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 2.122 2016/05/22 12:41:30 fabiankeil Exp $
32 Copyright (C) 2001-2014 Privoxy Developers https://www.privoxy.org/
35 Based partially on the Internet Junkbuster FAQ originally written by and
36 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
37 http://www.junkbusters.com/
39 <Qandaset defaultlabel='qanda'>
54 ========================================================================
55 NOTE: Please read developer-manual/documentation.html before touching
58 Please we keep the info in this file as version independent as possible
59 so we only have to maintain one FAQ. Where significant changes are
60 made to Privoxy configuration, please note the change in such a way that
61 it makes sense to both users of older and newer versions.
62 ========================================================================
68 <article id="index" class="faq">
70 <title>Privoxy Frequently Asked Questions</title>
74 <!-- Completely the wrong markup, but very little is allowed -->
75 <!-- in this part of an article. FIXME -->
76 <link linkend="copyright">Copyright</link> &my-copy; 2001-2014 by
77 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
81 <pubdate>$Id: faq.sgml,v 2.122 2016/05/22 12:41:30 fabiankeil Exp $</pubdate>
85 Note: this should generate a separate page, and a live link to it.
86 But it doesn't for some mysterious reason. Please leave commented
87 unless it can be fixed proper. For the time being, the copyright
88 statement will be in copyright.smgl.
92 <legalnotice id="legalnotice">
94 text goes here ........
104 <orgname>By: Privoxy Developers</orgname>
113 This is here to keep vim syntax file from breaking :/
114 If I knew enough to fix it, I would.
115 PLEASE DO NOT REMOVE! HB: hal@foobox.net
120 This FAQ gives quick answers to frequently asked questions about
121 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
122 It is not a substitute for the
123 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
125 This works, at least in some situtations:
126 Test: <ulink url="privoxy-user-manual.pdf"><citetitle>User Manual</citetitle></ulink>.
130 <!-- Include privoxy.sgml boilerplate: -->
131 <para>What is Privoxy?</para> &p-intro;
132 <!-- end boilerplate -->
135 Please note that this document is a work in progress. This copy represents
136 the state at the release of version &p-version;.
137 You can find the latest version of the document at <ulink
138 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
139 Please see the <link linkend="contact">Contact section</link> if you want to
140 contact the developers.
147 <!-- ~~~~~ New section ~~~~~ -->
149 <sect1 id="general"><title>General Information</title>
150 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
152 Anyone who is interested in security, privacy, or in
153 finer-grained control over their web and Internet experience.
157 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
160 &my-app; is certainly a good choice, especially for those who want more
161 control and security. Those with the willingness to read the documentation
162 and the ability to fine-tune their installation will benefit the most.
165 One of <application>Privoxy's</application>
166 strengths is that it is highly configurable giving you the ability to
167 completely personalize your installation. Being familiar with, or at least
168 having an interest in learning about <ulink
169 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
170 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
171 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
172 Expressions</quote></ulink>
173 will be a big plus and will help you get the most out of &my-app;.
174 A new installation just includes a very basic configuration. The user
175 should take this as a starting point only, and enhance it as he or she
176 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
180 Much of <application>Privoxy's</application> configuration can be done
181 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
182 But there are areas where configuration is done using a
183 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
184 to edit configuration files. Also note that the web-based action editor
185 doesn't use authentication and should only be enabled in environments
186 where all clients with access to &my-app; listening port can be trusted.
190 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
191 Privoxy work? </title>
193 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
194 is a service, based on a software such as &my-app;, that clients
195 (i.e. browsers) can use instead of connecting to web servers directly.
196 The clients then ask the proxy to request objects (web pages, images, movies etc)
197 on their behalf and to forward the data to the clients.
198 It is a <quote>go-between</quote>. For details, see
199 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
202 There are many reasons to use web proxies, such as security (firewalling),
203 efficiency (caching) and others, and there are any number of proxies
204 to accommodate those needs.
207 &my-app; is a proxy that is primarily focused on
208 privacy enhancement, ad and junk elimination and freeing the user from
209 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
210 it is in a perfect position to filter outbound personal information that your
211 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
212 this, all of which are under your complete control via the various configuration
213 files and options. Being a proxy also makes it easier to share
214 configurations among multiple browsers and/or users.
218 <sect2 renderas="sect3" id="otherstuff">
219 <title>Does Privoxy do anything more than ad blocking?</title>
221 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
222 can be used to sanitize and customize web browsing.
226 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
227 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
229 <!-- Include history.sgml -->
236 <sect2 renderas="sect3" id="whyprivoxy">
237 <title>Why <quote>Privoxy</quote>? Why change the name from
238 Junkbuster at all?</title>
240 Though outdated, Junkbusters Corporation continued to offer their original
241 version of the <application>Internet Junkbuster</application> for a while,
242 so publishing our <application> Junkbuster</application>-derived software
243 under the same name would have led to confusion.
246 There were also potential legal reasons not to use the
247 <application>Junkbuster</application> name, as it was (and maybe still is)
248 a registered trademark of Junkbusters Corporation.
249 There were, however, no objections from Junkbusters Corporation to the
250 <application>Privoxy</application> project itself, and they, in fact,
251 shared our ideals and goals.
254 The Privoxy developers also believed that there were so many improvements
255 over the original code, that it was time to make a clean break from the past
256 and make a name in their own right.
259 <application>Privoxy</application> is the
260 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
261 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
262 control, more freedom, and allows you to browse your personal and
263 <quote><emphasis>private</emphasis> edition</quote> of the web.
267 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
268 from the old Junkbuster?</title>
270 <application>Privoxy</application> picks up where
271 <application>Junkbuster</application> left off.
272 <application>Privoxy</application> still blocks ads and banners,
274 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
275 helps protect your privacy. But, most of these features have been enhanced,
276 and many new ones have been added, all in the same vein.
279 <application>Privoxy</application>'s new features include:
282 <!-- Include newfeatures.sgml: -->
288 <sect2 renderas="sect3" id="whatsanad">
289 <title>How does Privoxy know what is an ad, and what is not?</title>
291 <application>Privoxy</application>'s approach to blocking ads is twofold:
294 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
295 of banner images. This applies to both the path (you wouldn't guess how many
296 web sites serve their banners from a directory called <quote>banners</quote>!)
297 and the host (blocking the big banner hosting services like doublecklick.net
298 already helps a lot). <application>Privoxy</application> takes advantage of this
299 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
300 patterns</ulink> to sort out and block the requests for things that sound
301 like they would be ads or banners.
304 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
305 can't tell the size of an image by its URL without downloading it, and if you
306 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
307 also inspects the HTML sources of web pages while they are loaded, and replaces
308 references to images with standard banner sizes by dummy references, so that
309 your browser doesn't request them anymore in the first place.
312 Both of this involves a certain amount of guesswork and is, of course, freely
313 and readily configurable.
317 <sect2 renderas="sect3" id="mistakes">
318 <title>Can Privoxy make mistakes?
319 This does not sound very scientific.</title>
321 Actually, it's a black art ;-) And yes, it is always possible to have a broad
322 rule accidentally block or change something by mistake. You will almost surely
323 run into such situations at some point. It is tricky writing rules to
324 cover every conceivable possibility, and not occasionally get false positives.
328 But this should not be a big concern since the
329 <application>Privoxy</application> configuration is very flexible, and
330 includes tools to help identify these types of situations so they can be
331 addressed as needed, allowing you to customize your installation.
332 (<link linkend="badsite">See the Troubleshooting section below</link>.)
337 <sect2 renderas="sect3" id="configornot">
338 <title>Will I have to configure Privoxy
339 before I can use it?</title>
341 That depends on your expectations.
342 The default installation should give you a good starting
343 point, and block <emphasis>most</emphasis> ads and unwanted content,
344 but many of the more advanced features are off by default, and require
345 you to activate them.
348 You do have to set up your browser to use
349 <application>Privoxy</application> (see the <link
350 linkend="firststep">Installation section below</link>).
353 And you will certainly run into situations where there are false positives,
354 or ads not being blocked that you may not want to see. In these cases, you
355 would certainly benefit by customizing <application>Privoxy's</application>
356 configuration to more closely match your individual situation. And we
357 encourage you to do this. This is where the real power of
358 <application>Privoxy</application> lies!
363 <sect2 renderas="sect3" id="lan">
364 <title>Can Privoxy run as a server on a network?</title>
366 Yes, &my-app; runs as a server already, and can easily be configured to
367 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
368 How can I set up Privoxy to act as a proxy for my LAN</link> below.
372 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
373 Privoxy. Why should I use Privoxy at all?</title>
375 Modern browsers do indeed have <emphasis>some</emphasis> of the same
376 functionality as <application>Privoxy</application>. Maybe this is
377 adequate for you. But <application>Privoxy</application> is very
378 versatile and powerful, and can probably do a number of things
379 your browser just can't.
382 In addition, a proxy is good choice if you use multiple browsers, or
383 have a LAN with multiple computers since &my-app; can run as a server
384 application. This way all the configuration is in one place, and you don't
385 have to maintain a similar configuration for possibly many browsers or
389 Note, however, that it's recommended to leverage both your browser's
390 and <application>Privoxy's</application> privacy enhancing features
391 at the same time. While your browser probably lacks some features
392 &my-app; offers, it should also be able to do some things more
393 reliably, for example restricting and suppressing JavaScript.
397 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
399 The most important reason is because you have access to
400 <emphasis>everything</emphasis>, and you can control everything. You can
401 check every line of every configuration file yourself. You can check every
402 last bit of source code should you desire. And even if you can't read code,
403 there should be some comfort in knowing that <!-- thousands of -->other people can,
404 and do read it. You can build the software from scratch, if you want,
405 so that you know the executable is clean, and that it is
406 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
407 is one reason we use &my-app; ourselves.
411 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
412 warranty? Registration?</title>
414 <application>Privoxy</application> is free software and licensed under the <ulink
415 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
416 It is free to use, copy, modify or distribute as you wish under the terms of this
417 license. Please see the <link linkend="copyright">Copyright</link> section for more
418 information on the license and copyright. Or the <filename>LICENSE</filename> file
419 that should be included.
422 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
423 That is something that would cost real money ;-) There is no registration either.
428 <sect2 renderas="sect3" id="spyware">
429 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
431 No, at least not reliably enough to trust it. &my-app; is not designed to be
432 a malware removal tool and the default configuration doesn't even try to
433 filter out any malware.
436 &my-app; could help prevent contact from (known) sites that use such
437 tactics with appropriate configuration rules, and thus could conceivably
438 prevent contamination from such sites. However, keeping such a configuration
439 up to date would require a lot of time and effort that would be better spend
440 on keeping your software itself up to date so it doesn't have known
446 <sect2 renderas="sect3" id="otherads">
447 <title>Can I use Privoxy with other ad-blocking software?</title>
449 &my-app; should work fine with other proxies and other software in general.
452 But it is probably not necessary to use &my-app; in conjunction with other
453 ad-blocking products, and this could conceivably cause undesirable results.
454 It might be better to choose one software or the other and work a little to
455 tweak its configuration to your liking.
458 Note that this is an advice specific to ad blocking.
462 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
464 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
466 Well, we <emphasis>always</emphasis> need help. There is something for
467 everybody who wants to help us. We welcome new developers, packagers,
468 testers, documentation writers or really anyone with a desire to help in
469 any way. You <emphasis>DO NOT</emphasis> need to be a
470 <quote>programmer</quote>. There are many other tasks available. In fact,
471 the programmers often can't spend as much time programming because of some
472 of the other, more mundane things that need to be done, like checking the
473 Tracker feedback sections or responding to user questions on the mailing
477 So first thing, subscribe to the <ulink
478 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
479 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
480 Developers</ulink> mailing list, join the discussion, help out other users, provide general
481 feedback or report problems you noticed.
484 If you intend to help out with the trackers, you also might want to <ulink
485 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
486 so we don't confuse you with the other name-less users.
489 We also have a <ulink
490 url="../developer-manual/index.html">Developer's Manual</ulink>.
491 While it is partly out of date, it's still worth reading.
494 Our <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup">TODO list</ulink>
495 may be of interest to you as well.
496 Please let us know if you want to work on one of the items listed.
500 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
502 Donations are welcome. Our
503 <ulink url="http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup">TODO list</ulink>
504 is rather long and being able to pay one (or more) developers to work on Privoxy
505 would make a huge difference, even if it was only for a couple of weeks. Donations may
506 also be used for Privoxy-related travel expenses (for example to attend conferences),
507 for hardware used for Privoxy development and for hosting expenses etc.
511 <application>Privoxy</application> is an associated
512 project of <ulink url="http://www.spi-inc.org/">Software
513 in the Public Interest (SPI)</ulink>, which allows us to receive
514 tax-deductible donations in the United States. If you want to donate through
515 SPI, please use <ulink url="http://www.spi-inc.org/donations">SPI's donation page</ulink>
516 to see what the options are.
520 You can also donate to Privoxy using a bank account or a "Paypal" address:
523 Name on account: <ulink url="https://www.zwiebelfreunde.de/">Zwiebelfreunde e.V.</ulink>
524 IBAN: DE95430609671126825604
529 "Paypal" address: privoxy@zwiebelfreunde.de
532 Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany
533 and other countries that recognize German charitable clubs. Feel free to
534 use the Subject field to provide a name to be credited and a list of TODO
535 list items you are interested in the most. For example: Max Mustermann: #16, #1, #14.
539 Note that donations made through Zwiebelfreunde e.V. currently can't be checked
540 automatically so you may not get credited right away. The credits currently
541 reflect donations received before 2016-01-14.
545 If you have any questions regarding donations please mail to either the
546 public user mailing list or, if it's a private matter, to
547 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
556 <!-- ~~~~~ New section ~~~~~ -->
558 <sect1 id="installation"><title>Installation</title>
560 <sect2 renderas="sect3" id="whichbrowsers">
561 <title>Which browsers are supported by Privoxy?</title>
563 Any browser that can be configured to use a proxy, which
564 should be virtually all browsers, including
565 <application>Firefox</application>, <application>Internet
566 Explorer</application>, <application>Opera</application>, and
567 <application>Safari</application> among others.
568 Direct browser support is not an absolute requirement since
569 <application>Privoxy</application> runs as a separate application and talks
570 to the browser in the standardized HTTP protocol, just like a web server
575 <sect2 renderas="sect3" id="whichos">
576 <title>Which operating systems are supported?</title>
578 Include supported.sgml here:
583 <sect2 renderas="sect3" id="email-client">
584 <title>Can I use Privoxy with my email client?</title>
586 As long as there is some way to set a HTTP proxy for the client, then yes,
587 any application can be used, whether it is strictly speaking a
588 <quote>browser</quote> or not. Though this may not be the best approach for
589 dealing with some of the common abuses of HTML in email. See <link
590 linkend="outlook">How can I configure <application>Privoxy</application>
591 with <application>Outlook</application>?</link> below for more on
595 Be aware that HTML email presents a number of unique security and privacy
596 related issues, that can require advanced skills to overcome. The developers
597 recommend using email clients that can be configured to convert HTML to plain
598 text for these reasons.
602 <!-- Nobody is going to still be doing this!
603 <sect2 renderas="sect3" id="newinstall"><title>Can I install
604 Privoxy over Junkbuster?</title>
606 We recommend you un-install <application>Junkbuster</application>
607 first to minimize conflicts and confusion. You may want to
608 save your old configuration files for future reference. The configuration
609 files and syntax have substantially changed, so you will need to manually
610 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
611 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
612 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
616 Note: Some installers may automatically un-install
617 <application>Junkbuster</application>, if present!
623 <sect2 renderas="sect3" id="firststep">
624 <title>I just installed Privoxy. Is there anything
625 special I have to do now?</title>
628 All browsers should be told to use <application>Privoxy</application>
629 as a proxy by specifying the correct proxy address and port number
630 in the appropriate configuration area for the browser. It's possible
631 to combine &my-app; with a packet filter to intercept HTTP requests
632 even if the client isn't explicitly configured to use &my-app;,
633 but where possible, configuring the client is recommended. See
634 <ulink url="../user-manual/startup.html">the User Manual for more
635 details</ulink>. You should also flush your browser's memory and disk
636 cache to get rid of any cached junk items, and remove any stored
637 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
643 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
645 If you set up the <application>Privoxy</application> to run on
646 the computer you browse from (rather than your ISP's server or some
647 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
648 (sometimes referred to as <quote>localhost</quote>,
649 which is the special name used by every computer on the Internet to refer
650 to itself) and the port will be 8118 (unless you used the <ulink
651 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
652 config option to tell <application>Privoxy</application> to run on
656 When configuring your browser's proxy settings you typically enter
657 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
658 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
659 then the number <quote>8118</quote> for <quote>port</quote>.
660 This tells your browser to send all web requests to <application>Privoxy</application>
661 instead of directly to the Internet.
664 <application>Privoxy</application> can also be used to proxy for
665 a Local Area Network. In this case, your would enter either the IP
666 address of the LAN host where <application>Privoxy</application>
667 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
668 Port assignment would be same as above. Note that
669 <application>Privoxy</application> doesn't listen on any LAN interfaces by
673 <application>Privoxy</application> does not currently handle
674 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
678 <sect2 renderas="sect3" id="nothing">
679 <title>I just installed Privoxy, and nothing is happening.
680 All the ads are there. What's wrong?</title>
683 Did you configure your browser to use <application>Privoxy</application>
684 as a proxy? It does not sound like it. See above. You might also try flushing
685 the browser's caches to force a full re-reading of pages. You can verify
686 that <application>Privoxy</application> is running, and your browser
687 is correctly configured by entering the special URL:
688 <ulink url="http://p.p/">http://p.p/</ulink>.
689 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
690 of potential redirect caching problem (see next Q). -->
691 This should take you to a page titled <quote>This is Privoxy..</quote> with
692 access to <application>Privoxy's</application> internal configuration.
693 If you see this, then you are good to go. If you receive a page saying
694 <quote>Privoxy is not running</quote>, then the browser is not set up to use
695 your <application>Privoxy</application> installation.
696 If you receive anything else (probably nothing at all), it could either
697 be that the browser is not set up correctly, or that
698 <application>Privoxy</application> is not running at all. Check the <ulink
699 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
700 on starting <application>Privoxy</application> and browser configuration,
701 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
702 on starting <application>Privoxy</application></ulink> in the
703 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
708 <sect2 renderas="sect3" id="notused">
709 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
710 Privoxy is running and being used.</title>
713 First, make sure that Privoxy is <emphasis>really</emphasis> running and
714 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
715 should see the <application>Privoxy</application> main page. If not, see
716 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
717 on starting <application>Privoxy</application></ulink> in the
718 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
722 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
723 other parts of <application>Privoxy</application>'s web interface show
724 the dummy page, your browser has cached a redirection it encountered before
725 <application>Privoxy</application> was being used. You need to clear your
726 browser's cache. Note that shift-reloading the dummy page won't help, since
727 that'll only refresh the dummy page, not the redirection that lead you there.
731 The procedure for clearing the cache varies from browser to browser. For
732 example, <application>Mozilla/Netscape</application> users would click
733 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
734 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
735 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
736 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
737 In some <application>Firefox</application> versions it's
738 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
739 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
740 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
741 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
748 <!-- ~~~~~ New section ~~~~~ -->
750 <sect1 id="configuration"><title>Configuration</title>
751 <sect2 renderas="sect3" id="actionsfile">
752 <title>What exactly is an <quote>actions</quote> file?</title>
755 &my-app; utilizes the concept of <quote>
756 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
757 that are used to manipulate and control web page data.
758 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
759 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
760 that <application>Privoxy</application> could take while processing a certain
761 request, are configured. Typically, you would define a set of default actions
762 that apply globally to all URLs, then add exceptions to these defaults where needed.
763 There is a wide array of actions available that give the user a high degree
764 of control and flexibility on how to process each and every web page.
768 Actions can be defined on a <ulink
769 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
770 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
771 grouped together and then applied to requests matching one or more patterns.
772 There are many possible actions that might apply to any given site. As an example,
773 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
774 as one of your default actions, but need to accept cookies from a given site,
775 you would need to define an exception for this site in one of your actions
776 files, preferably in <filename>user.action</filename>.
781 <sect2 renderas="sect3" id="actionss">
782 <title>The <quote>actions</quote> concept confuses me. Please list
783 some of these <quote>actions</quote>.</title>
785 For a comprehensive discussion of the actions concept, please refer
786 to the <ulink url="../user-manual/actions-file.html">actions file
787 chapter</ulink> in the <ulink url="../user-manual/index.html">User
788 Manual</ulink>. It includes a <ulink
789 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
790 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
791 file tutorial</ulink> to get you started.
796 <sect2 renderas="sect3" id="actconfig">
797 <title>How are actions files configured? What is the easiest
798 way to do this?</title>
801 Actions files are just text files in a special syntax and can be edited
802 with a text editor. But probably the easiest way is to access
803 <application>Privoxy</application>'s user interface with your web browser
804 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
805 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
806 <quote><ulink url="http://config.privoxy.org/show-status">View &
807 change the current configuration</ulink></quote> from the menu. Note
808 that this feature must be explicitly enabled in the main config file
810 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
815 <sect2 renderas="sect3">
816 <title>There are several different <quote>actions</quote> files. What are
817 the differences?</title>
819 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
820 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
825 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
827 Based on your feedback and the continuing development, updates of
828 <filename>default.action</filename> will be
829 made available from time to time on the <ulink
830 url="https://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
831 our <ulink url="https://sourceforge.net/projects/ijbswa/">project page</ulink>.
835 If you wish to receive an email notification whenever we release updates of
836 <application>Privoxy</application> or the actions file, <ulink
837 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
838 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
843 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
845 The syntax and purpose of configuration files has remained roughly the
846 same throughout the 3.x series, but backwards compatibility is not guaranteed.
847 Also each release contains updated, <quote>improved</quote> versions and it is
848 therefore strongly recommended to install the newer configuration files
849 and merge back your modifications.
853 <sect2 renderas="sect3" id="difficult">
854 <title>Why is the configuration so complicated?</title>
856 <quote>Complicated</quote> is in the eye of the beholder.
859 Privoxy is currently mainly written by and for people who are already
860 familiar with the underlying concepts like regular expressions, HTTP and HTML,
861 or are willing to become familiar with them to be able to get the most
862 out of a powerful and flexible tool such as Privoxy.
865 While everybody is expected to be able to get a Privoxy default installation
866 up and running, fine-tuning requires a certain amount of background
867 information and Privoxy's documentation mainly concentrates on the
868 Privoxy-specific parts while only providing references to the rest.
871 If you or anyone you know has the skills, time and energy to
872 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
876 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
878 The default configuration shouldn't impact the usability of any of these services.
879 It may, however, make all <ulink
880 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
881 temporary, so that your browser will forget your
882 login credentials in between browser sessions. If you would like not to have to log
883 in manually each time you access those websites, simply turn off all cookie handling
884 for them in the <filename>user.action</filename> file. An example for yahoo might
888 <screen># Allow all cookies for Yahoo login:
890 { -<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> }
891 .login.yahoo.com</screen>
894 These kinds of sites are often quite complex and heavy with
895 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
896 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
898 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
902 <screen># Gmail is a _fragile_ site:
904 { <literal>fragile</literal> }
906 mail.google.com</screen>
909 Be sure to flush your browser's caches whenever making these kinds of
910 changes, just to make sure the changes <quote>take</quote>.
913 Make sure the domain, host and path are appropriate as well. Your browser can
914 tell you where you are specifically and you should use that information for
915 your configuration settings. Note that above it is not referenced as
916 <literal>gmail.com</literal>, which is a valid domain name.
921 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
922 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
924 Configuring <application>Privoxy</application> is not entirely trivial. To
925 help you get started, we provide you with three different default action
926 <quote>profiles</quote> in the web based actions file editor at <ulink
927 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
928 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
929 Manual</citetitle></ulink> for a list of actions, and how the default
934 Where the defaults are likely to break some sites, exceptions for
935 known popular <quote>problem</quote> sites are included, but in
936 general, the more aggressive your default settings are, the more exceptions
937 you will have to make later. New users are best to start off in
938 <quote>Cautious</quote> setting. This is safest and will have the fewest
939 problems. See the <ulink
940 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
941 for a more detailed discussion.
945 It should be noted that the <quote>Advanced</quote> profile (formerly known
946 as the <quote>Adventuresome</quote> profile) is more
947 aggressive, and will make use of some of
948 <application>Privoxy's</application> advanced features. Use at your own risk!
953 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
954 with a browser? Does that not raise security issues?</title>
956 It may seem strange that regular users can edit the config files with their
957 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
958 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
961 When you use the browser-based editor, <application>Privoxy</application>
962 itself is writing to the config files. Because
963 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
964 it can update its own config files.
967 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
968 a LAN) or aren't entirely in control of your own browser, you will probably want
969 to make sure that the web-based editor and remote toggle features are
970 <quote>off</quote> by setting <quote><literal><ulink
971 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
972 0</literal></quote> and <quote><literal><ulink
973 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
974 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
977 As of &my-app; 3.0.7 these options are disabled by default.
982 <sect2 renderas="sect3" id="filterfile">
983 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
985 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
986 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
987 Filters are a special subset of actions that can be used to modify or
988 remove web page content or headers on the fly. Content filters can
989 be applied to <emphasis>anything</emphasis> in the page source,
990 header filters can be applied to either server or client headers.
991 Regular expressions are used to accomplish this.
994 There are a number of pre-defined filters to deal with common annoyances. The
995 filters are only defined here, to invoke them, you need to use the
997 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
998 action</ulink> in one of the actions files. Content filtering is automatically
999 disabled for inappropriate MIME types, but if you know better than Privoxy
1000 what should or should not be filtered you can filter any content you like.
1004 <emphasis>not</emphasis> be confused with <ulink
1005 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1006 is a completely different action, and is more typically used to block ads and
1011 If you are familiar with regular expressions, and HTML, you can look at
1012 the provided <filename>default.filter</filename> with a text editor and define
1013 your own filters. This is potentially a very powerful feature, but
1014 requires some expertise in both regular expressions and HTML/HTTP.
1015 <![%p-newstuff;[ You should
1016 place any modifications to the default filters, or any new ones you create
1017 in a separate file, such as <filename>user.filter</filename>, so they won't
1018 be overwritten during upgrades.
1019 The ability to define multiple filter files
1020 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1024 There is no GUI editor option for this part of the configuration,
1025 but you can disable/enable the various pre-defined filters of the included
1026 <filename>default.filter</filename> file with the <ulink
1027 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1028 Note that the custom actions editor must be explicitly enabled in
1029 the main config file (see <ulink
1030 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1034 If you intend to develop your own filters, you might want to have a look at
1036 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1041 <sect2 renderas="sect3" id="lanconfig">
1042 <title>How can I set up Privoxy to act as a proxy for my
1045 By default, <application>Privoxy</application> only responds to requests
1046 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1047 a network, this needs to be changed in the <ulink
1048 url="../user-manual/config.html">main configuration file</ulink>. Look for
1050 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1051 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1052 it is uncommented, and assign it the address of the LAN gateway interface,
1053 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1054 wish to run <application>Privoxy</application> on port 8118, this line
1060 listen-address 192.168.1.1:8118</screen>
1064 Save the file, and restart <application>Privoxy</application>. Configure
1065 all browsers on the network then to use this address and port number.
1069 Alternately, you can have <application>Privoxy</application> listen on
1070 all available interfaces:
1075 listen-address :8118</screen>
1079 And then use <application>Privoxy's</application>
1081 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1082 feature to limit connections. A firewall in this situation is recommended
1087 The above steps should be the same for any TCP network, regardless of
1092 If you run <application>Privoxy</application> on a LAN with untrusted users,
1093 we recommend that you double-check the <ulink
1094 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1101 <sect2 renderas="sect3" id="noseeum">
1102 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1104 The replacement for blocked images can be controlled with the <ulink
1105 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1106 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1107 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1108 Note that this choice only has effect for images which are blocked as images, i.e.
1109 whose URLs match both a <literal><ulink
1110 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1111 <emphasis>and</emphasis> <literal><ulink
1112 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1115 If you want to see nothing, then change the <ulink
1116 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1117 action</ulink> to <quote>blank</quote>. This can be done by editing the
1118 <filename>user.action</filename> file, or through the <ulink
1119 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1124 <sect2 renderas="sect3" id="whyseeum">
1125 <title>Why would anybody want to see a checkerboard pattern?</title>
1127 Remember that <link linkend="whatsanad">telling which image is an ad and which
1128 isn't</link>, is an educated guess. While we hope that the standard configuration
1129 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1130 decent, and it shows you where images have been blocked, which can be very
1131 helpful in case some navigation aid or otherwise innocent image was
1132 erroneously blocked. It is recommended for new users so they can
1133 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1134 many banners they <emphasis>don't</emphasis> have to see.
1139 <sect2 renderas="sect3" id="blockedbytext">
1140 <title>I see some images being replaced with text
1141 instead of the checkerboard image. Why and how do I get rid of this?</title>
1143 This happens when the banners are not embedded in the HTML code of the
1144 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1145 or (i)layers, and these external HTML documents are blocked. Being non-images
1146 they get replaced by a substitute HTML page rather than a substitute image,
1147 which wouldn't work out technically, since the browser expects and accepts
1148 only HTML when it has requested an HTML document.
1151 The substitute page adapts to the available space and shows itself as a
1152 miniature two-liner if loaded into small frames, or full-blown with a
1153 large red "BLOCKED" banner if space allows.
1156 If you prefer the banners to be blocked by images, you must see to it that
1157 the HTML documents in which they are embedded are not blocked. Clicking
1158 the <quote>See why</quote> link offered in the substitute page will show
1159 you which rule blocked the page. After changing the rule and un-blocking
1160 the HTML documents, the browser will try to load the actual banner images
1161 and the usual image blocking will (hopefully!) kick in.
1166 <sect2 renderas="sect3" id="srvany">
1167 <title>Can Privoxy run as a service
1168 on Win2K/NT/XP?</title>
1171 Yes. Version 3.0.5 introduces full <application>Windows</application> service
1172 functionality. See <ulink url="../user-manual/installation.html#installation-pack-win">
1173 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1174 <application>Privoxy</application> as a service.
1177 Earlier ]]>3.x versions could run as a system service using <command>srvany.exe</command>.
1178 See the discussion at <ulink
1179 url="https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</ulink>,
1180 for details, and a sample configuration.
1185 <sect2 renderas="sect3" id="otherproxy">
1186 <title>How can I make Privoxy work with other proxies?</title>
1188 This can be done and is often useful to combine the benefits of
1189 <application>Privoxy</application> with those of a another proxy,
1190 for example to cache content.
1192 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1193 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1194 describes how to do this. If you intend to use Privoxy with Tor,
1195 please also have a look at
1196 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1200 <sect2 renderas="sect3" id="port-80">
1201 <title>Can I just set Privoxy to use port 80
1202 and thus avoid individual browser configuration?</title>
1205 No, its more complicated than that. This only works with special kinds
1206 of proxies known as <quote>intercepting</quote> proxies
1207 (<link linkend="INTERCEPTING">see below</link>).
1212 <sect2 renderas="sect3" id="transparent">
1213 <title>Can Privoxy run as a <quote>transparent
1214 </quote> proxy?</title>
1216 The whole idea of Privoxy is to modify client requests
1217 and server responses in all sorts of ways and therefore
1218 it's not a transparent proxy as described in
1219 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1222 However, some people say <quote>transparent proxy</quote> when they
1223 mean <quote>intercepting proxy</quote>. If you are one of them,
1224 please read the <link linkend="INTERCEPTING">next entry</link>.
1229 <sect2 renderas="sect3" id="intercepting">
1230 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1232 <application>Privoxy</application> can't intercept traffic itself,
1233 but it can handle requests that where intercepted and redirected
1234 with a packet filter (like <application>PF</application> or
1235 <application>iptables</application>), as long as the <literal>Host</literal>
1239 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1240 web sites rely on it anyway, this limitation shouldn't be a problem.
1243 Please refer to your packet filter's documentation to learn how to
1244 intercept and redirect traffic into <application>Privoxy</application>.
1245 Afterward you just have to configure <application>Privoxy</application> to
1246 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1247 intercepted requests</ulink>.
1252 <sect2 renderas="sect3" id="outlook">
1253 <title>How can I configure Privoxy for use with Outlook?</title>
1255 Versions of <application>Outlook</application> prior to Office 2007, use
1256 <application>Internet Explorer</application> components to both render HTML,
1257 and fetch any HTTP requests that may be embedded in an HTML email. So however
1258 you have <application>Privoxy</application> configured to work with IE, this
1259 configuration should automatically be shared, at least with older version of
1263 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1264 engine with Outlook. It is unknown whether this can be configured to use a
1266 <!-- FIXME HB 2009-02-15 -->
1270 <sect2 renderas="sect3" id="outlook-more">
1271 <title>How can I have separate rules just for HTML mail?</title>
1273 The short answer is, you can't. <application>Privoxy</application> has no way
1274 of knowing which particular application makes a request, so there is no way to
1275 distinguish between web pages and HTML mail.
1276 <application>Privoxy</application> just blindly proxies all requests. In the
1277 case of <application>Outlook Express</application> (see above), OE uses
1278 IE anyway, and there is no way for <application>Privoxy</application> to ever
1279 be able to distinguish between them (nor could any other proxy type application for
1283 For a good discussion of some of the issues involved (including privacy and
1284 security issues), see
1285 <ulink url="https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1289 <sect2 renderas="sect3" id="sneaky-cookies">
1290 <title>I sometimes notice cookies sneaking through. How?</title>
1293 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1294 set in several ways. The classic method is via the
1295 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1296 easy one to manipulate, such as the &my-app; concept of
1297 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1298 There is also the possibility of using
1299 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1300 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1301 is trickier because the syntax can vary widely, and thus requires a certain
1302 amount of guesswork. It is not realistic to catch all of these short of
1303 disabling Javascript, which would break many sites. And lastly, if the
1304 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1305 <application>Privoxy's</application> reach.
1308 All in all, &my-app; can help manage cookies in general, can help minimize
1309 the loss of privacy posed by cookies, but can't realistically stop all
1314 <sect2 renderas="sect3" id="evil-cookies">
1315 <title>Are all cookies bad? Why?</title>
1317 No, in fact there are many beneficial uses of
1319 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1320 method that browsers can use to store data between pages, or between browser
1321 sessions. Sometimes there is a good reason for this, and the user's life is a
1322 bit easier as a result. But there is a long history of some websites taking
1323 advantage of this layer of trust, and using the data they glean from you and
1324 your browsing habits for their own purposes, and maybe to your potential
1325 detriment. Such sites are using you and storing their data on your system.
1326 That is why the privacy conscious watch from whom those cookies come, and why
1327 they really <emphasis>need</emphasis> to be there.
1331 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1332 definition</ulink> for more.
1336 <sect2 renderas="sect3" id="allow-cookies">
1337 <title>How can I allow permanent cookies for my trusted sites?</title>
1340 There are several actions that relate to cookies. The default behavior is to
1341 allow only <quote>session cookies</quote>, which means the cookies only last
1342 for the current browser session. This eliminates most kinds of abuse related
1343 to cookies. But there may be cases where you want cookies to last.
1346 To disable all cookie actions, so that cookies are allowed unrestricted,
1347 both in and out, for <literal>example.com</literal>:
1351 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1352 .example.com</screen>
1355 Place the above in <filename>user.action</filename>. Note that some of these may
1356 be off by default anyway, so this might be redundant, but there is no harm
1357 being explicit in what you want to happen. <filename>user.action</filename>
1358 includes an alias for this situation, called
1359 <literal>allow-all-cookies</literal>.
1363 <sect2 renderas="sect3" id="multiples">
1364 <title>Can I have separate configurations for different users?</title>
1366 Each instance of <application>Privoxy</application> has its own
1367 configuration, including such attributes as the TCP port that it listens on.
1368 What you can do is run multiple instances of <application>Privoxy</application>, each with
1370 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1371 configuration setting, and configuration path, and then
1372 each of these can have their own configurations. Think of it as per-port
1376 Simple enough for a few users, but for large installations, consider having
1377 groups of users that might share like configurations.
1381 <sect2 renderas="sect3" id="whitelists">
1382 <title>Can I set-up Privoxy as a whitelist of
1383 <quote>good</quote> sites?</title>
1385 Sure. There are a couple of things you can do for simple white-listing.
1386 Here's one real easy one:
1389 ############################################################
1391 ############################################################
1392 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1393 / # Block *all* URLs
1395 ############################################################
1397 ############################################################
1398 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1401 games.example.com</screen>
1403 This allows access to only those three sites by first blocking all URLs, and
1404 then subsequently allowing three specific exceptions.
1407 Another approach is <application>Privoxy's</application>
1408 <literal>trustfile</literal> concept, which incorporates the notion of
1409 <quote>trusted referrers</quote>. See the <ulink
1410 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1414 These are fairly simple approaches and are not completely foolproof. There
1415 are various other configuration options that should be disabled (described
1416 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1417 so that users can't modify their own configuration and easily circumvent the
1422 <sect2 renderas="sect3" id="no-adblock">
1423 <title>How can I turn off ad-blocking?</title>
1425 Ad blocking is achieved through a complex application of various &my-app;
1426 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1427 actions are deployed against simple images, banners, flash animations,
1428 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1429 just turning one or two actions off. The various actions that make up
1430 &my-app; ad blocking are hard-coded into the default configuration files. It
1431 has been assumed that everyone using &my-app; is interested in this
1435 If you want to do without this, there are several approaches you can take:
1436 You can manually undo the many block rules in
1437 <filename>default.action</filename>. Or even easier, just create your own
1438 <filename>default.action</filename> file from scratch without the many ad
1439 blocking rules, and corresponding exceptions. Or lastly, if you are not
1440 concerned about the additional blocks that are done for privacy reasons, you
1441 can very easily over-ride <emphasis>all</emphasis> blocking with the
1442 following very simple rule in your <filename>user.action</filename>:
1446 # Unblock everybody, everywhere
1447 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1448 / # UN-Block *all* URLs</screen>
1451 Or even a more comprehensive reversing of various ad related actions:
1455 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1456 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1457 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1458 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1459 <literal>allow-popups</literal> \
1461 / # UN-Block *all* URLs and allow ads</screen>
1464 This last <quote>action</quote> in this compound statement,
1465 <literal>allow-popups</literal>, is an <ulink
1466 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1467 various pop-up blocking features.
1471 <sect2 renderas="sect3" id="templates">
1472 <title>How can I have custom template pages, like the
1473 <emphasis>BLOCKED</emphasis> page?</title>
1475 &my-app; <quote>templates</quote> are specialized text files utilized by
1476 &my-app; for various purposes and can easily be modified using any text
1477 editor. All the template pages are installed in a sub-directory appropriately
1478 named: <filename>templates</filename>. Knowing something about HTML syntax
1479 will of course be helpful.
1482 Be forewarned that the default templates are subject to being overwritten
1483 during upgrades. You can, however, create completely new templates,
1484 place them in another directory and specify the alternate path in the main
1485 <filename>config</filename>. For details, have a look at the <ulink
1486 url="../user-manual/config.html#templdir">templdir</ulink> option.
1490 <sect2 renderas="sect3" id="blockall">
1491 <title>How can I remove the <quote>Go There Anyway</quote> link from
1492 the <emphasis>BLOCKED</emphasis> page?</title>
1494 There is more than one way to do it (although Perl is not involved).
1497 Editing the BLOCKED template page (see above) may dissuade some users, but
1498 this method is easily circumvented. Where you need this level of control, you
1499 might want to build &my-app; from source, and disable various features that are
1500 available as compile-time options. You should
1501 <command>configure</command> the sources as follows:
1505 ./configure --disable-toggle --disable-editor --disable-force</screen>
1508 This will create an executable with hard-coded security features so that
1509 &my-app; does not allow easy bypassing of blocked sites, or changing the
1510 current configuration via any connected user's web browser.
1513 Finally, all of these features can also be toggled on/off via options in
1514 <application>Privoxy's</application> main <ulink
1515 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1516 means you don't have to recompile anything.
1522 <!-- ~ End section ~ -->
1525 <!-- ~~~~~ New section ~~~~~ -->
1527 <sect1 id="misc"><title>Miscellaneous</title>
1529 <sect2 renderas="sect3" id="slowsme">
1530 <title>How much does Privoxy slow my browsing down? This
1531 has to add extra time to browsing.</title>
1533 How much of an impact depends on many things, including the CPU of the host
1534 system, how aggressive the configuration is, which specific actions are being triggered,
1535 the size of the page, the bandwidth of the connection, etc.
1538 Overall, it should not slow you down any in real terms, and may actually help
1539 speed things up since ads, banners and other junk are not typically being
1540 retrieved and displayed. The actual processing time required by
1541 <application>Privoxy</application> itself for each page, is relatively small
1542 in the overall scheme of things, and happens very quickly. This is typically
1543 more than offset by time saved not downloading and rendering ad images and
1544 other junk content (if ad blocking is being used).
1548 <quote>Filtering</quote> content via the <literal><ulink
1549 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1551 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1552 actions may cause a perceived slowdown, since the entire document
1553 needs to be buffered before displaying. And on very large documents,
1554 filtering may have some measurable impact. How much depends on the page size,
1555 the actual definition of the filter(s), etc. See below. Most other actions
1556 have little to no impact on speed.
1559 Also, when filtering is enabled but zlib support isn't available, compression
1560 is often disabled (see <ulink
1561 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1562 This can have an impact on speed as well, although it's probably smaller than
1563 you might think. Again, the page size, etc. will determine how much of an impact.
1569 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1570 delays in page requests. What's wrong?</title>
1572 If you use any <literal><ulink
1573 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1574 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1575 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1576 action, the entire document must be loaded into memory in order for the filtering
1577 mechanism to work, and nothing is sent to the browser during this time.
1580 The loading time typically does not really change much in real numbers, but
1581 the feeling is different, because most browsers are able to start rendering
1582 incomplete content, giving the user a feeling of "it works". This effect is
1583 more noticeable on slower dialup connections. Extremely large documents
1584 may have some impact on the time to load the page where there is filtering
1585 being done. But overall, the difference should be very minimal. If there is a
1586 big impact, then probably some other situation is contributing (like
1587 anti-virus software).
1590 Filtering is automatically disabled for inappropriate MIME types. But note
1591 that if the web server mis-reports the MIME type, then content that should
1592 not be filtered, could be. <application>Privoxy</application> only knows how
1593 to differentiate filterable content because of the MIME type as reported by
1594 the server, or because of some configuration setting that enables/disables
1599 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1600 "http://p.p/"?</title>
1602 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1603 address of <application>Privoxy</application>'s built-in user interface, and
1604 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1607 Since <application>Privoxy</application> sits between your web browser and the Internet,
1608 it can simply intercept requests for these addresses and answer them with its built-in
1609 <quote>web server</quote>.
1612 This also makes for a good test for your browser configuration: If entering the
1613 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1614 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1615 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1616 your browser didn't use <application>Privoxy</application> for the request,
1617 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1618 web site at config.privoxy.org.
1621 Note that config.privoxy.org resolves to a public IP address.
1622 If you use config.privoxy.org as ping or traceroute target you will
1623 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1624 If you want to ping the system Privoxy runs on,
1625 you should use its IP address or local DNS name (if it has got one).
1631 out of date 09/02/06 HB
1632 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1634 No. The patterns for blocking now reside (among other things) in the <ulink
1635 url="../user-manual/actions-file.html">actions files</ulink>, which are
1636 actively maintained instead. See next question ...
1640 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1643 Please see the <link linkend="contact">Contact section</link> for
1644 various ways to interact with the developers.
1649 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1650 they be included in future updates?</title>
1652 Whether such submissions are eventually included in the
1653 <filename>default.action</filename> configuration file depends on how
1654 significant the issue is. We of course want to address any potential
1655 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1656 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1657 has a good chance of being a candidate. But at the other end of the spectrum
1658 are any number of smaller, low-profile sites such as for local clubs or
1659 schools. Since their reach and impact are much less, they are best handled by
1660 inclusion in the user's <filename>user.action</filename>, and thus would be
1661 unlikely to be included.
1667 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1670 Rest assured that it has been read and considered. Why it is not answered,
1671 could be for various reasons, including no one has a good answer for it, no
1672 one has had time to yet investigate it thoroughly, it has been reported
1673 numerous times already, or because not enough information was provided to help
1674 us help you. Your efforts are not wasted, and we do appreciate them.
1680 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1682 If you run both the browser and &my-app; locally, you cannot hide your IP
1683 address with <application>Privoxy</application> or ultimately any other
1684 software alone. The server needs to know your IP address so that it knows
1685 where to send the responses back.
1688 There are many publicly usable "anonymous" proxies out there, which
1689 provide a further level of indirection between you and the web server.
1692 However, these proxies are called "anonymous" because you don't need
1693 to authenticate, not because they would offer any real anonymity.
1694 Most of them will log your IP address and make it available to the
1695 authorities in case you violate the law of the country they run in. In fact
1696 you can't even rule out that some of them only exist to *collect* information
1697 on (those suspicious) people with a more than average preference for privacy.
1700 If you want to hide your IP address from most adversaries,
1701 you should consider chaining <application>Privoxy</application>
1702 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1703 The configuration details can be found in
1704 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1705 with <application>Tor</application> section</ulink>
1710 <sect2 renderas="sect3" id="anonforsure">
1711 <title>Can Privoxy guarantee I am anonymous?</title>
1713 No. Your chances of remaining anonymous are improved, but unless you
1714 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1715 or a similar proxy and know what you're doing when it comes to configuring
1716 the rest of your system, you should assume that everything you do
1717 on the Web can be traced back to you.
1720 <application>Privoxy</application> can remove various information about you,
1721 and allows <emphasis>you</emphasis> more freedom to decide which sites
1722 you can trust, and what details you want to reveal. But it neither
1723 hides your IP address, nor can it guarantee that the rest of the system
1724 behaves correctly. There are several possibilities how a web sites can find
1725 out who you are, even if you are using a strict <application>Privoxy</application>
1726 configuration and chained it with <application>Tor</application>.
1729 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1730 by an insecure browser configuration, therefore you should use a browser that can
1731 be configured to only execute code from trusted sites, and be careful which sites you trust.
1732 For example there is no point in having <application>Privoxy</application>
1733 modify the User-Agent header, if websites can get all the information they want
1734 through JavaScript, ActiveX, Flash, Java etc.
1737 A few browsers disclose the user's email address in certain situations, such
1738 as when transferring a file by FTP. <application>Privoxy</application>
1739 does not filter FTP. If you need this feature, or are concerned about the
1740 mail handler of your browser disclosing your email address, you might
1741 consider products such as <application>NSClean</application>.
1744 Browsers available only as binaries could use non-standard headers to give
1745 out any information they can have access to: see the manufacturer's license
1746 agreement. It's impossible to anticipate and prevent every breach of privacy
1747 that might occur. The professionally paranoid prefer browsers available as
1748 source code, because anticipating their behavior is easier. Trust the source,
1754 <sect2 renderas="sect3" id="proxytest">
1755 <title>A test site says I am not using a Proxy.</title>
1757 Good! Actually, they are probably testing for some other kinds of proxies.
1758 Hiding yourself completely would require additional steps.
1762 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1763 together with Tor?</title>
1765 Before you configure <application>Privoxy</application> to use
1766 <ulink url="https://www.torproject.org/">Tor</ulink>,
1767 please follow the <citetitle>User Manual</citetitle> chapters
1768 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1769 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1770 <application>Privoxy</application> itself is setup correctly.
1773 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1774 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1775 and make sure <application>Tor</application>'s logfile says that
1776 <quote>Tor has successfully opened a circuit</quote> and it
1777 <quote>looks like client functionality is working</quote>.
1780 If either <application>Tor</application> or <application>Privoxy</application>
1781 isn't working, their combination most likely will neither. Testing them on their
1782 own will also help you to direct problem reports to the right audience.
1783 If <application>Privoxy</application> isn't working, don't bother the
1784 <application>Tor</application> developers. If <application>Tor</application>
1785 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1788 If you verified that <application>Privoxy</application> and <application>Tor</application>
1789 are working, it is time to connect them. As far as <application>Privoxy</application>
1790 is concerned, <application>Tor</application> is just another proxy that can be reached
1791 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1792 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1793 requests are done through <application>Tor</application> and thus invisible to your
1794 local network. Using socks4a would work too, but with socks5 you get more precise error
1799 <application>Privoxy's</application>
1800 <ulink url="../user-manual/config.html">main configuration file</ulink>
1801 is already prepared for <application>Tor</application>, if you are using a
1802 default <application>Tor</application> configuration and run it on the same
1803 system as &my-app;, you just have to edit the
1804 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1805 and uncomment the line:
1809 # forward-socks5t / 127.0.0.1:9050 .
1813 Note that if you got Tor through one of the bundles, you may
1814 have to change the port from 9050 to 9150 (or even another one).
1815 For details, please check the documentation on the
1816 <ulink url="https://torproject.org/">Tor website</ulink>.
1820 This is enough to reach the Internet, but additionally you might want to
1821 uncomment the following forward rules, to make sure your local network is still
1822 reachable through Privoxy:
1826 # forward 192.168.*.*/ .
1827 # forward 10.*.*.*/ .
1828 # forward 127.*.*.*/ .
1832 Unencrypted connections to systems in these address ranges will
1833 be as (un)secure as the local network is, but the alternative is
1834 that your browser can't reach the network at all. Then again,
1835 that may actually be desired and if you don't know for sure
1836 that your browser has to be able to reach the local network,
1837 there's no reason to allow it.
1840 If you want your browser to be able to reach servers in your local
1841 network by using their names, you will need additional exceptions
1842 that look like this:
1846 # forward localhost/ .
1850 Save the modified configuration file and open
1851 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1852 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1853 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1855 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1856 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1859 Afterward, please take the time to at least skim through the rest
1860 of <application>Tor's</application> documentation. Make sure you understand
1861 what <application>Tor</application> does, why it is no replacement for
1862 application level security, and why you probably don't want to
1863 use it for unencrypted logins.
1867 <sect2 renderas="sect3" id="sitebreak">
1868 <title>Might some things break because header information or
1869 content is being altered?</title>
1872 Definitely. It is common for sites to use browser type, browser version,
1873 HTTP header content, and various other techniques in order to dynamically
1874 decide what to display and how to display it. What you see, and what I see,
1875 might be very different. There are many, many ways that this can be handled,
1876 so having hard and fast rules, is tricky.
1880 The <quote>User-Agent</quote> is sometimes used in this way to identify
1881 the browser, and adjust content accordingly.
1885 Also, different browsers use different encodings of non-English
1886 characters, certain web servers convert pages on-the-fly according to the
1887 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1888 operating system or browser manufacturer causes some sites in these languages
1889 to be garbled; Surfers to Eastern European sites should change it to
1890 something closer. And then some page access counters work by looking at the
1891 <quote>Referer</quote> header; they may fail or break if unavailable. The
1892 weather maps of Intellicast have been blocked by their server when no
1893 <quote>Referer</quote> or cookie is provided, is another example. (But you
1894 can forge both headers without giving information away). There are
1895 many other ways things can go wrong when trying to fool a web server. The
1896 results of which could inadvertently cause pages to load incorrectly,
1897 partially, or even not at all. And there may be no obvious clues as to just
1898 what went wrong, or why. Nowhere will there be a message that says
1899 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1904 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1909 If you have problems with a site, you will have to adjust your configuration
1910 accordingly. Cookies are probably the most likely adjustment that may
1911 be required, but by no means the only one.
1917 <sect2 renderas="sect3" id="caching">
1918 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1919 speed up web browsing?</title>
1921 No, it does not have this ability at all. You want something like
1922 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1923 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1924 And, yes, before you ask, <application>Privoxy</application> can co-exist
1925 with other kinds of proxies like <application>Squid</application>.
1926 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1927 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1928 manual</ulink> for details.
1932 <sect2 renderas="sect3" id="firewall">
1933 <title>What about as a firewall? Can Privoxy protect me?</title>
1935 Not in the way you mean, or in the way some firewall vendors claim they can.
1936 <application>Privoxy</application> can help protect your privacy, but can't
1937 protect your system from intrusion attempts. It is, of course, perfectly possible
1938 to use <emphasis>both</emphasis>.
1942 <sect2 renderas="sect3" id="wasted">
1943 <title>I have large empty spaces / a checkerboard pattern now where
1944 ads used to be. Why?</title>
1946 It is technically possible to eliminate banners and ads in a way that frees
1947 their allocated page space. This could easily be done by blocking with
1948 <application>Privoxy's</application> filters,
1949 and eliminating the <emphasis>entire</emphasis> image references from the
1953 But, this would consume considerably more CPU resources (IOW, slow things
1954 down), would likely destroy the layout of some web pages which rely on the
1955 banners utilizing a certain amount of page space, and might fail in other
1956 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1957 Also, making ads and banners disappear without any trace complicates
1958 troubleshooting, and would sooner or later be problematic.
1961 The better alternative is to instead let them stay, and block the resulting
1962 requests for the banners themselves as is now the case. This leaves either
1963 empty space, or the familiar checkerboard pattern.
1966 So the developers won't support this in the default configuration, but you
1967 can of course define appropriate filters yourself to achieve this.
1971 <sect2 renderas="sect3" id="ssl">
1972 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1974 Since secure HTTP connections are encrypted SSL sessions between your browser
1975 and the secure site, and are meant to be reliably <emphasis>secure</emphasis>,
1976 there is little that <application>Privoxy</application> can do but hand the raw
1977 gibberish data though from one end to the other unprocessed.
1980 The only exception to this is blocking by host patterns, as the client needs
1981 to tell <application>Privoxy</application> the name of the remote server,
1982 so that <application>Privoxy</application> can establish the connection.
1983 If that name matches a host-only pattern, the connection will be blocked.
1986 As far as ad blocking is concerned, this is less of a restriction than it may
1987 seem, since ad sources are often identifiable by the host name, and often
1988 the banners to be placed in an encrypted page come unencrypted nonetheless
1989 for efficiency reasons, which exposes them to the full power of
1990 <application>Privoxy</application>'s ad blocking.
1993 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
1994 JS page content, see <literal><ulink
1995 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
1996 in an SSL transaction will be impossible to block under these conditions.
1997 Fortunately, this does not seem to be a very common scenario since most
1998 cookies come by traditional means.
2003 <sect2 renderas="sect3" id="secure">
2004 <title>Privoxy runs as a <quote>server</quote>. How
2005 secure is it? Do I need to take any special precautions?</title>
2007 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2008 user, which is how we recommend it be run. Also, by default
2009 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2013 The server aspect of <application>Privoxy</application> is not itself directly
2014 exposed to the Internet in this configuration. If you want to have
2015 <application>Privoxy</application> serve as a LAN proxy, this will have to
2016 be opened up to allow for LAN requests. In this case, we'd recommend
2017 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2018 <application>Privoxy</application> configuration file and check all <ulink
2019 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2020 options</ulink>. All LAN hosts can then use this as their proxy address
2021 in the browser proxy configuration, but <application>Privoxy</application>
2022 will not listen on any external interfaces. ACLs can be defined in addition,
2023 and using a firewall is always good too. Better safe than sorry.
2028 <sect2 renderas="sect3" id="turnoff">
2029 <title>Can I temporarily disable Privoxy?</title>
2031 &my-app; doesn't have a transparent proxy mode,
2032 but you can toggle off blocking and content filtering.
2035 The easiest way to do that is to point your browser
2036 to the remote toggle URL: <ulink
2037 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2040 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2041 of the <citetitle>User Manual</citetitle> for an easy way to access this
2042 feature. Note that this is a feature that may need to be enabled in the main
2043 <filename>config</filename> file.
2048 <sect2 renderas="sect3" id="reallyoff">
2049 <title>When <quote>disabled</quote> is Privoxy totally
2050 out of the picture?</title>
2052 No, this just means all optional filtering and actions are disabled.
2053 <application>Privoxy</application> is still acting as a proxy, but just
2054 doing less of the things that <application>Privoxy</application> would
2055 normally be expected to do. It is still a <quote>middle-man</quote> in
2056 the interaction between your browser and web sites. See below to bypass
2061 <sect2 renderas="sect3" id="turnoff2">
2062 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2064 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2065 configuration issue, not a &my-app; issue. Modern browsers typically do have
2066 settings for not proxying certain sites. Check your browser's help files.
2071 <sect2 renderas="sect3" id="crunch">
2072 <title>My logs show Privoxy <quote>crunches</quote>
2073 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2075 A <quote>crunch</quote> simply means <application>Privoxy</application> intercepted
2076 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2077 banners, but <application>Privoxy</application> uses the same mechanism for
2078 trapping requests for its own internal pages. For instance, a request for
2079 <application>Privoxy's</application> configuration page at: <ulink
2080 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2081 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2082 configuration is returned to the browser, and the log consequently will show
2083 a <quote>crunch</quote>.
2086 Since version 3.0.7, Privoxy will also log the crunch reason.
2087 If you are using an older version you might want to upgrade.
2091 <sect2 renderas="sect3" id="downloads">
2092 <title>Can Privoxy affect files that I download
2093 from a webserver? FTP server?</title>
2095 From the webserver's perspective, there is no difference between
2096 viewing a document (i.e. a page), and downloading a file. The same is true of
2097 <application>Privoxy</application>. If there is a match for a <literal><ulink
2098 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2099 it will still be blocked, and of course this is obvious.
2102 Filtering is potentially more of a concern since the results are not always
2103 so obvious, and the effects of filtering are there whether the file is simply
2104 viewed, or downloaded. And potentially whether the content is some obnoxious
2105 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2106 one of these presumably is <quote>bad</quote> content that we don't want, and
2107 the other is <quote>good</quote> content that we do want.
2108 <application>Privoxy</application> is blind to the differences, and can only
2109 distinguish <quote>good from bad</quote> by the configuration parameters
2110 <emphasis>we</emphasis> give it.
2113 <application>Privoxy</application> knows the differences in files according
2114 to the <quote>Content Type</quote> as reported by the webserver. If this is
2115 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2116 then <application>Privoxy</application> knows to ignore these where
2117 appropriate. <application>Privoxy</application> potentially can filter HTML
2118 as well as plain text documents, subject to configuration parameters of
2119 course. Also, documents that are of an unknown type (generally assumed to be
2120 <quote>text/plain</quote>) can be filtered, as will those that might be
2121 incorrectly reported by the webserver. If such a file is a downloaded file
2122 that is intended to be saved to disk, then any content that might have been
2123 altered by filtering, will be saved too, for these (probably rare) cases.
2126 Note that versions later than 3.0.2 do NOT filter document types reported as
2127 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2128 did filter this document type.
2131 In short, filtering is <quote>ON</quote> if a) the content type as reported
2132 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2133 allows it (or at least does not disallow it). That's it. There is no magic
2134 cookie anywhere to say this is <quote>good</quote> and this is
2135 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2138 If you download text files, you probably do not want these to be filtered,
2139 particularly if the content is source code, or other critical content. Source
2140 code sometimes might be mistaken for Javascript (i.e. the kind that might
2141 open a pop-up window). It is recommended to turn off filtering for download
2142 sites (particularly if the content may be plain text files and you are using
2143 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2144 also, for any site or page where making <emphasis>any</emphasis> changes at
2145 all to the content is to be avoided.
2148 <application>Privoxy</application> does not do FTP at all, only HTTP
2149 and HTTPS (SSL) protocols.
2153 <sect2 renderas="sect3" id="downloads2">
2154 <title>I just downloaded a Perl script, and Privoxy
2155 altered it! Yikes, what is wrong!</title>
2161 <sect2 renderas="sect3" id="hostsfile">
2162 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2164 One time-tested technique to defeat common ads is to trick the local DNS
2165 system by giving a phony IP address for the ad generator in the local
2166 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2167 <literal>localhost</literal>. This effectively blocks the ad.
2170 There is no reason to use this technique in conjunction with
2171 <application>Privoxy</application>. <application>Privoxy</application>
2172 does essentially the same thing, much more elegantly and with much more
2173 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2174 duplicates effort, but may get in the way and seriously slow down your system.
2175 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2176 your hosts list is neglected by <application>Privoxy's </application>
2177 configuration, consider adding your list to your <filename>user.action</filename> file:
2184 ads.galore.example.com
2185 etc.example.com</screen>
2189 <sect2 renderas="sect3" id="seealso">
2190 <title>Where can I find more information about Privoxy
2191 and related issues?</title>
2192 <!-- Include seealso.sgml boilerplate: -->
2194 <!-- end boilerplate -->
2199 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2205 <sect2 renderas="sect3" id="microsuck">
2206 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2207 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2210 We're not. The text substitutions that you are seeing are disabled
2211 in the default configuration as shipped. You have either manually
2212 activated the <quote><literal>fun</literal></quote> filter which
2213 is clearly labeled <quote>Text replacements for subversive browsing
2214 fun!</quote> or you are using an older Privoxy version and have implicitly
2215 activated it by choosing the <quote>Advanced</quote> profile in the
2216 web-based editor. Please upgrade.
2220 <sect2 renderas="sect3" id="valid">
2221 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2224 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2225 whenever there are text substitutions via a &my-app; filter. While this
2226 should always conform to the HTML 4.01 specifications, it has not been
2227 validated against this or any other standard.
2231 <sect2 renderas="sect3" id="surprise-privoxy">
2232 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2235 We didn't. We make Privoxy available for download, but we don't go
2236 around installing it on other people's systems behind their back.
2237 If you discover Privoxy running on your system and are sure you didn't
2238 install it yourself, somebody else did. You may not even be running
2239 the real Privoxy, but maybe something else that only pretends to be
2240 Privoxy, or maybe something that is based on the real Privoxy,
2241 but has been modified.
2244 Lately there have been reports of problems with some kind of
2245 "parental control" software based on Privoxy that came preinstalled on
2246 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2247 The problems described are inconsistent with the behaviour of official
2248 Privoxy versions, which suggests that the preinstalled software may
2249 contain vendor modifications that we don't know about and thus can't debug.
2252 Privoxy's <link linkend="copyright">license</link> allows vendor
2253 modifications, but the vendor has to comply with the license,
2254 which involves informing the user about the changes and to make
2255 the changes available under the same license as Privoxy itself.
2258 If you are having trouble with a modified Privoxy version,
2259 please try to talk to whoever made the modifications before
2260 reporting the problem to us. Please also try to convince
2261 whoever made the modifications to talk to us. If you think
2262 somebody gave you a modified Privoxy version without complying
2263 to the license, please let us know.
2271 <!-- ~~~~~ New section ~~~~~ -->
2273 <sect1 id="trouble">
2274 <title>Troubleshooting</title>
2276 <sect2 renderas="sect3" id="refused">
2277 <title>I cannot connect to any websites. Or, I am getting
2278 <quote>connection refused</quote> message with every web page. Why?</title>
2280 There are several possibilities:
2285 <application>Privoxy</application> is not running. Solution: verify
2286 that &my-app; is installed correctly, has not crashed, and is indeed running.
2287 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2289 <listitem><para>Or your browser is configured for a different port than what
2290 <application>Privoxy</application> is using. Solution: verify that &my-app;
2291 and your browser are set to the same port (<literal>listen-address</literal>).
2293 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2294 problem with a host in the forwarding chain. Solution: temporarily alter your
2295 configuration and take the forwarders out of the equation.
2298 Or you have a firewall that is interfering and blocking you. Solution:
2299 try disabling or removing the firewall as a simple test.
2306 <!-- ~~~~~ New section ~~~~~ -->
2307 <sect2 renderas="sect3" id="error503">
2308 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2310 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2311 been reported to cause this symptom -- even if not running! The solution is
2312 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2313 something better behaved in its place. Other personal firewall type products
2314 may cause similar type problems if not configured correctly.
2318 <sect2 renderas="sect3" id="flushit">
2319 <title>I just added a new rule, but the steenkin ad is
2320 still getting through. How?</title>
2322 If the ad had been displayed before you added its URL, it will probably be
2323 held in the browser's cache for some time, so it will be displayed without
2324 the need for any request to the server, and <application>Privoxy</application>
2325 will not be involved. Flush the browser's caches, and then try again.
2329 If this doesn't help, you probably have an error in the rule you
2330 applied. Try pasting the full URL of the offending ad into <ulink
2331 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2332 and see if it really matches your new rule. Blocking ads is like blocking
2333 spam: a lot of tinkering is required to stay ahead of the game. And
2334 remember you need to block the URL of the ad in question, which may be
2335 entirely different from the site URL itself. Most ads are hosted on different
2336 servers than the main site itself. If you right-click on the ad, you should
2337 be able to get all the relevant information you need. Alternately, you can
2338 find the correct URL by looking at <application>Privoxy's</application> logs
2339 (you may need to enable logging in the main config file if its disabled).
2342 Below is a slightly modified real-life log snippet that originates with one
2343 requested URL: <literal>www.example.com</literal> (name of site was changed
2344 for this example, the number of requests is real). You can see in this the
2345 complexity of what goes into making up this one <quote>page</quote>. There
2346 are eight different domains involved here, with thirty two separate URLs
2347 requested in all, making up all manner of images, Shockwave Flash,
2348 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2349 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2350 Many of the more questionable looking requests, are going to outside domains
2351 that seem to be identifying themselves with suspicious looking names, making
2352 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2353 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2358 Request: www.example.com/
2359 Request: www.example.com/favicon.ico
2360 Request: img.example.com/main.css
2361 Request: img.example.com/sr.js
2362 Request: example.betamarker.com/example.html
2363 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2364 Request: img.example.com/pb.png
2365 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2366 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2367 Request: img.example.com/p.gif
2368 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2369 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2370 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2371 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2372 Request: www.adtrak.net/adx.js crunch! (Blocked)
2373 Request: img.example.com/hbg.gif
2374 Request: img.example.com/example.jpg
2375 Request: img.example.com/mt.png
2376 Request: img.example.com/mm.png
2377 Request: img.example.com/mb.png
2378 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2379 Request: www.example.com/tracker.js
2380 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2381 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2382 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2383 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2384 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2385 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2386 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2387 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2388 Request: 66.70.21.80/img/pixel.gif
2389 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2390 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2395 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2396 behave perfectly <quote>normal</quote> (minus some ads, of course).
2401 <sect2 renderas="sect3" id="badsite">
2402 <title>One of my favorite sites does not work with Privoxy.
2403 What can I do?</title>
2406 First verify that it is indeed a <application>Privoxy</application> problem,
2407 by toggling off <application>Privoxy</application> through <ulink
2408 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2409 (the toggle feature may need to be enabled in the main
2410 <filename>config</filename>),
2411 and then shift-reloading the problem page (i.e. holding down the shift key
2412 while clicking reload. Alternatively, flush your browser's disk and memory
2417 If the problem went away, we know we have a configuration related problem.
2419 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2420 and paste the full URL of the page in question into the prompt. See which
2421 actions are being applied to the URL, and which matches in which actions
2422 files are responsible for that. It might be helpful also to look at your logs
2423 for this site too, to see what else might be happening (note: logging may need
2424 to be enabled in the main config file). Many sites are
2425 complex and require a number of related pages to help present their content.
2426 Look at what else might be used by the page in question, and what of that
2427 might be <emphasis>required</emphasis>.
2428 Now, armed with this information, go to
2430 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2431 and select the appropriate actions files for editing. </para>
2433 You can now either look for a section which disables the actions that
2434 you suspect to cause the problem and add a pattern for your site there,
2435 or make up a completely new section for your site. In any case, the recommended
2436 way is to disable only the prime suspect, reload the problem page, and only
2437 if the problem persists, disable more and more actions until you have
2438 identified the culprit. You may or may not want to turn the other actions
2439 on again. Remember to flush your browser's caches in between any such changes!
2442 Alternately, if you are comfortable with a text editor, you can accomplish
2443 the same thing by editing the appropriate actions file. Probably the easiest
2444 way to deal with such problems when editing by hand is to add your
2445 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2446 which is an alias that turns off most <quote>dangerous</quote>
2447 actions, but is also likely to turn off more actions then needed, and thus lower
2448 your privacy and protection more than necessary,
2451 Troubleshooting actions is discussed in more detail in the <ulink
2452 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2453 Troubleshooting: the Anatomy of an Action</ulink>.
2454 There is also an <ulink
2455 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2456 with general configuration information and examples.
2459 As a last resort, you can always see if your browser has a setting that will
2460 bypass the proxy setting for selective sites. Modern browsers can do this.
2466 <!-- ~~~~~ New section ~~~~~ -->
2467 <sect2 id="dun" renderas="sect3">
2468 <title>After installing Privoxy, I have to log in
2469 every time I start IE. What gives?</title>
2472 This is a quirk that affects the installation of
2473 <application>Privoxy</application>, in conjunction with Internet Explorer and
2474 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2475 appear to be corrupted or invalid DUN settings, or passwords.
2479 When setting up an NT based Windows system with
2480 <application>Privoxy</application> you may find that things do not seem to be
2481 doing what you expect. When you set your system up you will probably have set
2482 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2483 logged in with administrator privileges. You will probably have made this DUN
2484 connection available to other accounts that you may have set-up on your
2485 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2486 configured for the kids.
2490 When setting up <application>Privoxy</application> in this environment you
2491 will have to alter the proxy set-up of Internet Explorer (IE) for the
2492 specific DUN connection on which you wish to use
2493 <application>Privoxy</application>. When you do this the ICS DUN set-up
2494 becomes user specific. In this instance you will see no difference if you
2495 change the DUN connection under the account used to set-up the connection.
2496 However when you do this from another user you will notice that the DUN
2497 connection changes to make available to "Me only". You will also find that
2498 you have to store the password under each different user!
2502 The reason for this is that each user's set-up for IE is user specific. Each
2503 set-up DUN connection and each LAN connection in IE store the settings for
2504 each user individually. As such this enforces individual configurations
2505 rather than common ones. Hence the first time you use a DUN connection after
2506 re-booting your system it may not perform as you expect, and prompt you for
2507 the password. Just set and save the password again and all should be OK.
2511 [Thanks to Ray Griffith for this submission.]
2516 <!-- ~~~~~ New section ~~~~~ -->
2517 <sect2 id="ftp" renderas="sect3">
2518 <title>I cannot connect to any FTP sites. Privoxy
2519 is blocking me.</title>
2521 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2522 so do not configure your browser to use <application>Privoxy</application>
2523 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2524 or HTTPS (SSL)</emphasis>.
2527 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2528 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2529 an FTP connection, and not a HTTP connection. So while your browser may
2530 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2534 To complicate matters, some systems may have a generic <quote>proxy</quote>
2535 setting, which will enable various protocols, including
2536 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2537 accidentally enable FTP proxying in these cases. And of course, if this
2538 happens, <application>Privoxy</application> will indeed cause problems since
2539 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2540 message if a FTP connection is attempted.]]> Just disable the FTP setting
2541 and all will be well again.
2544 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2545 There just is not much reason, and the work to make this happen is more than
2550 <!-- ~~~~~ New section ~~~~~ -->
2551 <sect2 id="macosxie" renderas="sect3">
2552 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2553 Privoxy as the HTTP proxy.</title>
2555 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2556 network settings. In order to change the HTTP proxy, open System
2557 Preferences, and click on the Network icon. In the settings pane that
2558 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2559 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2560 Enter <literal>8118</literal> in the Port field. The next time you start
2561 IE, it should reflect these values.
2565 <!-- ~~~~~ New section ~~~~~ -->
2566 <sect2 renderas="sect3" id="macosxuninstall">
2567 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2568 uninstall it. Now the finder tells me I don't have sufficient privileges to
2569 empty the trash.</title>
2571 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2574 Just dragging the <application>Privoxy</application> folder to the trash is
2575 not enough to delete it. <application>Privoxy</application> supplies an
2576 <application>uninstall.command</application> file that takes care of
2577 these details. Open the trash, drag the <application>uninstall.command</application>
2578 file out of the trash and double-click on it. You will be prompted for
2579 confirmation and the administration password.
2582 The trash may still appear full after this command; emptying the trash
2583 from the desktop should make it appear empty again.
2587 <!-- ~~~~~ New section ~~~~~ -->
2588 <sect2 renderas="sect3" id="macosximages">
2589 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2590 experience random delays in page loading. I'm using
2591 <literal>localhost</literal> as my browser's proxy setting.</title>
2593 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2594 understand the issue yet. In any case, changing the proxy setting to
2595 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2596 works around the problem.
2600 <!-- ~~~~~ New section ~~~~~ -->
2601 <sect2 renderas="sect3" id="macosxaccountdeletion">
2602 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2605 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2606 X deletes all user accounts that are either not part of OS X itself or are
2607 not interactive user accounts (ones you log in with). Since, for the sake of
2608 security, &my-app; runs as a non-privileged user that is created by its
2609 installer (_privoxy), it can no longer start up once that account gets deleted.
2610 The solution is to perform a complete uninstall using the supplied
2611 <application>uninstall.command</application> script (either back up your
2612 configuration files or select to not have the uninstaller remove them when it
2613 prompts you) and then reinstall &my-app; using the installer package and merge
2614 in your configuration.
2618 <!-- ~~~~~ New section ~~~~~ -->
2619 <!-- XXX: Is this still relevant now that we have gzip support? -->
2620 <sect2 renderas="sect3" id="blankpage">
2621 <title>I get a completely blank page at one site. <quote>View Source</quote>
2622 shows only: <markup><![CDATA[<html><body></body></html>]]></markup>. Without
2623 Privoxy the page loads fine.</title>
2625 Chances are that the site suffers from a bug in
2626 <ulink url="http://www.php.net/"><application>PHP</application></ulink>,
2627 which results in empty pages being sent if the client explicitly requests
2628 an uncompressed page, like <application>Privoxy</application> does.
2629 This bug has been fixed in PHP 4.2.3.
2632 To find out if this is in fact the source of the problem, try adding
2633 the site to a <literal>-prevent-compression</literal> section in
2634 <filename>user.action</filename>:
2637 # Make exceptions for ill-behaved sites:
2639 {-prevent-compression}
2640 .example.com</screen>
2642 If that works, you may also want to report the problem to the
2643 site's webmasters, telling them to use zlib.output_compression
2644 instead of ob_gzhandler in their PHP applications (workaround)
2645 or upgrade to PHP 4.2.3 or later (fix).
2649 <sect2 renderas="sect3" id="nohostname">
2650 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2653 <application>Privoxy</application> tries to get the hostname of the system
2654 its running on from the IP address of the system interface it is bound to
2655 (from the <filename>config</filename> file
2656 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2657 this information, <application>Privoxy</application> logs this condition.
2660 Typically, this would be considered a minor system configuration error. It is
2661 not a fatal error to <application>Privoxy</application> however, but may
2662 result in a much slower response from <application>Privoxy</application> on
2663 some platforms due to DNS timeouts.
2666 This can be caused by a problem with the local <filename>hosts</filename>
2667 file. If this file has been changed from the original, try reverting it to
2668 see if that helps. Make sure whatever name(s) are used for the local system,
2669 that they resolve both ways.
2672 You should also be able to work around the problem with the
2673 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2677 <sect2 renderas="sect3" id="inuse">
2678 <title>When I try to launch Privoxy, I get an
2679 error message <quote>port 8118 is already in use</quote> (or similar wording).
2682 Port 8118 is <application>Privoxy's</application> default TCP
2683 <quote>listening</quote> port. Typically this message would mean that there
2684 is already one instance of <application>Privoxy</application> running, and
2685 your system is actually trying to start a second
2686 <application>Privoxy</application> on the same port, which will not work.
2687 (You can have multiple instances but they must be assigned different ports.)
2688 How and why this might happen varies from platform to platform, but you need
2689 to check your installation and start-up procedures.
2693 <sect2 renderas="sect3" id="demoronizer">
2695 Pages with UTF-8 fonts are garbled.
2698 This may be the result of an overly aggressive filter. The filters that
2699 are enabled in the default configuration aren't expected to cause problems
2700 like this. If you enabled the <quote>demoronizer</quote> filter, please
2701 try temporarily disabling it.
2704 If that doesn't help, temporarily disable all filters to see if another
2705 filter could be the culprit. If the problem disappears, enable the filters
2706 one by one, until the problem reappears and the offending filter is found.
2709 Once the problem-causing filter is known, it can be fixed or disabled.
2712 Upgrading <application>Privoxy</application>, or going to the most recent
2713 <filename>default.action</filename> file available from <ulink
2714 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2715 might be worth a try, too.
2719 <sect2 renderas="sect3" id="demoronizer2">
2721 Why are binary files (such as images) corrupted when Privoxy
2725 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2726 filter</link> in conjunction with a web server that is misreporting the content
2727 type. By default binary files are exempted from
2728 <application>Privoxy's</application> filtering
2729 (unless the web server by mistake says the file is something else).
2733 <sect2 renderas="sect3" id="demoronizer3">
2735 What is the <quote>demoronizer</quote> and why is it there?
2738 The original demoronizer was a Perl script that cleaned up HTML pages which
2739 were created with certain Microsoft products. MS has used proprietary extensions
2740 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2741 that are viewed with non-Microsoft products (and are expecting to see a
2742 standard set of fonts). The demoronizer corrected these errors so the pages
2743 displayed correctly. <application>Privoxy</application> borrowed from this
2744 script, introducing a filter based on the original demoronizer, which in turn could
2745 correct these errors on the fly.
2748 But this is only needed in some situations, and will cause serious problems in some
2752 If you are using Microsoft products, you do not need it. If you need to view
2753 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2754 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2757 On the other hand, if you use non-Microsoft products, and you occasionally
2758 notice weird characters on pages, you might want to try it.
2762 <sect2 renderas="sect3" id="windowopen">
2764 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2767 <application>Privoxy</application> is attempting to disable malicious
2768 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2769 in this case, with the <literal>unsolicited-popups</literal>
2770 filter. <application>Privoxy</application> cannot tell very well
2771 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2774 If you see this in HTML source, and the page displays without problems, then
2775 this is good, and likely some pop-up window was disabled. If you see this
2776 where it is causing a problem, such as a downloaded program source code file,
2777 then you should set an exception for this site or page such that the
2778 integrity of the page stays in tact by disabling all filtering.
2782 <sect2 renderas="sect3" id="dnserrors">
2784 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2785 can't Privoxy do this better?
2788 There are potentially several factors here. First of all, the DNS resolution
2789 is done by the underlying operating system -- not
2790 <application>Privoxy</application> itself. <application>Privoxy</application>
2791 merely initiates the process and hands it off, and then later reports
2792 whatever the outcome was and tries to give a coherent message if there seems
2793 to be a problem. In some cases, this might otherwise be mitigated by the
2794 browser itself which might try some work-arounds and alternate approaches (e.g
2795 adding <quote>www.</quote> to the URL).
2798 In other cases, if <application>Privoxy</application> is being chained
2799 with another proxy, this could complicate the issue, and cause undue
2800 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2801 server handles all the DNS. <application>Privoxy</application> would just be
2802 the <quote>messenger</quote> which is reporting whatever problem occurred
2803 downstream, and not the root cause of the error.
2807 In any case, versions newer than 3.0.3 include various improvements to help
2808 <application>Privoxy</application> better handle these cases.
2812 <sect2 renderas="sect3" id="allcpu">
2814 At one site Privoxy just hangs, and starts taking
2815 all CPU. Why is this?
2818 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2819 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2820 are in the raw HTML source of the page, and the browser just ignores them. But the
2821 pattern matching in <application>Privoxy's</application> page filtering
2822 mechanism is trying to match against absurdly long strings and this becomes
2823 very CPU-intensive, taking a long, long time to complete.
2826 Until a better solution comes along, disable filtering on these pages,
2827 particularly the <literal>js-annoyances</literal> and
2828 <literal>unsolicited-popups</literal> filters. If you run into this problem
2829 with a recent &my-app; version, please send a problem report.
2833 <sect2 renderas="sect3" id="slowcrawl">
2834 <title>I just installed Privoxy, and all my
2835 browsing has slowed to a crawl. What gives? </title>
2837 This should not happen, and for the overwhelming number of users world-wide,
2838 it does not happen. I would suspect some inadvertent interaction of software
2839 components such as anti-virus software, spyware protectors, personal
2840 firewalls or similar components. Try disabling (or uninstalling) these one
2841 at a time and see if that helps. Either way, if you are using a
2842 recent &my-app; version, please report the problem.
2846 <sect2 renderas="sect3" id="preventcomp">
2847 <title>Why do my filters work on some sites but not on others? </title>
2849 It's probably due to compression. It is a common practice for web servers to
2850 send their content <quote>compressed</quote> in order to speed things up, and
2851 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2852 &my-app; can decompress content before filtering, otherwise you may want to enable
2854 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2857 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2862 <sect2 renderas="sect3" id="ssl-warnings">
2863 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2864 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2865 What's going on?</title>
2867 Probably the browser is requesting ads through HTTPS and &my-app;
2868 is blocking the requests. Privoxy's error messages are delivered
2869 unencrypted and while it's obvious for the browser that the HTTPS
2870 request is already blocked by the proxy, some warn about unauthenticated
2874 To work around the problem you can redirect those requests to an invalid
2875 local address instead of blocking them. While the redirects aren't
2876 encrypted either, many browsers don't care. They simply follow the
2877 redirect, fail to reach a server and display an error message instead
2881 To do that, enable logging to figure out which requests get blocked by
2882 &my-app; and add the hosts (no path patterns) to a section like this:
2887 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2893 Additionally you have to configure your browser to contact
2894 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2897 To add a proxy exception in <application>Mozilla Firefox</application>
2898 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2899 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2900 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2906 <sect2 renderas="sect3" id="se-linux">
2907 <title>I get selinux error messages. How can I fix this?</title>
2909 Please report the problem to the creator of your selinux policies.
2912 The problem is that some selinux policy writers aren't familiar
2913 with the application they are trying to <quote>secure</quote> and
2914 thus create policies that make no sense.
2917 In <application>Privoxy's</application> case the problem usually
2918 is that the policy only allows outgoing connections for certain
2919 destination ports (e.g. 80 and 443). While this may cover the
2920 standard ports, websites occasionally use other ports as well.
2921 This isn't a security problem and therefore <application>Privoxy's</application>
2922 default configuration doesn't block these requests.
2925 If you really want to block these ports (and don't be able
2926 to load websites that don't use standard ports), you should
2927 configure Privoxy to block these ports as well, so it doesn't
2928 trigger the selinux warnings.
2933 <sect2 renderas="sect3" id="gentoo-ricers">
2934 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2936 Probably you unintentionally compiled &my-app; without threading support
2937 in which case requests have to be serialized and only one can be served
2941 Check your <quote>USE</quote> flags and make sure they include
2942 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2945 If you compiled &my-app; with threading support (on POSIX-based systems),
2946 the <quote>Conditional #defines</quote> section on <ulink
2947 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2948 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2952 <sect2 renderas="sect3" id="tainted-sockets">
2953 <title>What are tainted sockets and how do I prevent them?</title>
2955 &my-app; marks sockets as tainted when it can't use them to
2956 serve additional requests.
2957 This does not necessarily mean that something went wrong and
2958 information about tainted sockets is only logged if connection
2959 debugging is enabled (debug 2).
2962 For example server sockets that were used for CONNECT requests
2963 (which are used to tunnel https:// requests) are considered tainted
2964 once the client closed its connection to &my-app;.
2965 Technically &my-app; could keep the connection to the server open,
2966 but the server would not accept requests that do not belong to the
2967 previous TLS/SSL session (and the client may even have terminated
2971 Server sockets are also marked tainted when a client requests a
2972 resource, but closes the connection before &my-app; has completely
2973 received (and forwarded) the resource to the client.
2974 In this case the server would (probably) accept additional requests,
2975 but &my-app; could not get the response without completely reading
2976 the leftovers from the previous response.
2979 These are just two examples, there are currently a bit more than
2980 25 scenarios in which a socket is considered tainted.
2983 While sockets can also be marked tainted as a result of a technical
2984 problem that may be worth fixing, the problem will be explicitly
2989 <sect2 renderas="sect3" id="pcre-stack-limit">
2990 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2992 This can happen if your custom filters require more memory than &my-app;
2994 Usually the problem is that the operating system enforces a stack size limit
2995 that isn't sufficient.
2998 Unless the problem occurs with the filters available in the default configuration,
2999 this is not considered a Privoxy bug.
3002 To prevent the crashes you can rewrite your filter to use less ressources,
3003 increase the relevant memory limit or recompile pcre to use less stack space.
3004 For details please see the
3005 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
3006 and the documentation of your operating system.
3011 <!-- ~~~~~ New section ~~~~~ -->
3012 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3013 <!-- Include contacting.sgml -->
3015 <!-- end contacting -->
3018 <!-- ~~~~~ New section ~~~~~ -->
3019 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3021 <!-- Include copyright.sgml -->
3027 Portions of this document are <quote>borrowed</quote> from the original
3028 <application>Junkbuster</application> (tm) FAQ, and modified as
3029 appropriate for <application>Privoxy</application>.
3032 <!-- ~~~~~ New section ~~~~~ -->
3033 <sect2><title>License</title>
3034 <!-- Include copyright.sgml: -->
3036 <!-- end copyright -->
3038 <!-- ~ End section ~ -->
3040 <!-- ~~~~~ New section ~~~~~ -->
3041 <sect2><title>History</title>
3042 <!-- Include history.sgml -->
3048 <!-- ~ End section ~ -->
3051 <!-- ~~~~~ New section ~~~~~ -->
3053 <sect1 id="seealso"><title>See also</title>
3055 <!-- Include seealso.sgml -->
3065 This program is free software; you can redistribute it
3066 and/or modify it under the terms of the GNU General
3067 Public License as published by the Free Software
3068 Foundation; either version 2 of the License, or (at
3069 your option) any later version.
3071 This program is distributed in the hope that it will
3072 be useful, but WITHOUT ANY WARRANTY; without even the
3073 implied warranty of MERCHANTABILITY or FITNESS FOR A
3074 PARTICULAR PURPOSE. See the GNU General Public
3075 License for more details.
3077 The GNU General Public License should be included with
3078 this file. If not, you can view it at
3079 http://www.gnu.org/copyleft/gpl.html
3080 or write to the Free Software Foundation, Inc.,
3081 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA