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 "UNRELEASED">
13 <!entity % p-not-stable "INCLUDE">
14 <!entity % p-stable "IGNORE">
15 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
16 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
17 <!entity % p-supp-userman "INCLUDE"> <!-- Include all from supported.sgml -->
18 <!entity my-copy "©"> <!-- kludge for docbook2man -->
19 <!entity % p-newstuff "INCLUDE"> <!-- exclude stuff from devel versions -->
20 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
21 <!entity my-app "<application>Privoxy</application>">
24 File : doc/source/faq.sgml
28 Copyright (C) 2001-2018 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; 2001-2018 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>.
119 This works, at least in some situations:
120 Test: <ulink url="privoxy-user-manual.pdf"><citetitle>User Manual</citetitle></ulink>.
124 <!-- Include privoxy.sgml boilerplate: -->
125 <para>What is Privoxy?</para> &p-intro;
126 <!-- end boilerplate -->
129 Please note that this document is a work in progress. This copy represents
130 the state at the release of version &p-version;.
131 You can find the latest version of the document at <ulink
132 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
133 Please see the <link linkend="contact">Contact section</link> if you want to
134 contact the developers.
141 <!-- ~~~~~ New section ~~~~~ -->
143 <sect1 id="general"><title>General Information</title>
144 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
146 Anyone who is interested in security, privacy, or in
147 finer-grained control over their web and Internet experience.
151 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
154 &my-app; is certainly a good choice, especially for those who want more
155 control and security. Those with the willingness to read the documentation
156 and the ability to fine-tune their installation will benefit the most.
159 One of <application>Privoxy's</application>
160 strengths is that it is highly configurable giving you the ability to
161 completely personalize your installation. Being familiar with, or at least
162 having an interest in learning about <ulink
163 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
164 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
165 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
166 Expressions</quote></ulink>
167 will be a big plus and will help you get the most out of &my-app;.
168 A new installation just includes a very basic configuration. The user
169 should take this as a starting point only, and enhance it as he or she
170 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
174 Much of <application>Privoxy's</application> configuration can be done
175 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
176 But there are areas where configuration is done using a
177 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
178 to edit configuration files. Also note that the web-based action editor
179 doesn't use authentication and should only be enabled in environments
180 where all clients with access to &my-app; listening port can be trusted.
184 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
185 Privoxy work? </title>
187 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
188 is a service, based on a software such as &my-app;, that clients
189 (i.e. browsers) can use instead of connecting to web servers directly.
190 The clients then ask the proxy to request objects (web pages, images, movies etc)
191 on their behalf and to forward the data to the clients.
192 It is a <quote>go-between</quote>. For details, see
193 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
196 There are many reasons to use web proxies, such as security (firewalling),
197 efficiency (caching) and others, and there are any number of proxies
198 to accommodate those needs.
201 &my-app; is a proxy that is primarily focused on
202 privacy enhancement, ad and junk elimination and freeing the user from
203 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
204 it is in a perfect position to filter outbound personal information that your
205 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
206 this, all of which are under your complete control via the various configuration
207 files and options. Being a proxy also makes it easier to share
208 configurations among multiple browsers and/or users.
212 <sect2 renderas="sect3" id="otherstuff">
213 <title>Does Privoxy do anything more than ad blocking?</title>
215 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
216 can be used to sanitize and customize web browsing.
220 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
221 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
223 <!-- Include history.sgml -->
230 <sect2 renderas="sect3" id="whyprivoxy">
231 <title>Why <quote>Privoxy</quote>? Why change the name from
232 Junkbuster at all?</title>
234 Though outdated, Junkbusters Corporation continued to offer their original
235 version of the <application>Internet Junkbuster</application> for a while,
236 so publishing our <application> Junkbuster</application>-derived software
237 under the same name would have led to confusion.
240 There were also potential legal reasons not to use the
241 <application>Junkbuster</application> name, as it was (and maybe still is)
242 a registered trademark of Junkbusters Corporation.
243 There were, however, no objections from Junkbusters Corporation to the
244 <application>Privoxy</application> project itself, and they, in fact,
245 shared our ideals and goals.
248 The Privoxy developers also believed that there were so many improvements
249 over the original code, that it was time to make a clean break from the past
250 and make a name in their own right.
253 <application>Privoxy</application> is the
254 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
255 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
256 control, more freedom, and allows you to browse your personal and
257 <quote><emphasis>private</emphasis> edition</quote> of the web.
261 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
262 from the old Junkbuster?</title>
264 <application>Privoxy</application> picks up where
265 <application>Junkbuster</application> left off.
266 <application>Privoxy</application> still blocks ads and banners,
268 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
269 helps protect your privacy. But, most of these features have been enhanced,
270 and many new ones have been added, all in the same vein.
273 <application>Privoxy</application>'s new features include:
276 <!-- Include newfeatures.sgml: -->
282 <sect2 renderas="sect3" id="whatsanad">
283 <title>How does Privoxy know what is an ad, and what is not?</title>
285 <application>Privoxy</application>'s approach to blocking ads is twofold:
288 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
289 of banner images. This applies to both the path (you wouldn't guess how many
290 web sites serve their banners from a directory called <quote>banners</quote>!)
291 and the host (blocking the big banner hosting services like doublecklick.net
292 already helps a lot). <application>Privoxy</application> takes advantage of this
293 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
294 patterns</ulink> to sort out and block the requests for things that sound
295 like they would be ads or banners.
298 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
299 can't tell the size of an image by its URL without downloading it, and if you
300 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
301 also inspects the HTML sources of web pages while they are loaded, and replaces
302 references to images with standard banner sizes by dummy references, so that
303 your browser doesn't request them anymore in the first place.
306 Both of this involves a certain amount of guesswork and is, of course, freely
307 and readily configurable.
311 <sect2 renderas="sect3" id="mistakes">
312 <title>Can Privoxy make mistakes?
313 This does not sound very scientific.</title>
315 Actually, it's a black art ;-) And yes, it is always possible to have a broad
316 rule accidentally block or change something by mistake. You will almost surely
317 run into such situations at some point. It is tricky writing rules to
318 cover every conceivable possibility, and not occasionally get false positives.
322 But this should not be a big concern since the
323 <application>Privoxy</application> configuration is very flexible, and
324 includes tools to help identify these types of situations so they can be
325 addressed as needed, allowing you to customize your installation.
326 (<link linkend="badsite">See the Troubleshooting section below</link>.)
331 <sect2 renderas="sect3" id="configornot">
332 <title>Will I have to configure Privoxy
333 before I can use it?</title>
335 That depends on your expectations.
336 The default installation should give you a good starting
337 point, and block <emphasis>most</emphasis> ads and unwanted content,
338 but many of the more advanced features are off by default, and require
339 you to activate them.
342 You do have to set up your browser to use
343 <application>Privoxy</application> (see the <link
344 linkend="firststep">Installation section below</link>).
347 And you will certainly run into situations where there are false positives,
348 or ads not being blocked that you may not want to see. In these cases, you
349 would certainly benefit by customizing <application>Privoxy's</application>
350 configuration to more closely match your individual situation. And we
351 encourage you to do this. This is where the real power of
352 <application>Privoxy</application> lies!
357 <sect2 renderas="sect3" id="lan">
358 <title>Can Privoxy run as a server on a network?</title>
360 Yes, &my-app; runs as a server already, and can easily be configured to
361 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
362 How can I set up Privoxy to act as a proxy for my LAN</link> below.
366 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
367 Privoxy. Why should I use Privoxy at all?</title>
369 Modern browsers do indeed have <emphasis>some</emphasis> of the same
370 functionality as <application>Privoxy</application>. Maybe this is
371 adequate for you. But <application>Privoxy</application> is very
372 versatile and powerful, and can probably do a number of things
373 your browser just can't.
376 In addition, a proxy is good choice if you use multiple browsers, or
377 have a LAN with multiple computers since &my-app; can run as a server
378 application. This way all the configuration is in one place, and you don't
379 have to maintain a similar configuration for possibly many browsers or
383 Note, however, that it's recommended to leverage both your browser's
384 and <application>Privoxy's</application> privacy enhancing features
385 at the same time. While your browser probably lacks some features
386 &my-app; offers, it should also be able to do some things more
387 reliably, for example restricting and suppressing JavaScript.
391 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
393 The most important reason is because you have access to
394 <emphasis>everything</emphasis>, and you can control everything. You can
395 check every line of every configuration file yourself. You can check every
396 last bit of source code should you desire. And even if you can't read code,
397 there should be some comfort in knowing that <!-- thousands of -->other people can,
398 and do read it. You can build the software from scratch, if you want,
399 so that you know the executable is clean, and that it is
400 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
401 is one reason we use &my-app; ourselves.
405 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
406 warranty? Registration?</title>
408 <application>Privoxy</application> is free software and licensed under the <ulink
409 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
410 It is free to use, copy, modify or distribute as you wish under the terms of this
411 license. Please see the <link linkend="copyright">Copyright</link> section for more
412 information on the license and copyright. Or the <filename>LICENSE</filename> file
413 that should be included.
416 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
417 That is something that would cost real money ;-) There is no registration either.
422 <sect2 renderas="sect3" id="spyware">
423 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
425 No, at least not reliably enough to trust it. &my-app; is not designed to be
426 a malware removal tool and the default configuration doesn't even try to
427 filter out any malware.
430 &my-app; could help prevent contact from (known) sites that use such
431 tactics with appropriate configuration rules, and thus could conceivably
432 prevent contamination from such sites. However, keeping such a configuration
433 up to date would require a lot of time and effort that would be better spend
434 on keeping your software itself up to date so it doesn't have known
440 <sect2 renderas="sect3" id="otherads">
441 <title>Can I use Privoxy with other ad-blocking software?</title>
443 &my-app; should work fine with other proxies and other software in general.
446 But it is probably not necessary to use &my-app; in conjunction with other
447 ad-blocking products, and this could conceivably cause undesirable results.
448 It might be better to choose one software or the other and work a little to
449 tweak its configuration to your liking.
452 Note that this is an advice specific to ad blocking.
456 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
458 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
460 Well, we <emphasis>always</emphasis> need help. There is something for
461 everybody who wants to help us. We welcome new developers, packagers,
462 testers, documentation writers or really anyone with a desire to help in
463 any way. You <emphasis>DO NOT</emphasis> need to be a
464 <quote>programmer</quote>. There are many other tasks available. In fact,
465 the programmers often can't spend as much time programming because of some
466 of the other, more mundane things that need to be done, like checking the
467 Tracker feedback sections or responding to user questions on the mailing
471 So first thing, subscribe to the <ulink
472 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
473 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
474 Developers</ulink> mailing list, join the discussion, help out other users, provide general
475 feedback or report problems you noticed.
478 If you intend to help out with the trackers, you also might want to <ulink
479 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
480 so we don't confuse you with the other name-less users.
483 We also have a <ulink
484 url="../developer-manual/index.html">Developer's Manual</ulink>.
485 While it is partly out of date, it's still worth reading.
488 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
489 may be of interest to you as well.
490 Please let us know if you want to work on one of the items listed.
494 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
496 Donations are welcome. Our
497 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
498 is rather long and being able to pay one (or more) developers to work on Privoxy
499 would make a huge difference, even if it was only for a couple of weeks. Donations may
500 also be used for Privoxy-related travel expenses (for example to attend conferences),
501 for hardware used for Privoxy development and for hosting expenses etc.
505 <application>Privoxy</application> is an associated
506 project of <ulink url="https://www.spi-inc.org/">Software
507 in the Public Interest (SPI)</ulink>, which allows us to receive
508 tax-deductible donations in the United States.
509 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
510 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
511 For details, please have a look at
512 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
516 You can also donate to Privoxy using a bank account or a "Paypal" address:
519 Name on account: <ulink url="https://www.zwiebelfreunde.de/">Zwiebelfreunde e.V.</ulink>
520 IBAN: DE95430609671126825604
525 "Paypal" address: privoxy@zwiebelfreunde.de
528 Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany
529 and other countries that recognize German charitable clubs. Feel free to
530 use the Subject field to provide a name to be credited and a list of TODO
531 list items you are interested in the most. For example: Max Mustermann: #16, #1, #14.
535 Note that donations made through Zwiebelfreunde e.V. currently can't be checked
536 automatically so you may not get credited right away. The credits currently
537 reflect donations received before 2016-01-14.
541 If you have any questions regarding donations please mail to either the
542 public user mailing list or, if it's a private matter, to
543 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
548 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
550 We are currently offering the following sponsor levels as an experiment:
554 <term>Gold (12000 USD/year)</term>
557 Logo shown at the bottom of the
558 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
559 Logo, link and self description on the
560 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
565 <term>Silver (1200 USD/year)</term>
568 Logo shown randomly at the bottom of the
569 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
570 Logo, link and self description on the
571 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
576 <term>Bronze (600 USD/year)</term>
579 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
585 The logo sizes depend on the sponsor level. Logos are served from
586 our server, no requests are made to the sponsor website unless
587 the links are being used.
590 The details may change over time but changes will only affect new sponsors
591 (or existing sponsors that explicitly agreed to the changes).
594 If you want to become a sponsor, please contact
595 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
596 New sponsors are only accepted if no developer objects.
604 <!-- ~~~~~ New section ~~~~~ -->
606 <sect1 id="installation"><title>Installation</title>
608 <sect2 renderas="sect3" id="whichbrowsers">
609 <title>Which browsers are supported by Privoxy?</title>
611 Any browser that can be configured to use a proxy, which
612 should be virtually all browsers, including
613 <application>Firefox</application>, <application>Internet
614 Explorer</application>, <application>Opera</application>, and
615 <application>Safari</application> among others.
616 Direct browser support is not an absolute requirement since
617 <application>Privoxy</application> runs as a separate application and talks
618 to the browser in the standardized HTTP protocol, just like a web server
623 <sect2 renderas="sect3" id="whichos">
624 <title>Which operating systems are supported?</title>
626 Include supported.sgml here:
631 <sect2 renderas="sect3" id="email-client">
632 <title>Can I use Privoxy with my email client?</title>
634 As long as there is some way to set a HTTP proxy for the client, then yes,
635 any application can be used, whether it is strictly speaking a
636 <quote>browser</quote> or not. Though this may not be the best approach for
637 dealing with some of the common abuses of HTML in email. See <link
638 linkend="outlook">How can I configure <application>Privoxy</application>
639 with <application>Outlook</application>?</link> below for more on
643 Be aware that HTML email presents a number of unique security and privacy
644 related issues, that can require advanced skills to overcome. The developers
645 recommend using email clients that can be configured to convert HTML to plain
646 text for these reasons.
650 <!-- Nobody is going to still be doing this!
651 <sect2 renderas="sect3" id="newinstall"><title>Can I install
652 Privoxy over Junkbuster?</title>
654 We recommend you un-install <application>Junkbuster</application>
655 first to minimize conflicts and confusion. You may want to
656 save your old configuration files for future reference. The configuration
657 files and syntax have substantially changed, so you will need to manually
658 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
659 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
660 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
664 Note: Some installers may automatically un-install
665 <application>Junkbuster</application>, if present!
671 <sect2 renderas="sect3" id="firststep">
672 <title>I just installed Privoxy. Is there anything
673 special I have to do now?</title>
676 All browsers should be told to use <application>Privoxy</application>
677 as a proxy by specifying the correct proxy address and port number
678 in the appropriate configuration area for the browser. It's possible
679 to combine &my-app; with a packet filter to intercept HTTP requests
680 even if the client isn't explicitly configured to use &my-app;,
681 but where possible, configuring the client is recommended. See
682 <ulink url="../user-manual/startup.html">the User Manual for more
683 details</ulink>. You should also flush your browser's memory and disk
684 cache to get rid of any cached junk items, and remove any stored
685 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
690 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
692 If you set up the <application>Privoxy</application> to run on
693 the computer you browse from (rather than your ISP's server or some
694 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
695 (sometimes referred to as <quote>localhost</quote>,
696 which is the special name used by every computer on the Internet to refer
697 to itself) and the port will be 8118 (unless you used the <ulink
698 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
699 config option to tell <application>Privoxy</application> to run on
703 When configuring your browser's proxy settings you typically enter
704 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
705 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
706 then the number <quote>8118</quote> for <quote>port</quote>.
707 This tells your browser to send all web requests to <application>Privoxy</application>
708 instead of directly to the Internet.
711 <application>Privoxy</application> can also be used to proxy for
712 a Local Area Network. In this case, your would enter either the IP
713 address of the LAN host where <application>Privoxy</application>
714 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
715 Port assignment would be same as above. Note that
716 <application>Privoxy</application> doesn't listen on any LAN interfaces by
720 <application>Privoxy</application> does not currently handle
721 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
725 <sect2 renderas="sect3" id="nothing">
726 <title>I just installed Privoxy, and nothing is happening.
727 All the ads are there. What's wrong?</title>
730 Did you configure your browser to use <application>Privoxy</application>
731 as a proxy? It does not sound like it. See above. You might also try flushing
732 the browser's caches to force a full re-reading of pages. You can verify
733 that <application>Privoxy</application> is running, and your browser
734 is correctly configured by entering the special URL:
735 <ulink url="http://p.p/">http://p.p/</ulink>.
736 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
737 of potential redirect caching problem (see next Q). -->
738 This should take you to a page titled <quote>This is Privoxy..</quote> with
739 access to <application>Privoxy's</application> internal configuration.
740 If you see this, then you are good to go. If you receive a page saying
741 <quote>Privoxy is not running</quote>, then the browser is not set up to use
742 your <application>Privoxy</application> installation.
743 If you receive anything else (probably nothing at all), it could either
744 be that the browser is not set up correctly, or that
745 <application>Privoxy</application> is not running at all. Check the <ulink
746 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
747 on starting <application>Privoxy</application> and browser configuration,
748 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
749 on starting <application>Privoxy</application></ulink> in the
750 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
755 <sect2 renderas="sect3" id="notused">
756 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
757 Privoxy is running and being used.</title>
760 First, make sure that Privoxy is <emphasis>really</emphasis> running and
761 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
762 should see the <application>Privoxy</application> main page. If not, see
763 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
764 on starting <application>Privoxy</application></ulink> in the
765 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
769 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
770 other parts of <application>Privoxy</application>'s web interface show
771 the dummy page, your browser has cached a redirection it encountered before
772 <application>Privoxy</application> was being used. You need to clear your
773 browser's cache. Note that shift-reloading the dummy page won't help, since
774 that'll only refresh the dummy page, not the redirection that lead you there.
778 The procedure for clearing the cache varies from browser to browser. For
779 example, <application>Mozilla/Netscape</application> users would click
780 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
781 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
782 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
783 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
784 In some <application>Firefox</application> versions it's
785 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
786 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
787 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
788 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
795 <!-- ~~~~~ New section ~~~~~ -->
797 <sect1 id="configuration"><title>Configuration</title>
798 <sect2 renderas="sect3" id="actionsfile">
799 <title>What exactly is an <quote>actions</quote> file?</title>
802 &my-app; utilizes the concept of <quote>
803 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
804 that are used to manipulate and control web page data.
805 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
806 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
807 that <application>Privoxy</application> could take while processing a certain
808 request, are configured. Typically, you would define a set of default actions
809 that apply globally to all URLs, then add exceptions to these defaults where needed.
810 There is a wide array of actions available that give the user a high degree
811 of control and flexibility on how to process each and every web page.
815 Actions can be defined on a <ulink
816 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
817 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
818 grouped together and then applied to requests matching one or more patterns.
819 There are many possible actions that might apply to any given site. As an example,
820 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
821 as one of your default actions, but need to accept cookies from a given site,
822 you would need to define an exception for this site in one of your actions
823 files, preferably in <filename>user.action</filename>.
828 <sect2 renderas="sect3" id="actionss">
829 <title>The <quote>actions</quote> concept confuses me. Please list
830 some of these <quote>actions</quote>.</title>
832 For a comprehensive discussion of the actions concept, please refer
833 to the <ulink url="../user-manual/actions-file.html">actions file
834 chapter</ulink> in the <ulink url="../user-manual/index.html">User
835 Manual</ulink>. It includes a <ulink
836 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
837 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
838 file tutorial</ulink> to get you started.
843 <sect2 renderas="sect3" id="actconfig">
844 <title>How are actions files configured? What is the easiest
845 way to do this?</title>
848 Actions files are just text files in a special syntax and can be edited
849 with a text editor. But probably the easiest way is to access
850 <application>Privoxy</application>'s user interface with your web browser
851 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
852 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
853 <quote><ulink url="http://config.privoxy.org/show-status">View &
854 change the current configuration</ulink></quote> from the menu. Note
855 that this feature must be explicitly enabled in the main config file
857 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
862 <sect2 renderas="sect3">
863 <title>There are several different <quote>actions</quote> files. What are
864 the differences?</title>
866 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
867 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
872 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
874 Based on your feedback and the continuing development, updates of
875 <filename>default.action</filename> will be
876 made available from time to time on the <ulink
877 url="https://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
878 our <ulink url="https://sourceforge.net/projects/ijbswa/">project page</ulink>.
882 If you wish to receive an email notification whenever we release updates of
883 <application>Privoxy</application> or the actions file, <ulink
884 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
885 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
890 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
892 The syntax and purpose of configuration files has remained roughly the
893 same throughout the 3.x series, but backwards compatibility is not guaranteed.
894 Also each release contains updated, <quote>improved</quote> versions and it is
895 therefore strongly recommended to install the newer configuration files
896 and merge back your modifications.
900 <sect2 renderas="sect3" id="difficult">
901 <title>Why is the configuration so complicated?</title>
903 <quote>Complicated</quote> is in the eye of the beholder.
906 Privoxy is currently mainly written by and for people who are already
907 familiar with the underlying concepts like regular expressions, HTTP and HTML,
908 or are willing to become familiar with them to be able to get the most
909 out of a powerful and flexible tool such as Privoxy.
912 While everybody is expected to be able to get a Privoxy default installation
913 up and running, fine-tuning requires a certain amount of background
914 information and Privoxy's documentation mainly concentrates on the
915 Privoxy-specific parts while only providing references to the rest.
918 If you or anyone you know has the skills, time and energy to
919 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
923 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
925 The default configuration shouldn't impact the usability of any of these services.
926 It may, however, make all <ulink
927 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
928 temporary, so that your browser will forget your
929 login credentials in between browser sessions. If you would like not to have to log
930 in manually each time you access those websites, simply turn off all cookie handling
931 for them in the <filename>user.action</filename> file. An example for yahoo might
934 <screen># Allow all cookies for Yahoo login:
936 { -<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> }
937 .login.yahoo.com</screen>
939 These kinds of sites are often quite complex and heavy with
940 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
941 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
943 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
946 <screen># Gmail is a _fragile_ site:
948 { <literal>fragile</literal> }
950 mail.google.com</screen>
952 Be sure to flush your browser's caches whenever making these kinds of
953 changes, just to make sure the changes <quote>take</quote>.
956 Make sure the domain, host and path are appropriate as well. Your browser can
957 tell you where you are specifically and you should use that information for
958 your configuration settings. Note that above it is not referenced as
959 <literal>gmail.com</literal>, which is a valid domain name.
964 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
965 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
967 Configuring <application>Privoxy</application> is not entirely trivial. To
968 help you get started, we provide you with three different default action
969 <quote>profiles</quote> in the web based actions file editor at <ulink
970 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
971 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
972 Manual</citetitle></ulink> for a list of actions, and how the default
977 Where the defaults are likely to break some sites, exceptions for
978 known popular <quote>problem</quote> sites are included, but in
979 general, the more aggressive your default settings are, the more exceptions
980 you will have to make later. New users are best to start off in
981 <quote>Cautious</quote> setting. This is safest and will have the fewest
982 problems. See the <ulink
983 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
984 for a more detailed discussion.
988 It should be noted that the <quote>Advanced</quote> profile (formerly known
989 as the <quote>Adventuresome</quote> profile) is more
990 aggressive, and will make use of some of
991 <application>Privoxy's</application> advanced features. Use at your own risk!
996 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
997 with a browser? Does that not raise security issues?</title>
999 It may seem strange that regular users can edit the config files with their
1000 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
1001 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
1004 When you use the browser-based editor, <application>Privoxy</application>
1005 itself is writing to the config files. Because
1006 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
1007 it can update its own config files.
1010 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
1011 a LAN) or aren't entirely in control of your own browser, you will probably want
1012 to make sure that the web-based editor and remote toggle features are
1013 <quote>off</quote> by setting <quote><literal><ulink
1014 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
1015 0</literal></quote> and <quote><literal><ulink
1016 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
1017 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
1020 As of &my-app; 3.0.7 these options are disabled by default.
1025 <sect2 renderas="sect3" id="filterfile">
1026 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
1028 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
1029 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1030 Filters are a special subset of actions that can be used to modify or
1031 remove web page content or headers on the fly. Content filters can
1032 be applied to <emphasis>anything</emphasis> in the page source,
1033 header filters can be applied to either server or client headers.
1034 Regular expressions are used to accomplish this.
1037 There are a number of pre-defined filters to deal with common annoyances. The
1038 filters are only defined here, to invoke them, you need to use the
1040 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1041 action</ulink> in one of the actions files. Content filtering is automatically
1042 disabled for inappropriate MIME types, but if you know better than Privoxy
1043 what should or should not be filtered you can filter any content you like.
1047 <emphasis>not</emphasis> be confused with <ulink
1048 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1049 is a completely different action, and is more typically used to block ads and
1054 If you are familiar with regular expressions, and HTML, you can look at
1055 the provided <filename>default.filter</filename> with a text editor and define
1056 your own filters. This is potentially a very powerful feature, but
1057 requires some expertise in both regular expressions and HTML/HTTP.
1058 <![%p-newstuff;[ You should
1059 place any modifications to the default filters, or any new ones you create
1060 in a separate file, such as <filename>user.filter</filename>, so they won't
1061 be overwritten during upgrades.
1062 The ability to define multiple filter files
1063 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1067 There is no GUI editor option for this part of the configuration,
1068 but you can disable/enable the various pre-defined filters of the included
1069 <filename>default.filter</filename> file with the <ulink
1070 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1071 Note that the custom actions editor must be explicitly enabled in
1072 the main config file (see <ulink
1073 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1077 If you intend to develop your own filters, you might want to have a look at
1079 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1084 <sect2 renderas="sect3" id="lanconfig">
1085 <title>How can I set up Privoxy to act as a proxy for my
1088 By default, <application>Privoxy</application> only responds to requests
1089 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1090 a network, this needs to be changed in the <ulink
1091 url="../user-manual/config.html">main configuration file</ulink>. Look for
1093 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1094 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1095 it is uncommented, and assign it the address of the LAN gateway interface,
1096 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1097 wish to run <application>Privoxy</application> on port 8118, this line
1102 listen-address 192.168.1.1:8118</screen>
1105 Save the file, and restart <application>Privoxy</application>. Configure
1106 all browsers on the network then to use this address and port number.
1110 Alternately, you can have <application>Privoxy</application> listen on
1111 all available interfaces:
1115 listen-address :8118</screen>
1118 And then use <application>Privoxy's</application>
1120 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1121 feature to limit connections. A firewall in this situation is recommended
1126 The above steps should be the same for any TCP network, regardless of
1131 If you run <application>Privoxy</application> on a LAN with untrusted users,
1132 we recommend that you double-check the <ulink
1133 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1140 <sect2 renderas="sect3" id="noseeum">
1141 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1143 The replacement for blocked images can be controlled with the <ulink
1144 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1145 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1146 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1147 Note that this choice only has effect for images which are blocked as images, i.e.
1148 whose URLs match both a <literal><ulink
1149 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1150 <emphasis>and</emphasis> <literal><ulink
1151 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1154 If you want to see nothing, then change the <ulink
1155 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1156 action</ulink> to <quote>blank</quote>. This can be done by editing the
1157 <filename>user.action</filename> file, or through the <ulink
1158 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1163 <sect2 renderas="sect3" id="whyseeum">
1164 <title>Why would anybody want to see a checkerboard pattern?</title>
1166 Remember that <link linkend="whatsanad">telling which image is an ad and which
1167 isn't</link>, is an educated guess. While we hope that the standard configuration
1168 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1169 decent, and it shows you where images have been blocked, which can be very
1170 helpful in case some navigation aid or otherwise innocent image was
1171 erroneously blocked. It is recommended for new users so they can
1172 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1173 many banners they <emphasis>don't</emphasis> have to see.
1178 <sect2 renderas="sect3" id="blockedbytext">
1179 <title>I see some images being replaced with text
1180 instead of the checkerboard image. Why and how do I get rid of this?</title>
1182 This happens when the banners are not embedded in the HTML code of the
1183 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1184 or (i)layers, and these external HTML documents are blocked. Being non-images
1185 they get replaced by a substitute HTML page rather than a substitute image,
1186 which wouldn't work out technically, since the browser expects and accepts
1187 only HTML when it has requested an HTML document.
1190 The substitute page adapts to the available space and shows itself as a
1191 miniature two-liner if loaded into small frames, or full-blown with a
1192 large red "BLOCKED" banner if space allows.
1195 If you prefer the banners to be blocked by images, you must see to it that
1196 the HTML documents in which they are embedded are not blocked. Clicking
1197 the <quote>See why</quote> link offered in the substitute page will show
1198 you which rule blocked the page. After changing the rule and un-blocking
1199 the HTML documents, the browser will try to load the actual banner images
1200 and the usual image blocking will (hopefully!) kick in.
1205 <sect2 renderas="sect3" id="srvany">
1206 <title>Can Privoxy run as a service
1207 on Win2K/NT/XP?</title>
1210 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1211 functionality. See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1212 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1213 <application>Privoxy</application> as a service.
1216 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1217 See the discussion at <ulink
1218 url="https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</ulink>,
1219 for details, and a sample configuration.
1224 <sect2 renderas="sect3" id="otherproxy">
1225 <title>How can I make Privoxy work with other proxies?</title>
1227 This can be done and is often useful to combine the benefits of
1228 <application>Privoxy</application> with those of a another proxy,
1229 for example to cache content.
1231 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1232 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1233 describes how to do this. If you intend to use Privoxy with Tor,
1234 please also have a look at
1235 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1239 <sect2 renderas="sect3" id="port-80">
1240 <title>Can I just set Privoxy to use port 80
1241 and thus avoid individual browser configuration?</title>
1244 No, its more complicated than that. This only works with special kinds
1245 of proxies known as <quote>intercepting</quote> proxies
1246 (<link linkend="INTERCEPTING">see below</link>).
1251 <sect2 renderas="sect3" id="transparent">
1252 <title>Can Privoxy run as a <quote>transparent
1253 </quote> proxy?</title>
1255 The whole idea of Privoxy is to modify client requests
1256 and server responses in all sorts of ways and therefore
1257 it's not a transparent proxy as described in
1258 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1261 However, some people say <quote>transparent proxy</quote> when they
1262 mean <quote>intercepting proxy</quote>. If you are one of them,
1263 please read the <link linkend="INTERCEPTING">next entry</link>.
1268 <sect2 renderas="sect3" id="intercepting">
1269 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1271 <application>Privoxy</application> can't intercept traffic itself,
1272 but it can handle requests that where intercepted and redirected
1273 with a packet filter (like <application>PF</application> or
1274 <application>iptables</application>), as long as the <literal>Host</literal>
1278 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1279 web sites rely on it anyway, this limitation shouldn't be a problem.
1282 Please refer to your packet filter's documentation to learn how to
1283 intercept and redirect traffic into <application>Privoxy</application>.
1284 Afterward you just have to configure <application>Privoxy</application> to
1285 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1286 intercepted requests</ulink>.
1291 <sect2 renderas="sect3" id="outlook">
1292 <title>How can I configure Privoxy for use with Outlook?</title>
1294 Versions of <application>Outlook</application> prior to Office 2007, use
1295 <application>Internet Explorer</application> components to both render HTML,
1296 and fetch any HTTP requests that may be embedded in an HTML email. So however
1297 you have <application>Privoxy</application> configured to work with IE, this
1298 configuration should automatically be shared, at least with older version of
1302 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1303 engine with Outlook. It is unknown whether this can be configured to use a
1305 <!-- FIXME HB 2009-02-15 -->
1309 <sect2 renderas="sect3" id="outlook-more">
1310 <title>How can I have separate rules just for HTML mail?</title>
1312 The short answer is, you can't. <application>Privoxy</application> has no way
1313 of knowing which particular application makes a request, so there is no way to
1314 distinguish between web pages and HTML mail.
1315 <application>Privoxy</application> just blindly proxies all requests. In the
1316 case of <application>Outlook Express</application> (see above), OE uses
1317 IE anyway, and there is no way for <application>Privoxy</application> to ever
1318 be able to distinguish between them (nor could any other proxy type application for
1322 For a good discussion of some of the issues involved (including privacy and
1323 security issues), see
1324 <ulink url="https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1328 <sect2 renderas="sect3" id="sneaky-cookies">
1329 <title>I sometimes notice cookies sneaking through. How?</title>
1332 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1333 set in several ways. The classic method is via the
1334 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1335 easy one to manipulate, such as the &my-app; concept of
1336 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1337 There is also the possibility of using
1338 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1339 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1340 is trickier because the syntax can vary widely, and thus requires a certain
1341 amount of guesswork. It is not realistic to catch all of these short of
1342 disabling Javascript, which would break many sites. And lastly, if the
1343 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1344 <application>Privoxy's</application> reach unless you enable
1345 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1348 All in all, &my-app; can help manage cookies in general, can help minimize
1349 the loss of privacy posed by cookies, but can't realistically stop all
1354 <sect2 renderas="sect3" id="evil-cookies">
1355 <title>Are all cookies bad? Why?</title>
1357 No, in fact there are many beneficial uses of
1359 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1360 method that browsers can use to store data between pages, or between browser
1361 sessions. Sometimes there is a good reason for this, and the user's life is a
1362 bit easier as a result. But there is a long history of some websites taking
1363 advantage of this layer of trust, and using the data they glean from you and
1364 your browsing habits for their own purposes, and maybe to your potential
1365 detriment. Such sites are using you and storing their data on your system.
1366 That is why the privacy conscious watch from whom those cookies come, and why
1367 they really <emphasis>need</emphasis> to be there.
1371 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1372 definition</ulink> for more.
1376 <sect2 renderas="sect3" id="allow-cookies">
1377 <title>How can I allow permanent cookies for my trusted sites?</title>
1380 There are several actions that relate to cookies. The default behavior is to
1381 allow only <quote>session cookies</quote>, which means the cookies only last
1382 for the current browser session. This eliminates most kinds of abuse related
1383 to cookies. But there may be cases where you want cookies to last.
1386 To disable all cookie actions, so that cookies are allowed unrestricted,
1387 both in and out, for <literal>example.com</literal>:
1390 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1391 .example.com</screen>
1393 Place the above in <filename>user.action</filename>. Note that some of these may
1394 be off by default anyway, so this might be redundant, but there is no harm
1395 being explicit in what you want to happen. <filename>user.action</filename>
1396 includes an alias for this situation, called
1397 <literal>allow-all-cookies</literal>.
1401 <sect2 renderas="sect3" id="multiples">
1402 <title>Can I have separate configurations for different users?</title>
1404 Each instance of <application>Privoxy</application> has its own
1405 configuration, including such attributes as the TCP port that it listens on.
1406 What you can do is run multiple instances of <application>Privoxy</application>, each with
1408 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1409 configuration setting, and configuration path, and then
1410 each of these can have their own configurations. Think of it as per-port
1414 Simple enough for a few users, but for large installations, consider having
1415 groups of users that might share like configurations.
1419 <sect2 renderas="sect3" id="whitelists">
1420 <title>Can I set-up Privoxy as a whitelist of
1421 <quote>good</quote> sites?</title>
1423 Sure. There are a couple of things you can do for simple white-listing.
1424 Here's one real easy one:
1427 ############################################################
1429 ############################################################
1430 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1431 / # Block *all* URLs
1433 ############################################################
1435 ############################################################
1436 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1439 games.example.com</screen>
1441 This allows access to only those three sites by first blocking all URLs, and
1442 then subsequently allowing three specific exceptions.
1445 Another approach is <application>Privoxy's</application>
1446 <literal>trustfile</literal> concept, which incorporates the notion of
1447 <quote>trusted referrers</quote>. See the <ulink
1448 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1452 These are fairly simple approaches and are not completely foolproof. There
1453 are various other configuration options that should be disabled (described
1454 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1455 so that users can't modify their own configuration and easily circumvent the
1460 <sect2 renderas="sect3" id="no-adblock">
1461 <title>How can I turn off ad-blocking?</title>
1463 Ad blocking is achieved through a complex application of various &my-app;
1464 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1465 actions are deployed against simple images, banners, flash animations,
1466 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1467 just turning one or two actions off. The various actions that make up
1468 &my-app; ad blocking are hard-coded into the default configuration files. It
1469 has been assumed that everyone using &my-app; is interested in this
1473 If you want to do without this, there are several approaches you can take:
1474 You can manually undo the many block rules in
1475 <filename>default.action</filename>. Or even easier, just create your own
1476 <filename>default.action</filename> file from scratch without the many ad
1477 blocking rules, and corresponding exceptions. Or lastly, if you are not
1478 concerned about the additional blocks that are done for privacy reasons, you
1479 can very easily over-ride <emphasis>all</emphasis> blocking with the
1480 following very simple rule in your <filename>user.action</filename>:
1483 # Unblock everybody, everywhere
1484 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1485 / # UN-Block *all* URLs</screen>
1487 Or even a more comprehensive reversing of various ad related actions:
1490 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1491 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1492 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1493 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1494 <literal>allow-popups</literal> \
1496 / # UN-Block *all* URLs and allow ads</screen>
1498 This last <quote>action</quote> in this compound statement,
1499 <literal>allow-popups</literal>, is an <ulink
1500 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1501 various pop-up blocking features.
1505 <sect2 renderas="sect3" id="templates">
1506 <title>How can I have custom template pages, like the
1507 <emphasis>BLOCKED</emphasis> page?</title>
1509 &my-app; <quote>templates</quote> are specialized text files utilized by
1510 &my-app; for various purposes and can easily be modified using any text
1511 editor. All the template pages are installed in a sub-directory appropriately
1512 named: <filename>templates</filename>. Knowing something about HTML syntax
1513 will of course be helpful.
1516 Be forewarned that the default templates are subject to being overwritten
1517 during upgrades. You can, however, create completely new templates,
1518 place them in another directory and specify the alternate path in the main
1519 <filename>config</filename>. For details, have a look at the <ulink
1520 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1524 <sect2 renderas="sect3" id="blockall">
1525 <title>How can I remove the <quote>Go There Anyway</quote> link from
1526 the <emphasis>BLOCKED</emphasis> page?</title>
1528 There is more than one way to do it (although Perl is not involved).
1531 Editing the BLOCKED template page (see above) may dissuade some users, but
1532 this method is easily circumvented. Where you need this level of control, you
1533 might want to build &my-app; from source, and disable various features that are
1534 available as compile-time options. You should
1535 <command>configure</command> the sources as follows:
1538 ./configure --disable-toggle --disable-editor --disable-force</screen>
1540 This will create an executable with hard-coded security features so that
1541 &my-app; does not allow easy bypassing of blocked sites, or changing the
1542 current configuration via any connected user's web browser.
1545 Finally, all of these features can also be toggled on/off via options in
1546 <application>Privoxy's</application> main <ulink
1547 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1548 means you don't have to recompile anything.
1554 <!-- ~ End section ~ -->
1557 <!-- ~~~~~ New section ~~~~~ -->
1559 <sect1 id="misc"><title>Miscellaneous</title>
1561 <sect2 renderas="sect3" id="slowsme">
1562 <title>How much does Privoxy slow my browsing down? This
1563 has to add extra time to browsing.</title>
1565 How much of an impact depends on many things, including the CPU of the host
1566 system, how aggressive the configuration is, which specific actions are being triggered,
1567 the size of the page, the bandwidth of the connection, etc.
1570 Overall, it should not slow you down any in real terms, and may actually help
1571 speed things up since ads, banners and other junk are not typically being
1572 retrieved and displayed. The actual processing time required by
1573 <application>Privoxy</application> itself for each page, is relatively small
1574 in the overall scheme of things, and happens very quickly. This is typically
1575 more than offset by time saved not downloading and rendering ad images and
1576 other junk content (if ad blocking is being used).
1580 <quote>Filtering</quote> content via the <literal><ulink
1581 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1583 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1584 actions may cause a perceived slowdown, since the entire document
1585 needs to be buffered before displaying. And on very large documents,
1586 filtering may have some measurable impact. How much depends on the page size,
1587 the actual definition of the filter(s), etc. See below. Most other actions
1588 have little to no impact on speed.
1591 Also, when filtering is enabled but zlib support isn't available, compression
1592 is often disabled (see <ulink
1593 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1594 This can have an impact on speed as well, although it's probably smaller than
1595 you might think. Again, the page size, etc. will determine how much of an impact.
1601 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1602 delays in page requests. What's wrong?</title>
1604 If you use any <literal><ulink
1605 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1606 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1607 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1608 action, the entire document must be loaded into memory in order for the filtering
1609 mechanism to work, and nothing is sent to the browser during this time.
1612 The loading time typically does not really change much in real numbers, but
1613 the feeling is different, because most browsers are able to start rendering
1614 incomplete content, giving the user a feeling of "it works". This effect is
1615 more noticeable on slower dialup connections. Extremely large documents
1616 may have some impact on the time to load the page where there is filtering
1617 being done. But overall, the difference should be very minimal. If there is a
1618 big impact, then probably some other situation is contributing (like
1619 anti-virus software).
1622 Filtering is automatically disabled for inappropriate MIME types. But note
1623 that if the web server mis-reports the MIME type, then content that should
1624 not be filtered, could be. <application>Privoxy</application> only knows how
1625 to differentiate filterable content because of the MIME type as reported by
1626 the server, or because of some configuration setting that enables/disables
1631 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1632 "http://p.p/"?</title>
1634 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1635 address of <application>Privoxy</application>'s built-in user interface, and
1636 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1639 Since <application>Privoxy</application> sits between your web browser and the Internet,
1640 it can simply intercept requests for these addresses and answer them with its built-in
1641 <quote>web server</quote>.
1644 This also makes for a good test for your browser configuration: If entering the
1645 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1646 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1647 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1648 your browser didn't use <application>Privoxy</application> for the request,
1649 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1650 web site at config.privoxy.org.
1653 Note that config.privoxy.org resolves to a public IP address.
1654 If you use config.privoxy.org as ping or traceroute target you will
1655 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1656 If you want to ping the system Privoxy runs on,
1657 you should use its IP address or local DNS name (if it has got one).
1663 out of date 09/02/06 HB
1664 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1666 No. The patterns for blocking now reside (among other things) in the <ulink
1667 url="../user-manual/actions-file.html">actions files</ulink>, which are
1668 actively maintained instead. See next question ...
1672 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1675 Please see the <link linkend="contact">Contact section</link> for
1676 various ways to interact with the developers.
1681 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1682 they be included in future updates?</title>
1684 Whether such submissions are eventually included in the
1685 <filename>default.action</filename> configuration file depends on how
1686 significant the issue is. We of course want to address any potential
1687 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1688 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1689 has a good chance of being a candidate. But at the other end of the spectrum
1690 are any number of smaller, low-profile sites such as for local clubs or
1691 schools. Since their reach and impact are much less, they are best handled by
1692 inclusion in the user's <filename>user.action</filename>, and thus would be
1693 unlikely to be included.
1699 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1702 Rest assured that it has been read and considered. Why it is not answered,
1703 could be for various reasons, including no one has a good answer for it, no
1704 one has had time to yet investigate it thoroughly, it has been reported
1705 numerous times already, or because not enough information was provided to help
1706 us help you. Your efforts are not wasted, and we do appreciate them.
1712 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1714 If you run both the browser and &my-app; locally, you cannot hide your IP
1715 address with <application>Privoxy</application> or ultimately any other
1716 software alone. The server needs to know your IP address so that it knows
1717 where to send the responses back.
1720 There are many publicly usable "anonymous" proxies out there, which
1721 provide a further level of indirection between you and the web server.
1724 However, these proxies are called "anonymous" because you don't need
1725 to authenticate, not because they would offer any real anonymity.
1726 Most of them will log your IP address and make it available to the
1727 authorities in case you violate the law of the country they run in. In fact
1728 you can't even rule out that some of them only exist to *collect* information
1729 on (those suspicious) people with a more than average preference for privacy.
1732 If you want to hide your IP address from most adversaries,
1733 you should consider chaining <application>Privoxy</application>
1734 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1735 The configuration details can be found in
1736 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1737 with <application>Tor</application> section</ulink>
1742 <sect2 renderas="sect3" id="anonforsure">
1743 <title>Can Privoxy guarantee I am anonymous?</title>
1745 No. Your chances of remaining anonymous are improved, but unless you
1746 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1747 or a similar proxy and know what you're doing when it comes to configuring
1748 the rest of your system, you should assume that everything you do
1749 on the Web can be traced back to you.
1752 <application>Privoxy</application> can remove various information about you,
1753 and allows <emphasis>you</emphasis> more freedom to decide which sites
1754 you can trust, and what details you want to reveal. But it neither
1755 hides your IP address, nor can it guarantee that the rest of the system
1756 behaves correctly. There are several possibilities how a web sites can find
1757 out who you are, even if you are using a strict <application>Privoxy</application>
1758 configuration and chained it with <application>Tor</application>.
1761 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1762 by an insecure browser configuration, therefore you should use a browser that can
1763 be configured to only execute code from trusted sites, and be careful which sites you trust.
1764 For example there is no point in having <application>Privoxy</application>
1765 modify the User-Agent header, if websites can get all the information they want
1766 through JavaScript, ActiveX, Flash, Java etc.
1769 A few browsers disclose the user's email address in certain situations, such
1770 as when transferring a file by FTP. <application>Privoxy</application>
1771 does not filter FTP. If you need this feature, or are concerned about the
1772 mail handler of your browser disclosing your email address, you might
1773 consider products such as <application>NSClean</application>.
1776 Browsers available only as binaries could use non-standard headers to give
1777 out any information they can have access to: see the manufacturer's license
1778 agreement. It's impossible to anticipate and prevent every breach of privacy
1779 that might occur. The professionally paranoid prefer browsers available as
1780 source code, because anticipating their behavior is easier. Trust the source,
1786 <sect2 renderas="sect3" id="proxytest">
1787 <title>A test site says I am not using a Proxy.</title>
1789 Good! Actually, they are probably testing for some other kinds of proxies.
1790 Hiding yourself completely would require additional steps.
1794 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1795 together with Tor?</title>
1797 Before you configure <application>Privoxy</application> to use
1798 <ulink url="https://www.torproject.org/">Tor</ulink>,
1799 please follow the <citetitle>User Manual</citetitle> chapters
1800 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1801 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1802 <application>Privoxy</application> itself is setup correctly.
1805 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1806 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1807 and make sure <application>Tor</application>'s logfile says that
1808 <quote>Tor has successfully opened a circuit</quote> and it
1809 <quote>looks like client functionality is working</quote>.
1812 If either <application>Tor</application> or <application>Privoxy</application>
1813 isn't working, their combination most likely will neither. Testing them on their
1814 own will also help you to direct problem reports to the right audience.
1815 If <application>Privoxy</application> isn't working, don't bother the
1816 <application>Tor</application> developers. If <application>Tor</application>
1817 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1820 If you verified that <application>Privoxy</application> and <application>Tor</application>
1821 are working, it is time to connect them. As far as <application>Privoxy</application>
1822 is concerned, <application>Tor</application> is just another proxy that can be reached
1823 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1824 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1825 requests are done through <application>Tor</application> and thus invisible to your
1826 local network. Using socks4a would work too, but with socks5 you get more precise error
1831 <application>Privoxy's</application>
1832 <ulink url="../user-manual/config.html">main configuration file</ulink>
1833 is already prepared for <application>Tor</application>, if you are using a
1834 default <application>Tor</application> configuration and run it on the same
1835 system as &my-app;, you just have to edit the
1836 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1837 and uncomment the line:
1840 # forward-socks5t / 127.0.0.1:9050 .
1843 Note that if you got Tor through one of the bundles, you may
1844 have to change the port from 9050 to 9150 (or even another one).
1845 For details, please check the documentation on the
1846 <ulink url="https://torproject.org/">Tor website</ulink>.
1850 This is enough to reach the Internet, but additionally you might want to
1851 uncomment the following forward rules, to make sure your local network is still
1852 reachable through Privoxy:
1855 # forward 192.168.*.*/ .
1856 # forward 10.*.*.*/ .
1857 # forward 127.*.*.*/ .
1860 Unencrypted connections to systems in these address ranges will
1861 be as (un)secure as the local network is, but the alternative is
1862 that your browser can't reach the network at all. Then again,
1863 that may actually be desired and if you don't know for sure
1864 that your browser has to be able to reach the local network,
1865 there's no reason to allow it.
1868 If you want your browser to be able to reach servers in your local
1869 network by using their names, you will need additional exceptions
1870 that look like this:
1873 # forward localhost/ .
1876 Save the modified configuration file and open
1877 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1878 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1879 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1881 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1882 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1885 Afterward, please take the time to at least skim through the rest
1886 of <application>Tor's</application> documentation. Make sure you understand
1887 what <application>Tor</application> does, why it is no replacement for
1888 application level security, and why you probably don't want to
1889 use it for unencrypted logins.
1893 <sect2 renderas="sect3" id="sitebreak">
1894 <title>Might some things break because header information or
1895 content is being altered?</title>
1898 Definitely. It is common for sites to use browser type, browser version,
1899 HTTP header content, and various other techniques in order to dynamically
1900 decide what to display and how to display it. What you see, and what I see,
1901 might be very different. There are many, many ways that this can be handled,
1902 so having hard and fast rules, is tricky.
1906 The <quote>User-Agent</quote> is sometimes used in this way to identify
1907 the browser, and adjust content accordingly.
1911 Also, different browsers use different encodings of non-English
1912 characters, certain web servers convert pages on-the-fly according to the
1913 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1914 operating system or browser manufacturer causes some sites in these languages
1915 to be garbled; Surfers to Eastern European sites should change it to
1916 something closer. And then some page access counters work by looking at the
1917 <quote>Referer</quote> header; they may fail or break if unavailable. The
1918 weather maps of Intellicast have been blocked by their server when no
1919 <quote>Referer</quote> or cookie is provided, is another example. (But you
1920 can forge both headers without giving information away). There are
1921 many other ways things can go wrong when trying to fool a web server. The
1922 results of which could inadvertently cause pages to load incorrectly,
1923 partially, or even not at all. And there may be no obvious clues as to just
1924 what went wrong, or why. Nowhere will there be a message that says
1925 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1930 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1935 If you have problems with a site, you will have to adjust your configuration
1936 accordingly. Cookies are probably the most likely adjustment that may
1937 be required, but by no means the only one.
1943 <sect2 renderas="sect3" id="caching">
1944 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1945 speed up web browsing?</title>
1947 No, it does not have this ability at all. You want something like
1948 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1949 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1950 And, yes, before you ask, <application>Privoxy</application> can co-exist
1951 with other kinds of proxies like <application>Squid</application>.
1952 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1953 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1954 manual</ulink> for details.
1958 <sect2 renderas="sect3" id="firewall">
1959 <title>What about as a firewall? Can Privoxy protect me?</title>
1961 Not in the way you mean, or in the way some firewall vendors claim they can.
1962 <application>Privoxy</application> can help protect your privacy, but can't
1963 protect your system from intrusion attempts. It is, of course, perfectly possible
1964 to use <emphasis>both</emphasis>.
1968 <sect2 renderas="sect3" id="wasted">
1969 <title>I have large empty spaces / a checkerboard pattern now where
1970 ads used to be. Why?</title>
1972 It is technically possible to eliminate banners and ads in a way that frees
1973 their allocated page space. This could easily be done by blocking with
1974 <application>Privoxy's</application> filters,
1975 and eliminating the <emphasis>entire</emphasis> image references from the
1979 But, this would consume considerably more CPU resources (IOW, slow things
1980 down), would likely destroy the layout of some web pages which rely on the
1981 banners utilizing a certain amount of page space, and might fail in other
1982 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1983 Also, making ads and banners disappear without any trace complicates
1984 troubleshooting, and would sooner or later be problematic.
1987 The better alternative is to instead let them stay, and block the resulting
1988 requests for the banners themselves as is now the case. This leaves either
1989 empty space, or the familiar checkerboard pattern.
1992 So the developers won't support this in the default configuration, but you
1993 can of course define appropriate filters yourself to achieve this.
1997 <sect2 renderas="sect3" id="ssl">
1998 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
2001 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
2002 <application>Privoxy</application> will impersonate the destination
2003 server and can thus filter encrypted requests and responses as well.
2007 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
2008 secure HTTP connections are encrypted SSL sessions between your
2009 browser and the secure site, and there is little
2010 that <application>Privoxy</application> can do but hand the raw
2011 gibberish data though from one end to the other unprocessed.
2014 The only exception to this is blocking by host patterns, as the client needs
2015 to tell <application>Privoxy</application> the name of the remote server,
2016 so that <application>Privoxy</application> can establish the connection.
2017 If that name matches a host-only pattern, the connection will be blocked.
2020 As far as ad blocking is concerned, this is less of a restriction than it may
2021 seem, since ad sources are often identifiable by the host name, and often
2022 the banners to be placed in an encrypted page come unencrypted nonetheless
2023 for efficiency reasons, which exposes them to the full power of
2024 <application>Privoxy</application>'s ad blocking.
2027 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
2028 JS page content, see <literal><ulink
2029 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2030 in an SSL transaction will be impossible to block under these conditions.
2031 Fortunately, this does not seem to be a very common scenario since most
2032 cookies come by traditional means.
2037 <sect2 renderas="sect3" id="http2">
2038 <title>Does Privoxy support HTTP/2?</title>
2040 Privoxy currently doesn't parse HTTP/2 but applications
2041 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2042 to allow CONNECT requests (default) which are also used
2046 Adding HTTP/2 support is on the
2047 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2048 list but currently nobody is known to work on it.
2052 <sect2 renderas="sect3" id="secure">
2053 <title>Privoxy runs as a <quote>server</quote>. How
2054 secure is it? Do I need to take any special precautions?</title>
2056 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2057 user, which is how we recommend it be run. Also, by default
2058 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2062 The server aspect of <application>Privoxy</application> is not itself directly
2063 exposed to the Internet in this configuration. If you want to have
2064 <application>Privoxy</application> serve as a LAN proxy, this will have to
2065 be opened up to allow for LAN requests. In this case, we'd recommend
2066 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2067 <application>Privoxy</application> configuration file and check all <ulink
2068 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2069 options</ulink>. All LAN hosts can then use this as their proxy address
2070 in the browser proxy configuration, but <application>Privoxy</application>
2071 will not listen on any external interfaces. ACLs can be defined in addition,
2072 and using a firewall is always good too. Better safe than sorry.
2077 <sect2 renderas="sect3" id="turnoff">
2078 <title>Can I temporarily disable Privoxy?</title>
2080 &my-app; doesn't have a transparent proxy mode,
2081 but you can toggle off blocking and content filtering.
2084 The easiest way to do that is to point your browser
2085 to the remote toggle URL: <ulink
2086 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2089 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2090 of the <citetitle>User Manual</citetitle> for an easy way to access this
2091 feature. Note that this is a feature that may need to be enabled in the main
2092 <filename>config</filename> file.
2097 <sect2 renderas="sect3" id="reallyoff">
2098 <title>When <quote>disabled</quote> is Privoxy totally
2099 out of the picture?</title>
2101 No, this just means all optional filtering and actions are disabled.
2102 <application>Privoxy</application> is still acting as a proxy, but just
2103 doing less of the things that <application>Privoxy</application> would
2104 normally be expected to do. It is still a <quote>middle-man</quote> in
2105 the interaction between your browser and web sites. See below to bypass
2110 <sect2 renderas="sect3" id="turnoff2">
2111 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2113 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2114 configuration issue, not a &my-app; issue. Modern browsers typically do have
2115 settings for not proxying certain sites. Check your browser's help files.
2120 <sect2 renderas="sect3" id="crunch">
2121 <title>My logs show Privoxy <quote>crunches</quote>
2122 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2124 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2125 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2126 banners, but <application>Privoxy</application> uses the same mechanism for
2127 trapping requests for its own internal pages. For instance, a request for
2128 <application>Privoxy's</application> configuration page at: <ulink
2129 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2130 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2131 configuration is returned to the browser, and the log consequently will show
2132 a <quote>crunch</quote>.
2135 Since version 3.0.7, Privoxy will also log the crunch reason.
2136 If you are using an older version you might want to upgrade.
2140 <sect2 renderas="sect3" id="downloads">
2141 <title>Can Privoxy affect files that I download
2142 from a webserver? FTP server?</title>
2144 From the webserver's perspective, there is no difference between
2145 viewing a document (i.e. a page), and downloading a file. The same is true of
2146 <application>Privoxy</application>. If there is a match for a <literal><ulink
2147 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2148 it will still be blocked, and of course this is obvious.
2151 Filtering is potentially more of a concern since the results are not always
2152 so obvious, and the effects of filtering are there whether the file is simply
2153 viewed, or downloaded. And potentially whether the content is some obnoxious
2154 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2155 one of these presumably is <quote>bad</quote> content that we don't want, and
2156 the other is <quote>good</quote> content that we do want.
2157 <application>Privoxy</application> is blind to the differences, and can only
2158 distinguish <quote>good from bad</quote> by the configuration parameters
2159 <emphasis>we</emphasis> give it.
2162 <application>Privoxy</application> knows the differences in files according
2163 to the <quote>Content Type</quote> as reported by the webserver. If this is
2164 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2165 then <application>Privoxy</application> knows to ignore these where
2166 appropriate. <application>Privoxy</application> potentially can filter HTML
2167 as well as plain text documents, subject to configuration parameters of
2168 course. Also, documents that are of an unknown type (generally assumed to be
2169 <quote>text/plain</quote>) can be filtered, as will those that might be
2170 incorrectly reported by the webserver. If such a file is a downloaded file
2171 that is intended to be saved to disk, then any content that might have been
2172 altered by filtering, will be saved too, for these (probably rare) cases.
2175 Note that versions later than 3.0.2 do NOT filter document types reported as
2176 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2177 did filter this document type.
2180 In short, filtering is <quote>ON</quote> if a) the content type as reported
2181 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2182 allows it (or at least does not disallow it). That's it. There is no magic
2183 cookie anywhere to say this is <quote>good</quote> and this is
2184 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2187 If you download text files, you probably do not want these to be filtered,
2188 particularly if the content is source code, or other critical content. Source
2189 code sometimes might be mistaken for Javascript (i.e. the kind that might
2190 open a pop-up window). It is recommended to turn off filtering for download
2191 sites (particularly if the content may be plain text files and you are using
2192 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2193 also, for any site or page where making <emphasis>any</emphasis> changes at
2194 all to the content is to be avoided.
2197 <application>Privoxy</application> does not do FTP at all, only HTTP
2198 and HTTPS (SSL) protocols.
2202 <sect2 renderas="sect3" id="downloads2">
2203 <title>I just downloaded a Perl script, and Privoxy
2204 altered it! Yikes, what is wrong!</title>
2210 <sect2 renderas="sect3" id="hostsfile">
2211 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2213 One time-tested technique to defeat common ads is to trick the local DNS
2214 system by giving a phony IP address for the ad generator in the local
2215 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2216 <literal>localhost</literal>. This effectively blocks the ad.
2219 There is no reason to use this technique in conjunction with
2220 <application>Privoxy</application>. <application>Privoxy</application>
2221 does essentially the same thing, much more elegantly and with much more
2222 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2223 duplicates effort, but may get in the way and seriously slow down your system.
2224 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2225 your hosts list is neglected by <application>Privoxy's </application>
2226 configuration, consider adding your list to your <filename>user.action</filename> file:
2232 ads.galore.example.com
2233 etc.example.com</screen>
2236 <sect2 renderas="sect3" id="seealso">
2237 <title>Where can I find more information about Privoxy
2238 and related issues?</title>
2239 <!-- Include seealso.sgml boilerplate: -->
2241 <!-- end boilerplate -->
2246 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2252 <sect2 renderas="sect3" id="microsuck">
2253 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2254 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2257 We're not. The text substitutions that you are seeing are disabled
2258 in the default configuration as shipped. You have either manually
2259 activated the <quote><literal>fun</literal></quote> filter which
2260 is clearly labeled <quote>Text replacements for subversive browsing
2261 fun!</quote> or you are using an older Privoxy version and have implicitly
2262 activated it by choosing the <quote>Advanced</quote> profile in the
2263 web-based editor. Please upgrade.
2267 <sect2 renderas="sect3" id="valid">
2268 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2271 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2272 whenever there are text substitutions via a &my-app; filter. While this
2273 should always conform to the HTML 4.01 specifications, it has not been
2274 validated against this or any other standard.
2278 <sect2 renderas="sect3" id="surprise-privoxy">
2279 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2282 We didn't. We make Privoxy available for download, but we don't go
2283 around installing it on other people's systems behind their back.
2284 If you discover Privoxy running on your system and are sure you didn't
2285 install it yourself, somebody else did. You may not even be running
2286 the real Privoxy, but maybe something else that only pretends to be
2287 Privoxy, or maybe something that is based on the real Privoxy,
2288 but has been modified.
2291 Lately there have been reports of problems with some kind of
2292 "parental control" software based on Privoxy that came preinstalled on
2293 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2294 The problems described are inconsistent with the behaviour of official
2295 Privoxy versions, which suggests that the preinstalled software may
2296 contain vendor modifications that we don't know about and thus can't debug.
2299 Privoxy's <link linkend="copyright">license</link> allows vendor
2300 modifications, but the vendor has to comply with the license,
2301 which involves informing the user about the changes and to make
2302 the changes available under the same license as Privoxy itself.
2305 If you are having trouble with a modified Privoxy version,
2306 please try to talk to whoever made the modifications before
2307 reporting the problem to us. Please also try to convince
2308 whoever made the modifications to talk to us. If you think
2309 somebody gave you a modified Privoxy version without complying
2310 to the license, please let us know.
2318 <!-- ~~~~~ New section ~~~~~ -->
2320 <sect1 id="trouble">
2321 <title>Troubleshooting</title>
2323 <sect2 renderas="sect3" id="refused">
2324 <title>I cannot connect to any websites. Or, I am getting
2325 <quote>connection refused</quote> message with every web page. Why?</title>
2327 There are several possibilities:
2331 <application>Privoxy</application> is not running. Solution: verify
2332 that &my-app; is installed correctly, has not crashed, and is indeed running.
2333 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2335 <listitem><para>Or your browser is configured for a different port than what
2336 <application>Privoxy</application> is using. Solution: verify that &my-app;
2337 and your browser are set to the same port (<literal>listen-address</literal>).
2339 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2340 problem with a host in the forwarding chain. Solution: temporarily alter your
2341 configuration and take the forwarders out of the equation.
2344 Or you have a firewall that is interfering and blocking you. Solution:
2345 try disabling or removing the firewall as a simple test.
2351 <!-- ~~~~~ New section ~~~~~ -->
2352 <sect2 renderas="sect3" id="error503">
2353 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2355 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2356 been reported to cause this symptom -- even if not running! The solution is
2357 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2358 something better behaved in its place. Other personal firewall type products
2359 may cause similar type problems if not configured correctly.
2363 <sect2 renderas="sect3" id="flushit">
2364 <title>I just added a new rule, but the steenkin ad is
2365 still getting through. How?</title>
2367 If the ad had been displayed before you added its URL, it will probably be
2368 held in the browser's cache for some time, so it will be displayed without
2369 the need for any request to the server, and <application>Privoxy</application>
2370 will not be involved. Flush the browser's caches, and then try again.
2374 If this doesn't help, you probably have an error in the rule you
2375 applied. Try pasting the full URL of the offending ad into <ulink
2376 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2377 and see if it really matches your new rule. Blocking ads is like blocking
2378 spam: a lot of tinkering is required to stay ahead of the game. And
2379 remember you need to block the URL of the ad in question, which may be
2380 entirely different from the site URL itself. Most ads are hosted on different
2381 servers than the main site itself. If you right-click on the ad, you should
2382 be able to get all the relevant information you need. Alternately, you can
2383 find the correct URL by looking at <application>Privoxy's</application> logs
2384 (you may need to enable logging in the main config file if its disabled).
2387 Below is a slightly modified real-life log snippet that originates with one
2388 requested URL: <literal>www.example.com</literal> (name of site was changed
2389 for this example, the number of requests is real). You can see in this the
2390 complexity of what goes into making up this one <quote>page</quote>. There
2391 are eight different domains involved here, with thirty two separate URLs
2392 requested in all, making up all manner of images, Shockwave Flash,
2393 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2394 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2395 Many of the more questionable looking requests, are going to outside domains
2396 that seem to be identifying themselves with suspicious looking names, making
2397 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2398 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2402 Request: www.example.com/
2403 Request: www.example.com/favicon.ico
2404 Request: img.example.com/main.css
2405 Request: img.example.com/sr.js
2406 Request: example.betamarker.com/example.html
2407 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2408 Request: img.example.com/pb.png
2409 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2410 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2411 Request: img.example.com/p.gif
2412 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2413 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2414 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2415 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2416 Request: www.adtrak.net/adx.js crunch! (Blocked)
2417 Request: img.example.com/hbg.gif
2418 Request: img.example.com/example.jpg
2419 Request: img.example.com/mt.png
2420 Request: img.example.com/mm.png
2421 Request: img.example.com/mb.png
2422 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2423 Request: www.example.com/tracker.js
2424 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2425 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2426 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2427 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2428 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2429 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2430 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2431 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2432 Request: 66.70.21.80/img/pixel.gif
2433 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2434 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2438 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2439 behave perfectly <quote>normal</quote> (minus some ads, of course).
2444 <sect2 renderas="sect3" id="badsite">
2445 <title>One of my favorite sites does not work with Privoxy.
2446 What can I do?</title>
2449 First verify that it is indeed a <application>Privoxy</application> problem,
2450 by toggling off <application>Privoxy</application> through <ulink
2451 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2452 (the toggle feature may need to be enabled in the main
2453 <filename>config</filename>),
2454 and then shift-reloading the problem page (i.e. holding down the shift key
2455 while clicking reload. Alternatively, flush your browser's disk and memory
2460 If the problem went away, we know we have a configuration related problem.
2462 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2463 and paste the full URL of the page in question into the prompt. See which
2464 actions are being applied to the URL, and which matches in which actions
2465 files are responsible for that. It might be helpful also to look at your logs
2466 for this site too, to see what else might be happening (note: logging may need
2467 to be enabled in the main config file). Many sites are
2468 complex and require a number of related pages to help present their content.
2469 Look at what else might be used by the page in question, and what of that
2470 might be <emphasis>required</emphasis>.
2471 Now, armed with this information, go to
2473 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2474 and select the appropriate actions files for editing. </para>
2476 You can now either look for a section which disables the actions that
2477 you suspect to cause the problem and add a pattern for your site there,
2478 or make up a completely new section for your site. In any case, the recommended
2479 way is to disable only the prime suspect, reload the problem page, and only
2480 if the problem persists, disable more and more actions until you have
2481 identified the culprit. You may or may not want to turn the other actions
2482 on again. Remember to flush your browser's caches in between any such changes!
2485 Alternately, if you are comfortable with a text editor, you can accomplish
2486 the same thing by editing the appropriate actions file. Probably the easiest
2487 way to deal with such problems when editing by hand is to add your
2488 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2489 which is an alias that turns off most <quote>dangerous</quote>
2490 actions, but is also likely to turn off more actions then needed, and thus lower
2491 your privacy and protection more than necessary,
2494 Troubleshooting actions is discussed in more detail in the <ulink
2495 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2496 Troubleshooting: the Anatomy of an Action</ulink>.
2497 There is also an <ulink
2498 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2499 with general configuration information and examples.
2502 As a last resort, you can always see if your browser has a setting that will
2503 bypass the proxy setting for selective sites. Modern browsers can do this.
2509 <!-- ~~~~~ New section ~~~~~ -->
2510 <sect2 id="dun" renderas="sect3">
2511 <title>After installing Privoxy, I have to log in
2512 every time I start IE. What gives?</title>
2515 This is a quirk that affects the installation of
2516 <application>Privoxy</application>, in conjunction with Internet Explorer and
2517 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2518 appear to be corrupted or invalid DUN settings, or passwords.
2522 When setting up an NT based Windows system with
2523 <application>Privoxy</application> you may find that things do not seem to be
2524 doing what you expect. When you set your system up you will probably have set
2525 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2526 logged in with administrator privileges. You will probably have made this DUN
2527 connection available to other accounts that you may have set-up on your
2528 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2529 configured for the kids.
2533 When setting up <application>Privoxy</application> in this environment you
2534 will have to alter the proxy set-up of Internet Explorer (IE) for the
2535 specific DUN connection on which you wish to use
2536 <application>Privoxy</application>. When you do this the ICS DUN set-up
2537 becomes user specific. In this instance you will see no difference if you
2538 change the DUN connection under the account used to set-up the connection.
2539 However when you do this from another user you will notice that the DUN
2540 connection changes to make available to "Me only". You will also find that
2541 you have to store the password under each different user!
2545 The reason for this is that each user's set-up for IE is user specific. Each
2546 set-up DUN connection and each LAN connection in IE store the settings for
2547 each user individually. As such this enforces individual configurations
2548 rather than common ones. Hence the first time you use a DUN connection after
2549 re-booting your system it may not perform as you expect, and prompt you for
2550 the password. Just set and save the password again and all should be OK.
2554 [Thanks to Ray Griffith for this submission.]
2559 <!-- ~~~~~ New section ~~~~~ -->
2560 <sect2 id="ftp" renderas="sect3">
2561 <title>I cannot connect to any FTP sites. Privoxy
2562 is blocking me.</title>
2564 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2565 so do not configure your browser to use <application>Privoxy</application>
2566 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2567 or HTTPS (SSL)</emphasis>.
2570 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2571 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2572 an FTP connection, and not a HTTP connection. So while your browser may
2573 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2577 To complicate matters, some systems may have a generic <quote>proxy</quote>
2578 setting, which will enable various protocols, including
2579 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2580 accidentally enable FTP proxying in these cases. And of course, if this
2581 happens, <application>Privoxy</application> will indeed cause problems since
2582 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2583 message if a FTP connection is attempted.]]> Just disable the FTP setting
2584 and all will be well again.
2587 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2588 There just is not much reason, and the work to make this happen is more than
2593 <!-- ~~~~~ New section ~~~~~ -->
2594 <sect2 id="macosxie" renderas="sect3">
2595 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2596 Privoxy as the HTTP proxy.</title>
2598 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2599 network settings. In order to change the HTTP proxy, open System
2600 Preferences, and click on the Network icon. In the settings pane that
2601 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2602 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2603 Enter <literal>8118</literal> in the Port field. The next time you start
2604 IE, it should reflect these values.
2608 <!-- ~~~~~ New section ~~~~~ -->
2609 <sect2 renderas="sect3" id="macosxuninstall">
2610 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2611 uninstall it. Now the finder tells me I don't have sufficient privileges to
2612 empty the trash.</title>
2614 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2617 Just dragging the <application>Privoxy</application> folder to the trash is
2618 not enough to delete it. <application>Privoxy</application> supplies an
2619 <application>uninstall.command</application> file that takes care of
2620 these details. Open the trash, drag the <application>uninstall.command</application>
2621 file out of the trash and double-click on it. You will be prompted for
2622 confirmation and the administration password.
2625 The trash may still appear full after this command; emptying the trash
2626 from the desktop should make it appear empty again.
2630 <!-- ~~~~~ New section ~~~~~ -->
2631 <sect2 renderas="sect3" id="macosximages">
2632 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2633 experience random delays in page loading. I'm using
2634 <literal>localhost</literal> as my browser's proxy setting.</title>
2636 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2637 understand the issue yet. In any case, changing the proxy setting to
2638 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2639 works around the problem.
2643 <!-- ~~~~~ New section ~~~~~ -->
2644 <sect2 renderas="sect3" id="macosxaccountdeletion">
2645 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2648 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2649 X deletes all user accounts that are either not part of OS X itself or are
2650 not interactive user accounts (ones you log in with). Since, for the sake of
2651 security, &my-app; runs as a non-privileged user that is created by its
2652 installer (_privoxy), it can no longer start up once that account gets deleted.
2653 The solution is to perform a complete uninstall using the supplied
2654 <application>uninstall.command</application> script (either back up your
2655 configuration files or select to not have the uninstaller remove them when it
2656 prompts you) and then reinstall &my-app; using the installer package and merge
2657 in your configuration.
2661 <sect2 renderas="sect3" id="nohostname">
2662 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2665 <application>Privoxy</application> tries to get the hostname of the system
2666 its running on from the IP address of the system interface it is bound to
2667 (from the <filename>config</filename> file
2668 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2669 this information, <application>Privoxy</application> logs this condition.
2672 Typically, this would be considered a minor system configuration error. It is
2673 not a fatal error to <application>Privoxy</application> however, but may
2674 result in a much slower response from <application>Privoxy</application> on
2675 some platforms due to DNS timeouts.
2678 This can be caused by a problem with the local <filename>hosts</filename>
2679 file. If this file has been changed from the original, try reverting it to
2680 see if that helps. Make sure whatever name(s) are used for the local system,
2681 that they resolve both ways.
2684 You should also be able to work around the problem with the
2685 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2689 <sect2 renderas="sect3" id="inuse">
2690 <title>When I try to launch Privoxy, I get an
2691 error message <quote>port 8118 is already in use</quote> (or similar wording).
2694 Port 8118 is <application>Privoxy's</application> default TCP
2695 <quote>listening</quote> port. Typically this message would mean that there
2696 is already one instance of <application>Privoxy</application> running, and
2697 your system is actually trying to start a second
2698 <application>Privoxy</application> on the same port, which will not work.
2699 (You can have multiple instances but they must be assigned different ports.)
2700 How and why this might happen varies from platform to platform, but you need
2701 to check your installation and start-up procedures.
2705 <sect2 renderas="sect3" id="demoronizer">
2707 Pages with UTF-8 fonts are garbled.
2710 This may be the result of an overly aggressive filter. The filters that
2711 are enabled in the default configuration aren't expected to cause problems
2712 like this. If you enabled the <quote>demoronizer</quote> filter, please
2713 try temporarily disabling it.
2716 If that doesn't help, temporarily disable all filters to see if another
2717 filter could be the culprit. If the problem disappears, enable the filters
2718 one by one, until the problem reappears and the offending filter is found.
2721 Once the problem-causing filter is known, it can be fixed or disabled.
2724 Upgrading <application>Privoxy</application>, or going to the most recent
2725 <filename>default.action</filename> file available from <ulink
2726 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2727 might be worth a try, too.
2731 <sect2 renderas="sect3" id="demoronizer2">
2733 Why are binary files (such as images) corrupted when Privoxy
2737 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2738 filter</link> in conjunction with a web server that is misreporting the content
2739 type. By default binary files are exempted from
2740 <application>Privoxy's</application> filtering
2741 (unless the web server by mistake says the file is something else).
2745 <sect2 renderas="sect3" id="demoronizer3">
2747 What is the <quote>demoronizer</quote> and why is it there?
2750 The original demoronizer was a Perl script that cleaned up HTML pages which
2751 were created with certain Microsoft products. MS has used proprietary extensions
2752 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2753 that are viewed with non-Microsoft products (and are expecting to see a
2754 standard set of fonts). The demoronizer corrected these errors so the pages
2755 displayed correctly. <application>Privoxy</application> borrowed from this
2756 script, introducing a filter based on the original demoronizer, which in turn could
2757 correct these errors on the fly.
2760 But this is only needed in some situations, and will cause serious problems in some
2764 If you are using Microsoft products, you do not need it. If you need to view
2765 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2766 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2769 On the other hand, if you use non-Microsoft products, and you occasionally
2770 notice weird characters on pages, you might want to try it.
2774 <sect2 renderas="sect3" id="windowopen">
2776 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2779 <application>Privoxy</application> is attempting to disable malicious
2780 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2781 in this case, with the <literal>unsolicited-popups</literal>
2782 filter. <application>Privoxy</application> cannot tell very well
2783 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2786 If you see this in HTML source, and the page displays without problems, then
2787 this is good, and likely some pop-up window was disabled. If you see this
2788 where it is causing a problem, such as a downloaded program source code file,
2789 then you should set an exception for this site or page such that the
2790 integrity of the page stays in tact by disabling all filtering.
2794 <sect2 renderas="sect3" id="dnserrors">
2796 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2797 can't Privoxy do this better?
2800 There are potentially several factors here. First of all, the DNS resolution
2801 is done by the underlying operating system -- not
2802 <application>Privoxy</application> itself. <application>Privoxy</application>
2803 merely initiates the process and hands it off, and then later reports
2804 whatever the outcome was and tries to give a coherent message if there seems
2805 to be a problem. In some cases, this might otherwise be mitigated by the
2806 browser itself which might try some work-arounds and alternate approaches (e.g
2807 adding <quote>www.</quote> to the URL).
2810 In other cases, if <application>Privoxy</application> is being chained
2811 with another proxy, this could complicate the issue, and cause undue
2812 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2813 server handles all the DNS. <application>Privoxy</application> would just be
2814 the <quote>messenger</quote> which is reporting whatever problem occurred
2815 downstream, and not the root cause of the error.
2819 In any case, versions newer than 3.0.3 include various improvements to help
2820 <application>Privoxy</application> better handle these cases.
2824 <sect2 renderas="sect3" id="allcpu">
2826 At one site Privoxy just hangs, and starts taking
2827 all CPU. Why is this?
2830 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2831 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2832 are in the raw HTML source of the page, and the browser just ignores them. But the
2833 pattern matching in <application>Privoxy's</application> page filtering
2834 mechanism is trying to match against absurdly long strings and this becomes
2835 very CPU-intensive, taking a long, long time to complete.
2838 Until a better solution comes along, disable filtering on these pages,
2839 particularly the <literal>js-annoyances</literal> and
2840 <literal>unsolicited-popups</literal> filters. If you run into this problem
2841 with a recent &my-app; version, please send a problem report.
2845 <sect2 renderas="sect3" id="slowcrawl">
2846 <title>I just installed Privoxy, and all my
2847 browsing has slowed to a crawl. What gives? </title>
2849 This should not happen, and for the overwhelming number of users world-wide,
2850 it does not happen. I would suspect some inadvertent interaction of software
2851 components such as anti-virus software, spyware protectors, personal
2852 firewalls or similar components. Try disabling (or uninstalling) these one
2853 at a time and see if that helps. Either way, if you are using a
2854 recent &my-app; version, please report the problem.
2858 <sect2 renderas="sect3" id="preventcomp">
2859 <title>Why do my filters work on some sites but not on others? </title>
2861 It's probably due to compression. It is a common practice for web servers to
2862 send their content <quote>compressed</quote> in order to speed things up, and
2863 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2864 &my-app; can decompress content before filtering, otherwise you may want to enable
2866 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2869 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2874 <sect2 renderas="sect3" id="ssl-warnings">
2875 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2876 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2877 What's going on?</title>
2879 Probably the browser is requesting ads through HTTPS and &my-app;
2880 is blocking the requests. Privoxy's error messages are delivered
2881 unencrypted and while it's obvious for the browser that the HTTPS
2882 request is already blocked by the proxy, some warn about unauthenticated
2886 To work around the problem you can redirect those requests to an invalid
2887 local address instead of blocking them. While the redirects aren't
2888 encrypted either, many browsers don't care. They simply follow the
2889 redirect, fail to reach a server and display an error message instead
2893 To do that, enable logging to figure out which requests get blocked by
2894 &my-app; and add the hosts (no path patterns) to a section like this:
2898 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2903 Additionally you have to configure your browser to contact
2904 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2907 To add a proxy exception in <application>Mozilla Firefox</application>
2908 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2909 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2910 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2916 <sect2 renderas="sect3" id="se-linux">
2917 <title>I get selinux error messages. How can I fix this?</title>
2919 Please report the problem to the creator of your selinux policies.
2922 The problem is that some selinux policy writers aren't familiar
2923 with the application they are trying to <quote>secure</quote> and
2924 thus create policies that make no sense.
2927 In <application>Privoxy's</application> case the problem usually
2928 is that the policy only allows outgoing connections for certain
2929 destination ports (e.g. 80 and 443). While this may cover the
2930 standard ports, websites occasionally use other ports as well.
2931 This isn't a security problem and therefore <application>Privoxy's</application>
2932 default configuration doesn't block these requests.
2935 If you really want to block these ports (and don't be able
2936 to load websites that don't use standard ports), you should
2937 configure Privoxy to block these ports as well, so it doesn't
2938 trigger the selinux warnings.
2943 <sect2 renderas="sect3" id="gentoo-ricers">
2944 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2946 Probably you unintentionally compiled &my-app; without threading support
2947 in which case requests have to be serialized and only one can be served
2951 Check your <quote>USE</quote> flags and make sure they include
2952 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2955 If you compiled &my-app; with threading support (on POSIX-based systems),
2956 the <quote>Conditional #defines</quote> section on <ulink
2957 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2958 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2962 <sect2 renderas="sect3" id="tainted-sockets">
2963 <title>What are tainted sockets and how do I prevent them?</title>
2965 &my-app; marks sockets as tainted when it can't use them to
2966 serve additional requests.
2967 This does not necessarily mean that something went wrong and
2968 information about tainted sockets is only logged if connection
2969 debugging is enabled (debug 2).
2972 For example server sockets that were used for CONNECT requests
2973 (which are used to tunnel https:// requests) are considered tainted
2974 once the client closed its connection to &my-app;.
2975 Technically &my-app; could keep the connection to the server open,
2976 but the server would not accept requests that do not belong to the
2977 previous TLS/SSL session (and the client may even have terminated
2981 Server sockets are also marked tainted when a client requests a
2982 resource, but closes the connection before &my-app; has completely
2983 received (and forwarded) the resource to the client.
2984 In this case the server would (probably) accept additional requests,
2985 but &my-app; could not get the response without completely reading
2986 the leftovers from the previous response.
2989 These are just two examples, there are currently a bit more than
2990 25 scenarios in which a socket is considered tainted.
2993 While sockets can also be marked tainted as a result of a technical
2994 problem that may be worth fixing, the problem will be explicitly
2999 <sect2 renderas="sect3" id="pcre-stack-limit">
3000 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
3002 This can happen if your custom filters require more memory than &my-app;
3004 Usually the problem is that the operating system enforces a stack size limit
3005 that isn't sufficient.
3008 Unless the problem occurs with the filters available in the default configuration,
3009 this is not considered a Privoxy bug.
3012 To prevent the crashes you can rewrite your filter to use less resources,
3013 increase the relevant memory limit or recompile pcre to use less stack space.
3014 For details please see the
3015 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3016 and the documentation of your operating system.
3020 <sect2 renderas="sect3" id="file-permissions">
3021 <title>What to do if editing the config file of privoxy is access denied?</title>
3023 Your userid probably isn't allowed to edit the file.
3024 <!-- show how to check permissions? -->
3025 On Windows you can use the windows equivalent of sudo:
3027 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
3030 or fix the file permissions:
3032 <screen>C:\Privoxy>icacls config.txt
3033 config.txt BUILTIN\Administrators:(I)(F)
3034 NT AUTHORITY\SYSTEM:(I)(F)
3035 BUILTIN\Users:(I)(RX)
3036 NT AUTHORITY\Authenticated Users:(I)(M)
3038 Successfully processed 1 files; Failed processing 0 files
3040 C:\Privoxy>icacls config.txt /grant Lee:F
3041 processed file: config.txt
3042 Successfully processed 1 files; Failed processing 0 files
3044 C:\Privoxy>icacls config.txt
3045 config.txt I3668\Lee:(F)
3046 BUILTIN\Administrators:(I)(F)
3047 NT AUTHORITY\SYSTEM:(I)(F)
3048 BUILTIN\Users:(I)(RX)
3049 NT AUTHORITY\Authenticated Users:(I)(M)
3051 Successfully processed 1 files; Failed processing 0 files
3053 C:\Privoxy></screen>
3056 or try to point-n-click your way through adjusting the file
3057 permissions in windows explorer.
3063 <!-- ~~~~~ New section ~~~~~ -->
3064 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3065 <!-- Include contacting.sgml -->
3067 <!-- end contacting -->
3070 <!-- ~~~~~ New section ~~~~~ -->
3071 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3073 <!-- Include copyright.sgml -->
3079 Portions of this document are <quote>borrowed</quote> from the original
3080 <application>Junkbuster</application> (tm) FAQ, and modified as
3081 appropriate for <application>Privoxy</application>.
3084 <!-- ~~~~~ New section ~~~~~ -->
3085 <sect2><title>License</title>
3086 <!-- Include copyright.sgml: -->
3088 <!-- end copyright -->
3090 <!-- ~ End section ~ -->
3092 <!-- ~~~~~ New section ~~~~~ -->
3093 <sect2><title>History</title>
3094 <!-- Include history.sgml -->
3100 <!-- ~ End section ~ -->
3103 <!-- ~~~~~ New section ~~~~~ -->
3105 <sect1 id="seealso"><title>See also</title>
3107 <!-- Include seealso.sgml -->
3117 This program is free software; you can redistribute it
3118 and/or modify it under the terms of the GNU General
3119 Public License as published by the Free Software
3120 Foundation; either version 2 of the License, or (at
3121 your option) any later version.
3123 This program is distributed in the hope that it will
3124 be useful, but WITHOUT ANY WARRANTY; without even the
3125 implied warranty of MERCHANTABILITY or FITNESS FOR A
3126 PARTICULAR PURPOSE. See the GNU General Public
3127 License for more details.
3129 The GNU General Public License should be included with
3130 this file. If not, you can view it at
3131 http://www.gnu.org/copyleft/gpl.html
3132 or write to the Free Software Foundation, Inc.,
3133 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA