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 "3.0.25">
12 <!entity p-status "UNRELEASED">
13 <!entity % p-not-stable "INCLUDE">
14 <!entity % p-stable "IGNORE">
15 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
16 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
17 <!entity % p-supp-userman "INCLUDE"> <!-- Include all from supported.sgml -->
18 <!entity my-copy "©"> <!-- kludge for docbook2man -->
19 <!entity % p-newstuff "INCLUDE"> <!-- exclude stuff from devel versions -->
20 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
21 <!entity my-app "<application>Privoxy</application>">
24 File : $Source: /cvsroot/ijbswa/current/doc/source/faq.sgml,v $
27 This file belongs into
28 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
30 $Id: faq.sgml,v 2.115 2016/02/26 12:32:39 fabiankeil Exp $
32 Copyright (C) 2001-2014 Privoxy Developers http://www.privoxy.org/
35 Based partially on the Internet Junkbuster FAQ originally written by and
36 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
37 http://www.junkbusters.com/
39 <Qandaset defaultlabel='qanda'>
54 ========================================================================
55 NOTE: Please read developer-manual/documentation.html before touching
58 Please we keep the info in this file as version independent as possible
59 so we only have to maintain one FAQ. Where significant changes are
60 made to Privoxy configuration, please note the change in such a way that
61 it makes sense to both users of older and newer versions.
62 ========================================================================
68 <article id="index" class="faq">
70 <title>Privoxy Frequently Asked Questions</title>
74 <!-- Completely the wrong markup, but very little is allowed -->
75 <!-- in this part of an article. FIXME -->
76 <link linkend="copyright">Copyright</link> &my-copy; 2001-2014 by
77 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
81 <pubdate>$Id: faq.sgml,v 2.115 2016/02/26 12:32:39 fabiankeil Exp $</pubdate>
85 Note: this should generate a separate page, and a live link to it.
86 But it doesn't for some mysterious reason. Please leave commented
87 unless it can be fixed proper. For the time being, the copyright
88 statement will be in copyright.smgl.
92 <legalnotice id="legalnotice">
94 text goes here ........
104 <orgname>By: Privoxy Developers</orgname>
113 This is here to keep vim syntax file from breaking :/
114 If I knew enough to fix it, I would.
115 PLEASE DO NOT REMOVE! HB: hal@foobox.net
120 This FAQ gives quick answers to frequently asked questions about
121 <ulink url="http://www.privoxy.org/">Privoxy</ulink>.
122 It is not a substitute for the
123 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
125 This works, at least in some situtations:
126 Test: <ulink url="privoxy-user-manual.pdf"><citetitle>User Manual</citetitle></ulink>.
130 <!-- Include privoxy.sgml boilerplate: -->
131 <para>What is Privoxy?</para> &p-intro;
132 <!-- end boilerplate -->
135 Please note that this document is a work in progress. This copy represents
136 the state at the release of version &p-version;.
137 You can find the latest version of the document at <ulink
138 url="http://www.privoxy.org/faq/">http://www.privoxy.org/faq/</ulink>.
139 Please see the <link linkend="contact">Contact section</link> if you want to
140 contact the developers.
144 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
150 <!-- ~~~~~ New section ~~~~~ -->
152 <sect1 id="general"><title>General Information</title>
153 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
155 Anyone who is interested in security, privacy, or in
156 finer-grained control over their web and Internet experience.
160 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
163 &my-app; is certainly a good choice, especially for those who want more
164 control and security. Those with the willingness to read the documentation
165 and the ability to fine-tune their installation will benefit the most.
168 One of <application>Privoxy's</application>
169 strengths is that it is highly configurable giving you the ability to
170 completely personalize your installation. Being familiar with, or at least
171 having an interest in learning about <ulink
172 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
173 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
174 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
175 Expressions</quote></ulink>
176 will be a big plus and will help you get the most out of &my-app;.
177 A new installation just includes a very basic configuration. The user
178 should take this as a starting point only, and enhance it as he or she
179 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
183 Much of <application>Privoxy's</application> configuration can be done
184 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
185 But there are areas where configuration is done using a
186 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
187 to edit configuration files. Also note that the web-based action editor
188 doesn't use authentication and should only be enabled in environments
189 where all clients with access to &my-app; listening port can be trusted.
193 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
194 Privoxy work? </title>
196 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
197 is a service, based on a software such as &my-app;, that clients
198 (i.e. browsers) can use instead of connecting to web servers directly.
199 The clients then ask the proxy to request objects (web pages, images, movies etc)
200 on their behalf and to forward the data to the clients.
201 It is a <quote>go-between</quote>. For details, see
202 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
205 There are many reasons to use web proxies, such as security (firewalling),
206 efficiency (caching) and others, and there are any number of proxies
207 to accommodate those needs.
210 &my-app; is a proxy that is primarily focused on
211 privacy enhancement, ad and junk elimination and freeing the user from
212 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
213 it is in a perfect position to filter outbound personal information that your
214 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
215 this, all of which are under your complete control via the various configuration
216 files and options. Being a proxy also makes it easier to share
217 configurations among multiple browsers and/or users.
221 <sect2 renderas="sect3" id="otherstuff">
222 <title>Does Privoxy do anything more than ad blocking?</title>
224 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
225 can be used to sanitize and customize web browsing.
229 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
230 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
232 <!-- Include history.sgml -->
239 <sect2 renderas="sect3">
240 <title id="whyprivoxy">Why <quote>Privoxy</quote>? Why change the name from
241 Junkbuster at all?</title>
243 Though outdated, Junkbusters Corporation continued to offer their original
244 version of the <application>Internet Junkbuster</application> for a while,
245 so publishing our <application> Junkbuster</application>-derived software
246 under the same name would have led to confusion.
249 There were also potential legal reasons not to use the
250 <application>Junkbuster</application> name, as it was (and maybe still is)
251 a registered trademark of Junkbusters Corporation.
252 There were, however, no objections from Junkbusters Corporation to the
253 <application>Privoxy</application> project itself, and they, in fact,
254 shared our ideals and goals.
257 The Privoxy developers also believed that there were so many improvements
258 over the original code, that it was time to make a clean break from the past
259 and make a name in their own right.
262 <application>Privoxy</application> is the
263 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
264 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
265 control, more freedom, and allows you to browse your personal and
266 <quote><emphasis>private</emphasis> edition</quote> of the web.
270 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
271 from the old Junkbuster?</title>
273 <application>Privoxy</application> picks up where
274 <application>Junkbuster</application> left off.
275 <application>Privoxy</application> still blocks ads and banners,
277 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
278 helps protect your privacy. But, most of these features have been enhanced,
279 and many new ones have been added, all in the same vein.
282 <application>Privoxy</application>'s new features include:
285 <!-- Include newfeatures.sgml: -->
291 <sect2 renderas="sect3" id="whatsanad">
292 <title id="knows">How does Privoxy know what is
293 an ad, and what is not?</title>
295 <application>Privoxy</application>'s approach to blocking ads is twofold:
298 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
299 of banner images. This applies to both the path (you wouldn't guess how many
300 web sites serve their banners from a directory called <quote>banners</quote>!)
301 and the host (blocking the big banner hosting services like doublecklick.net
302 already helps a lot). <application>Privoxy</application> takes advantage of this
303 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
304 patterns</ulink> to sort out and block the requests for things that sound
305 like they would be ads or banners.
308 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
309 can't tell the size of an image by its URL without downloading it, and if you
310 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
311 also inspects the HTML sources of web pages while they are loaded, and replaces
312 references to images with standard banner sizes by dummy references, so that
313 your browser doesn't request them anymore in the first place.
316 Both of this involves a certain amount of guesswork and is, of course, freely
317 and readily configurable.
321 <sect2 renderas="sect3">
322 <title id="mistakes">Can Privoxy make mistakes?
323 This does not sound very scientific.</title>
325 Actually, it's a black art ;-) And yes, it is always possible to have a broad
326 rule accidentally block or change something by mistake. You will almost surely
327 run into such situations at some point. It is tricky writing rules to
328 cover every conceivable possibility, and not occasionally get false positives.
332 But this should not be a big concern since the
333 <application>Privoxy</application> configuration is very flexible, and
334 includes tools to help identify these types of situations so they can be
335 addressed as needed, allowing you to customize your installation.
336 (<link linkend="badsite">See the Troubleshooting section below</link>.)
341 <sect2 renderas="sect3">
342 <title id="configornot">Will I have to configure Privoxy
343 before I can use it?</title>
345 That depends on your expectations.
346 The default installation should give you a good starting
347 point, and block <emphasis>most</emphasis> ads and unwanted content,
348 but many of the more advanced features are off by default, and require
349 you to activate them.
352 You do have to set up your browser to use
353 <application>Privoxy</application> (see the <link
354 linkend="firststep">Installation section below</link>).
357 And you will certainly run into situations where there are false positives,
358 or ads not being blocked that you may not want to see. In these cases, you
359 would certainly benefit by customizing <application>Privoxy's</application>
360 configuration to more closely match your individual situation. And we
361 encourage you to do this. This is where the real power of
362 <application>Privoxy</application> lies!
367 <sect2 renderas="sect3" id="lan">
368 <title>Can Privoxy run as a server on a network?</title>
370 Yes, &my-app; runs as a server already, and can easily be configured to
371 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
372 How can I set up Privoxy to act as a proxy for my LAN</link> below.
376 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
377 Privoxy. Why should I use Privoxy at all?</title>
379 Modern browsers do indeed have <emphasis>some</emphasis> of the same
380 functionality as <application>Privoxy</application>. Maybe this is
381 adequate for you. But <application>Privoxy</application> is very
382 versatile and powerful, and can probably do a number of things
383 your browser just can't.
386 In addition, a proxy is good choice if you use multiple browsers, or
387 have a LAN with multiple computers since &my-app; can run as a server
388 application. This way all the configuration is in one place, and you don't
389 have to maintain a similar configuration for possibly many browsers or
393 Note, however, that it's recommended to leverage both your browser's
394 and <application>Privoxy's</application> privacy enhancing features
395 at the same time. While your browser probably lacks some features
396 &my-app; offers, it should also be able to do some things more
397 reliably, for example restricting and suppressing JavaScript.
401 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
403 The most important reason is because you have access to
404 <emphasis>everything</emphasis>, and you can control everything. You can
405 check every line of every configuration file yourself. You can check every
406 last bit of source code should you desire. And even if you can't read code,
407 there should be some comfort in knowing that <!-- thousands of -->other people can,
408 and do read it. You can build the software from scratch, if you want,
409 so that you know the executable is clean, and that it is
410 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
411 is one reason we use &my-app; ourselves.
415 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
416 warranty? Registration?</title>
418 <application>Privoxy</application> is free software and licensed under the <ulink
419 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
420 It is free to use, copy, modify or distribute as you wish under the terms of this
421 license. Please see the <link linkend="copyright">Copyright</link> section for more
422 information on the license and copyright. Or the <filename>LICENSE</filename> file
423 that should be included.
426 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
427 That is something that would cost real money ;-) There is no registration either.
432 <sect2 renderas="sect3" id="spyware">
433 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
435 No, at least not reliably enough to trust it. &my-app; is not designed to be
436 a malware removal tool and the default configuration doesn't even try to
437 filter out any malware.
440 &my-app; could help prevent contact from (known) sites that use such
441 tactics with appropriate configuration rules, and thus could conceivably
442 prevent contamination from such sites. However, keeping such a configuration
443 up to date would require a lot of time and effort that would be better spend
444 on keeping your software itself up to date so it doesn't have known
450 <sect2 renderas="sect3" id="otherads">
451 <title>Can I use Privoxy with other ad-blocking software?</title>
453 &my-app; should work fine with other proxies and other software in general.
456 But it is probably not necessary to use &my-app; in conjunction with other
457 ad-blocking products, and this could conceivably cause undesirable results.
458 It might be better to choose one software or the other and work a little to
459 tweak its configuration to your liking.
462 Note that this is an advice specific to ad blocking.
466 <sect2 renderas="sect3" id="help-the-developers"><title id="jointeam">I would like to help you, what can I do?</title>
468 <sect3 renderas="sect4" id="participate"><title id="jointeam-work">Would you like to participate?</title>
470 Well, we <emphasis>always</emphasis> need help. There is something for
471 everybody who wants to help us. We welcome new developers, packagers,
472 testers, documentation writers or really anyone with a desire to help in
473 any way. You <emphasis>DO NOT</emphasis> need to be a
474 <quote>programmer</quote>. There are many other tasks available. In fact,
475 the programmers often can't spend as much time programming because of some
476 of the other, more mundane things that need to be done, like checking the
477 Tracker feedback sections or responding to user questions on the mailing
481 So first thing, subscribe to the <ulink
482 url="https://lists.sourceforge.net/lists/listinfo/ijbswa-users">Privoxy Users</ulink>
483 or the <ulink url="https://lists.sourceforge.net/lists/listinfo/ijbswa-developers">Privoxy
484 Developers</ulink> mailing list, join the discussion, help out other users, provide general
485 feedback or report problems you noticed.
488 If you intend to help out with the trackers, you also might want to <ulink
489 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
490 so we don't confuse you with the other name-less users.
493 We also have a <ulink
494 url="../developer-manual/index.html">Developer's Manual</ulink>.
495 While it is partly out of date, it's still worth reading.
498 Our <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup">TODO list</ulink>
499 may be of interest to you as well.
500 Please let us know if you want to work on one of the items listed.
504 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
506 Donations are welcome. Our
507 <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO">TODO list</ulink>
508 is rather long and being able to pay one (or more) developers to work on Privoxy
509 would make a huge difference, even if it was only for a couple of weeks. Donations may
510 also be used for Privoxy-related travel expenses (for example to attend conferences),
511 for hardware used for Privoxy development and for hosting expenses etc.
515 <application>Privoxy</application> is an associated
516 project of <ulink url="http://www.spi-inc.org/">Software
517 in the Public Interest (SPI)</ulink>, which allows us to receive
518 tax-deductible donations in the United States. If you want to donate through
519 SPI, please use <ulink url="http://www.spi-inc.org/donations">SPI's donation page</ulink>
520 to see what the options are.
524 You can also donate to Privoxy using a bank account or a "Paypal" address:
527 Name on account: <ulink url="https://www.zwiebelfreunde.de/">Zwiebelfreunde e.V.</ulink>
528 IBAN: DE95430609671126825604
533 "Paypal" address: privoxy@zwiebelfreunde.de
536 Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany
537 and other countries that recognize German charitable clubs. Feel free to
538 use the Subject field to provide a name to be credited and a list of TODO
539 list items you are interested in the most. For example: Max Mustermann: #16, #1, #14.
543 Note that donations made through Zwiebelfreunde e.V. currently can't be checked
544 automatically so you may not get credited right away. The credits currently
545 reflect donations received before 2016-01-14.
549 If you have any questions regarding donations please mail to either the
550 public user mailing list or, if it's a private matter, to
551 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liason)
560 <!-- ~~~~~ New section ~~~~~ -->
562 <sect1 id="installation"><title>Installation</title>
564 <sect2 renderas="sect3" id="whichbrowsers">
565 <title>Which browsers are supported by Privoxy?</title>
567 Any browser that can be configured to use a proxy, which
568 should be virtually all browsers, including
569 <application>Firefox</application>, <application>Internet
570 Explorer</application>, <application>Opera</application>, and
571 <application>Safari</application> among others.
572 Direct browser support is not an absolute requirement since
573 <application>Privoxy</application> runs as a separate application and talks
574 to the browser in the standardized HTTP protocol, just like a web server
579 <sect2 renderas="sect3" id="whichos">
580 <title>Which operating systems are supported?</title>
582 Include supported.sgml here:
587 <sect2 renderas="sect3" id="email-client">
588 <title>Can I use Privoxy with my email client?</title>
590 As long as there is some way to set a HTTP proxy for the client, then yes,
591 any application can be used, whether it is strictly speaking a
592 <quote>browser</quote> or not. Though this may not be the best approach for
593 dealing with some of the common abuses of HTML in email. See <link
594 linkend="outlook">How can I configure <application>Privoxy</application>
595 with <application>Outlook</application>?</link> below for more on
599 Be aware that HTML email presents a number of unique security and privacy
600 related issues, that can require advanced skills to overcome. The developers
601 recommend using email clients that can be configured to convert HTML to plain
602 text for these reasons.
606 <!-- Nobody is going to still be doing this!
607 <sect2 renderas="sect3" id="newinstall"><title>Can I install
608 Privoxy over Junkbuster?</title>
610 We recommend you un-install <application>Junkbuster</application>
611 first to minimize conflicts and confusion. You may want to
612 save your old configuration files for future reference. The configuration
613 files and syntax have substantially changed, so you will need to manually
614 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
615 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
616 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
620 Note: Some installers may automatically un-install
621 <application>Junkbuster</application>, if present!
627 <sect2 renderas="sect3" id="firststep">
628 <title>I just installed Privoxy. Is there anything
629 special I have to do now?</title>
632 All browsers should be told to use <application>Privoxy</application>
633 as a proxy by specifying the correct proxy address and port number
634 in the appropriate configuration area for the browser. It's possible
635 to combine &my-app; with a packet filter to intercept HTTP requests
636 even if the client isn't explicitly configured to use &my-app;,
637 but where possible, configuring the client is recommended. See
638 <ulink url="../user-manual/startup.html">the User Manual for more
639 details</ulink>. You should also flush your browser's memory and disk
640 cache to get rid of any cached junk items, and remove any stored
641 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
647 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
649 If you set up the <application>Privoxy</application> to run on
650 the computer you browse from (rather than your ISP's server or some
651 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
652 (sometimes referred to as <quote>localhost</quote>,
653 which is the special name used by every computer on the Internet to refer
654 to itself) and the port will be 8118 (unless you used the <ulink
655 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
656 config option to tell <application>Privoxy</application> to run on
660 When configuring your browser's proxy settings you typically enter
661 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
662 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
663 then the number <quote>8118</quote> for <quote>port</quote>.
664 This tells your browser to send all web requests to <application>Privoxy</application>
665 instead of directly to the Internet.
668 <application>Privoxy</application> can also be used to proxy for
669 a Local Area Network. In this case, your would enter either the IP
670 address of the LAN host where <application>Privoxy</application>
671 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
672 Port assignment would be same as above. Note that
673 <application>Privoxy</application> doesn't listen on any LAN interfaces by
677 <application>Privoxy</application> does not currently handle
678 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
682 <sect2 renderas="sect3" id="nothing">
683 <title>I just installed Privoxy, and nothing is happening.
684 All the ads are there. What's wrong?</title>
687 Did you configure your browser to use <application>Privoxy</application>
688 as a proxy? It does not sound like it. See above. You might also try flushing
689 the browser's caches to force a full re-reading of pages. You can verify
690 that <application>Privoxy</application> is running, and your browser
691 is correctly configured by entering the special URL:
692 <ulink url="http://p.p/">http://p.p/</ulink>.
693 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
694 of potential redirect caching problem (see next Q). -->
695 This should take you to a page titled <quote>This is Privoxy..</quote> with
696 access to <application>Privoxy's</application> internal configuration.
697 If you see this, then you are good to go. If you receive a page saying
698 <quote>Privoxy is not running</quote>, then the browser is not set up to use
699 your <application>Privoxy</application> installation.
700 If you receive anything else (probably nothing at all), it could either
701 be that the browser is not set up correctly, or that
702 <application>Privoxy</application> is not running at all. Check the <ulink
703 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
704 on starting <application>Privoxy</application> and browser configuration,
705 see the <ulink url="http://www.privoxy.org/user-manual/startup.html">chapter
706 on starting <application>Privoxy</application></ulink> in the
707 <ulink url="http://www.privoxy.org/user-manual/">User Manual</ulink>.
712 <sect2 renderas="sect3" id="notused">
713 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
714 Privoxy is running and being used.</title>
717 First, make sure that Privoxy is <emphasis>really</emphasis> running and
718 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
719 should see the <application>Privoxy</application> main page. If not, see
720 the <ulink url="http://www.privoxy.org/user-manual/startup.html">chapter
721 on starting <application>Privoxy</application></ulink> in the
722 <ulink url="http://www.privoxy.org/user-manual/">User Manual</ulink>.
726 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
727 other parts of <application>Privoxy</application>'s web interface show
728 the dummy page, your browser has cached a redirection it encountered before
729 <application>Privoxy</application> was being used. You need to clear your
730 browser's cache. Note that shift-reloading the dummy page won't help, since
731 that'll only refresh the dummy page, not the redirection that lead you there.
735 The procedure for clearing the cache varies from browser to browser. For
736 example, <application>Mozilla/Netscape</application> users would click
737 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
738 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
739 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
740 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
741 In some <application>Firefox</application> versions it's
742 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
743 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
744 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
745 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
752 <!-- ~~~~~ New section ~~~~~ -->
754 <sect1 id="configuration"><title>Configuration</title>
755 <sect2 renderas="sect3">
756 <title id="actionsfile">What exactly is an <quote>actions</quote> file?</title>
759 &my-app; utilizes the concept of <quote>
760 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
761 that are used to manipulate and control web page data.
762 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
763 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
764 that <application>Privoxy</application> could take while processing a certain
765 request, are configured. Typically, you would define a set of default actions
766 that apply globally to all URLs, then add exceptions to these defaults where needed.
767 There is a wide array of actions available that give the user a high degree
768 of control and flexibility on how to process each and every web page.
772 Actions can be defined on a <ulink
773 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
774 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
775 grouped together and then applied to requests matching one or more patterns.
776 There are many possible actions that might apply to any given site. As an example,
777 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
778 as one of your default actions, but need to accept cookies from a given site,
779 you would need to define an exception for this site in one of your actions
780 files, preferably in <filename>user.action</filename>.
785 <sect2 renderas="sect3" id="actionss">
786 <title>The <quote>actions</quote> concept confuses me. Please list
787 some of these <quote>actions</quote>.</title>
789 For a comprehensive discussion of the actions concept, please refer
790 to the <ulink url="../user-manual/actions-file.html">actions file
791 chapter</ulink> in the <ulink url="../user-manual/index.html">User
792 Manual</ulink>. It includes a <ulink
793 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
794 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
795 file tutorial</ulink> to get you started.
800 <sect2 renderas="sect3">
801 <title id="actconfig">How are actions files configured? What is the easiest
802 way to do this?</title>
805 Actions files are just text files in a special syntax and can be edited
806 with a text editor. But probably the easiest way is to access
807 <application>Privoxy</application>'s user interface with your web browser
808 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
809 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
810 <quote><ulink url="http://config.privoxy.org/show-status">View &
811 change the current configuration</ulink></quote> from the menu. Note
812 that this feature must be explicitly enabled in the main config file
814 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
819 <sect2 renderas="sect3">
820 <title>There are several different <quote>actions</quote> files. What are
821 the differences?</title>
823 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
824 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
829 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
831 Based on your feedback and the continuing development, updates of
832 <filename>default.action</filename> will be
833 made available from time to time on the <ulink
834 url="http://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
835 our <ulink url="http://sf.net/projects/ijbswa/">project page</ulink>.
839 If you wish to receive an email notification whenever we release updates of
840 <application>Privoxy</application> or the actions file, <ulink
841 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
842 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
847 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
849 The syntax and purpose of configuration files has remained roughly the
850 same throughout the 3.x series, but backwards compatibility is not guaranteed.
851 Also each release contains updated, <quote>improved</quote> versions and it is
852 therefore strongly recommended to install the newer configuration files
853 and merge back your modifications.
857 <sect2 renderas="sect3" id="difficult">
858 <title>Why is the configuration so complicated?</title>
860 <quote>Complicated</quote> is in the eye of the beholder.
863 Privoxy is currently mainly written by and for people who are already
864 familiar with the underlying concepts like regular expressions, HTTP and HTML,
865 or are willing to become familiar with them to be able to get the most
866 out of a powerful and flexible tool such as Privoxy.
869 While everybody is expected to be able to get a Privoxy default installation
870 up and running, fine-tuning requires a certain amount of background
871 information and Privoxy's documentation mainly concentrates on the
872 Privoxy-specific parts while only providing references to the rest.
875 If you or anyone you know has the skills, time and energy to
876 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
880 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
882 The default configuration shouldn't impact the usability of any of these services.
883 It may, however, make all <ulink
884 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
885 temporary, so that your browser will forget your
886 login credentials in between browser sessions. If you would like not to have to log
887 in manually each time you access those websites, simply turn off all cookie handling
888 for them in the <filename>user.action</filename> file. An example for yahoo might
892 <screen># Allow all cookies for Yahoo login:
894 { -<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> }
895 .login.yahoo.com</screen>
898 These kinds of sites are often quite complex and heavy with
899 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
900 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
902 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
906 <screen># Gmail is a _fragile_ site:
908 { <literal>fragile</literal> }
910 mail.google.com</screen>
913 Be sure to flush your browser's caches whenever making these kinds of
914 changes, just to make sure the changes <quote>take</quote>.
917 Make sure the domain, host and path are appropriate as well. Your browser can
918 tell you where you are specifically and you should use that information for
919 your configuration settings. Note that above it is not referenced as
920 <literal>gmail.com</literal>, which is a valid domain name.
925 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
926 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
928 Configuring <application>Privoxy</application> is not entirely trivial. To
929 help you get started, we provide you with three different default action
930 <quote>profiles</quote> in the web based actions file editor at <ulink
931 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
932 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
933 Manual</citetitle></ulink> for a list of actions, and how the default
938 Where the defaults are likely to break some sites, exceptions for
939 known popular <quote>problem</quote> sites are included, but in
940 general, the more aggressive your default settings are, the more exceptions
941 you will have to make later. New users are best to start off in
942 <quote>Cautious</quote> setting. This is safest and will have the fewest
943 problems. See the <ulink
944 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
945 for a more detailed discussion.
949 It should be noted that the <quote>Advanced</quote> profile (formerly known
950 as the <quote>Adventuresome</quote> profile) is more
951 aggressive, and will make use of some of
952 <application>Privoxy's</application> advanced features. Use at your own risk!
957 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
958 with a browser? Does that not raise security issues?</title>
960 It may seem strange that regular users can edit the config files with their
961 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
962 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
965 When you use the browser-based editor, <application>Privoxy</application>
966 itself is writing to the config files. Because
967 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
968 it can update its own config files.
971 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
972 a LAN) or aren't entirely in control of your own browser, you will probably want
973 to make sure that the web-based editor and remote toggle features are
974 <quote>off</quote> by setting <quote><literal><ulink
975 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
976 0</literal></quote> and <quote><literal><ulink
977 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
978 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
981 As of &my-app; 3.0.7 these options are disabled by default.
986 <sect2 renderas="sect3">
987 <title id="filterfile">What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
989 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
990 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
991 Filters are a special subset of actions that can be used to modify or
992 remove web page content or headers on the fly. Content filters can
993 be applied to <emphasis>anything</emphasis> in the page source,
994 header filters can be applied to either server or client headers.
995 Regular expressions are used to accomplish this.
998 There are a number of pre-defined filters to deal with common annoyances. The
999 filters are only defined here, to invoke them, you need to use the
1001 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1002 action</ulink> in one of the actions files. Content filtering is automatically
1003 disabled for inappropriate MIME types, but if you know better than Privoxy
1004 what should or should not be filtered you can filter any content you like.
1008 <emphasis>not</emphasis> be confused with <ulink
1009 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1010 is a completely different action, and is more typically used to block ads and
1015 If you are familiar with regular expressions, and HTML, you can look at
1016 the provided <filename>default.filter</filename> with a text editor and define
1017 your own filters. This is potentially a very powerful feature, but
1018 requires some expertise in both regular expressions and HTML/HTTP.
1019 <![%p-newstuff;[ You should
1020 place any modifications to the default filters, or any new ones you create
1021 in a separate file, such as <filename>user.filter</filename>, so they won't
1022 be overwritten during upgrades.
1023 The ability to define multiple filter files
1024 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1028 There is no GUI editor option for this part of the configuration,
1029 but you can disable/enable the various pre-defined filters of the included
1030 <filename>default.filter</filename> file with the <ulink
1031 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1032 Note that the custom actions editor must be explicitly enabled in
1033 the main config file (see <ulink
1034 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1038 If you intend to develop your own filters, you might want to have a look at
1040 url="http://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1045 <sect2 renderas="sect3" id="lanconfig">
1046 <title>How can I set up Privoxy to act as a proxy for my
1049 By default, <application>Privoxy</application> only responds to requests
1050 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1051 a network, this needs to be changed in the <ulink
1052 url="../user-manual/config.html">main configuration file</ulink>. Look for
1054 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1055 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1056 it is uncommented, and assign it the address of the LAN gateway interface,
1057 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1058 wish to run <application>Privoxy</application> on port 8118, this line
1064 listen-address 192.168.1.1:8118</screen>
1068 Save the file, and restart <application>Privoxy</application>. Configure
1069 all browsers on the network then to use this address and port number.
1073 Alternately, you can have <application>Privoxy</application> listen on
1074 all available interfaces:
1079 listen-address :8118</screen>
1083 And then use <application>Privoxy's</application>
1085 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1086 feature to limit connections. A firewall in this situation is recommended
1091 The above steps should be the same for any TCP network, regardless of
1096 If you run <application>Privoxy</application> on a LAN with untrusted users,
1097 we recommend that you double-check the <ulink
1098 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1105 <sect2 renderas="sect3">
1106 <title id="noseeum">Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1108 The replacement for blocked images can be controlled with the <ulink
1109 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1110 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1111 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1112 Note that this choice only has effect for images which are blocked as images, i.e.
1113 whose URLs match both a <literal><ulink
1114 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1115 <emphasis>and</emphasis> <literal><ulink
1116 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1119 If you want to see nothing, then change the <ulink
1120 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1121 action</ulink> to <quote>blank</quote>. This can be done by editing the
1122 <filename>user.action</filename> file, or through the <ulink
1123 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1128 <sect2 renderas="sect3">
1129 <title id="whyseeum">Why would anybody want to see a checkerboard pattern?</title>
1131 Remember that <link linkend="whatsanad">telling which image is an ad and which
1132 isn't</link>, is an educated guess. While we hope that the standard configuration
1133 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1134 decent, and it shows you where images have been blocked, which can be very
1135 helpful in case some navigation aid or otherwise innocent image was
1136 erroneously blocked. It is recommended for new users so they can
1137 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1138 many banners they <emphasis>don't</emphasis> have to see.
1143 <sect2 renderas="sect3">
1144 <title id="blockedbytext">I see some images being replaced with text
1145 instead of the checkerboard image. Why and how do I get rid of this?</title>
1147 This happens when the banners are not embedded in the HTML code of the
1148 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1149 or (i)layers, and these external HTML documents are blocked. Being non-images
1150 they get replaced by a substitute HTML page rather than a substitute image,
1151 which wouldn't work out technically, since the browser expects and accepts
1152 only HTML when it has requested an HTML document.
1155 The substitute page adapts to the available space and shows itself as a
1156 miniature two-liner if loaded into small frames, or full-blown with a
1157 large red "BLOCKED" banner if space allows.
1160 If you prefer the banners to be blocked by images, you must see to it that
1161 the HTML documents in which they are embedded are not blocked. Clicking
1162 the <quote>See why</quote> link offered in the substitute page will show
1163 you which rule blocked the page. After changing the rule and un-blocking
1164 the HTML documents, the browser will try to load the actual banner images
1165 and the usual image blocking will (hopefully!) kick in.
1170 <sect2 renderas="sect3" id="srvany">
1171 <title>Can Privoxy run as a service
1172 on Win2K/NT/XP?</title>
1175 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1176 functionality. See <ulink url="../user-manual/installation.html#installation-pack-win">
1177 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1178 <application>Privoxy</application> as a service.
1181 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1182 See the discussion at <ulink
1183 url="http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118">http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</ulink>,
1184 for details, and a sample configuration.
1189 <sect2 renderas="sect3" id="otherproxy">
1190 <title>How can I make Privoxy work with other proxies?</title>
1192 This can be done and is often useful to combine the benefits of
1193 <application>Privoxy</application> with those of a another proxy,
1194 for example to cache content.
1196 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1197 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1198 describes how to do this. If you intend to use Privoxy with Tor,
1199 please also have a look at
1200 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1204 <sect2 renderas="sect3" id="port-80">
1205 <title>Can I just set Privoxy to use port 80
1206 and thus avoid individual browser configuration?</title>
1209 No, its more complicated than that. This only works with special kinds
1210 of proxies known as <quote>intercepting</quote> proxies
1211 (<link linkend="INTERCEPTING">see below</link>).
1216 <sect2 renderas="sect3" id="transparent">
1217 <title>Can Privoxy run as a <quote>transparent
1218 </quote> proxy?</title>
1220 The whole idea of Privoxy is to modify client requests
1221 and server responses in all sorts of ways and therefore
1222 it's not a transparent proxy as described in
1223 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1226 However, some people say <quote>transparent proxy</quote> when they
1227 mean <quote>intercepting proxy</quote>. If you are one of them,
1228 please read the <link linkend="INTERCEPTING">next entry</link>.
1233 <sect2 renderas="sect3" id="intercepting">
1234 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1236 <application>Privoxy</application> can't intercept traffic itself,
1237 but it can handle requests that where intercepted and redirected
1238 with a packet filter (like <application>PF</application> or
1239 <application>iptables</application>), as long as the <literal>Host</literal>
1243 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1244 web sites rely on it anyway, this limitation shouldn't be a problem.
1247 Please refer to your packet filter's documentation to learn how to
1248 intercept and redirect traffic into <application>Privoxy</application>.
1249 Afterward you just have to configure <application>Privoxy</application> to
1250 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1251 intercepted requests</ulink>.
1256 <sect2 renderas="sect3" id="outlook">
1257 <title>How can I configure Privoxy for use with Outlook?</title>
1259 Versions of <application>Outlook</application> prior to Office 2007, use
1260 <application>Internet Explorer</application> components to both render HTML,
1261 and fetch any HTTP requests that may be embedded in an HTML email. So however
1262 you have <application>Privoxy</application> configured to work with IE, this
1263 configuration should automatically be shared, at least with older version of
1267 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1268 engine with Outlook. It is unknown whether this can be configured to use a
1270 <!-- FIXME HB 2009-02-15 -->
1274 <sect2 renderas="sect3" id="outlook-more">
1275 <title>How can I have separate rules just for HTML mail?</title>
1277 The short answer is, you can't. <application>Privoxy</application> has no way
1278 of knowing which particular application makes a request, so there is no way to
1279 distinguish between web pages and HTML mail.
1280 <application>Privoxy</application> just blindly proxies all requests. In the
1281 case of <application>Outlook Express</application> (see above), OE uses
1282 IE anyway, and there is no way for <application>Privoxy</application> to ever
1283 be able to distinguish between them (nor could any other proxy type application for
1287 For a good discussion of some of the issues involved (including privacy and
1288 security issues), see
1289 <ulink url="http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1293 <sect2 renderas="sect3" id="sneaky-cookies">
1294 <title>I sometimes notice cookies sneaking through. How?</title>
1297 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1298 set in several ways. The classic method is via the
1299 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1300 easy one to manipulate, such as the &my-app; concept of
1301 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1302 There is also the possibility of using
1303 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1304 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1305 is trickier because the syntax can vary widely, and thus requires a certain
1306 amount of guesswork. It is not realistic to catch all of these short of
1307 disabling Javascript, which would break many sites. And lastly, if the
1308 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1309 <application>Privoxy's</application> reach.
1312 All in all, &my-app; can help manage cookies in general, can help minimize
1313 the loss of privacy posed by cookies, but can't realistically stop all
1318 <sect2 renderas="sect3" id="evil-cookies">
1319 <title>Are all cookies bad? Why?</title>
1321 No, in fact there are many beneficial uses of
1323 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1324 method that browsers can use to store data between pages, or between browser
1325 sessions. Sometimes there is a good reason for this, and the user's life is a
1326 bit easier as a result. But there is a long history of some websites taking
1327 advantage of this layer of trust, and using the data they glean from you and
1328 your browsing habits for their own purposes, and maybe to your potential
1329 detriment. Such sites are using you and storing their data on your system.
1330 That is why the privacy conscious watch from whom those cookies come, and why
1331 they really <emphasis>need</emphasis> to be there.
1335 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1336 definition</ulink> for more.
1340 <sect2 renderas="sect3" id="allow-cookies">
1341 <title>How can I allow permanent cookies for my trusted sites?</title>
1344 There are several actions that relate to cookies. The default behavior is to
1345 allow only <quote>session cookies</quote>, which means the cookies only last
1346 for the current browser session. This eliminates most kinds of abuse related
1347 to cookies. But there may be cases where you want cookies to last.
1350 To disable all cookie actions, so that cookies are allowed unrestricted,
1351 both in and out, for <literal>example.com</literal>:
1355 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1356 .example.com</screen>
1359 Place the above in <filename>user.action</filename>. Note that some of these may
1360 be off by default anyway, so this might be redundant, but there is no harm
1361 being explicit in what you want to happen. <filename>user.action</filename>
1362 includes an alias for this situation, called
1363 <literal>allow-all-cookies</literal>.
1367 <sect2 renderas="sect3" id="multiples">
1368 <title>Can I have separate configurations for different users?</title>
1370 Each instance of <application>Privoxy</application> has its own
1371 configuration, including such attributes as the TCP port that it listens on.
1372 What you can do is run multiple instances of <application>Privoxy</application>, each with
1374 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1375 configuration setting, and configuration path, and then
1376 each of these can have their own configurations. Think of it as per-port
1380 Simple enough for a few users, but for large installations, consider having
1381 groups of users that might share like configurations.
1385 <sect2 renderas="sect3" id="whitelists">
1386 <title>Can I set-up Privoxy as a whitelist of
1387 <quote>good</quote> sites?</title>
1389 Sure. There are a couple of things you can do for simple white-listing.
1390 Here's one real easy one:
1393 ############################################################
1395 ############################################################
1396 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1397 / # Block *all* URLs
1399 ############################################################
1401 ############################################################
1402 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1405 games.example.com</screen>
1407 This allows access to only those three sites by first blocking all URLs, and
1408 then subsequently allowing three specific exceptions.
1411 Another approach is <application>Privoxy's</application>
1412 <literal>trustfile</literal> concept, which incorporates the notion of
1413 <quote>trusted referrers</quote>. See the <ulink
1414 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1418 These are fairly simple approaches and are not completely foolproof. There
1419 are various other configuration options that should be disabled (described
1420 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1421 so that users can't modify their own configuration and easily circumvent the
1426 <sect2 renderas="sect3" id="no-adblock">
1427 <title>How can I turn off ad-blocking?</title>
1429 Ad blocking is achieved through a complex application of various &my-app;
1430 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1431 actions are deployed against simple images, banners, flash animations,
1432 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1433 just turning one or two actions off. The various actions that make up
1434 &my-app; ad blocking are hard-coded into the default configuration files. It
1435 has been assumed that everyone using &my-app; is interested in this
1439 If you want to do without this, there are several approaches you can take:
1440 You can manually undo the many block rules in
1441 <filename>default.action</filename>. Or even easier, just create your own
1442 <filename>default.action</filename> file from scratch without the many ad
1443 blocking rules, and corresponding exceptions. Or lastly, if you are not
1444 concerned about the additional blocks that are done for privacy reasons, you
1445 can very easily over-ride <emphasis>all</emphasis> blocking with the
1446 following very simple rule in your <filename>user.action</filename>:
1450 # Unblock everybody, everywhere
1451 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1452 / # UN-Block *all* URLs</screen>
1455 Or even a more comprehensive reversing of various ad related actions:
1459 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1460 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1461 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1462 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1463 <literal>allow-popups</literal> \
1465 / # UN-Block *all* URLs and allow ads</screen>
1468 This last <quote>action</quote> in this compound statement,
1469 <literal>allow-popups</literal>, is an <ulink
1470 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1471 various pop-up blocking features.
1475 <sect2 renderas="sect3" id="templates">
1476 <title>How can I have custom template pages, like the
1477 <emphasis>BLOCKED</emphasis> page?</title>
1479 &my-app; <quote>templates</quote> are specialized text files utilized by
1480 &my-app; for various purposes and can easily be modified using any text
1481 editor. All the template pages are installed in a sub-directory appropriately
1482 named: <filename>templates</filename>. Knowing something about HTML syntax
1483 will of course be helpful.
1486 Be forewarned that the default templates are subject to being overwritten
1487 during upgrades. You can, however, create completely new templates,
1488 place them in another directory and specify the alternate path in the main
1489 <filename>config</filename>. For details, have a look at the <ulink
1490 url="../user-manual/config.html#templdir">templdir</ulink> option.
1494 <sect2 renderas="sect3" id="blockall">
1495 <title>How can I remove the <quote>Go There Anyway</quote> link from
1496 the <emphasis>BLOCKED</emphasis> page?</title>
1498 There is more than one way to do it (although Perl is not involved).
1501 Editing the BLOCKED template page (see above) may dissuade some users, but
1502 this method is easily circumvented. Where you need this level of control, you
1503 might want to build &my-app; from source, and disable various features that are
1504 available as compile-time options. You should
1505 <command>configure</command> the sources as follows:
1509 ./configure --disable-toggle --disable-editor --disable-force</screen>
1512 This will create an executable with hard-coded security features so that
1513 &my-app; does not allow easy bypassing of blocked sites, or changing the
1514 current configuration via any connected user's web browser.
1517 Finally, all of these features can also be toggled on/off via options in
1518 <application>Privoxy's</application> main <ulink
1519 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1520 means you don't have to recompile anything.
1526 <!-- ~ End section ~ -->
1529 <!-- ~~~~~ New section ~~~~~ -->
1531 <sect1 id="misc"><title>Miscellaneous</title>
1533 <sect2 renderas="sect3">
1534 <title id="slowsme">How much does Privoxy slow my browsing down? This
1535 has to add extra time to browsing.</title>
1537 How much of an impact depends on many things, including the CPU of the host
1538 system, how aggressive the configuration is, which specific actions are being triggered,
1539 the size of the page, the bandwidth of the connection, etc.
1542 Overall, it should not slow you down any in real terms, and may actually help
1543 speed things up since ads, banners and other junk are not typically being
1544 retrieved and displayed. The actual processing time required by
1545 <application>Privoxy</application> itself for each page, is relatively small
1546 in the overall scheme of things, and happens very quickly. This is typically
1547 more than offset by time saved not downloading and rendering ad images and
1548 other junk content (if ad blocking is being used).
1552 <quote>Filtering</quote> content via the <literal><ulink
1553 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1555 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1556 actions may cause a perceived slowdown, since the entire document
1557 needs to be buffered before displaying. And on very large documents,
1558 filtering may have some measurable impact. How much depends on the page size,
1559 the actual definition of the filter(s), etc. See below. Most other actions
1560 have little to no impact on speed.
1563 Also, when filtering is enabled but zlib support isn't available, compression
1564 is often disabled (see <ulink
1565 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1566 This can have an impact on speed as well, although it's probably smaller than
1567 you might think. Again, the page size, etc. will determine how much of an impact.
1573 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1574 delays in page requests. What's wrong?</title>
1576 If you use any <literal><ulink
1577 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1578 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1579 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1580 action, the entire document must be loaded into memory in order for the filtering
1581 mechanism to work, and nothing is sent to the browser during this time.
1584 The loading time typically does not really change much in real numbers, but
1585 the feeling is different, because most browsers are able to start rendering
1586 incomplete content, giving the user a feeling of "it works". This effect is
1587 more noticeable on slower dialup connections. Extremely large documents
1588 may have some impact on the time to load the page where there is filtering
1589 being done. But overall, the difference should be very minimal. If there is a
1590 big impact, then probably some other situation is contributing (like
1591 anti-virus software).
1594 Filtering is automatically disabled for inappropriate MIME types. But note
1595 that if the web server mis-reports the MIME type, then content that should
1596 not be filtered, could be. <application>Privoxy</application> only knows how
1597 to differentiate filterable content because of the MIME type as reported by
1598 the server, or because of some configuration setting that enables/disables
1603 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1604 "http://p.p/"?</title>
1606 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1607 address of <application>Privoxy</application>'s built-in user interface, and
1608 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1611 Since <application>Privoxy</application> sits between your web browser and the Internet,
1612 it can simply intercept requests for these addresses and answer them with its built-in
1613 <quote>web server</quote>.
1616 This also makes for a good test for your browser configuration: If entering the
1617 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1618 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1619 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1620 your browser didn't use <application>Privoxy</application> for the request,
1621 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1622 web site at config.privoxy.org.
1625 Note that config.privoxy.org resolves to a public IP address.
1626 If you use config.privoxy.org as ping or traceroute target you will
1627 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1628 If you want to ping the system Privoxy runs on,
1629 you should use its IP address or local DNS name (if it has got one).
1635 out of date 09/02/06 HB
1636 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1638 No. The patterns for blocking now reside (among other things) in the <ulink
1639 url="../user-manual/actions-file.html">actions files</ulink>, which are
1640 actively maintained instead. See next question ...
1644 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1647 Please see the <link linkend="contact">Contact section</link> for
1648 various ways to interact with the developers.
1653 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1654 they be included in future updates?</title>
1656 Whether such submissions are eventually included in the
1657 <filename>default.action</filename> configuration file depends on how
1658 significant the issue is. We of course want to address any potential
1659 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1660 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1661 has a good chance of being a candidate. But at the other end of the spectrum
1662 are any number of smaller, low-profile sites such as for local clubs or
1663 schools. Since their reach and impact are much less, they are best handled by
1664 inclusion in the user's <filename>user.action</filename>, and thus would be
1665 unlikely to be included.
1671 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1674 Rest assured that it has been read and considered. Why it is not answered,
1675 could be for various reasons, including no one has a good answer for it, no
1676 one has had time to yet investigate it thoroughly, it has been reported
1677 numerous times already, or because not enough information was provided to help
1678 us help you. Your efforts are not wasted, and we do appreciate them.
1684 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1686 If you run both the browser and &my-app; locally, you cannot hide your IP
1687 address with <application>Privoxy</application> or ultimately any other
1688 software alone. The server needs to know your IP address so that it knows
1689 where to send the responses back.
1692 There are many publicly usable "anonymous" proxies out there, which
1693 provide a further level of indirection between you and the web server.
1696 However, these proxies are called "anonymous" because you don't need
1697 to authenticate, not because they would offer any real anonymity.
1698 Most of them will log your IP address and make it available to the
1699 authorities in case you violate the law of the country they run in. In fact
1700 you can't even rule out that some of them only exist to *collect* information
1701 on (those suspicious) people with a more than average preference for privacy.
1704 If you want to hide your IP address from most adversaries,
1705 you should consider chaining <application>Privoxy</application>
1706 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1707 The configuration details can be found in
1708 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1709 with <application>Tor</application> section</ulink>
1714 <sect2 renderas="sect3">
1715 <title id="anonforsure">Can Privoxy guarantee I am anonymous?</title>
1717 No. Your chances of remaining anonymous are improved, but unless you
1718 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1719 or a similar proxy and know what you're doing when it comes to configuring
1720 the rest of your system, you should assume that everything you do
1721 on the Web can be traced back to you.
1724 <application>Privoxy</application> can remove various information about you,
1725 and allows <emphasis>you</emphasis> more freedom to decide which sites
1726 you can trust, and what details you want to reveal. But it neither
1727 hides your IP address, nor can it guarantee that the rest of the system
1728 behaves correctly. There are several possibilities how a web sites can find
1729 out who you are, even if you are using a strict <application>Privoxy</application>
1730 configuration and chained it with <application>Tor</application>.
1733 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1734 by an insecure browser configuration, therefore you should use a browser that can
1735 be configured to only execute code from trusted sites, and be careful which sites you trust.
1736 For example there is no point in having <application>Privoxy</application>
1737 modify the User-Agent header, if websites can get all the information they want
1738 through JavaScript, ActiveX, Flash, Java etc.
1741 A few browsers disclose the user's email address in certain situations, such
1742 as when transferring a file by FTP. <application>Privoxy</application>
1743 does not filter FTP. If you need this feature, or are concerned about the
1744 mail handler of your browser disclosing your email address, you might
1745 consider products such as <application>NSClean</application>.
1748 Browsers available only as binaries could use non-standard headers to give
1749 out any information they can have access to: see the manufacturer's license
1750 agreement. It's impossible to anticipate and prevent every breach of privacy
1751 that might occur. The professionally paranoid prefer browsers available as
1752 source code, because anticipating their behavior is easier. Trust the source,
1758 <sect2 renderas="sect3">
1759 <title id="proxytest">A test site says I am not using a Proxy.</title>
1761 Good! Actually, they are probably testing for some other kinds of proxies.
1762 Hiding yourself completely would require additional steps.
1766 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1767 together with Tor?</title>
1769 Before you configure <application>Privoxy</application> to use
1770 <ulink url="https://www.torproject.org/">Tor</ulink>,
1771 please follow the <citetitle>User Manual</citetitle> chapters
1772 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1773 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1774 <application>Privoxy</application> itself is setup correctly.
1777 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1778 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1779 and make sure <application>Tor</application>'s logfile says that
1780 <quote>Tor has successfully opened a circuit</quote> and it
1781 <quote>looks like client functionality is working</quote>.
1784 If either <application>Tor</application> or <application>Privoxy</application>
1785 isn't working, their combination most likely will neither. Testing them on their
1786 own will also help you to direct problem reports to the right audience.
1787 If <application>Privoxy</application> isn't working, don't bother the
1788 <application>Tor</application> developers. If <application>Tor</application>
1789 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1792 If you verified that <application>Privoxy</application> and <application>Tor</application>
1793 are working, it is time to connect them. As far as <application>Privoxy</application>
1794 is concerned, <application>Tor</application> is just another proxy that can be reached
1795 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1796 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1797 requests are done through <application>Tor</application> and thus invisible to your
1798 local network. Using socks4a would work too, but with socks5 you get more precise error
1803 <application>Privoxy's</application>
1804 <ulink url="../user-manual/config.html">main configuration file</ulink>
1805 is already prepared for <application>Tor</application>, if you are using a
1806 default <application>Tor</application> configuration and run it on the same
1807 system as &my-app;, you just have to edit the
1808 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1809 and uncomment the line:
1813 # forward-socks5t / 127.0.0.1:9050 .
1817 Note that if you got Tor through one of the bundles, you may
1818 have to change the port from 9050 to 9150 (or even another one).
1819 For details, please check the documentation on the
1820 <ulink url="https://torproject.org/">Tor website</ulink>.
1824 This is enough to reach the Internet, but additionally you might want to
1825 uncomment the following forward rules, to make sure your local network is still
1826 reachable through Privoxy:
1830 # forward 192.168.*.*/ .
1831 # forward 10.*.*.*/ .
1832 # forward 127.*.*.*/ .
1836 Unencrypted connections to systems in these address ranges will
1837 be as (un)secure as the local network is, but the alternative is
1838 that your browser can't reach the network at all. Then again,
1839 that may actually be desired and if you don't know for sure
1840 that your browser has to be able to reach the local network,
1841 there's no reason to allow it.
1844 If you want your browser to be able to reach servers in your local
1845 network by using their names, you will need additional exceptions
1846 that look like this:
1850 # forward localhost/ .
1854 Save the modified configuration file and open
1855 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1856 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1857 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1859 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1860 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1863 Afterward, please take the time to at least skim through the rest
1864 of <application>Tor's</application> documentation. Make sure you understand
1865 what <application>Tor</application> does, why it is no replacement for
1866 application level security, and why you probably don't want to
1867 use it for unencrypted logins.
1871 <sect2 renderas="sect3">
1872 <title id="sitebreak">Might some things break because header information or
1873 content is being altered?</title>
1876 Definitely. It is common for sites to use browser type, browser version,
1877 HTTP header content, and various other techniques in order to dynamically
1878 decide what to display and how to display it. What you see, and what I see,
1879 might be very different. There are many, many ways that this can be handled,
1880 so having hard and fast rules, is tricky.
1884 The <quote>User-Agent</quote> is sometimes used in this way to identify
1885 the browser, and adjust content accordingly.
1889 Also, different browsers use different encodings of non-English
1890 characters, certain web servers convert pages on-the-fly according to the
1891 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1892 operating system or browser manufacturer causes some sites in these languages
1893 to be garbled; Surfers to Eastern European sites should change it to
1894 something closer. And then some page access counters work by looking at the
1895 <quote>Referer</quote> header; they may fail or break if unavailable. The
1896 weather maps of Intellicast have been blocked by their server when no
1897 <quote>Referer</quote> or cookie is provided, is another example. (But you
1898 can forge both headers without giving information away). There are
1899 many other ways things can go wrong when trying to fool a web server. The
1900 results of which could inadvertently cause pages to load incorrectly,
1901 partially, or even not at all. And there may be no obvious clues as to just
1902 what went wrong, or why. Nowhere will there be a message that says
1903 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1908 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1913 If you have problems with a site, you will have to adjust your configuration
1914 accordingly. Cookies are probably the most likely adjustment that may
1915 be required, but by no means the only one.
1921 <sect2 renderas="sect3">
1922 <title id="caching">Can Privoxy act as a <quote>caching</quote> proxy to
1923 speed up web browsing?</title>
1925 No, it does not have this ability at all. You want something like
1926 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1927 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1928 And, yes, before you ask, <application>Privoxy</application> can co-exist
1929 with other kinds of proxies like <application>Squid</application>.
1930 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1931 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1932 manual</ulink> for details.
1936 <sect2 renderas="sect3">
1937 <title id="firewall">What about as a firewall? Can Privoxy protect me?</title>
1939 Not in the way you mean, or in the way some firewall vendors claim they can.
1940 <application>Privoxy</application> can help protect your privacy, but can't
1941 protect your system from intrusion attempts. It is, of course, perfectly possible
1942 to use <emphasis>both</emphasis>.
1946 <sect2 renderas="sect3">
1947 <title id="wasted">I have large empty spaces / a checkerboard pattern now where
1948 ads used to be. Why?</title>
1950 It is technically possible to eliminate banners and ads in a way that frees
1951 their allocated page space. This could easily be done by blocking with
1952 <application>Privoxy's</application> filters,
1953 and eliminating the <emphasis>entire</emphasis> image references from the
1957 But, this would consume considerably more CPU resources (IOW, slow things
1958 down), would likely destroy the layout of some web pages which rely on the
1959 banners utilizing a certain amount of page space, and might fail in other
1960 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1961 Also, making ads and banners disappear without any trace complicates
1962 troubleshooting, and would sooner or later be problematic.
1965 The better alternative is to instead let them stay, and block the resulting
1966 requests for the banners themselves as is now the case. This leaves either
1967 empty space, or the familiar checkerboard pattern.
1970 So the developers won't support this in the default configuration, but you
1971 can of course define appropriate filters yourself to achieve this.
1975 <sect2 renderas="sect3">
1976 <title id="ssl">How can Privoxy filter Secure (HTTPS) URLs?</title>
1978 Since secure HTTP connections are encrypted SSL sessions between your browser
1979 and the secure site, and are meant to be reliably <emphasis>secure</emphasis>,
1980 there is little that <application>Privoxy</application> can do but hand the raw
1981 gibberish data though from one end to the other unprocessed.
1984 The only exception to this is blocking by host patterns, as the client needs
1985 to tell <application>Privoxy</application> the name of the remote server,
1986 so that <application>Privoxy</application> can establish the connection.
1987 If that name matches a host-only pattern, the connection will be blocked.
1990 As far as ad blocking is concerned, this is less of a restriction than it may
1991 seem, since ad sources are often identifiable by the host name, and often
1992 the banners to be placed in an encrypted page come unencrypted nonetheless
1993 for efficiency reasons, which exposes them to the full power of
1994 <application>Privoxy</application>'s ad blocking.
1997 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
1998 JS page content, see <literal><ulink
1999 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
2000 in an SSL transaction will be impossible to block under these conditions.
2001 Fortunately, this does not seem to be a very common scenario since most
2002 cookies come by traditional means.
2007 <sect2 renderas="sect3">
2008 <title id="secure">Privoxy runs as a <quote>server</quote>. How
2009 secure is it? Do I need to take any special precautions?</title>
2011 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2012 user, which is how we recommend it be run. Also, by default
2013 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2017 The server aspect of <application>Privoxy</application> is not itself directly
2018 exposed to the Internet in this configuration. If you want to have
2019 <application>Privoxy</application> serve as a LAN proxy, this will have to
2020 be opened up to allow for LAN requests. In this case, we'd recommend
2021 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2022 <application>Privoxy</application> configuration file and check all <ulink
2023 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2024 options</ulink>. All LAN hosts can then use this as their proxy address
2025 in the browser proxy configuration, but <application>Privoxy</application>
2026 will not listen on any external interfaces. ACLs can be defined in addition,
2027 and using a firewall is always good too. Better safe than sorry.
2032 <sect2 renderas="sect3" id="turnoff">
2033 <title>Can I temporarily disable Privoxy?</title>
2035 &my-app; doesn't have a transparent proxy mode,
2036 but you can toggle off blocking and content filtering.
2039 The easiest way to do that is to point your browser
2040 to the remote toggle URL: <ulink
2041 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2044 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2045 of the <citetitle>User Manual</citetitle> for an easy way to access this
2046 feature. Note that this is a feature that may need to be enabled in the main
2047 <filename>config</filename> file.
2052 <sect2 renderas="sect3" id="reallyoff">
2053 <title>When <quote>disabled</quote> is Privoxy totally
2054 out of the picture?</title>
2056 No, this just means all optional filtering and actions are disabled.
2057 <application>Privoxy</application> is still acting as a proxy, but just
2058 doing less of the things that <application>Privoxy</application> would
2059 normally be expected to do. It is still a <quote>middle-man</quote> in
2060 the interaction between your browser and web sites. See below to bypass
2065 <sect2 renderas="sect3" id="turnoff2">
2066 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2068 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2069 configuration issue, not a &my-app; issue. Modern browsers typically do have
2070 settings for not proxying certain sites. Check your browser's help files.
2075 <sect2 renderas="sect3" id="crunch">
2076 <title>My logs show Privoxy <quote>crunches</quote>
2077 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2079 A <quote>crunch</quote> simply means <application>Privoxy</application> intercepted
2080 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2081 banners, but <application>Privoxy</application> uses the same mechanism for
2082 trapping requests for its own internal pages. For instance, a request for
2083 <application>Privoxy's</application> configuration page at: <ulink
2084 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2085 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2086 configuration is returned to the browser, and the log consequently will show
2087 a <quote>crunch</quote>.
2090 Since version 3.0.7, Privoxy will also log the crunch reason.
2091 If you are using an older version you might want to upgrade.
2095 <sect2 renderas="sect3" id="downloads">
2096 <title>Can Privoxy affect files that I download
2097 from a webserver? FTP server?</title>
2099 From the webserver's perspective, there is no difference between
2100 viewing a document (i.e. a page), and downloading a file. The same is true of
2101 <application>Privoxy</application>. If there is a match for a <literal><ulink
2102 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2103 it will still be blocked, and of course this is obvious.
2106 Filtering is potentially more of a concern since the results are not always
2107 so obvious, and the effects of filtering are there whether the file is simply
2108 viewed, or downloaded. And potentially whether the content is some obnoxious
2109 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2110 one of these presumably is <quote>bad</quote> content that we don't want, and
2111 the other is <quote>good</quote> content that we do want.
2112 <application>Privoxy</application> is blind to the differences, and can only
2113 distinguish <quote>good from bad</quote> by the configuration parameters
2114 <emphasis>we</emphasis> give it.
2117 <application>Privoxy</application> knows the differences in files according
2118 to the <quote>Content Type</quote> as reported by the webserver. If this is
2119 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2120 then <application>Privoxy</application> knows to ignore these where
2121 appropriate. <application>Privoxy</application> potentially can filter HTML
2122 as well as plain text documents, subject to configuration parameters of
2123 course. Also, documents that are of an unknown type (generally assumed to be
2124 <quote>text/plain</quote>) can be filtered, as will those that might be
2125 incorrectly reported by the webserver. If such a file is a downloaded file
2126 that is intended to be saved to disk, then any content that might have been
2127 altered by filtering, will be saved too, for these (probably rare) cases.
2130 Note that versions later than 3.0.2 do NOT filter document types reported as
2131 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2132 did filter this document type.
2135 In short, filtering is <quote>ON</quote> if a) the content type as reported
2136 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2137 allows it (or at least does not disallow it). That's it. There is no magic
2138 cookie anywhere to say this is <quote>good</quote> and this is
2139 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2142 If you download text files, you probably do not want these to be filtered,
2143 particularly if the content is source code, or other critical content. Source
2144 code sometimes might be mistaken for Javascript (i.e. the kind that might
2145 open a pop-up window). It is recommended to turn off filtering for download
2146 sites (particularly if the content may be plain text files and you are using
2147 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2148 also, for any site or page where making <emphasis>any</emphasis> changes at
2149 all to the content is to be avoided.
2152 <application>Privoxy</application> does not do FTP at all, only HTTP
2153 and HTTPS (SSL) protocols.
2157 <sect2 renderas="sect3" id="downloads2">
2158 <title>I just downloaded a Perl script, and Privoxy
2159 altered it! Yikes, what is wrong!</title>
2165 <sect2 renderas="sect3" id="hostsfile">
2166 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2168 One time-tested technique to defeat common ads is to trick the local DNS
2169 system by giving a phony IP address for the ad generator in the local
2170 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2171 <literal>localhost</literal>. This effectively blocks the ad.
2174 There is no reason to use this technique in conjunction with
2175 <application>Privoxy</application>. <application>Privoxy</application>
2176 does essentially the same thing, much more elegantly and with much more
2177 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2178 duplicates effort, but may get in the way and seriously slow down your system.
2179 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2180 your hosts list is neglected by <application>Privoxy's </application>
2181 configuration, consider adding your list to your <filename>user.action</filename> file:
2188 ads.galore.example.com
2189 etc.example.com</screen>
2193 <sect2 renderas="sect3" id="seealso">
2194 <title>Where can I find more information about Privoxy
2195 and related issues?</title>
2196 <!-- Include seealso.sgml boilerplate: -->
2198 <!-- end boilerplate -->
2203 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2209 <sect2 renderas="sect3" id="microsuck">
2210 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2211 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2214 We're not. The text substitutions that you are seeing are disabled
2215 in the default configuration as shipped. You have either manually
2216 activated the <quote><literal>fun</literal></quote> filter which
2217 is clearly labeled <quote>Text replacements for subversive browsing
2218 fun!</quote> or you are using an older Privoxy version and have implicitly
2219 activated it by choosing the <quote>Advanced</quote> profile in the
2220 web-based editor. Please upgrade.
2224 <sect2 renderas="sect3" id="valid">
2225 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2228 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2229 whenever there are text substitutions via a &my-app; filter. While this
2230 should always conform to the HTML 4.01 specifications, it has not been
2231 validated against this or any other standard.
2235 <sect2 renderas="sect3" id="surprise-privoxy">
2236 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2239 We didn't. We make Privoxy available for download, but we don't go
2240 around installing it on other people's systems behind their back.
2241 If you discover Privoxy running on your system and are sure you didn't
2242 install it yourself, somebody else did. You may not even be running
2243 the real Privoxy, but maybe something else that only pretends to be
2244 Privoxy, or maybe something that is based on the real Privoxy,
2245 but has been modified.
2248 Lately there have been reports of problems with some kind of
2249 "parental control" software based on Privoxy that came preinstalled on
2250 certain <ulink url="http://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2251 The problems described are inconsistent with the behaviour of official
2252 Privoxy versions, which suggests that the preinstalled software may
2253 contain vendor modifications that we don't know about and thus can't debug.
2256 Privoxy's <link linkend="copyright">license</link> allows vendor
2257 modifications, but the vendor has to comply with the license,
2258 which involves informing the user about the changes and to make
2259 the changes available under the same license as Privoxy itself.
2262 If you are having trouble with a modified Privoxy version,
2263 please try to talk to whoever made the modifications before
2264 reporting the problem to us. Please also try to convince
2265 whoever made the modifications to talk to us. If you think
2266 somebody gave you a modified Privoxy version without complying
2267 to the license, please let us know.
2275 <!-- ~~~~~ New section ~~~~~ -->
2277 <sect1 id="trouble">
2278 <title>Troubleshooting</title>
2280 <sect2 renderas="sect3">
2281 <title id="refused">I cannot connect to any websites. Or, I am getting
2282 <quote>connection refused</quote> message with every web page. Why?</title>
2284 There are several possibilities:
2289 <application>Privoxy</application> is not running. Solution: verify
2290 that &my-app; is installed correctly, has not crashed, and is indeed running.
2291 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2293 <listitem><para>Or your browser is configured for a different port than what
2294 <application>Privoxy</application> is using. Solution: verify that &my-app;
2295 and your browser are set to the same port (<literal>listen-address</literal>).
2297 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2298 problem with a host in the forwarding chain. Solution: temporarily alter your
2299 configuration and take the forwarders out of the equation.
2302 Or you have a firewall that is interfering and blocking you. Solution:
2303 try disabling or removing the firewall as a simple test.
2310 <!-- ~~~~~ New section ~~~~~ -->
2311 <sect2 renderas="sect3" id="error503">
2312 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2314 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2315 been reported to cause this symptom -- even if not running! The solution is
2316 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2317 something better behaved in its place. Other personal firewall type products
2318 may cause similar type problems if not configured correctly.
2322 <sect2 renderas="sect3">
2323 <title id="flushit">I just added a new rule, but the steenkin ad is
2324 still getting through. How?</title>
2326 If the ad had been displayed before you added its URL, it will probably be
2327 held in the browser's cache for some time, so it will be displayed without
2328 the need for any request to the server, and <application>Privoxy</application>
2329 will not be involved. Flush the browser's caches, and then try again.
2333 If this doesn't help, you probably have an error in the rule you
2334 applied. Try pasting the full URL of the offending ad into <ulink
2335 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2336 and see if it really matches your new rule. Blocking ads is like blocking
2337 spam: a lot of tinkering is required to stay ahead of the game. And
2338 remember you need to block the URL of the ad in question, which may be
2339 entirely different from the site URL itself. Most ads are hosted on different
2340 servers than the main site itself. If you right-click on the ad, you should
2341 be able to get all the relevant information you need. Alternately, you can
2342 find the correct URL by looking at <application>Privoxy's</application> logs
2343 (you may need to enable logging in the main config file if its disabled).
2346 Below is a slightly modified real-life log snippet that originates with one
2347 requested URL: <literal>www.example.com</literal> (name of site was changed
2348 for this example, the number of requests is real). You can see in this the
2349 complexity of what goes into making up this one <quote>page</quote>. There
2350 are eight different domains involved here, with thirty two separate URLs
2351 requested in all, making up all manner of images, Shockwave Flash,
2352 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2353 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2354 Many of the more questionable looking requests, are going to outside domains
2355 that seem to be identifying themselves with suspicious looking names, making
2356 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2357 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2362 Request: www.example.com/
2363 Request: www.example.com/favicon.ico
2364 Request: img.example.com/main.css
2365 Request: img.example.com/sr.js
2366 Request: example.betamarker.com/example.html
2367 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2368 Request: img.example.com/pb.png
2369 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2370 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2371 Request: img.example.com/p.gif
2372 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2373 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2374 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2375 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2376 Request: www.adtrak.net/adx.js crunch! (Blocked)
2377 Request: img.example.com/hbg.gif
2378 Request: img.example.com/example.jpg
2379 Request: img.example.com/mt.png
2380 Request: img.example.com/mm.png
2381 Request: img.example.com/mb.png
2382 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2383 Request: www.example.com/tracker.js
2384 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2385 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2386 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2387 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2388 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2389 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2390 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2391 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2392 Request: 66.70.21.80/img/pixel.gif
2393 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2394 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2399 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2400 behave perfectly <quote>normal</quote> (minus some ads, of course).
2405 <sect2 id="badsite" renderas="sect3">
2406 <title >One of my favorite sites does not work with Privoxy.
2407 What can I do?</title>
2410 First verify that it is indeed a <application>Privoxy</application> problem,
2411 by toggling off <application>Privoxy</application> through <ulink
2412 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2413 (the toggle feature may need to be enabled in the main
2414 <filename>config</filename>),
2415 and then shift-reloading the problem page (i.e. holding down the shift key
2416 while clicking reload. Alternatively, flush your browser's disk and memory
2421 If the problem went away, we know we have a configuration related problem.
2423 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2424 and paste the full URL of the page in question into the prompt. See which
2425 actions are being applied to the URL, and which matches in which actions
2426 files are responsible for that. It might be helpful also to look at your logs
2427 for this site too, to see what else might be happening (note: logging may need
2428 to be enabled in the main config file). Many sites are
2429 complex and require a number of related pages to help present their content.
2430 Look at what else might be used by the page in question, and what of that
2431 might be <emphasis>required</emphasis>.
2432 Now, armed with this information, go to
2434 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2435 and select the appropriate actions files for editing. </para>
2437 You can now either look for a section which disables the actions that
2438 you suspect to cause the problem and add a pattern for your site there,
2439 or make up a completely new section for your site. In any case, the recommended
2440 way is to disable only the prime suspect, reload the problem page, and only
2441 if the problem persists, disable more and more actions until you have
2442 identified the culprit. You may or may not want to turn the other actions
2443 on again. Remember to flush your browser's caches in between any such changes!
2446 Alternately, if you are comfortable with a text editor, you can accomplish
2447 the same thing by editing the appropriate actions file. Probably the easiest
2448 way to deal with such problems when editing by hand is to add your
2449 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2450 which is an alias that turns off most <quote>dangerous</quote>
2451 actions, but is also likely to turn off more actions then needed, and thus lower
2452 your privacy and protection more than necessary,
2455 Troubleshooting actions is discussed in more detail in the <ulink
2456 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2457 Troubleshooting: the Anatomy of an Action</ulink>.
2458 There is also an <ulink
2459 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2460 with general configuration information and examples.
2463 As a last resort, you can always see if your browser has a setting that will
2464 bypass the proxy setting for selective sites. Modern browsers can do this.
2470 <!-- ~~~~~ New section ~~~~~ -->
2471 <sect2 id="dun" renderas="sect3">
2472 <title>After installing Privoxy, I have to log in
2473 every time I start IE. What gives?</title>
2476 This is a quirk that affects the installation of
2477 <application>Privoxy</application>, in conjunction with Internet Explorer and
2478 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2479 appear to be corrupted or invalid DUN settings, or passwords.
2483 When setting up an NT based Windows system with
2484 <application>Privoxy</application> you may find that things do not seem to be
2485 doing what you expect. When you set your system up you will probably have set
2486 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2487 logged in with administrator privileges. You will probably have made this DUN
2488 connection available to other accounts that you may have set-up on your
2489 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2490 configured for the kids.
2494 When setting up <application>Privoxy</application> in this environment you
2495 will have to alter the proxy set-up of Internet Explorer (IE) for the
2496 specific DUN connection on which you wish to use
2497 <application>Privoxy</application>. When you do this the ICS DUN set-up
2498 becomes user specific. In this instance you will see no difference if you
2499 change the DUN connection under the account used to set-up the connection.
2500 However when you do this from another user you will notice that the DUN
2501 connection changes to make available to "Me only". You will also find that
2502 you have to store the password under each different user!
2506 The reason for this is that each user's set-up for IE is user specific. Each
2507 set-up DUN connection and each LAN connection in IE store the settings for
2508 each user individually. As such this enforces individual configurations
2509 rather than common ones. Hence the first time you use a DUN connection after
2510 re-booting your system it may not perform as you expect, and prompt you for
2511 the password. Just set and save the password again and all should be OK.
2515 [Thanks to Ray Griffith for this submission.]
2520 <!-- ~~~~~ New section ~~~~~ -->
2521 <sect2 id="ftp" renderas="sect3">
2522 <title>I cannot connect to any FTP sites. Privoxy
2523 is blocking me.</title>
2525 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2526 so do not configure your browser to use <application>Privoxy</application>
2527 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2528 or HTTPS (SSL)</emphasis>.
2531 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2532 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2533 an FTP connection, and not a HTTP connection. So while your browser may
2534 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2538 To complicate matters, some systems may have a generic <quote>proxy</quote>
2539 setting, which will enable various protocols, including
2540 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2541 accidentally enable FTP proxying in these cases. And of course, if this
2542 happens, <application>Privoxy</application> will indeed cause problems since
2543 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2544 message if a FTP connection is attempted.]]> Just disable the FTP setting
2545 and all will be well again.
2548 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2549 There just is not much reason, and the work to make this happen is more than
2554 <!-- ~~~~~ New section ~~~~~ -->
2555 <sect2 id="macosxie" renderas="sect3">
2556 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2557 Privoxy as the HTTP proxy.</title>
2559 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2560 network settings. In order to change the HTTP proxy, open System
2561 Preferences, and click on the Network icon. In the settings pane that
2562 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2563 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2564 Enter <literal>8118</literal> in the Port field. The next time you start
2565 IE, it should reflect these values.
2569 <!-- ~~~~~ New section ~~~~~ -->
2570 <sect2 renderas="sect3" id="macosxuninstall">
2571 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2572 uninstall it. Now the finder tells me I don't have sufficient privileges to
2573 empty the trash.</title>
2575 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2578 Just dragging the <application>Privoxy</application> folder to the trash is
2579 not enough to delete it. <application>Privoxy</application> supplies an
2580 <application>uninstall.command</application> file that takes care of
2581 these details. Open the trash, drag the <application>uninstall.command</application>
2582 file out of the trash and double-click on it. You will be prompted for
2583 confirmation and the administration password.
2586 The trash may still appear full after this command; emptying the trash
2587 from the desktop should make it appear empty again.
2591 <!-- ~~~~~ New section ~~~~~ -->
2592 <sect2 renderas="sect3" id="macosximages">
2593 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2594 experience random delays in page loading. I'm using
2595 <literal>localhost</literal> as my browser's proxy setting.</title>
2597 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2598 understand the issue yet. In any case, changing the proxy setting to
2599 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2600 works around the problem.
2604 <!-- ~~~~~ New section ~~~~~ -->
2605 <sect2 renderas="sect3" id="macosxaccountdeletion">
2606 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2609 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2610 X deletes all user accounts that are either not part of OS X itself or are
2611 not interactive user accounts (ones you log in with). Since, for the sake of
2612 security, &my-app; runs as a non-privileged user that is created by its
2613 installer (_privoxy), it can no longer start up once that account gets deleted.
2614 The solution is to perform a complete uninstall using the supplied
2615 <application>uninstall.command</application> script (either back up your
2616 configuration files or select to not have the uninstaller remove them when it
2617 prompts you) and then reinstall &my-app; using the installer package and merge
2618 in your configuration.
2622 <!-- ~~~~~ New section ~~~~~ -->
2623 <!-- XXX: Is this still relevant now that we have gzip support? -->
2624 <sect2 renderas="sect3" id="blankpage">
2625 <title>I get a completely blank page at one site. <quote>View Source</quote>
2626 shows only: <markup><![CDATA[<html><body></body></html>]]></markup>. Without
2627 Privoxy the page loads fine.</title>
2629 Chances are that the site suffers from a bug in
2630 <ulink url="http://www.php.net/"><application>PHP</application></ulink>,
2631 which results in empty pages being sent if the client explicitly requests
2632 an uncompressed page, like <application>Privoxy</application> does.
2633 This bug has been fixed in PHP 4.2.3.
2636 To find out if this is in fact the source of the problem, try adding
2637 the site to a <literal>-prevent-compression</literal> section in
2638 <filename>user.action</filename>:
2641 # Make exceptions for ill-behaved sites:
2643 {-prevent-compression}
2644 .example.com</screen>
2646 If that works, you may also want to report the problem to the
2647 site's webmasters, telling them to use zlib.output_compression
2648 instead of ob_gzhandler in their PHP applications (workaround)
2649 or upgrade to PHP 4.2.3 or later (fix).
2653 <sect2 renderas="sect3" id="nohostname">
2654 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2657 <application>Privoxy</application> tries to get the hostname of the system
2658 its running on from the IP address of the system interface it is bound to
2659 (from the <filename>config</filename> file
2660 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2661 this information, <application>Privoxy</application> logs this condition.
2664 Typically, this would be considered a minor system configuration error. It is
2665 not a fatal error to <application>Privoxy</application> however, but may
2666 result in a much slower response from <application>Privoxy</application> on
2667 some platforms due to DNS timeouts.
2670 This can be caused by a problem with the local <filename>hosts</filename>
2671 file. If this file has been changed from the original, try reverting it to
2672 see if that helps. Make sure whatever name(s) are used for the local system,
2673 that they resolve both ways.
2676 You should also be able to work around the problem with the
2677 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2681 <sect2 renderas="sect3" id="inuse">
2682 <title>When I try to launch Privoxy, I get an
2683 error message <quote>port 8118 is already in use</quote> (or similar wording).
2686 Port 8118 is <application>Privoxy's</application> default TCP
2687 <quote>listening</quote> port. Typically this message would mean that there
2688 is already one instance of <application>Privoxy</application> running, and
2689 your system is actually trying to start a second
2690 <application>Privoxy</application> on the same port, which will not work.
2691 (You can have multiple instances but they must be assigned different ports.)
2692 How and why this might happen varies from platform to platform, but you need
2693 to check your installation and start-up procedures.
2697 <sect2 renderas="sect3" id="demoronizer">
2699 Pages with UTF-8 fonts are garbled.
2702 This may be the result of an overly aggressive filter. The filters that
2703 are enabled in the default configuration aren't expected to cause problems
2704 like this. If you enabled the <quote>demoronizer</quote> filter, please
2705 try temporarily disabling it.
2708 If that doesn't help, temporarily disable all filters to see if another
2709 filter could be the culprit. If the problem disappears, enable the filters
2710 one by one, until the problem reappears and the offending filter is found.
2713 Once the problem-causing filter is known, it can be fixed or disabled.
2716 Upgrading <application>Privoxy</application>, or going to the most recent
2717 <filename>default.action</filename> file available from <ulink
2718 url="http://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2719 might be worth a try, too.
2723 <sect2 renderas="sect3" id="demoronizer2">
2725 Why are binary files (such as images) corrupted when Privoxy
2729 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2730 filter</link> in conjunction with a web server that is misreporting the content
2731 type. By default binary files are exempted from
2732 <application>Privoxy's</application> filtering
2733 (unless the web server by mistake says the file is something else).
2737 <sect2 renderas="sect3" id="demoronizer3">
2739 What is the <quote>demoronizer</quote> and why is it there?
2742 The original demoronizer was a Perl script that cleaned up HTML pages which
2743 were created with certain Microsoft products. MS has used proprietary extensions
2744 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2745 that are viewed with non-Microsoft products (and are expecting to see a
2746 standard set of fonts). The demoronizer corrected these errors so the pages
2747 displayed correctly. <application>Privoxy</application> borrowed from this
2748 script, introducing a filter based on the original demoronizer, which in turn could
2749 correct these errors on the fly.
2752 But this is only needed in some situations, and will cause serious problems in some
2756 If you are using Microsoft products, you do not need it. If you need to view
2757 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2758 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2761 On the other hand, if you use non-Microsoft products, and you occasionally
2762 notice weird characters on pages, you might want to try it.
2766 <sect2 renderas="sect3" id="windowopen">
2768 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2771 <application>Privoxy</application> is attempting to disable malicious
2772 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2773 in this case, with the <literal>unsolicited-popups</literal>
2774 filter. <application>Privoxy</application> cannot tell very well
2775 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2778 If you see this in HTML source, and the page displays without problems, then
2779 this is good, and likely some pop-up window was disabled. If you see this
2780 where it is causing a problem, such as a downloaded program source code file,
2781 then you should set an exception for this site or page such that the
2782 integrity of the page stays in tact by disabling all filtering.
2786 <sect2 renderas="sect3" id="dnserrors">
2788 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2789 can't Privoxy do this better?
2792 There are potentially several factors here. First of all, the DNS resolution
2793 is done by the underlying operating system -- not
2794 <application>Privoxy</application> itself. <application>Privoxy</application>
2795 merely initiates the process and hands it off, and then later reports
2796 whatever the outcome was and tries to give a coherent message if there seems
2797 to be a problem. In some cases, this might otherwise be mitigated by the
2798 browser itself which might try some work-arounds and alternate approaches (e.g
2799 adding <quote>www.</quote> to the URL).
2802 In other cases, if <application>Privoxy</application> is being chained
2803 with another proxy, this could complicate the issue, and cause undue
2804 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2805 server handles all the DNS. <application>Privoxy</application> would just be
2806 the <quote>messenger</quote> which is reporting whatever problem occurred
2807 downstream, and not the root cause of the error.
2811 In any case, versions newer than 3.0.3 include various improvements to help
2812 <application>Privoxy</application> better handle these cases.
2816 <sect2 renderas="sect3" id="allcpu">
2818 At one site Privoxy just hangs, and starts taking
2819 all CPU. Why is this?
2822 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2823 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2824 are in the raw HTML source of the page, and the browser just ignores them. But the
2825 pattern matching in <application>Privoxy's</application> page filtering
2826 mechanism is trying to match against absurdly long strings and this becomes
2827 very CPU-intensive, taking a long, long time to complete.
2830 Until a better solution comes along, disable filtering on these pages,
2831 particularly the <literal>js-annoyances</literal> and
2832 <literal>unsolicited-popups</literal> filters. If you run into this problem
2833 with a recent &my-app; version, please send a problem report.
2837 <sect2 renderas="sect3" id="slowcrawl">
2838 <title>I just installed Privoxy, and all my
2839 browsing has slowed to a crawl. What gives? </title>
2841 This should not happen, and for the overwhelming number of users world-wide,
2842 it does not happen. I would suspect some inadvertent interaction of software
2843 components such as anti-virus software, spyware protectors, personal
2844 firewalls or similar components. Try disabling (or uninstalling) these one
2845 at a time and see if that helps. Either way, if you are using a
2846 recent &my-app; version, please report the problem.
2850 <sect2 renderas="sect3" id="preventcomp">
2851 <title>Why do my filters work on some sites but not on others? </title>
2853 It's probably due to compression. It is a common practice for web servers to
2854 send their content <quote>compressed</quote> in order to speed things up, and
2855 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2856 &my-app; can decompress content before filtering, otherwise you may want to enable
2858 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2861 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2866 <sect2 renderas="sect3" id="ssl-warnings">
2867 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2868 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2869 What's going on?</title>
2871 Probably the browser is requesting ads through HTTPS and &my-app;
2872 is blocking the requests. Privoxy's error messages are delivered
2873 unencrypted and while it's obvious for the browser that the HTTPS
2874 request is already blocked by the proxy, some warn about unauthenticated
2878 To work around the problem you can redirect those requests to an invalid
2879 local address instead of blocking them. While the redirects aren't
2880 encrypted either, many browsers don't care. They simply follow the
2881 redirect, fail to reach a server and display an error message instead
2885 To do that, enable logging to figure out which requests get blocked by
2886 &my-app; and add the hosts (no path patterns) to a section like this:
2891 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2897 Additionally you have to configure your browser to contact
2898 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2901 To add a proxy exception in <application>Mozilla Firefox</application>
2902 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2903 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2904 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2910 <sect2 renderas="sect3" id="se-linux">
2911 <title>I get selinux error messages. How can I fix this?</title>
2913 Please report the problem to the creator of your selinux policies.
2916 The problem is that some selinux policy writers aren't familiar
2917 with the application they are trying to <quote>secure</quote> and
2918 thus create policies that make no sense.
2921 In <application>Privoxy's</application> case the problem usually
2922 is that the policy only allows outgoing connections for certain
2923 destination ports (e.g. 80 and 443). While this may cover the
2924 standard ports, websites occasionally use other ports as well.
2925 This isn't a security problem and therefore <application>Privoxy's</application>
2926 default configuration doesn't block these requests.
2929 If you really want to block these ports (and don't be able
2930 to load websites that don't use standard ports), you should
2931 configure Privoxy to block these ports as well, so it doesn't
2932 trigger the selinux warnings.
2937 <sect2 renderas="sect3" id="gentoo-ricers">
2938 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2940 Probably you unintentionally compiled &my-app; without threading support
2941 in which case requests have to be serialized and only one can be served
2945 Check your <quote>USE</quote> flags and make sure they include
2946 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2949 If you compiled &my-app; with threading support (on POSIX-based systems),
2950 the <quote>Conditional #defines</quote> section on <ulink
2951 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2952 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2959 <!-- ~~~~~ New section ~~~~~ -->
2960 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
2961 <!-- Include contacting.sgml -->
2963 <!-- end contacting -->
2966 <!-- ~~~~~ New section ~~~~~ -->
2967 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
2969 <!-- Include copyright.sgml -->
2975 Portions of this document are <quote>borrowed</quote> from the original
2976 <application>Junkbuster</application> (tm) FAQ, and modified as
2977 appropriate for <application>Privoxy</application>.
2980 <!-- ~~~~~ New section ~~~~~ -->
2981 <sect2><title>License</title>
2982 <!-- Include copyright.sgml: -->
2984 <!-- end copyright -->
2986 <!-- ~ End section ~ -->
2988 <!-- ~~~~~ New section ~~~~~ -->
2989 <sect2><title>History</title>
2990 <!-- Include history.sgml -->
2996 <!-- ~ End section ~ -->
2999 <!-- ~~~~~ New section ~~~~~ -->
3001 <sect1 id="seealso"><title>See also</title>
3003 <!-- Include seealso.sgml -->
3013 This program is free software; you can redistribute it
3014 and/or modify it under the terms of the GNU General
3015 Public License as published by the Free Software
3016 Foundation; either version 2 of the License, or (at
3017 your option) any later version.
3019 This program is distributed in the hope that it will
3020 be useful, but WITHOUT ANY WARRANTY; without even the
3021 implied warranty of MERCHANTABILITY or FITNESS FOR A
3022 PARTICULAR PURPOSE. See the GNU General Public
3023 License for more details.
3025 The GNU General Public License should be included with
3026 this file. If not, you can view it at
3027 http://www.gnu.org/copyleft/gpl.html
3028 or write to the Free Software Foundation, Inc.,
3029 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA