145 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2146 did filter this document type.
2149 In short, filtering is <quote>ON</quote> if a) the content type as reported
2150 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2151 allows it (or at least does not disallow it). That's it. There is no magic
2152 cookie anywhere to say this is <quote>good</quote> and this is
2153 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2156 If you download text files, you probably do not want these to be filtered,
2157 particularly if the content is source code, or other critical content. Source
2158 code sometimes might be mistaken for Javascript (i.e. the kind that might
2159 open a pop-up window). It is recommended to turn off filtering for download
2160 sites (particularly if the content may be plain text files and you are using
2161 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2162 also, for any site or page where making <emphasis>any</emphasis> changes at
2163 all to the content is to be avoided.
2166 <application>Privoxy</application> does not do FTP at all, only HTTP
2167 and HTTPS (SSL) protocols.
2171 <sect2 renderas="sect3" id="downloads2">
2172 <title>I just downloaded a Perl script, and Privoxy
2173 altered it! Yikes, what is wrong!</title>
2179 <sect2 renderas="sect3" id="hostsfile">
2180 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2182 One time-tested technique to defeat common ads is to trick the local DNS
2183 system by giving a phony IP address for the ad generator in the local
2184 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2185 <literal>localhost</literal>. This effectively blocks the ad.
2188 There is no reason to use this technique in conjunction with
2189 <application>Privoxy</application>. <application>Privoxy</application>
2190 does essentially the same thing, much more elegantly and with much more
2191 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2192 duplicates effort, but may get in the way and seriously slow down your system.
2193 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2194 your hosts list is neglected by <application>Privoxy's </application>
2195 configuration, consider adding your list to your <filename>user.action</filename> file:
2201 ads.galore.example.com
2202 etc.example.com</screen>
2205 <sect2 renderas="sect3" id="seealso">
2206 <title>Where can I find more information about Privoxy
2207 and related issues?</title>
2208 <!-- Include seealso.sgml boilerplate: -->
2210 <!-- end boilerplate -->
2215 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2221 <sect2 renderas="sect3" id="microsuck">
2222 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2223 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2226 We're not. The text substitutions that you are seeing are disabled
2227 in the default configuration as shipped. You have either manually
2228 activated the <quote><literal>fun</literal></quote> filter which
2229 is clearly labeled <quote>Text replacements for subversive browsing
2230 fun!</quote> or you are using an older Privoxy version and have implicitly
2231 activated it by choosing the <quote>Advanced</quote> profile in the
2232 web-based editor. Please upgrade.
2236 <sect2 renderas="sect3" id="valid">
2237 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2240 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2241 whenever there are text substitutions via a &my-app; filter. While this
2242 should always conform to the HTML 4.01 specifications, it has not been
2243 validated against this or any other standard.
2247 <sect2 renderas="sect3" id="surprise-privoxy">
2248 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2251 We didn't. We make Privoxy available for download, but we don't go
2252 around installing it on other people's systems behind their back.
2253 If you discover Privoxy running on your system and are sure you didn't
2254 install it yourself, somebody else did. You may not even be running
2255 the real Privoxy, but maybe something else that only pretends to be
2256 Privoxy, or maybe something that is based on the real Privoxy,
2257 but has been modified.
2260 Lately there have been reports of problems with some kind of
2261 "parental control" software based on Privoxy that came preinstalled on
2262 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2263 The problems described are inconsistent with the behaviour of official
2264 Privoxy versions, which suggests that the preinstalled software may
2265 contain vendor modifications that we don't know about and thus can't debug.
2268 Privoxy's <link linkend="copyright">license</link> allows vendor
2269 modifications, but the vendor has to comply with the license,
2270 which involves informing the user about the changes and to make
2271 the changes available under the same license as Privoxy itself.
2274 If you are having trouble with a modified Privoxy version,
2275 please try to talk to whoever made the modifications before
2276 reporting the problem to us. Please also try to convince
2277 whoever made the modifications to talk to us. If you think
2278 somebody gave you a modified Privoxy version without complying
2279 to the license, please let us know.
2287 <!-- ~~~~~ New section ~~~~~ -->
2289 <sect1 id="trouble">
2290 <title>Troubleshooting</title>
2292 <sect2 renderas="sect3" id="refused">
2293 <title>I cannot connect to any websites. Or, I am getting
2294 <quote>connection refused</quote> message with every web page. Why?</title>
2296 There are several possibilities:
2300 <application>Privoxy</application> is not running. Solution: verify
2301 that &my-app; is installed correctly, has not crashed, and is indeed running.
2302 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2304 <listitem><para>Or your browser is configured for a different port than what
2305 <application>Privoxy</application> is using. Solution: verify that &my-app;
2306 and your browser are set to the same port (<literal>listen-address</literal>).
2308 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2309 problem with a host in the forwarding chain. Solution: temporarily alter your
2310 configuration and take the forwarders out of the equation.
2313 Or you have a firewall that is interfering and blocking you. Solution:
2314 try disabling or removing the firewall as a simple test.
2320 <!-- ~~~~~ New section ~~~~~ -->
2321 <sect2 renderas="sect3" id="error503">
2322 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2324 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2325 been reported to cause this symptom -- even if not running! The solution is
2326 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2327 something better behaved in its place. Other personal firewall type products
2328 may cause similar type problems if not configured correctly.
2332 <sect2 renderas="sect3" id="flushit">
2333 <title>I just added a new rule, but the steenkin ad is
2334 still getting through. How?</title>
2336 If the ad had been displayed before you added its URL, it will probably be
2337 held in the browser's cache for some time, so it will be displayed without
2338 the need for any request to the server, and <application>Privoxy</application>
2339 will not be involved. Flush the browser's caches, and then try again.
2343 If this doesn't help, you probably have an error in the rule you
2344 applied. Try pasting the full URL of the offending ad into <ulink
2345 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2346 and see if it really matches your new rule. Blocking ads is like blocking
2347 spam: a lot of tinkering is required to stay ahead of the game. And
2348 remember you need to block the URL of the ad in question, which may be
2349 entirely different from the site URL itself. Most ads are hosted on different
2350 servers than the main site itself. If you right-click on the ad, you should
2351 be able to get all the relevant information you need. Alternately, you can
2352 find the correct URL by looking at <application>Privoxy's</application> logs
2353 (you may need to enable logging in the main config file if its disabled).
2356 Below is a slightly modified real-life log snippet that originates with one
2357 requested URL: <literal>www.example.com</literal> (name of site was changed
2358 for this example, the number of requests is real). You can see in this the
2359 complexity of what goes into making up this one <quote>page</quote>. There
2360 are eight different domains involved here, with thirty two separate URLs
2361 requested in all, making up all manner of images, Shockwave Flash,
2362 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2363 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2364 Many of the more questionable looking requests, are going to outside domains
2365 that seem to be identifying themselves with suspicious looking names, making
2366 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2367 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2371 Request: www.example.com/
2372 Request: www.example.com/favicon.ico
2373 Request: img.example.com/main.css
2374 Request: img.example.com/sr.js
2375 Request: example.betamarker.com/example.html
2376 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2377 Request: img.example.com/pb.png
2378 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2379 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2380 Request: img.example.com/p.gif
2381 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2382 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2383 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2384 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2385 Request: www.adtrak.net/adx.js crunch! (Blocked)
2386 Request: img.example.com/hbg.gif
2387 Request: img.example.com/example.jpg
2388 Request: img.example.com/mt.png
2389 Request: img.example.com/mm.png
2390 Request: img.example.com/mb.png
2391 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2392 Request: www.example.com/tracker.js
2393 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2394 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2395 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2396 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2397 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2398 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2399 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2400 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2401 Request: 66.70.21.80/img/pixel.gif
2402 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2403 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2407 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2408 behave perfectly <quote>normal</quote> (minus some ads, of course).
2413 <sect2 renderas="sect3" id="badsite">
2414 <title>One of my favorite sites does not work with Privoxy.
2415 What can I do?</title>
2418 First verify that it is indeed a <application>Privoxy</application> problem,
2419 by toggling off <application>Privoxy</application> through <ulink
2420 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2421 (the toggle feature may need to be enabled in the main
2422 <filename>config</filename>),
2423 and then shift-reloading the problem page (i.e. holding down the shift key
2424 while clicking reload. Alternatively, flush your browser's disk and memory
2429 If the problem went away, we know we have a configuration related problem.
2431 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2432 and paste the full URL of the page in question into the prompt. See which
2433 actions are being applied to the URL, and which matches in which actions
2434 files are responsible for that. It might be helpful also to look at your logs
2435 for this site too, to see what else might be happening (note: logging may need
2436 to be enabled in the main config file). Many sites are
2437 complex and require a number of related pages to help present their content.
2438 Look at what else might be used by the page in question, and what of that
2439 might be <emphasis>required</emphasis>.
2440 Now, armed with this information, go to
2442 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2443 and select the appropriate actions files for editing. </para>
2445 You can now either look for a section which disables the actions that
2446 you suspect to cause the problem and add a pattern for your site there,
2447 or make up a completely new section for your site. In any case, the recommended
2448 way is to disable only the prime suspect, reload the problem page, and only
2449 if the problem persists, disable more and more actions until you have
2450 identified the culprit. You may or may not want to turn the other actions
2451 on again. Remember to flush your browser's caches in between any such changes!
2454 Alternately, if you are comfortable with a text editor, you can accomplish
2455 the same thing by editing the appropriate actions file. Probably the easiest
2456 way to deal with such problems when editing by hand is to add your
2457 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2458 which is an alias that turns off most <quote>dangerous</quote>
2459 actions, but is also likely to turn off more actions then needed, and thus lower
2460 your privacy and protection more than necessary,
2463 Troubleshooting actions is discussed in more detail in the <ulink
2464 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2465 Troubleshooting: the Anatomy of an Action</ulink>.
2466 There is also an <ulink
2467 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2468 with general configuration information and examples.
2471 As a last resort, you can always see if your browser has a setting that will
2472 bypass the proxy setting for selective sites. Modern browsers can do this.
2478 <!-- ~~~~~ New section ~~~~~ -->
2479 <sect2 id="dun" renderas="sect3">
2480 <title>After installing Privoxy, I have to log in
2481 every time I start IE. What gives?</title>
2484 This is a quirk that affects the installation of
2485 <application>Privoxy</application>, in conjunction with Internet Explorer and
2486 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2487 appear to be corrupted or invalid DUN settings, or passwords.
2491 When setting up an NT based Windows system with
2492 <application>Privoxy</application> you may find that things do not seem to be
2493 doing what you expect. When you set your system up you will probably have set
2494 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2495 logged in with administrator privileges. You will probably have made this DUN
2496 connection available to other accounts that you may have set-up on your
2497 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2498 configured for the kids.
2502 When setting up <application>Privoxy</application> in this environment you
2503 will have to alter the proxy set-up of Internet Explorer (IE) for the
2504 specific DUN connection on which you wish to use
2505 <application>Privoxy</application>. When you do this the ICS DUN set-up
2506 becomes user specific. In this instance you will see no difference if you
2507 change the DUN connection under the account used to set-up the connection.
2508 However when you do this from another user you will notice that the DUN
2509 connection changes to make available to "Me only". You will also find that
2510 you have to store the password under each different user!
2514 The reason for this is that each user's set-up for IE is user specific. Each
2515 set-up DUN connection and each LAN connection in IE store the settings for
2516 each user individually. As such this enforces individual configurations
2517 rather than common ones. Hence the first time you use a DUN connection after
2518 re-booting your system it may not perform as you expect, and prompt you for
2519 the password. Just set and save the password again and all should be OK.
2523 [Thanks to Ray Griffith for this submission.]
2528 <!-- ~~~~~ New section ~~~~~ -->
2529 <sect2 id="ftp" renderas="sect3">
2530 <title>I cannot connect to any FTP sites. Privoxy
2531 is blocking me.</title>
2533 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2534 so do not configure your browser to use <application>Privoxy</application>
2535 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2536 or HTTPS (SSL)</emphasis>.
2539 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2540 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2541 an FTP connection, and not a HTTP connection. So while your browser may
2542 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2546 To complicate matters, some systems may have a generic <quote>proxy</quote>
2547 setting, which will enable various protocols, including
2548 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2549 accidentally enable FTP proxying in these cases. And of course, if this
2550 happens, <application>Privoxy</application> will indeed cause problems since
2551 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2552 message if a FTP connection is attempted.]]> Just disable the FTP setting
2553 and all will be well again.
2556 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2557 There just is not much reason, and the work to make this happen is more than
2562 <!-- ~~~~~ New section ~~~~~ -->
2563 <sect2 id="macosxie" renderas="sect3">
2564 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2565 Privoxy as the HTTP proxy.</title>
2567 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2568 network settings. In order to change the HTTP proxy, open System
2569 Preferences, and click on the Network icon. In the settings pane that
2570 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2571 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2572 Enter <literal>8118</literal> in the Port field. The next time you start
2573 IE, it should reflect these values.
2577 <!-- ~~~~~ New section ~~~~~ -->
2578 <sect2 renderas="sect3" id="macosxuninstall">
2579 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2580 uninstall it. Now the finder tells me I don't have sufficient privileges to
2581 empty the trash.</title>
2583 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2586 Just dragging the <application>Privoxy</application> folder to the trash is
2587 not enough to delete it. <application>Privoxy</application> supplies an
2588 <application>uninstall.command</application> file that takes care of
2589 these details. Open the trash, drag the <application>uninstall.command</application>
2590 file out of the trash and double-click on it. You will be prompted for
2591 confirmation and the administration password.
2594 The trash may still appear full after this command; emptying the trash
2595 from the desktop should make it appear empty again.
2599 <!-- ~~~~~ New section ~~~~~ -->
2600 <sect2 renderas="sect3" id="macosximages">
2601 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2602 experience random delays in page loading. I'm using
2603 <literal>localhost</literal> as my browser's proxy setting.</title>
2605 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2606 understand the issue yet. In any case, changing the proxy setting to
2607 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2608 works around the problem.
2612 <!-- ~~~~~ New section ~~~~~ -->
2613 <sect2 renderas="sect3" id="macosxaccountdeletion">
2614 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2617 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2618 X deletes all user accounts that are either not part of OS X itself or are
2619 not interactive user accounts (ones you log in with). Since, for the sake of
2620 security, &my-app; runs as a non-privileged user that is created by its
2621 installer (_privoxy), it can no longer start up once that account gets deleted.
2622 The solution is to perform a complete uninstall using the supplied
2623 <application>uninstall.command</application> script (either back up your
2624 configuration files or select to not have the uninstaller remove them when it
2625 prompts you) and then reinstall &my-app; using the installer package and merge
2626 in your configuration.
2630 <sect2 renderas="sect3" id="nohostname">
2631 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2634 <application>Privoxy</application> tries to get the hostname of the system
2635 its running on from the IP address of the system interface it is bound to
2636 (from the <filename>config</filename> file
2637 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2638 this information, <application>Privoxy</application> logs this condition.
2641 Typically, this would be considered a minor system configuration error. It is
2642 not a fatal error to <application>Privoxy</application> however, but may
2643 result in a much slower response from <application>Privoxy</application> on
2644 some platforms due to DNS timeouts.
2647 This can be caused by a problem with the local <filename>hosts</filename>
2648 file. If this file has been changed from the original, try reverting it to
2649 see if that helps. Make sure whatever name(s) are used for the local system,
2650 that they resolve both ways.
2653 You should also be able to work around the problem with the
2654 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2658 <sect2 renderas="sect3" id="inuse">
2659 <title>When I try to launch Privoxy, I get an
2660 error message <quote>port 8118 is already in use</quote> (or similar wording).
2663 Port 8118 is <application>Privoxy's</application> default TCP
2664 <quote>listening</quote> port. Typically this message would mean that there
2665 is already one instance of <application>Privoxy</application> running, and
2666 your system is actually trying to start a second
2667 <application>Privoxy</application> on the same port, which will not work.
2668 (You can have multiple instances but they must be assigned different ports.)
2669 How and why this might happen varies from platform to platform, but you need
2670 to check your installation and start-up procedures.
2674 <sect2 renderas="sect3" id="demoronizer">
2676 Pages with UTF-8 fonts are garbled.
2679 This may be the result of an overly aggressive filter. The filters that
2680 are enabled in the default configuration aren't expected to cause problems
2681 like this. If you enabled the <quote>demoronizer</quote> filter, please
2682 try temporarily disabling it.
2685 If that doesn't help, temporarily disable all filters to see if another
2686 filter could be the culprit. If the problem disappears, enable the filters
2687 one by one, until the problem reappears and the offending filter is found.
2690 Once the problem-causing filter is known, it can be fixed or disabled.
2693 Upgrading <application>Privoxy</application>, or going to the most recent
2694 <filename>default.action</filename> file available from <ulink
2695 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>
2696 might be worth a try, too.
2700 <sect2 renderas="sect3" id="demoronizer2">
2702 Why are binary files (such as images) corrupted when Privoxy
2706 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2707 filter</link> in conjunction with a web server that is misreporting the content
2708 type. By default binary files are exempted from
2709 <application>Privoxy's</application> filtering
2710 (unless the web server by mistake says the file is something else).
2714 <sect2 renderas="sect3" id="demoronizer3">
2716 What is the <quote>demoronizer</quote> and why is it there?
2719 The original demoronizer was a Perl script that cleaned up HTML pages which
2720 were created with certain Microsoft products. MS has used proprietary extensions
2721 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2722 that are viewed with non-Microsoft products (and are expecting to see a
2723 standard set of fonts). The demoronizer corrected these errors so the pages
2724 displayed correctly. <application>Privoxy</application> borrowed from this
2725 script, introducing a filter based on the original demoronizer, which in turn could
2726 correct these errors on the fly.
2729 But this is only needed in some situations, and will cause serious problems in some
2733 If you are using Microsoft products, you do not need it. If you need to view
2734 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2735 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2738 On the other hand, if you use non-Microsoft products, and you occasionally
2739 notice weird characters on pages, you might want to try it.
2743 <sect2 renderas="sect3" id="windowopen">
2745 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2748 <application>Privoxy</application> is attempting to disable malicious
2749 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2750 in this case, with the <literal>unsolicited-popups</literal>
2751 filter. <application>Privoxy</application> cannot tell very well
2752 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2755 If you see this in HTML source, and the page displays without problems, then
2756 this is good, and likely some pop-up window was disabled. If you see this
2757 where it is causing a problem, such as a downloaded program source code file,
2758 then you should set an exception for this site or page such that the
2759 integrity of the page stays in tact by disabling all filtering.
2763 <sect2 renderas="sect3" id="dnserrors">
2765 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2766 can't Privoxy do this better?
2769 There are potentially several factors here. First of all, the DNS resolution
2770 is done by the underlying operating system -- not
2771 <application>Privoxy</application> itself. <application>Privoxy</application>
2772 merely initiates the process and hands it off, and then later reports
2773 whatever the outcome was and tries to give a coherent message if there seems
2774 to be a problem. In some cases, this might otherwise be mitigated by the
2775 browser itself which might try some work-arounds and alternate approaches (e.g
2776 adding <quote>www.</quote> to the URL).
2779 In other cases, if <application>Privoxy</application> is being chained
2780 with another proxy, this could complicate the issue, and cause undue
2781 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2782 server handles all the DNS. <application>Privoxy</application> would just be
2783 the <quote>messenger</quote> which is reporting whatever problem occurred
2784 downstream, and not the root cause of the error.
2788 In any case, versions newer than 3.0.3 include various improvements to help
2789 <application>Privoxy</application> better handle these cases.
2793 <sect2 renderas="sect3" id="allcpu">
2795 At one site Privoxy just hangs, and starts taking
2796 all CPU. Why is this?
2799 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2800 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2801 are in the raw HTML source of the page, and the browser just ignores them. But the
2802 pattern matching in <application>Privoxy's</application> page filtering
2803 mechanism is trying to match against absurdly long strings and this becomes
2804 very CPU-intensive, taking a long, long time to complete.
2807 Until a better solution comes along, disable filtering on these pages,
2808 particularly the <literal>js-annoyances</literal> and
2809 <literal>unsolicited-popups</literal> filters. If you run into this problem
2810 with a recent &my-app; version, please send a problem report.
2814 <sect2 renderas="sect3" id="slowcrawl">
2815 <title>I just installed Privoxy, and all my
2816 browsing has slowed to a crawl. What gives? </title>
2818 This should not happen, and for the overwhelming number of users world-wide,
2819 it does not happen. I would suspect some inadvertent interaction of software
2820 components such as anti-virus software, spyware protectors, personal
2821 firewalls or similar components. Try disabling (or uninstalling) these one
2822 at a time and see if that helps. Either way, if you are using a
2823 recent &my-app; version, please report the problem.
2827 <sect2 renderas="sect3" id="preventcomp">
2828 <title>Why do my filters work on some sites but not on others? </title>
2830 It's probably due to compression. It is a common practice for web servers to
2831 send their content <quote>compressed</quote> in order to speed things up, and
2832 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2833 &my-app; can decompress content before filtering, otherwise you may want to enable
2835 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2838 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2843 <sect2 renderas="sect3" id="ssl-warnings">
2844 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2845 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2846 What's going on?</title>
2848 Probably the browser is requesting ads through HTTPS and &my-app;
2849 is blocking the requests. Privoxy's error messages are delivered
2850 unencrypted and while it's obvious for the browser that the HTTPS
2851 request is already blocked by the proxy, some warn about unauthenticated
2855 To work around the problem you can redirect those requests to an invalid
2856 local address instead of blocking them. While the redirects aren't
2857 encrypted either, many browsers don't care. They simply follow the
2858 redirect, fail to reach a server and display an error message instead
2862 To do that, enable logging to figure out which requests get blocked by
2863 &my-app; and add the hosts (no path patterns) to a section like this:
2867 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2872 Additionally you have to configure your browser to contact
2873 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2876 To add a proxy exception in <application>Mozilla Firefox</application>
2877 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2878 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2879 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2885 <sect2 renderas="sect3" id="se-linux">
2886 <title>I get selinux error messages. How can I fix this?</title>
2888 Please report the problem to the creator of your selinux policies.
2891 The problem is that some selinux policy writers aren't familiar
2892 with the application they are trying to <quote>secure</quote> and
2893 thus create policies that make no sense.
2896 In <application>Privoxy's</application> case the problem usually
2897 is that the policy only allows outgoing connections for certain
2898 destination ports (e.g. 80 and 443). While this may cover the
2899 standard ports, websites occasionally use other ports as well.
2900 This isn't a security problem and therefore <application>Privoxy's</application>
2901 default configuration doesn't block these requests.
2904 If you really want to block these ports (and don't be able
2905 to load websites that don't use standard ports), you should
2906 configure Privoxy to block these ports as well, so it doesn't
2907 trigger the selinux warnings.
2912 <sect2 renderas="sect3" id="gentoo-ricers">
2913 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2915 Probably you unintentionally compiled &my-app; without threading support
2916 in which case requests have to be serialized and only one can be served
2920 Check your <quote>USE</quote> flags and make sure they include
2921 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2924 If you compiled &my-app; with threading support (on POSIX-based systems),
2925 the <quote>Conditional #defines</quote> section on <ulink
2926 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2927 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2931 <sect2 renderas="sect3" id="tainted-sockets">
2932 <title>What are tainted sockets and how do I prevent them?</title>
2934 &my-app; marks sockets as tainted when it can't use them to
2935 serve additional requests.
2936 This does not necessarily mean that something went wrong and
2937 information about tainted sockets is only logged if connection
2938 debugging is enabled (debug 2).
2941 For example server sockets that were used for CONNECT requests
2942 (which are used to tunnel https:// requests) are considered tainted
2943 once the client closed its connection to &my-app;.
2944 Technically &my-app; could keep the connection to the server open,
2945 but the server would not accept requests that do not belong to the
2946 previous TLS/SSL session (and the client may even have terminated
2950 Server sockets are also marked tainted when a client requests a
2951 resource, but closes the connection before &my-app; has completely
2952 received (and forwarded) the resource to the client.
2953 In this case the server would (probably) accept additional requests,
2954 but &my-app; could not get the response without completely reading
2955 the leftovers from the previous response.
2958 These are just two examples, there are currently a bit more than
2959 25 scenarios in which a socket is considered tainted.
2962 While sockets can also be marked tainted as a result of a technical
2963 problem that may be worth fixing, the problem will be explicitly
2968 <sect2 renderas="sect3" id="pcre-stack-limit">
2969 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2971 This can happen if your custom filters require more memory than &my-app;
2973 Usually the problem is that the operating system enforces a stack size limit
2974 that isn't sufficient.
2977 Unless the problem occurs with the filters available in the default configuration,
2978 this is not considered a Privoxy bug.
2981 To prevent the crashes you can rewrite your filter to use less resources,
2982 increase the relevant memory limit or recompile pcre to use less stack space.
2983 For details please see the
2984 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
2985 and the documentation of your operating system.
2989 <sect2 renderas="sect3" id="file-permissions">
2990 <title>What to do if editing the config file of privoxy is access denied?</title>
2992 Your userid probably isn't allowed to edit the file.
2993 <!-- show how to check permissions? -->
2994 On Windows you can use the windows equivalent of sudo:
2996 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
2999 or fix the file permissions:
3001 <screen>C:\Privoxy>icacls config.txt
3002 config.txt BUILTIN\Administrators:(I)(F)
3003 NT AUTHORITY\SYSTEM:(I)(F)
3004 BUILTIN\Users:(I)(RX)
3005 NT AUTHORITY\Authenticated Users:(I)(M)
3007 Successfully processed 1 files; Failed processing 0 files
3009 C:\Privoxy>icacls config.txt /grant Lee:F
3010 processed file: config.txt
3011 Successfully processed 1 files; Failed processing 0 files
3013 C:\Privoxy>icacls config.txt
3014 config.txt I3668\Lee:(F)
3015 BUILTIN\Administrators:(I)(F)
3016 NT AUTHORITY\SYSTEM:(I)(F)
3017 BUILTIN\Users:(I)(RX)
3018 NT AUTHORITY\Authenticated Users:(I)(M)
3020 Successfully processed 1 files; Failed processing 0 files
3022 C:\Privoxy></screen>
3025 or try to point-n-click your way through adjusting the file
3026 permissions in windows explorer.
3032 <!-- ~~~~~ New section ~~~~~ -->
3033 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3034 <!-- Include contacting.sgml -->
3036 <!-- end contacting -->
3039 <!-- ~~~~~ New section ~~~~~ -->
3040 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3042 <!-- Include copyright.sgml -->
3048 Portions of this document are <quote>borrowed</quote> from the original
3049 <application>Junkbuster</application> (tm) FAQ, and modified as
3050 appropriate for <application>Privoxy</application>.
3053 <!-- ~~~~~ New section ~~~~~ -->
3054 <sect2><title>License</title>
3055 <!-- Include copyright.sgml: -->
3057 <!-- end copyright -->
3059 <!-- ~ End section ~ -->
3061 <!-- ~~~~~ New section ~~~~~ -->
3062 <sect2><title>History</title>
3063 <!-- Include history.sgml -->
3069 <!-- ~ End section ~ -->
3072 <!-- ~~~~~ New section ~~~~~ -->
3074 <sect1 id="seealso"><title>See also</title>
3076 <!-- Include seealso.sgml -->
3086 This program is free software; you can redistribute it
3087 and/or modify it under the terms of the GNU General
3088 Public License as published by the Free Software
3089 Foundation; either version 2 of the License, or (at
3090 your option) any later version.
3092 This program is distributed in the hope that it will
3093 be useful, but WITHOUT ANY WARRANTY; without even the
3094 implied warranty of MERCHANTABILITY or FITNESS FOR A
3095 PARTICULAR PURPOSE. See the GNU General Public
3096 License for more details.
3098 The GNU General Public License should be included with
3099 this file. If not, you can view it at
3100 http://www.gnu.org/copyleft/gpl.html
3101 or write to the Free Software Foundation, Inc.,
3102 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA