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.
1347 All in all, &my-app; can help manage cookies in general, can help minimize
1348 the loss of privacy posed by cookies, but can't realistically stop all
1353 <sect2 renderas="sect3" id="evil-cookies">
1354 <title>Are all cookies bad? Why?</title>
1356 No, in fact there are many beneficial uses of
1358 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1359 method that browsers can use to store data between pages, or between browser
1360 sessions. Sometimes there is a good reason for this, and the user's life is a
1361 bit easier as a result. But there is a long history of some websites taking
1362 advantage of this layer of trust, and using the data they glean from you and
1363 your browsing habits for their own purposes, and maybe to your potential
1364 detriment. Such sites are using you and storing their data on your system.
1365 That is why the privacy conscious watch from whom those cookies come, and why
1366 they really <emphasis>need</emphasis> to be there.
1370 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1371 definition</ulink> for more.
1375 <sect2 renderas="sect3" id="allow-cookies">
1376 <title>How can I allow permanent cookies for my trusted sites?</title>
1379 There are several actions that relate to cookies. The default behavior is to
1380 allow only <quote>session cookies</quote>, which means the cookies only last
1381 for the current browser session. This eliminates most kinds of abuse related
1382 to cookies. But there may be cases where you want cookies to last.
1385 To disable all cookie actions, so that cookies are allowed unrestricted,
1386 both in and out, for <literal>example.com</literal>:
1389 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1390 .example.com</screen>
1392 Place the above in <filename>user.action</filename>. Note that some of these may
1393 be off by default anyway, so this might be redundant, but there is no harm
1394 being explicit in what you want to happen. <filename>user.action</filename>
1395 includes an alias for this situation, called
1396 <literal>allow-all-cookies</literal>.
1400 <sect2 renderas="sect3" id="multiples">
1401 <title>Can I have separate configurations for different users?</title>
1403 Each instance of <application>Privoxy</application> has its own
1404 configuration, including such attributes as the TCP port that it listens on.
1405 What you can do is run multiple instances of <application>Privoxy</application>, each with
1407 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1408 configuration setting, and configuration path, and then
1409 each of these can have their own configurations. Think of it as per-port
1413 Simple enough for a few users, but for large installations, consider having
1414 groups of users that might share like configurations.
1418 <sect2 renderas="sect3" id="whitelists">
1419 <title>Can I set-up Privoxy as a whitelist of
1420 <quote>good</quote> sites?</title>
1422 Sure. There are a couple of things you can do for simple white-listing.
1423 Here's one real easy one:
1426 ############################################################
1428 ############################################################
1429 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1430 / # Block *all* URLs
1432 ############################################################
1434 ############################################################
1435 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1438 games.example.com</screen>
1440 This allows access to only those three sites by first blocking all URLs, and
1441 then subsequently allowing three specific exceptions.
1444 Another approach is <application>Privoxy's</application>
1445 <literal>trustfile</literal> concept, which incorporates the notion of
1446 <quote>trusted referrers</quote>. See the <ulink
1447 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1451 These are fairly simple approaches and are not completely foolproof. There
1452 are various other configuration options that should be disabled (described
1453 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1454 so that users can't modify their own configuration and easily circumvent the
1459 <sect2 renderas="sect3" id="no-adblock">
1460 <title>How can I turn off ad-blocking?</title>
1462 Ad blocking is achieved through a complex application of various &my-app;
1463 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1464 actions are deployed against simple images, banners, flash animations,
1465 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1466 just turning one or two actions off. The various actions that make up
1467 &my-app; ad blocking are hard-coded into the default configuration files. It
1468 has been assumed that everyone using &my-app; is interested in this
1472 If you want to do without this, there are several approaches you can take:
1473 You can manually undo the many block rules in
1474 <filename>default.action</filename>. Or even easier, just create your own
1475 <filename>default.action</filename> file from scratch without the many ad
1476 blocking rules, and corresponding exceptions. Or lastly, if you are not
1477 concerned about the additional blocks that are done for privacy reasons, you
1478 can very easily over-ride <emphasis>all</emphasis> blocking with the
1479 following very simple rule in your <filename>user.action</filename>:
1482 # Unblock everybody, everywhere
1483 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1484 / # UN-Block *all* URLs</screen>
1486 Or even a more comprehensive reversing of various ad related actions:
1489 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1490 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1491 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1492 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1493 <literal>allow-popups</literal> \
1495 / # UN-Block *all* URLs and allow ads</screen>
1497 This last <quote>action</quote> in this compound statement,
1498 <literal>allow-popups</literal>, is an <ulink
1499 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1500 various pop-up blocking features.
1504 <sect2 renderas="sect3" id="templates">
1505 <title>How can I have custom template pages, like the
1506 <emphasis>BLOCKED</emphasis> page?</title>
1508 &my-app; <quote>templates</quote> are specialized text files utilized by
1509 &my-app; for various purposes and can easily be modified using any text
1510 editor. All the template pages are installed in a sub-directory appropriately
1511 named: <filename>templates</filename>. Knowing something about HTML syntax
1512 will of course be helpful.
1515 Be forewarned that the default templates are subject to being overwritten
1516 during upgrades. You can, however, create completely new templates,
1517 place them in another directory and specify the alternate path in the main
1518 <filename>config</filename>. For details, have a look at the <ulink
1519 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1523 <sect2 renderas="sect3" id="blockall">
1524 <title>How can I remove the <quote>Go There Anyway</quote> link from
1525 the <emphasis>BLOCKED</emphasis> page?</title>
1527 There is more than one way to do it (although Perl is not involved).
1530 Editing the BLOCKED template page (see above) may dissuade some users, but
1531 this method is easily circumvented. Where you need this level of control, you
1532 might want to build &my-app; from source, and disable various features that are
1533 available as compile-time options. You should
1534 <command>configure</command> the sources as follows:
1537 ./configure --disable-toggle --disable-editor --disable-force</screen>
1539 This will create an executable with hard-coded security features so that
1540 &my-app; does not allow easy bypassing of blocked sites, or changing the
1541 current configuration via any connected user's web browser.
1544 Finally, all of these features can also be toggled on/off via options in
1545 <application>Privoxy's</application> main <ulink
1546 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1547 means you don't have to recompile anything.
1553 <!-- ~ End section ~ -->
1556 <!-- ~~~~~ New section ~~~~~ -->
1558 <sect1 id="misc"><title>Miscellaneous</title>
1560 <sect2 renderas="sect3" id="slowsme">
1561 <title>How much does Privoxy slow my browsing down? This
1562 has to add extra time to browsing.</title>
1564 How much of an impact depends on many things, including the CPU of the host
1565 system, how aggressive the configuration is, which specific actions are being triggered,
1566 the size of the page, the bandwidth of the connection, etc.
1569 Overall, it should not slow you down any in real terms, and may actually help
1570 speed things up since ads, banners and other junk are not typically being
1571 retrieved and displayed. The actual processing time required by
1572 <application>Privoxy</application> itself for each page, is relatively small
1573 in the overall scheme of things, and happens very quickly. This is typically
1574 more than offset by time saved not downloading and rendering ad images and
1575 other junk content (if ad blocking is being used).
1579 <quote>Filtering</quote> content via the <literal><ulink
1580 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1582 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1583 actions may cause a perceived slowdown, since the entire document
1584 needs to be buffered before displaying. And on very large documents,
1585 filtering may have some measurable impact. How much depends on the page size,
1586 the actual definition of the filter(s), etc. See below. Most other actions
1587 have little to no impact on speed.
1590 Also, when filtering is enabled but zlib support isn't available, compression
1591 is often disabled (see <ulink
1592 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1593 This can have an impact on speed as well, although it's probably smaller than
1594 you might think. Again, the page size, etc. will determine how much of an impact.
1600 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1601 delays in page requests. What's wrong?</title>
1603 If you use any <literal><ulink
1604 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1605 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1606 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1607 action, the entire document must be loaded into memory in order for the filtering
1608 mechanism to work, and nothing is sent to the browser during this time.
1611 The loading time typically does not really change much in real numbers, but
1612 the feeling is different, because most browsers are able to start rendering
1613 incomplete content, giving the user a feeling of "it works". This effect is
1614 more noticeable on slower dialup connections. Extremely large documents
1615 may have some impact on the time to load the page where there is filtering
1616 being done. But overall, the difference should be very minimal. If there is a
1617 big impact, then probably some other situation is contributing (like
1618 anti-virus software).
1621 Filtering is automatically disabled for inappropriate MIME types. But note
1622 that if the web server mis-reports the MIME type, then content that should
1623 not be filtered, could be. <application>Privoxy</application> only knows how
1624 to differentiate filterable content because of the MIME type as reported by
1625 the server, or because of some configuration setting that enables/disables
1630 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1631 "http://p.p/"?</title>
1633 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1634 address of <application>Privoxy</application>'s built-in user interface, and
1635 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1638 Since <application>Privoxy</application> sits between your web browser and the Internet,
1639 it can simply intercept requests for these addresses and answer them with its built-in
1640 <quote>web server</quote>.
1643 This also makes for a good test for your browser configuration: If entering the
1644 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1645 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1646 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1647 your browser didn't use <application>Privoxy</application> for the request,
1648 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1649 web site at config.privoxy.org.
1652 Note that config.privoxy.org resolves to a public IP address.
1653 If you use config.privoxy.org as ping or traceroute target you will
1654 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1655 If you want to ping the system Privoxy runs on,
1656 you should use its IP address or local DNS name (if it has got one).
1662 out of date 09/02/06 HB
1663 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1665 No. The patterns for blocking now reside (among other things) in the <ulink
1666 url="../user-manual/actions-file.html">actions files</ulink>, which are
1667 actively maintained instead. See next question ...
1671 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1674 Please see the <link linkend="contact">Contact section</link> for
1675 various ways to interact with the developers.
1680 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1681 they be included in future updates?</title>
1683 Whether such submissions are eventually included in the
1684 <filename>default.action</filename> configuration file depends on how
1685 significant the issue is. We of course want to address any potential
1686 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1687 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1688 has a good chance of being a candidate. But at the other end of the spectrum
1689 are any number of smaller, low-profile sites such as for local clubs or
1690 schools. Since their reach and impact are much less, they are best handled by
1691 inclusion in the user's <filename>user.action</filename>, and thus would be
1692 unlikely to be included.
1698 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1701 Rest assured that it has been read and considered. Why it is not answered,
1702 could be for various reasons, including no one has a good answer for it, no
1703 one has had time to yet investigate it thoroughly, it has been reported
1704 numerous times already, or because not enough information was provided to help
1705 us help you. Your efforts are not wasted, and we do appreciate them.
1711 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1713 If you run both the browser and &my-app; locally, you cannot hide your IP
1714 address with <application>Privoxy</application> or ultimately any other
1715 software alone. The server needs to know your IP address so that it knows
1716 where to send the responses back.
1719 There are many publicly usable "anonymous" proxies out there, which
1720 provide a further level of indirection between you and the web server.
1723 However, these proxies are called "anonymous" because you don't need
1724 to authenticate, not because they would offer any real anonymity.
1725 Most of them will log your IP address and make it available to the
1726 authorities in case you violate the law of the country they run in. In fact
1727 you can't even rule out that some of them only exist to *collect* information
1728 on (those suspicious) people with a more than average preference for privacy.
1731 If you want to hide your IP address from most adversaries,
1732 you should consider chaining <application>Privoxy</application>
1733 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1734 The configuration details can be found in
1735 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1736 with <application>Tor</application> section</ulink>
1741 <sect2 renderas="sect3" id="anonforsure">
1742 <title>Can Privoxy guarantee I am anonymous?</title>
1744 No. Your chances of remaining anonymous are improved, but unless you
1745 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1746 or a similar proxy and know what you're doing when it comes to configuring
1747 the rest of your system, you should assume that everything you do
1748 on the Web can be traced back to you.
1751 <application>Privoxy</application> can remove various information about you,
1752 and allows <emphasis>you</emphasis> more freedom to decide which sites
1753 you can trust, and what details you want to reveal. But it neither
1754 hides your IP address, nor can it guarantee that the rest of the system
1755 behaves correctly. There are several possibilities how a web sites can find
1756 out who you are, even if you are using a strict <application>Privoxy</application>
1757 configuration and chained it with <application>Tor</application>.
1760 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1761 by an insecure browser configuration, therefore you should use a browser that can
1762 be configured to only execute code from trusted sites, and be careful which sites you trust.
1763 For example there is no point in having <application>Privoxy</application>
1764 modify the User-Agent header, if websites can get all the information they want
1765 through JavaScript, ActiveX, Flash, Java etc.
1768 A few browsers disclose the user's email address in certain situations, such
1769 as when transferring a file by FTP. <application>Privoxy</application>
1770 does not filter FTP. If you need this feature, or are concerned about the
1771 mail handler of your browser disclosing your email address, you might
1772 consider products such as <application>NSClean</application>.
1775 Browsers available only as binaries could use non-standard headers to give
1776 out any information they can have access to: see the manufacturer's license
1777 agreement. It's impossible to anticipate and prevent every breach of privacy
1778 that might occur. The professionally paranoid prefer browsers available as
1779 source code, because anticipating their behavior is easier. Trust the source,
1785 <sect2 renderas="sect3" id="proxytest">
1786 <title>A test site says I am not using a Proxy.</title>
1788 Good! Actually, they are probably testing for some other kinds of proxies.
1789 Hiding yourself completely would require additional steps.
1793 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1794 together with Tor?</title>
1796 Before you configure <application>Privoxy</application> to use
1797 <ulink url="https://www.torproject.org/">Tor</ulink>,
1798 please follow the <citetitle>User Manual</citetitle> chapters
1799 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1800 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1801 <application>Privoxy</application> itself is setup correctly.
1804 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1805 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1806 and make sure <application>Tor</application>'s logfile says that
1807 <quote>Tor has successfully opened a circuit</quote> and it
1808 <quote>looks like client functionality is working</quote>.
1811 If either <application>Tor</application> or <application>Privoxy</application>
1812 isn't working, their combination most likely will neither. Testing them on their
1813 own will also help you to direct problem reports to the right audience.
1814 If <application>Privoxy</application> isn't working, don't bother the
1815 <application>Tor</application> developers. If <application>Tor</application>
1816 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1819 If you verified that <application>Privoxy</application> and <application>Tor</application>
1820 are working, it is time to connect them. As far as <application>Privoxy</application>
1821 is concerned, <application>Tor</application> is just another proxy that can be reached
1822 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1823 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1824 requests are done through <application>Tor</application> and thus invisible to your
1825 local network. Using socks4a would work too, but with socks5 you get more precise error
1830 <application>Privoxy's</application>
1831 <ulink url="../user-manual/config.html">main configuration file</ulink>
1832 is already prepared for <application>Tor</application>, if you are using a
1833 default <application>Tor</application> configuration and run it on the same
1834 system as &my-app;, you just have to edit the
1835 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1836 and uncomment the line:
1839 # forward-socks5t / 127.0.0.1:9050 .
1842 Note that if you got Tor through one of the bundles, you may
1843 have to change the port from 9050 to 9150 (or even another one).
1844 For details, please check the documentation on the
1845 <ulink url="https://torproject.org/">Tor website</ulink>.
1849 This is enough to reach the Internet, but additionally you might want to
1850 uncomment the following forward rules, to make sure your local network is still
1851 reachable through Privoxy:
1854 # forward 192.168.*.*/ .
1855 # forward 10.*.*.*/ .
1856 # forward 127.*.*.*/ .
1859 Unencrypted connections to systems in these address ranges will
1860 be as (un)secure as the local network is, but the alternative is
1861 that your browser can't reach the network at all. Then again,
1862 that may actually be desired and if you don't know for sure
1863 that your browser has to be able to reach the local network,
1864 there's no reason to allow it.
1867 If you want your browser to be able to reach servers in your local
1868 network by using their names, you will need additional exceptions
1869 that look like this:
1872 # forward localhost/ .
1875 Save the modified configuration file and open
1876 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1877 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1878 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1880 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1881 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1884 Afterward, please take the time to at least skim through the rest
1885 of <application>Tor's</application> documentation. Make sure you understand
1886 what <application>Tor</application> does, why it is no replacement for
1887 application level security, and why you probably don't want to
1888 use it for unencrypted logins.
1892 <sect2 renderas="sect3" id="sitebreak">
1893 <title>Might some things break because header information or
1894 content is being altered?</title>
1897 Definitely. It is common for sites to use browser type, browser version,
1898 HTTP header content, and various other techniques in order to dynamically
1899 decide what to display and how to display it. What you see, and what I see,
1900 might be very different. There are many, many ways that this can be handled,
1901 so having hard and fast rules, is tricky.
1905 The <quote>User-Agent</quote> is sometimes used in this way to identify
1906 the browser, and adjust content accordingly.
1910 Also, different browsers use different encodings of non-English
1911 characters, certain web servers convert pages on-the-fly according to the
1912 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1913 operating system or browser manufacturer causes some sites in these languages
1914 to be garbled; Surfers to Eastern European sites should change it to
1915 something closer. And then some page access counters work by looking at the
1916 <quote>Referer</quote> header; they may fail or break if unavailable. The
1917 weather maps of Intellicast have been blocked by their server when no
1918 <quote>Referer</quote> or cookie is provided, is another example. (But you
1919 can forge both headers without giving information away). There are
1920 many other ways things can go wrong when trying to fool a web server. The
1921 results of which could inadvertently cause pages to load incorrectly,
1922 partially, or even not at all. And there may be no obvious clues as to just
1923 what went wrong, or why. Nowhere will there be a message that says
1924 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1929 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1934 If you have problems with a site, you will have to adjust your configuration
1935 accordingly. Cookies are probably the most likely adjustment that may
1936 be required, but by no means the only one.
1942 <sect2 renderas="sect3" id="caching">
1943 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1944 speed up web browsing?</title>
1946 No, it does not have this ability at all. You want something like
1947 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1948 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1949 And, yes, before you ask, <application>Privoxy</application> can co-exist
1950 with other kinds of proxies like <application>Squid</application>.
1951 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1952 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1953 manual</ulink> for details.
1957 <sect2 renderas="sect3" id="firewall">
1958 <title>What about as a firewall? Can Privoxy protect me?</title>
1960 Not in the way you mean, or in the way some firewall vendors claim they can.
1961 <application>Privoxy</application> can help protect your privacy, but can't
1962 protect your system from intrusion attempts. It is, of course, perfectly possible
1963 to use <emphasis>both</emphasis>.
1967 <sect2 renderas="sect3" id="wasted">
1968 <title>I have large empty spaces / a checkerboard pattern now where
1969 ads used to be. Why?</title>
1971 It is technically possible to eliminate banners and ads in a way that frees
1972 their allocated page space. This could easily be done by blocking with
1973 <application>Privoxy's</application> filters,
1974 and eliminating the <emphasis>entire</emphasis> image references from the
1978 But, this would consume considerably more CPU resources (IOW, slow things
1979 down), would likely destroy the layout of some web pages which rely on the
1980 banners utilizing a certain amount of page space, and might fail in other
1981 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1982 Also, making ads and banners disappear without any trace complicates
1983 troubleshooting, and would sooner or later be problematic.
1986 The better alternative is to instead let them stay, and block the resulting
1987 requests for the banners themselves as is now the case. This leaves either
1988 empty space, or the familiar checkerboard pattern.
1991 So the developers won't support this in the default configuration, but you
1992 can of course define appropriate filters yourself to achieve this.
1996 <sect2 renderas="sect3" id="ssl">
1997 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1999 Since secure HTTP connections are encrypted SSL sessions between your browser
2000 and the secure site, and are meant to be reliably <emphasis>secure</emphasis>,
2001 there is little that <application>Privoxy</application> can do but hand the raw
2002 gibberish data though from one end to the other unprocessed.
2005 The only exception to this is blocking by host patterns, as the client needs
2006 to tell <application>Privoxy</application> the name of the remote server,
2007 so that <application>Privoxy</application> can establish the connection.
2008 If that name matches a host-only pattern, the connection will be blocked.
2011 As far as ad blocking is concerned, this is less of a restriction than it may
2012 seem, since ad sources are often identifiable by the host name, and often
2013 the banners to be placed in an encrypted page come unencrypted nonetheless
2014 for efficiency reasons, which exposes them to the full power of
2015 <application>Privoxy</application>'s ad blocking.
2018 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
2019 JS page content, see <literal><ulink
2020 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2021 in an SSL transaction will be impossible to block under these conditions.
2022 Fortunately, this does not seem to be a very common scenario since most
2023 cookies come by traditional means.
2028 <sect2 renderas="sect3" id="http2">
2029 <title>Does Privoxy support HTTP/2?</title>
2031 Privoxy currently doesn't parse HTTP/2 but applications
2032 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2033 to allow CONNECT requests (default) which are also used
2037 Adding HTTP/2 support is on the TODO list but currently
2038 nobody is known to work on it.
2042 <sect2 renderas="sect3" id="secure">
2043 <title>Privoxy runs as a <quote>server</quote>. How
2044 secure is it? Do I need to take any special precautions?</title>
2046 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2047 user, which is how we recommend it be run. Also, by default
2048 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2052 The server aspect of <application>Privoxy</application> is not itself directly
2053 exposed to the Internet in this configuration. If you want to have
2054 <application>Privoxy</application> serve as a LAN proxy, this will have to
2055 be opened up to allow for LAN requests. In this case, we'd recommend
2056 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2057 <application>Privoxy</application> configuration file and check all <ulink
2058 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2059 options</ulink>. All LAN hosts can then use this as their proxy address
2060 in the browser proxy configuration, but <application>Privoxy</application>
2061 will not listen on any external interfaces. ACLs can be defined in addition,
2062 and using a firewall is always good too. Better safe than sorry.
2067 <sect2 renderas="sect3" id="turnoff">
2068 <title>Can I temporarily disable Privoxy?</title>
2070 &my-app; doesn't have a transparent proxy mode,
2071 but you can toggle off blocking and content filtering.
2074 The easiest way to do that is to point your browser
2075 to the remote toggle URL: <ulink
2076 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2079 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2080 of the <citetitle>User Manual</citetitle> for an easy way to access this
2081 feature. Note that this is a feature that may need to be enabled in the main
2082 <filename>config</filename> file.
2087 <sect2 renderas="sect3" id="reallyoff">
2088 <title>When <quote>disabled</quote> is Privoxy totally
2089 out of the picture?</title>
2091 No, this just means all optional filtering and actions are disabled.
2092 <application>Privoxy</application> is still acting as a proxy, but just
2093 doing less of the things that <application>Privoxy</application> would
2094 normally be expected to do. It is still a <quote>middle-man</quote> in
2095 the interaction between your browser and web sites. See below to bypass
2100 <sect2 renderas="sect3" id="turnoff2">
2101 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2103 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2104 configuration issue, not a &my-app; issue. Modern browsers typically do have
2105 settings for not proxying certain sites. Check your browser's help files.
2110 <sect2 renderas="sect3" id="crunch">
2111 <title>My logs show Privoxy <quote>crunches</quote>
2112 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2114 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2115 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2116 banners, but <application>Privoxy</application> uses the same mechanism for
2117 trapping requests for its own internal pages. For instance, a request for
2118 <application>Privoxy's</application> configuration page at: <ulink
2119 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2120 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2121 configuration is returned to the browser, and the log consequently will show
2122 a <quote>crunch</quote>.
2125 Since version 3.0.7, Privoxy will also log the crunch reason.
2126 If you are using an older version you might want to upgrade.
2130 <sect2 renderas="sect3" id="downloads">
2131 <title>Can Privoxy affect files that I download
2132 from a webserver? FTP server?</title>
2134 From the webserver's perspective, there is no difference between
2135 viewing a document (i.e. a page), and downloading a file. The same is true of
2136 <application>Privoxy</application>. If there is a match for a <literal><ulink
2137 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2138 it will still be blocked, and of course this is obvious.
2141 Filtering is potentially more of a concern since the results are not always
2142 so obvious, and the effects of filtering are there whether the file is simply
2143 viewed, or downloaded. And potentially whether the content is some obnoxious
2144 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2145 one of these presumably is <quote>bad</quote> content that we don't want, and
2146 the other is <quote>good</quote> content that we do want.
2147 <application>Privoxy</application> is blind to the differences, and can only
2148 distinguish <quote>good from bad</quote> by the configuration parameters
2149 <emphasis>we</emphasis> give it.
2152 <application>Privoxy</application> knows the differences in files according
2153 to the <quote>Content Type</quote> as reported by the webserver. If this is
2154 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2155 then <application>Privoxy</application> knows to ignore these where
2156 appropriate. <application>Privoxy</application> potentially can filter HTML
2157 as well as plain text documents, subject to configuration parameters of
2158 course. Also, documents that are of an unknown type (generally assumed to be
2159 <quote>text/plain</quote>) can be filtered, as will those that might be
2160 incorrectly reported by the webserver. If such a file is a downloaded file
2161 that is intended to be saved to disk, then any content that might have been
2162 altered by filtering, will be saved too, for these (probably rare) cases.
2165 Note that versions later than 3.0.2 do NOT filter document types reported as
2166 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2167 did filter this document type.
2170 In short, filtering is <quote>ON</quote> if a) the content type as reported
2171 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2172 allows it (or at least does not disallow it). That's it. There is no magic
2173 cookie anywhere to say this is <quote>good</quote> and this is
2174 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2177 If you download text files, you probably do not want these to be filtered,
2178 particularly if the content is source code, or other critical content. Source
2179 code sometimes might be mistaken for Javascript (i.e. the kind that might
2180 open a pop-up window). It is recommended to turn off filtering for download
2181 sites (particularly if the content may be plain text files and you are using
2182 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2183 also, for any site or page where making <emphasis>any</emphasis> changes at
2184 all to the content is to be avoided.
2187 <application>Privoxy</application> does not do FTP at all, only HTTP
2188 and HTTPS (SSL) protocols.
2192 <sect2 renderas="sect3" id="downloads2">
2193 <title>I just downloaded a Perl script, and Privoxy
2194 altered it! Yikes, what is wrong!</title>
2200 <sect2 renderas="sect3" id="hostsfile">
2201 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2203 One time-tested technique to defeat common ads is to trick the local DNS
2204 system by giving a phony IP address for the ad generator in the local
2205 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2206 <literal>localhost</literal>. This effectively blocks the ad.
2209 There is no reason to use this technique in conjunction with
2210 <application>Privoxy</application>. <application>Privoxy</application>
2211 does essentially the same thing, much more elegantly and with much more
2212 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2213 duplicates effort, but may get in the way and seriously slow down your system.
2214 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2215 your hosts list is neglected by <application>Privoxy's </application>
2216 configuration, consider adding your list to your <filename>user.action</filename> file:
2222 ads.galore.example.com
2223 etc.example.com</screen>
2226 <sect2 renderas="sect3" id="seealso">
2227 <title>Where can I find more information about Privoxy
2228 and related issues?</title>
2229 <!-- Include seealso.sgml boilerplate: -->
2231 <!-- end boilerplate -->
2236 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2242 <sect2 renderas="sect3" id="microsuck">
2243 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2244 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2247 We're not. The text substitutions that you are seeing are disabled
2248 in the default configuration as shipped. You have either manually
2249 activated the <quote><literal>fun</literal></quote> filter which
2250 is clearly labeled <quote>Text replacements for subversive browsing
2251 fun!</quote> or you are using an older Privoxy version and have implicitly
2252 activated it by choosing the <quote>Advanced</quote> profile in the
2253 web-based editor. Please upgrade.
2257 <sect2 renderas="sect3" id="valid">
2258 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2261 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2262 whenever there are text substitutions via a &my-app; filter. While this
2263 should always conform to the HTML 4.01 specifications, it has not been
2264 validated against this or any other standard.
2268 <sect2 renderas="sect3" id="surprise-privoxy">
2269 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2272 We didn't. We make Privoxy available for download, but we don't go
2273 around installing it on other people's systems behind their back.
2274 If you discover Privoxy running on your system and are sure you didn't
2275 install it yourself, somebody else did. You may not even be running
2276 the real Privoxy, but maybe something else that only pretends to be
2277 Privoxy, or maybe something that is based on the real Privoxy,
2278 but has been modified.
2281 Lately there have been reports of problems with some kind of
2282 "parental control" software based on Privoxy that came preinstalled on
2283 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2284 The problems described are inconsistent with the behaviour of official
2285 Privoxy versions, which suggests that the preinstalled software may
2286 contain vendor modifications that we don't know about and thus can't debug.
2289 Privoxy's <link linkend="copyright">license</link> allows vendor
2290 modifications, but the vendor has to comply with the license,
2291 which involves informing the user about the changes and to make
2292 the changes available under the same license as Privoxy itself.
2295 If you are having trouble with a modified Privoxy version,
2296 please try to talk to whoever made the modifications before
2297 reporting the problem to us. Please also try to convince
2298 whoever made the modifications to talk to us. If you think
2299 somebody gave you a modified Privoxy version without complying
2300 to the license, please let us know.
2308 <!-- ~~~~~ New section ~~~~~ -->
2310 <sect1 id="trouble">
2311 <title>Troubleshooting</title>
2313 <sect2 renderas="sect3" id="refused">
2314 <title>I cannot connect to any websites. Or, I am getting
2315 <quote>connection refused</quote> message with every web page. Why?</title>
2317 There are several possibilities:
2321 <application>Privoxy</application> is not running. Solution: verify
2322 that &my-app; is installed correctly, has not crashed, and is indeed running.
2323 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2325 <listitem><para>Or your browser is configured for a different port than what
2326 <application>Privoxy</application> is using. Solution: verify that &my-app;
2327 and your browser are set to the same port (<literal>listen-address</literal>).
2329 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2330 problem with a host in the forwarding chain. Solution: temporarily alter your
2331 configuration and take the forwarders out of the equation.
2334 Or you have a firewall that is interfering and blocking you. Solution:
2335 try disabling or removing the firewall as a simple test.
2341 <!-- ~~~~~ New section ~~~~~ -->
2342 <sect2 renderas="sect3" id="error503">
2343 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2345 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2346 been reported to cause this symptom -- even if not running! The solution is
2347 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2348 something better behaved in its place. Other personal firewall type products
2349 may cause similar type problems if not configured correctly.
2353 <sect2 renderas="sect3" id="flushit">
2354 <title>I just added a new rule, but the steenkin ad is
2355 still getting through. How?</title>
2357 If the ad had been displayed before you added its URL, it will probably be
2358 held in the browser's cache for some time, so it will be displayed without
2359 the need for any request to the server, and <application>Privoxy</application>
2360 will not be involved. Flush the browser's caches, and then try again.
2364 If this doesn't help, you probably have an error in the rule you
2365 applied. Try pasting the full URL of the offending ad into <ulink
2366 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2367 and see if it really matches your new rule. Blocking ads is like blocking
2368 spam: a lot of tinkering is required to stay ahead of the game. And
2369 remember you need to block the URL of the ad in question, which may be
2370 entirely different from the site URL itself. Most ads are hosted on different
2371 servers than the main site itself. If you right-click on the ad, you should
2372 be able to get all the relevant information you need. Alternately, you can
2373 find the correct URL by looking at <application>Privoxy's</application> logs
2374 (you may need to enable logging in the main config file if its disabled).
2377 Below is a slightly modified real-life log snippet that originates with one
2378 requested URL: <literal>www.example.com</literal> (name of site was changed
2379 for this example, the number of requests is real). You can see in this the
2380 complexity of what goes into making up this one <quote>page</quote>. There
2381 are eight different domains involved here, with thirty two separate URLs
2382 requested in all, making up all manner of images, Shockwave Flash,
2383 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2384 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2385 Many of the more questionable looking requests, are going to outside domains
2386 that seem to be identifying themselves with suspicious looking names, making
2387 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2388 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2392 Request: www.example.com/
2393 Request: www.example.com/favicon.ico
2394 Request: img.example.com/main.css
2395 Request: img.example.com/sr.js
2396 Request: example.betamarker.com/example.html
2397 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2398 Request: img.example.com/pb.png
2399 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2400 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2401 Request: img.example.com/p.gif
2402 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2403 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2404 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2405 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2406 Request: www.adtrak.net/adx.js crunch! (Blocked)
2407 Request: img.example.com/hbg.gif
2408 Request: img.example.com/example.jpg
2409 Request: img.example.com/mt.png
2410 Request: img.example.com/mm.png
2411 Request: img.example.com/mb.png
2412 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2413 Request: www.example.com/tracker.js
2414 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2415 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2416 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2417 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2418 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2419 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2420 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2421 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2422 Request: 66.70.21.80/img/pixel.gif
2423 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2424 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2428 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2429 behave perfectly <quote>normal</quote> (minus some ads, of course).
2434 <sect2 renderas="sect3" id="badsite">
2435 <title>One of my favorite sites does not work with Privoxy.
2436 What can I do?</title>
2439 First verify that it is indeed a <application>Privoxy</application> problem,
2440 by toggling off <application>Privoxy</application> through <ulink
2441 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2442 (the toggle feature may need to be enabled in the main
2443 <filename>config</filename>),
2444 and then shift-reloading the problem page (i.e. holding down the shift key
2445 while clicking reload. Alternatively, flush your browser's disk and memory
2450 If the problem went away, we know we have a configuration related problem.
2452 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2453 and paste the full URL of the page in question into the prompt. See which
2454 actions are being applied to the URL, and which matches in which actions
2455 files are responsible for that. It might be helpful also to look at your logs
2456 for this site too, to see what else might be happening (note: logging may need
2457 to be enabled in the main config file). Many sites are
2458 complex and require a number of related pages to help present their content.
2459 Look at what else might be used by the page in question, and what of that
2460 might be <emphasis>required</emphasis>.
2461 Now, armed with this information, go to
2463 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2464 and select the appropriate actions files for editing. </para>
2466 You can now either look for a section which disables the actions that
2467 you suspect to cause the problem and add a pattern for your site there,
2468 or make up a completely new section for your site. In any case, the recommended
2469 way is to disable only the prime suspect, reload the problem page, and only
2470 if the problem persists, disable more and more actions until you have
2471 identified the culprit. You may or may not want to turn the other actions
2472 on again. Remember to flush your browser's caches in between any such changes!
2475 Alternately, if you are comfortable with a text editor, you can accomplish
2476 the same thing by editing the appropriate actions file. Probably the easiest
2477 way to deal with such problems when editing by hand is to add your
2478 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2479 which is an alias that turns off most <quote>dangerous</quote>
2480 actions, but is also likely to turn off more actions then needed, and thus lower
2481 your privacy and protection more than necessary,
2484 Troubleshooting actions is discussed in more detail in the <ulink
2485 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2486 Troubleshooting: the Anatomy of an Action</ulink>.
2487 There is also an <ulink
2488 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2489 with general configuration information and examples.
2492 As a last resort, you can always see if your browser has a setting that will
2493 bypass the proxy setting for selective sites. Modern browsers can do this.
2499 <!-- ~~~~~ New section ~~~~~ -->
2500 <sect2 id="dun" renderas="sect3">
2501 <title>After installing Privoxy, I have to log in
2502 every time I start IE. What gives?</title>
2505 This is a quirk that affects the installation of
2506 <application>Privoxy</application>, in conjunction with Internet Explorer and
2507 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2508 appear to be corrupted or invalid DUN settings, or passwords.
2512 When setting up an NT based Windows system with
2513 <application>Privoxy</application> you may find that things do not seem to be
2514 doing what you expect. When you set your system up you will probably have set
2515 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2516 logged in with administrator privileges. You will probably have made this DUN
2517 connection available to other accounts that you may have set-up on your
2518 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2519 configured for the kids.
2523 When setting up <application>Privoxy</application> in this environment you
2524 will have to alter the proxy set-up of Internet Explorer (IE) for the
2525 specific DUN connection on which you wish to use
2526 <application>Privoxy</application>. When you do this the ICS DUN set-up
2527 becomes user specific. In this instance you will see no difference if you
2528 change the DUN connection under the account used to set-up the connection.
2529 However when you do this from another user you will notice that the DUN
2530 connection changes to make available to "Me only". You will also find that
2531 you have to store the password under each different user!
2535 The reason for this is that each user's set-up for IE is user specific. Each
2536 set-up DUN connection and each LAN connection in IE store the settings for
2537 each user individually. As such this enforces individual configurations
2538 rather than common ones. Hence the first time you use a DUN connection after
2539 re-booting your system it may not perform as you expect, and prompt you for
2540 the password. Just set and save the password again and all should be OK.
2544 [Thanks to Ray Griffith for this submission.]
2549 <!-- ~~~~~ New section ~~~~~ -->
2550 <sect2 id="ftp" renderas="sect3">
2551 <title>I cannot connect to any FTP sites. Privoxy
2552 is blocking me.</title>
2554 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2555 so do not configure your browser to use <application>Privoxy</application>
2556 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2557 or HTTPS (SSL)</emphasis>.
2560 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2561 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2562 an FTP connection, and not a HTTP connection. So while your browser may
2563 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2567 To complicate matters, some systems may have a generic <quote>proxy</quote>
2568 setting, which will enable various protocols, including
2569 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2570 accidentally enable FTP proxying in these cases. And of course, if this
2571 happens, <application>Privoxy</application> will indeed cause problems since
2572 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2573 message if a FTP connection is attempted.]]> Just disable the FTP setting
2574 and all will be well again.
2577 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2578 There just is not much reason, and the work to make this happen is more than
2583 <!-- ~~~~~ New section ~~~~~ -->
2584 <sect2 id="macosxie" renderas="sect3">
2585 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2586 Privoxy as the HTTP proxy.</title>
2588 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2589 network settings. In order to change the HTTP proxy, open System
2590 Preferences, and click on the Network icon. In the settings pane that
2591 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2592 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2593 Enter <literal>8118</literal> in the Port field. The next time you start
2594 IE, it should reflect these values.
2598 <!-- ~~~~~ New section ~~~~~ -->
2599 <sect2 renderas="sect3" id="macosxuninstall">
2600 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2601 uninstall it. Now the finder tells me I don't have sufficient privileges to
2602 empty the trash.</title>
2604 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2607 Just dragging the <application>Privoxy</application> folder to the trash is
2608 not enough to delete it. <application>Privoxy</application> supplies an
2609 <application>uninstall.command</application> file that takes care of
2610 these details. Open the trash, drag the <application>uninstall.command</application>
2611 file out of the trash and double-click on it. You will be prompted for
2612 confirmation and the administration password.
2615 The trash may still appear full after this command; emptying the trash
2616 from the desktop should make it appear empty again.
2620 <!-- ~~~~~ New section ~~~~~ -->
2621 <sect2 renderas="sect3" id="macosximages">
2622 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2623 experience random delays in page loading. I'm using
2624 <literal>localhost</literal> as my browser's proxy setting.</title>
2626 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2627 understand the issue yet. In any case, changing the proxy setting to
2628 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2629 works around the problem.
2633 <!-- ~~~~~ New section ~~~~~ -->
2634 <sect2 renderas="sect3" id="macosxaccountdeletion">
2635 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2638 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2639 X deletes all user accounts that are either not part of OS X itself or are
2640 not interactive user accounts (ones you log in with). Since, for the sake of
2641 security, &my-app; runs as a non-privileged user that is created by its
2642 installer (_privoxy), it can no longer start up once that account gets deleted.
2643 The solution is to perform a complete uninstall using the supplied
2644 <application>uninstall.command</application> script (either back up your
2645 configuration files or select to not have the uninstaller remove them when it
2646 prompts you) and then reinstall &my-app; using the installer package and merge
2647 in your configuration.
2651 <sect2 renderas="sect3" id="nohostname">
2652 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2655 <application>Privoxy</application> tries to get the hostname of the system
2656 its running on from the IP address of the system interface it is bound to
2657 (from the <filename>config</filename> file
2658 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2659 this information, <application>Privoxy</application> logs this condition.
2662 Typically, this would be considered a minor system configuration error. It is
2663 not a fatal error to <application>Privoxy</application> however, but may
2664 result in a much slower response from <application>Privoxy</application> on
2665 some platforms due to DNS timeouts.
2668 This can be caused by a problem with the local <filename>hosts</filename>
2669 file. If this file has been changed from the original, try reverting it to
2670 see if that helps. Make sure whatever name(s) are used for the local system,
2671 that they resolve both ways.
2674 You should also be able to work around the problem with the
2675 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2679 <sect2 renderas="sect3" id="inuse">
2680 <title>When I try to launch Privoxy, I get an
2681 error message <quote>port 8118 is already in use</quote> (or similar wording).
2684 Port 8118 is <application>Privoxy's</application> default TCP
2685 <quote>listening</quote> port. Typically this message would mean that there
2686 is already one instance of <application>Privoxy</application> running, and
2687 your system is actually trying to start a second
2688 <application>Privoxy</application> on the same port, which will not work.
2689 (You can have multiple instances but they must be assigned different ports.)
2690 How and why this might happen varies from platform to platform, but you need
2691 to check your installation and start-up procedures.
2695 <sect2 renderas="sect3" id="demoronizer">
2697 Pages with UTF-8 fonts are garbled.
2700 This may be the result of an overly aggressive filter. The filters that
2701 are enabled in the default configuration aren't expected to cause problems
2702 like this. If you enabled the <quote>demoronizer</quote> filter, please
2703 try temporarily disabling it.
2706 If that doesn't help, temporarily disable all filters to see if another
2707 filter could be the culprit. If the problem disappears, enable the filters
2708 one by one, until the problem reappears and the offending filter is found.
2711 Once the problem-causing filter is known, it can be fixed or disabled.
2714 Upgrading <application>Privoxy</application>, or going to the most recent
2715 <filename>default.action</filename> file available from <ulink
2716 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2717 might be worth a try, too.
2721 <sect2 renderas="sect3" id="demoronizer2">
2723 Why are binary files (such as images) corrupted when Privoxy
2727 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2728 filter</link> in conjunction with a web server that is misreporting the content
2729 type. By default binary files are exempted from
2730 <application>Privoxy's</application> filtering
2731 (unless the web server by mistake says the file is something else).
2735 <sect2 renderas="sect3" id="demoronizer3">
2737 What is the <quote>demoronizer</quote> and why is it there?
2740 The original demoronizer was a Perl script that cleaned up HTML pages which
2741 were created with certain Microsoft products. MS has used proprietary extensions
2742 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2743 that are viewed with non-Microsoft products (and are expecting to see a
2744 standard set of fonts). The demoronizer corrected these errors so the pages
2745 displayed correctly. <application>Privoxy</application> borrowed from this
2746 script, introducing a filter based on the original demoronizer, which in turn could
2747 correct these errors on the fly.
2750 But this is only needed in some situations, and will cause serious problems in some
2754 If you are using Microsoft products, you do not need it. If you need to view
2755 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2756 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2759 On the other hand, if you use non-Microsoft products, and you occasionally
2760 notice weird characters on pages, you might want to try it.
2764 <sect2 renderas="sect3" id="windowopen">
2766 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2769 <application>Privoxy</application> is attempting to disable malicious
2770 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2771 in this case, with the <literal>unsolicited-popups</literal>
2772 filter. <application>Privoxy</application> cannot tell very well
2773 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2776 If you see this in HTML source, and the page displays without problems, then
2777 this is good, and likely some pop-up window was disabled. If you see this
2778 where it is causing a problem, such as a downloaded program source code file,
2779 then you should set an exception for this site or page such that the
2780 integrity of the page stays in tact by disabling all filtering.
2784 <sect2 renderas="sect3" id="dnserrors">
2786 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2787 can't Privoxy do this better?
2790 There are potentially several factors here. First of all, the DNS resolution
2791 is done by the underlying operating system -- not
2792 <application>Privoxy</application> itself. <application>Privoxy</application>
2793 merely initiates the process and hands it off, and then later reports
2794 whatever the outcome was and tries to give a coherent message if there seems
2795 to be a problem. In some cases, this might otherwise be mitigated by the
2796 browser itself which might try some work-arounds and alternate approaches (e.g
2797 adding <quote>www.</quote> to the URL).
2800 In other cases, if <application>Privoxy</application> is being chained
2801 with another proxy, this could complicate the issue, and cause undue
2802 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2803 server handles all the DNS. <application>Privoxy</application> would just be
2804 the <quote>messenger</quote> which is reporting whatever problem occurred
2805 downstream, and not the root cause of the error.
2809 In any case, versions newer than 3.0.3 include various improvements to help
2810 <application>Privoxy</application> better handle these cases.
2814 <sect2 renderas="sect3" id="allcpu">
2816 At one site Privoxy just hangs, and starts taking
2817 all CPU. Why is this?
2820 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2821 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2822 are in the raw HTML source of the page, and the browser just ignores them. But the
2823 pattern matching in <application>Privoxy's</application> page filtering
2824 mechanism is trying to match against absurdly long strings and this becomes
2825 very CPU-intensive, taking a long, long time to complete.
2828 Until a better solution comes along, disable filtering on these pages,
2829 particularly the <literal>js-annoyances</literal> and
2830 <literal>unsolicited-popups</literal> filters. If you run into this problem
2831 with a recent &my-app; version, please send a problem report.
2835 <sect2 renderas="sect3" id="slowcrawl">
2836 <title>I just installed Privoxy, and all my
2837 browsing has slowed to a crawl. What gives? </title>
2839 This should not happen, and for the overwhelming number of users world-wide,
2840 it does not happen. I would suspect some inadvertent interaction of software
2841 components such as anti-virus software, spyware protectors, personal
2842 firewalls or similar components. Try disabling (or uninstalling) these one
2843 at a time and see if that helps. Either way, if you are using a
2844 recent &my-app; version, please report the problem.
2848 <sect2 renderas="sect3" id="preventcomp">
2849 <title>Why do my filters work on some sites but not on others? </title>
2851 It's probably due to compression. It is a common practice for web servers to
2852 send their content <quote>compressed</quote> in order to speed things up, and
2853 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2854 &my-app; can decompress content before filtering, otherwise you may want to enable
2856 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2859 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2864 <sect2 renderas="sect3" id="ssl-warnings">
2865 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2866 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2867 What's going on?</title>
2869 Probably the browser is requesting ads through HTTPS and &my-app;
2870 is blocking the requests. Privoxy's error messages are delivered
2871 unencrypted and while it's obvious for the browser that the HTTPS
2872 request is already blocked by the proxy, some warn about unauthenticated
2876 To work around the problem you can redirect those requests to an invalid
2877 local address instead of blocking them. While the redirects aren't
2878 encrypted either, many browsers don't care. They simply follow the
2879 redirect, fail to reach a server and display an error message instead
2883 To do that, enable logging to figure out which requests get blocked by
2884 &my-app; and add the hosts (no path patterns) to a section like this:
2888 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2893 Additionally you have to configure your browser to contact
2894 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2897 To add a proxy exception in <application>Mozilla Firefox</application>
2898 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2899 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2900 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2906 <sect2 renderas="sect3" id="se-linux">
2907 <title>I get selinux error messages. How can I fix this?</title>
2909 Please report the problem to the creator of your selinux policies.
2912 The problem is that some selinux policy writers aren't familiar
2913 with the application they are trying to <quote>secure</quote> and
2914 thus create policies that make no sense.
2917 In <application>Privoxy's</application> case the problem usually
2918 is that the policy only allows outgoing connections for certain
2919 destination ports (e.g. 80 and 443). While this may cover the
2920 standard ports, websites occasionally use other ports as well.
2921 This isn't a security problem and therefore <application>Privoxy's</application>
2922 default configuration doesn't block these requests.
2925 If you really want to block these ports (and don't be able
2926 to load websites that don't use standard ports), you should
2927 configure Privoxy to block these ports as well, so it doesn't
2928 trigger the selinux warnings.
2933 <sect2 renderas="sect3" id="gentoo-ricers">
2934 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2936 Probably you unintentionally compiled &my-app; without threading support
2937 in which case requests have to be serialized and only one can be served
2941 Check your <quote>USE</quote> flags and make sure they include
2942 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2945 If you compiled &my-app; with threading support (on POSIX-based systems),
2946 the <quote>Conditional #defines</quote> section on <ulink
2947 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2948 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2952 <sect2 renderas="sect3" id="tainted-sockets">
2953 <title>What are tainted sockets and how do I prevent them?</title>
2955 &my-app; marks sockets as tainted when it can't use them to
2956 serve additional requests.
2957 This does not necessarily mean that something went wrong and
2958 information about tainted sockets is only logged if connection
2959 debugging is enabled (debug 2).
2962 For example server sockets that were used for CONNECT requests
2963 (which are used to tunnel https:// requests) are considered tainted
2964 once the client closed its connection to &my-app;.
2965 Technically &my-app; could keep the connection to the server open,
2966 but the server would not accept requests that do not belong to the
2967 previous TLS/SSL session (and the client may even have terminated
2971 Server sockets are also marked tainted when a client requests a
2972 resource, but closes the connection before &my-app; has completely
2973 received (and forwarded) the resource to the client.
2974 In this case the server would (probably) accept additional requests,
2975 but &my-app; could not get the response without completely reading
2976 the leftovers from the previous response.
2979 These are just two examples, there are currently a bit more than
2980 25 scenarios in which a socket is considered tainted.
2983 While sockets can also be marked tainted as a result of a technical
2984 problem that may be worth fixing, the problem will be explicitly
2989 <sect2 renderas="sect3" id="pcre-stack-limit">
2990 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2992 This can happen if your custom filters require more memory than &my-app;
2994 Usually the problem is that the operating system enforces a stack size limit
2995 that isn't sufficient.
2998 Unless the problem occurs with the filters available in the default configuration,
2999 this is not considered a Privoxy bug.
3002 To prevent the crashes you can rewrite your filter to use less resources,
3003 increase the relevant memory limit or recompile pcre to use less stack space.
3004 For details please see the
3005 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3006 and the documentation of your operating system.
3010 <sect2 renderas="sect3" id="file-permissions">
3011 <title>What to do if editing the config file of privoxy is access denied?</title>
3013 Your userid probably isn't allowed to edit the file.
3014 <!-- show how to check permissions? -->
3015 On Windows you can use the windows equivalent of sudo:
3017 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
3020 or fix the file permissions:
3022 <screen>C:\Privoxy>icacls config.txt
3023 config.txt BUILTIN\Administrators:(I)(F)
3024 NT AUTHORITY\SYSTEM:(I)(F)
3025 BUILTIN\Users:(I)(RX)
3026 NT AUTHORITY\Authenticated Users:(I)(M)
3028 Successfully processed 1 files; Failed processing 0 files
3030 C:\Privoxy>icacls config.txt /grant Lee:F
3031 processed file: config.txt
3032 Successfully processed 1 files; Failed processing 0 files
3034 C:\Privoxy>icacls config.txt
3035 config.txt I3668\Lee:(F)
3036 BUILTIN\Administrators:(I)(F)
3037 NT AUTHORITY\SYSTEM:(I)(F)
3038 BUILTIN\Users:(I)(RX)
3039 NT AUTHORITY\Authenticated Users:(I)(M)
3041 Successfully processed 1 files; Failed processing 0 files
3043 C:\Privoxy></screen>
3046 or try to point-n-click your way through adjusting the file
3047 permissions in windows explorer.
3053 <!-- ~~~~~ New section ~~~~~ -->
3054 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3055 <!-- Include contacting.sgml -->
3057 <!-- end contacting -->
3060 <!-- ~~~~~ New section ~~~~~ -->
3061 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3063 <!-- Include copyright.sgml -->
3069 Portions of this document are <quote>borrowed</quote> from the original
3070 <application>Junkbuster</application> (tm) FAQ, and modified as
3071 appropriate for <application>Privoxy</application>.
3074 <!-- ~~~~~ New section ~~~~~ -->
3075 <sect2><title>License</title>
3076 <!-- Include copyright.sgml: -->
3078 <!-- end copyright -->
3080 <!-- ~ End section ~ -->
3082 <!-- ~~~~~ New section ~~~~~ -->
3083 <sect2><title>History</title>
3084 <!-- Include history.sgml -->
3090 <!-- ~ End section ~ -->
3093 <!-- ~~~~~ New section ~~~~~ -->
3095 <sect1 id="seealso"><title>See also</title>
3097 <!-- Include seealso.sgml -->
3107 This program is free software; you can redistribute it
3108 and/or modify it under the terms of the GNU General
3109 Public License as published by the Free Software
3110 Foundation; either version 2 of the License, or (at
3111 your option) any later version.
3113 This program is distributed in the hope that it will
3114 be useful, but WITHOUT ANY WARRANTY; without even the
3115 implied warranty of MERCHANTABILITY or FITNESS FOR A
3116 PARTICULAR PURPOSE. See the GNU General Public
3117 License for more details.
3119 The GNU General Public License should be included with
3120 this file. If not, you can view it at
3121 http://www.gnu.org/copyleft/gpl.html
3122 or write to the Free Software Foundation, Inc.,
3123 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA