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9 $Id: faq.sgml,v 1.32 2002/03/27 00:57:03 hal9 Exp $
11 Written by and Copyright (C) 2001 the SourceForge
12 Privoxy team. http://www.privoxy.org/
14 Based on the Internet Junkbuster originally written
15 by and Copyright (C) 1997 Anonymous Coders and
16 Junkbusters Corporation. http://www.junkbusters.com
21 <title>Privoxy Frequently Asked Questions</title>
23 <pubdate>$Id: faq.sgml,v 1.32 2002/03/27 00:57:03 hal9 Exp $</pubdate>
28 <orgname>By: Privoxy Developers</orgname>
35 This FAQ gives users and developers alike answers to frequently asked
36 questions about <application>Privoxy</application>.
39 <application>Privoxy</application> is a web proxy with advanced filtering
40 capabilities for protecting privacy, filtering web page content, managing
41 cookies, controlling access, and removing ads, banners, pop-ups and other
42 obnoxious Internet junk. <application>Privoxy</application> has a very
43 flexible configuration and can be customized to suit individual needs and
44 tastes. <application>Privoxy</application> has application for both
45 stand-alone systems and multi-user networks.
48 <application>Privoxy</application> is based on the code of the
49 <application>Internet Junkbuster</application>.
50 <application>Junkbuster</application> was originally written by JunkBusters
51 Corporation, and was released as free open-source software under the GNU GPL.
52 Stefan Waldherr made many improvements, and started the SourceForge project
53 to continue development.
58 You can find the latest version of the document at <ulink url="http://www.privoxy.org/faq/">http://www.privoxy.org/faq/</ulink>.
59 Please see the Contact section in the
60 <ulink url="http://www.privoxy.org/user-manual/contact.html">user-manual</ulink> if you want to contact the developers.
64 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
70 <!-- ~~~~~ New section ~~~~~ -->
73 <sect1 id="introduction"><title>Introduction</title>
79 <!-- ~~~~~ New section ~~~~~ -->
81 <sect1 id="questions"><title>Frequently Asked Questions</title>
83 <!-- ~~~~~ New section ~~~~~ -->
85 <sect2 id="general"><title>General Information</title>
87 <sect3 id="newjb"><title>What is this new version of <application>Privoxy</application>?</title>
89 The original <application>Internet Junkbuster</application> (tm) is a
90 copyrighted product of <ulink url="http://www.junkbusters.com">Junkbusters
91 Corporation</ulink>. Development of this effort stopped some time ago as of
92 version 2.0.2. Stefan Waldherr started the ijbswa project on <ulink
93 url="http://sourceforge.net/projects/ijbswa/">Sourceforge</ulink> to rekindle
94 development. Other developers subsequently joined with Stefan, and have
95 since added many new features, refinements and enhancements. The result
96 of this effort is <application>Privoxy</application>.
99 <application>Privoxy</application> started with the same
100 <application>Junkbuster 2.0.2</application> code base, but has advanced
101 significantly at this point.
108 <title id="whyprivoxy">Why <quote>Privoxy</quote>? Why a name change at all?</title>
110 <application>Privoxy</application> is the
111 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>.
114 There are possible legal complications from the continued use of the
115 <application>Junkbuster</application> name, which is a trademark of
116 <ulink url="http://junkbusters.com">Junkbusters Corporation</ulink>.
117 (There are, however, no objections from Junkbusters Corporation to the
118 <application>Privoxy</application> project itself, and they, in fact, still
119 share our ideals and goals.)
123 The developers also believed that there so many changes from the original
124 code, that it was time to make a clean break from the past and make
125 a name in their own right, especially now with the pending release of
132 <sect3 id="differs"><title>How does <application>Privoxy</application> differ
133 from the old <application>Junkbuster?</application></title>
135 <application>Privoxy</application> picks up where
136 <application>Junkbuster</application> left off. All the old features remain.
137 The new <application>Privoxy</application> still blocks ads and banners,
138 still manages cookies, and still helps protect your privacy. But, these are
139 all enhanced, and many new features have been added, all in the same vein.
142 The configuration has changed significantly as well. This is something that
143 users will notice right off the bat. The <quote>blocklist</quote> file does
144 not exist any more. This is replaced by <quote>actions</quote> files, such
145 as <filename>default.actions</filename>. This is where most of the per site
146 configuration is now.
151 <sect3 id="features"><title>What are some of the new features?</title>
153 This section is in both user-manual and faq. Please keep in sync!!!
160 Integrated browser based configuration and control utility (<ulink
161 url="http://p.p">http://p.p</ulink>). Browser-based tracing of rule
168 Modularized configuration that will allow for system wide settings, and
169 individual user settings. (not implemented yet, probably a 3.1 feature)
175 Blocking of annoying pop-up browser windows.
181 HTTP/1.1 compliant (most, but not all 1.1 features are supported).
187 Support for Perl Compatible Regular Expressions in the configuration files, and
188 generally a more sophisticated and flexible configuration syntax over
201 Web page content filtering (removes banners based on size,
202 invisible <quote>web-bugs</quote>, JavaScript, pop-ups, status bar abuse,
209 Bypass many click-tracking scripts (avoids script redirection).
216 Multi-threaded (POSIX and native threads).
222 Auto-detection and re-reading of config file changes.
228 User-customizable HTML templates (e.g. 404 error page).
234 Improved cookie management features (e.g. session based cookies).
240 Builds from source on most UNIX-like systems. Packages available for: Linux
241 (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2, HP-UX 11 and AmigaOS.
248 In addition, the configuration is much more powerful and versatile over-all.
257 <sect3 id="proxymoron"><title>What is a <quote>proxy</quote>? How does
258 <application>Privoxy</application> work? </title>
260 When you connect to a web site with <application>Privoxy</application>,
261 you are really connecting to your locally running version of
262 <application>Privoxy</application>. <application>Privoxy</application>
263 intercepts your requests for the web page, and relays that to the
264 <quote>real</quote> web site. The web site sends the HTTP data stream
265 back to <application>Privoxy</application>, where
266 <application>Privoxy</application> can work its magic before it
267 relays this data back to your web browser.
271 Since <application>Privoxy</application> sits between you and the
272 WWW, it is in a position to intercept and completely manage all web traffic and
273 HTTP content before it gets to your browser.
274 <application>Privoxy</application> uses various programming methods to do
275 this, all of which is under your control via the various configuration
280 There are many kinds of proxies. <application>Privoxy</application> best
281 fits the <quote>filtering proxy</quote> category.
288 <title id="knows">How does <application>Privoxy</application> know what is
289 an ad, and what is not?</title>
291 <application>Privoxy</application> processes all the raw content of every
292 web page. So it reads everything on each page. It then compares this to the
293 rules as set up in the configuration files, and looks for any matches to
294 these rules. <application>Privoxy</application> makes heavy use of
295 <quote>regular expressions</quote>. (If you are not familiar with regular
296 expressions, it is explained briefly in <ulink
297 url="../user-manual/appendix.html">the user manual</ulink>.) Regular
298 expressions facilitate matching of one text string against another, using
299 wildcards to build complex patterns. So <application>Privoxy</application>
300 will typically look for URLs and other content that match certain key words
301 and expressions as defined in the configuration files. For instance a URL
302 that contains <quote>/banners</quote>, has a high probability of containing
303 ad banners, and thus would be a prime candidate to have a matching rule.
306 So <application>Privoxy</application> will look for these kinds of obvious
307 looking culprits. And also, will use lists of known organizations that
308 specialize in ads. Again, using complex patterns to match as many potential
309 combinations as possible since there tend to be many, many variations used by
310 advertisers, and new ones are being introduced all the time.
315 <title id="mistakes">Can <application>Privoxy</application> make mistakes?
316 This does not sound very scientific.</title>
318 Actually, it's a black art ;-) And yes, it is always possible to have a broad rule
319 accidentally block something by mistake. There is a good chance you may run
320 into such a situation at some point. It is tricky writing rules to cover
321 every conceivable possibility, and not occasionally get false positives.
325 But this should not be a big concern since the
326 <application>Privoxy</application> configuration is very flexible, and
327 includes tools to help identify these types of situations so they can be
328 addressed as needed, allowing you to customize your installation.
329 (<link linkend="badsite">See the appendix below</link>.)
335 <sect3 id="browsers2"><title>My browser does the same things as
336 <application>Privoxy</application>. Why should I use
337 <application>Privoxy</application> at all?</title>
339 Modern browsers do indeed have <emphasis>some</emphasis> of the same
340 functionality as <application>Privoxy</application>. Maybe this is
341 adequate for you. But <application>Privoxy</application> is much more
342 versatile and powerful, and can do a number of things that browsers just can't.
345 In addition, a proxy is good choice if you use multiple browsers, or
346 have a LAN with multiple computers. This way all the configuration
347 is in one place, and you don't have to maintain a similar configuration
348 for possibly many browsers.
355 <sect3 id="license"><title>Is there is a license or fee? What about a
356 warranty? Registration?</title>
358 <application>Privoxy</application> is licensed under the
359 GNU General Public License (GPL). It is free to use, copy,
360 modify or distribute as you wish under the terms of this license.
362 url="http://www.gnu.org/copyleft/gpl.html">http://www.gnu.org/copyleft/gpl.html</ulink>
366 There is no warranty of any kind, expressed, implied or otherwise. That is
367 something that would cost real money ;-) There is no registration either.
368 <application>Privoxy</application> really is <emphasis>free</emphasis>
374 <sect3 id="jointeam"><title>I would like to help you, what do I do?</title>
376 <sect4 id="jointeam-money"><title>Money Money Money</title>
378 We, of course, welcome donations and use the money for domain registering,
379 regular world-wide get-togethers (hahaha). Anyway, we'll soon describe the
380 process how to donate money to the team.
384 <sect4 id="jointeam-work"><title>You want to work with us?</title>
386 Well, helping the team is always a good idea. We welcome new developers,
387 RPM gurus or documentation makers. Simply get an account on sourceforge.net
388 and mail your id to the developer mailing list. Then read the
389 section Quickstart in the <ulink url="http://privoxy.org/developer-manual/quickstart.html">
390 Developer's Manual</ulink>.
393 Once we have added you to the team, you'll have write access to the CVS
394 repository, and together we'll find a suitable task for you.
403 <!-- ~~~~~ New section ~~~~~ -->
405 <sect2 id="installation"><title>Installation</title>
407 <sect3 id="whichbrowsers">
408 <title>Which browsers are supported by <application>Privoxy</application>?</title>
410 Any browser that can be configured to use a <quote>proxy</quote>, which
411 should be virtually all browsers. Direct browser support is not necessary
412 since <application>Privoxy</application> runs as a separate application and
413 just exchanges standard HTML data with your browser.
418 <title>Which operating systems are supported?</title>
420 Right now Win32, Mac OSX, OS/2, AmigaOS, Linux, and many
425 Source code is available, so porting to other operating systems,
426 is always a possibility.
431 <sect3 id="newinstall"><title>Can I install
432 <application>Privoxy</application> over <application>Junkbuster</application>?</title>
434 We recommend you uninstall <application>Junkbuster</application>
435 first to minimize conflicts and confusion. You may want to
436 save your old configuration files for future reference. The configuration
437 is substantially changed.
441 url="../user-manual/index.html">user-manual</ulink> for
442 platform specific installation instructions. [FIXME: This is meant for after
443 the name change for 3.0!]
446 Note: Some installers may automatically uninstall
447 <application>Junkbuster</application>, if present!
453 <title id="firststep">I just installed <application>Privoxy</application>. Is there anything
454 special I have to do now?</title>
457 All browsers must be told to use <application>Privoxy</application>
458 as a proxy by specifying the correct proxy address and port number
459 in the appropriate configuration area for the browser. See below.
460 Also, you should flush your browser's memory and disk cache to get rid of any
468 <sect3 id="localhost"><title>What is the proxy address of <application>Privoxy</application>?</title>
470 If you set up the <application>Privoxy</application> to run on
471 the computer you browse from (rather than your ISP's server or some
472 networked computer on a LAN), the proxy will be on <quote>localhost</quote>
473 (which is the special name used by every computer on the Internet to refer
474 to itself) and the port will be 8118 (unless you have <application>Privoxy</application> to run on a different port with the
475 <emphasis>listen-address</emphasis> config option).
478 When configuring your browser's proxy settings you typically enter
479 the word <quote>localhost</quote> in the boxes next to <quote>HTTP</quote>
480 and <quote>Secure</quote> (HTTPS) and then the number <quote>8118</quote>
481 for <quote>port</quote>. This tells your browser to send all web
482 requests to <application>Privoxy</application> instead of directly to the
486 <application>Privoxy</application> can also be used to proxy for
487 a Local Area Network. In this case, your would enter either the IP
488 address of the LAN host where <application>Privoxy</application>
489 is running, or the equivalent hostname. Port assignment would be
493 <application>Privoxy</application> does not currently handle
494 protocols such as FTP, SMTP, IM, IRC, ICQ, or other Internet
500 <title id="nothing">I just installed <application>Privoxy</application>, and nothing is happening.
501 All the ads are there. What's wrong?</title>
504 Did you configure your browser to use <application>Privoxy</application>
505 as a proxy? It does not sound like it. See above. You might also try flushing
506 the browser's caches to force a full re-reading of pages. You can verify
507 that <application>Privoxy</application> is running, and your browser
508 is correctly configured by entering the special URL:
509 <ulink url="http://p.p/">http://p.p/</ulink>. This should give you
510 a banner that says <quote>This is Privoxy</quote> and
511 access to <application>Privoxy's</application> internal configuration.
512 If you see this, then you are good to go. If not, the browser or
513 <application>Privoxy</application> are not set up correctly.
522 <!-- ~~~~~ New section ~~~~~ -->
524 <sect2 id="configuration"><title>Configuration</title>
526 <sect3 id="newconfig"><title>Can I use my old config files?</title>
528 There are major changes to <application>Junkbuster</application>
529 configuration from version 2.0.x to 2.9.x and later. The older files will
530 not work at all. If this is the case, you will need to re-enter your old
531 data into the new configuration structure. This is probably also a good
532 recommendation even if upgrading from 2.9.x to 3.x since there were
533 many minor changes along the way.
538 <title id="actionsfile">What is an <quote>actions</quote> file?</title>
541 <quote>actions</quote> files are where various actions that
542 <application>Privoxy</application> might take, are configured.
543 Typically, you would define a set of default actions that apply
544 to all URLs, then add exceptions to these defaults.
548 Actions can be defined on a per site basis, or for groups of sites. Actions
549 can also be grouped together and then applied to one or more sites. There
550 are many possible actions that might apply to any given site. As an example,
551 if we are blocking cookies as one of our default
552 <application>actions</application>, but need to accept cookies from a given
553 site, we would define this in our <quote>actions</quote> file.
558 <application>Privoxy</application> comes with several default
559 <application>actions</application> files, with varying degrees
560 of filtering and blocking, as starting points for your own
561 configuration (see below).
566 <sect3 id="actionss">
567 <title>The <quote>actions</quote>concept confuses me. Please list
568 some of these <quote>actions</quote>.</title>
570 These are all explained in the
571 <ulink url="../user-manual/configuration.html#ACTIONSFILE">user-manual</ulink>.
572 Please refer to that.
578 <title id="actconfig">How are actions files configured? What is the easiest
579 way to do this?</title>
582 The easiest way to do this, is to access <application>Privoxy</application>
583 with your web browser at <ulink url="http://p.p/">http://p.p/</ulink>,
585 "<ulink url="http://www.privoxy.org/config/edit-actions">Edit the actions list</ulink>"
586 from the selection list. You can also do this by editing the appropriate
587 file with a text editor.
593 url="../user-manual/configuration.html#ACTIONSFILE">user-manual</ulink> for a
594 detailed explanation of these and other configuration files, and their
595 various options and syntax.
601 FIXME: Commenting these out until we have some data there. HB 03/17/02.
603 <sect3 id="yahoo"><title>How can I make my Yahoo account work?</title>
609 <sect3 id="hotmail"> <title>How can I make my Hotmail account work?</title>
615 <sect3 id="gmx"> <title>How can I make my GMX account work?</title>
622 <sect3 id="configfiles"> <title>What are the differences between
623 intermediate.action, basic.action, etc.?</title>
625 Configuring <application>Privoxy</application> is not easy. To help you get
626 started, we provide you with three different default configurations. The
627 following table shows you, which features are enabled in each configuration.
630 <table frame=all><title>Default Configurations</title>
631 <tgroup cols=5 align=left colsep=1 rowsep=1>
639 <entry>Feature</entry>
640 <entry>default.action</entry>
641 <entry>basic.action</entry>
642 <entry>intermediate.action</entry>
643 <entry>advanced.action</entry>
649 <!-- <entry>f1</entry> -->
650 <!-- <entry>f2</entry> -->
651 <!-- <entry>f3</entry> -->
652 <!-- <entry>f4</entry> -->
653 <!-- <entry>f5</entry> -->
660 <entry>ad-filtering</entry>
668 <entry>blank image</entry>
676 <entry>de-animate GIFs</entry>
684 <entry>referer forging</entry>
692 <entry>jon's +no-cookies-keep (i.e. session cookies only)</entry>
700 <entry>no-popup windows</entry>
708 <entry>fast redirects</entry>
716 <entry>hide-referrer</entry>
724 <entry>hide-useragent</entry>
732 <entry>content-modification</entry>
740 <entry>feature-x</entry>
748 <entry>feature-y</entry>
756 <entry>feature-z</entry>
769 <sect3 id="browseconfig"> <title>Why can I change the configuration with a
770 browser? Does that not raise security issues?</title>
772 What I don't understand, is how I can browser edit the config file as a
773 regular user, while the whole /etc/privoxy hierarchy belongs to the user
774 "privoxy", with only 644 perms.
777 When you use the browser-based editor, <application>Privoxy</application>
778 itself is writing to the config files. Because
779 <application>Privoxy</application> is running as the user "privoxy", it can
780 update the config files.
783 If you don't like this, setting "enable-edit-actions 0" in the config file
784 will disable the browser-based editor. If you're that paranoid, you should
785 also consider setting "enable-remote-toggle 0" to prevent browser-based
786 enabling/disabling of <application>Privoxy</application>.
789 Note that normally only local users can connect to <application>Privoxy</application>, so this is not
790 (normally) a security problem.
796 <title id="filterfile">What is <quote>default.filter</quote>?</title>
798 The <quote>default.filter</quote> file is used to <quote>filter</quote> any
799 web page content. By <quote>filtering</quote> we mean it can modify, remove,
800 or change <emphasis>anything</emphasis> on the page, including HTML tags, and
801 JavaScript. Regular expressions are used to accomplish this, and operate
802 on a line by line basis. This is potentially a very powerful feature, but
803 requires some expertise.
807 If you are familiar with regular expressions, and HTML, you can look at
808 the provided <filename>default.filter</filename> with a text editor and see
809 some of things it can be used for.
813 Presently, there is no GUI editor option for this part of the configuration,
814 but you can disable/enable various sections of the included default
815 file with the <quote>Actions List Editor</quote> from your browser.
821 <title id="lanconfig">How can I set up <application>Privoxy</application> to act as a proxy for my
824 By default, <application>Privoxy</application> only responds to requests
825 from localhost. To have it act as a server for a network, this needs to be
826 changed in the main config file where the <application>Privoxy</application>
827 configuration is located. In that file is a <quote>listen-address</quote>
828 option. It may be commented out with a <quote>#</quote> symbol. Make sure
829 it is uncommented, and assign it the address of the LAN gateway interface,
830 and port number to use:
835 listen-address 192.168.1.1:8118
840 Save the file, and restart <application>Privoxy</application>. Configure
841 all browsers on the network then to use this address and port number.
848 <title id="noseeum">Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
850 This is a configuration option for images that
851 <application>Privoxy</application> is stopping. You have the choice <!-- of
852 the --> <!-- <application>Privoxy</application> logo, --> of a checkerboard
853 pattern, a transparent 1x1 GIF image (aka <quote>blank</quote>), or a custom
854 URL of your choice. Note that to fit this category, the URL must match both
855 the <quote>+image</quote> and <quote>+block</quote> actions.
859 If you want to see nothing, then change the <quote>+image-blocker</quote>
860 action to <quote>+image-blocker{blank}</quote>. This can be done from the
861 <quote>Edit Actions List</quote> selection at <ulink
862 url="http://p.p/">http://p.p/</ulink>. Or by hand editing the appropriate
863 actions file. This will only effect what is defined as <quote>images</quote>
864 though. Also, any URLs that generate the bright red <quote>Blocked</quote>
865 banner, can be moved to the <quote>+image-blocker</quote> section for the
874 <title id="whyseeum">Why would anybody want to see a checkerboard pattern?</title>
876 This can be helpful for troubleshooting problems. It might also be good
877 for anyone new to <application>Privoxy</application> so that they can
878 see if their favorite pages are displaying correctly, and
879 <application>Privoxy</application> is not inadvertently removing something
886 <title id="blockedisugly">I see large red banners on some pages that say
887 <quote>Blocked</quote>. Why and how do I get rid of this?</title>
889 These are URLs that match something in one of
890 <application>Privoxy's</application> block actions (+block). It is meant
891 to be a warning so that you know something has been blocked and an easy way
892 for you to see why. These are handled differently than what has been defined
893 explicitly as <quote>images</quote> (e.g. ad banners). Depending on the
894 URL itself, it is sometimes hard for <application>Privoxy</application> to
895 really know whether it is indeed an ad image or not.
899 If you want them to be treated as if they were images, so that they can be
900 made invisible, then move the offending URL from the <quote>+block</quote>
901 section to the <quote>+imageblock</quote> section of your actions file. Just
902 be forewarned, if make any URL is made <quote>invisible</quote>, you may not
903 have any inkling that something has been removed from that page.
906 Alternately, you could modify the <quote><filename>block</filename></quote>
907 HTML template that is used by <application>Privoxy</application> to display
908 this, and make it something more to your liking.
913 <sect3 id="alliseeisred">
914 <title>I cannot see all of the <quote>Blocked</quote> page banner. All I
915 see is a bright red square.</title>
917 There is not enough space to fit the entire page. Try right clicking on the
918 visible, red portion, and select <quote>Show Frame</quote>, or equivalent.
919 This will usually allow you to see the entire Privoxy <quote>Blocked</quote>
920 page, and from there you can see just what is being blocked, and why.
924 <sect3 id="otherproxy">
925 <title>How can I make <application>Privoxy</application> work with other
926 proxies like <application>Squid</application>?</title>
928 This can be done. See the <ulink
929 url="../user-manual/configuration.html#FORWARDING">user manual</ulink>,
930 which describes how to do this.
938 <!-- ~~~~~ New section ~~~~~ -->
940 <sect2 id="misc"><title>Miscellaneous</title>
943 <title id="slowsme">How much does <application>Privoxy</application> slow my browsing down? This
944 has to add extra time to browsing.</title>
946 It should not slow you down any in real terms, and may actually help
947 speed things up since ads, banners and other junk are not being displayed.
948 The actual processing time required by <application>Privoxy</application>
949 itself for each page, is relatively small in the overall scheme of things,
950 and happens very quickly. This is typically more than offset by time saved
951 not downloading and rendering ad images.
955 <quote>Filtering</quote> via the <filename>filterfile</filename>
956 mechanism may cause a perceived slowdown, since the entire page is buffered
957 before displaying. See below.
964 <sect3 id="loadingtimes"><title>I noticed considerable
965 delays in page requests compared to the old Junkbuster. What's wrong?</title>
967 Using the default filtering configuration, I noticed considerable delays in
968 page requests compared to the old Junkbuster. Loading pages with large contents
969 seemed to take forever, then suddenly delivering all the content at once.
972 The whole content must be loaded in order to filter, and nothing is is
973 sent to the browser during this time. The loading time does not really
974 change in real numbers, but the feeling is different, because most
975 browsers are able to start rendering incomplete content, giving the
976 user a feeling of "it works".
979 To modify the content of a page (i.e. make frames resizeable again, etc.) and
980 not just replace ads, <application>Privoxy</application> needs to download the
981 entire page first, do its content magic and then send the page to the browser.
986 <sect3 id="configurl"><title>What is the "http://p.p/"?</title>
988 Since <application>Privoxy</application> sits between your web browser and the Internet, it can be
989 programmed to handle certain pages specially.
993 With recent versions of <application>Privoxy</application> (version 2.9.x), you can get some
994 information about <application>Privoxy</application> and change some settings by going to
995 http://p.p/ or, equivalently, http://www.privoxy.org/config/
996 (Note that p.p is far easier to type but may not work in some
1001 These pages are *not* forwarded to a server on the Internet - instead they are
1002 handled by a special web server which is built in to <application>Privoxy</application>.
1006 If you are not running <application>Privoxy</application>, then http://p.p/ will fail, and
1007 http://www.privoxy.org/config/ will return a web page telling you
1008 you're not running <application>Privoxy</application>.
1012 If you have version 2.0.2, then the equivalent is
1013 http://example.com/show-proxy-args (but you get far less information, and you
1014 should really consider upgrading to 2.9.x).
1019 FIXME: commented out until we have data. HB 03/18/02.
1021 <sect3 id="badfiledesc"><title>I get the message 'Bad File Descriptor', why?</title>
1027 <sect3 id="proxy-chaining"><title>How do I chain <application>Privoxy</application> with other proxies
1028 (e.g. squid)?</title>
1035 <sect3 id="blocklist"><title>Do you still maintain the blocklists?</title>
1037 No. The format of the blocklists has changed significantly in the versions
1038 2.9.x. Once we have released the new version, there will again be
1039 blocklists that you can update automatically.
1043 <sect3 id="newads"><title>How can I submit new ads?</title>
1045 As of now, please discontinue to submit new ad blocking infos. Once we
1046 have released the new version, there will again be a form on the website,
1047 which you can use to contribute new ads.
1051 <sect3 id="ip"><title>How can I hide my IP address?</title>
1053 You cannot hide your IP address with <application>Privoxy</application> or any other software, since
1054 the server needs to know your IP address to send the answer to you.
1057 Fortunately there are many publicly usable anonymous proxies out there, which
1058 solve the problem by providing a further level of indirection between you and
1059 the web server, shared by many people and thus letting your requests "drown"
1060 in white noise of unrelated requests as far as user tracking is concerned.
1063 Most of them will, however, log your IP address and make it available to the
1064 authorities in case you abuse that anonymity for criminal purposes. In fact
1065 you can't even rule out that some of them only exist to *collect* information
1066 on (those suspicious) people with a more than average preference for privacy.
1069 You can find a list of anonymous public proxies at <ulink
1070 url="http://www.multiproxy.org/anon_list.htm">multiproxy.org</ulink> and many
1071 more through Google.
1075 <!-- <sect3 id="image"><title>What is the imagefile (simage.ini, etc.) for?</title> -->
1077 <!-- Anytime <application>Privoxy</application> determines (with the help of the blocklist) that a URL -->
1078 <!-- contains an advertisement, it has to decide whether this advertisement is an -->
1079 <!-- image or not. <application>Privoxy</application> uses the imagefile for that purpose. -->
1084 <title id="anonforsure">Can <application>Privoxy</application> guarantee I am anonymous?</title>
1086 No. Your chances of remaining anonymous are greatly improved, but unless you
1087 are an expert on Internet security it would be safest to assume that
1088 everything you do on the Web can be traced back to you.
1091 <application>Privoxy</application> can remove various information about you,
1092 and allows <emphasis>you</emphasis> more freedom to decide which sites
1093 you can trust. But it's still possible that web sites can find out who you
1094 are. Here's one way this can happen.
1097 A few browsers disclose the user's email address in certain situations, such
1098 as when transferring a file by FTP. <application>Privoxy</application>
1099 does not filter FTP. If you need this feature, or are concerned about the
1100 mail handler of your browser disclosing your email address, you might
1101 consider products such as <application>NSClean</application>.
1104 Browsers available only as binaries could use non-standard headers to give
1105 out any information they can have access to: see the manufacturer's license
1106 agreement. It's impossible to anticipate and prevent every breach of privacy
1107 that might occur. The professionally paranoid prefer browsers available as
1108 source code, because anticipating their behavior is easier. Trust the source,
1115 <title id="sitebreak">Might some things break because header information is
1116 being altered?</title>
1119 Definitely. More and more sites use HTTP header content to decide what to
1120 display and how to display it. There is many ways that this can be handled,
1121 so having hard and fast rules, is tricky.
1125 <quote>USER AGENT</quote> in particular is often used in this way to identify
1126 the browser, and adjust content accordingly. Changing this now is not
1127 recommended, since so many sites do look for this. You may get undesirable
1128 results by changing this.
1132 For instance, different browsers use different encodings of Russian and Czech
1133 characters, certain web servers convert pages on-the-fly according to the
1134 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1135 operating system or browser manufacturer causes some sites in these languages
1136 to be garbled; Surfers to Eastern European sites should change it to
1137 something closer. And then some page access counters work by looking at the
1138 <quote>REFERER</quote> header; they may fail or break if unavailable. The
1139 weather maps of Intellicast have been blocked by their server when no
1140 <quote>REFERER</quote> or cookie is provided, is another example. There are
1141 many, many other ways things can go wrong when trying to fool a web server.
1145 If you have problems with a site, you will have to adjust your configuration
1146 accordingly. Cookies are probably the most likely adjustment that may
1147 be required, but by no means the only one.
1155 <title id="caching">Can <application>Privoxy</application> act as a <quote>caching</quote> proxy to
1156 speed up web browsing?</title>
1158 No, it does not have this ability at all. You want something like
1159 <ulink url="http://www.squid-cache.org/">Squid</ulink> for this. And, yes,
1160 before you ask, <application>Privoxy</application> can co-exist
1161 with other kinds of proxies like <application>Squid</application>.
1166 <title id="firewall">What about as a firewall? Can <application>Privoxy</application> protect me?</title>
1168 Not in the way you mean, or in the way a true firewall can, or a proxy that
1169 has this specific capability. <application>Privoxy</application> can help
1170 protect your privacy, but not really protect you from intrusion attempts.
1176 <title id="logo">The <application>Privoxy</application> logo that replaces ads is very blocky
1177 and ugly looking. Can't a better font be used?</title>
1180 This is not a font problem. The logo is an image that is created by
1181 <application>Privoxy</application> on the fly. So as to not waste
1182 memory, the image is rather small. The blockiness comes when the
1183 image is scaled to fill a largish area. There is not much to be done
1184 about this, other than to use one of the other
1185 <quote>imageblock</quote> directives: <emphasis>pattern</emphasis>,
1186 <emphasis>blank</emphasis>, or a URL of your choosing.
1189 Given the above problem, we have decided to remove the logo option entirely
1196 <title id="wasted">I have large empty spaces now where ads used to be.
1199 It would be easy enough to just eliminate this space altogether, rather than
1200 fill it with blank space. But, this would create problems with many pages
1201 that use the overall size of the ad to help organize the page layout and
1202 position the various components of the page where they were intended to be.
1203 It is best left this way.
1209 <title id="ssl">How can <application>Privoxy</application> filter Secure (HTTPS) URLs?</title>
1211 This is a limitation since HTTPS transactions are encrypted SSL sessions
1212 between your browser and the secure site, and are meant to be reliably
1213 <emphasis>secure</emphasis> and private. This means that all cookies and HTTP
1214 header information are also encrypted from the time they leave your browser,
1215 to the site, and vice versa. <application>Privoxy</application> does not
1216 try to unencrypt this information, so it just passes through as is.
1217 <application>Privoxy</application> can still catch images and ads that
1218 are embedded in the SSL stream though.
1225 <title id="secure"><application>Privoxy</application> runs as a <quote>server</quote>. How
1226 secure is it? Do I need to take any special precautions?</title>
1228 There are no known exploits that might effect
1229 <application>Privoxy</application>. On Unix-like systems,
1230 <application>Privoxy</application> can run as a non-privileged
1231 user, which is how we recommend it be run. Also, by default
1232 <application>Privoxy</application> only listens to requests
1233 from <quote>localhost</quote>. The server aspect of
1234 <application>Privoxy</application> is not itself directly exposed to the
1235 Internet in this configuration. If you want to have
1236 <application>Privoxy</application> serve as a LAN proxy, this will have to
1237 be opened up to allow for LAN requests. In this case, we'd recommend
1238 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
1239 <application>Privoxy</application> config file. All LAN hosts can then use
1240 this as their proxy address in the browser proxy configuration. In this way,
1241 <application>Privoxy</application> will not listen on any external ports.
1242 Of course, a firewall is always good too. Better safe than sorry.
1247 <sect3 id="turnoff">
1248 <title>How can I temporarily disable <application>Privoxy</application>?</title>
1250 The easiest way is to access <application>Privoxy</application> with your
1251 browser by using the special URL: <ulink url="http://p.p/">http://p.p/</ulink>
1252 and select "Toggle Privoxy on or off" from that page.
1260 <!-- ~~~~~ New section ~~~~~ -->
1263 <title id="trouble">Troubleshooting</title>
1266 <title id="refused">I just upgraded and am getting <quote>connection refused</quote>
1267 with every web page?</title>
1269 Either <application>Privoxy</application> is not running, or your
1270 browser is configured for a different port than what
1271 <application>Privoxy</application> is using.
1275 The old <application>Privoxy</application> (and also
1276 <application>Junkbuster</application>) used port 8000 by
1277 default. This has been changed to port 8118 now, due to a conflict
1278 with NAS (Network Audio Service), which uses port 8000. If you haven't,
1279 you need to change your browser to the new port number, or alternately
1280 change <application>Privoxy's</application> <quote>listen-address</quote>
1281 setting in the <filename>config</filename> file used to start
1282 <application>Privoxy</application>.
1288 <title id="flushit">I just added a new rule, but the steenkin ad is
1289 still getting through. How?</title>
1291 If the ad had been displayed before you added its URL, it will probably be
1292 held in the browser's cache for some time, so it will be displayed without
1293 the need for any request to the server, and <application>Privoxy</application>
1294 will not be in the picture. The best thing to do is try flushing the browser's
1295 caches. And then try again.
1299 If this doesn't help, you probably have an error in the rule you
1300 applied. Try pasting the full URL of the offending ad into <ulink
1301 url="http://www.privoxy.org/config/show-url-info">http://www.privoxy.org/config/show-url-info</ulink>
1302 and see if any actions match your new rule.
1308 <title id="badsite">One of my favorite sites does not work with <application>Privoxy</application>.
1309 What can I do?</title>
1312 First verify that it is indeed a <application>Privoxy</application> problem,
1313 by disabling <application>Privoxy</application> filtering and blocking.
1314 Go to <ulink url="http://p.p/">http://p.p/</ulink> and click on
1315 <quote>Toggle Privoxy On or Off</quote>, then disable it. Now try that
1320 If still a problem, go to <quote>Show which actions apply to a URL and
1321 why</quote> from <ulink url="http://p.p/">http://p.p/</ulink> and paste
1322 the full URL of the page in question into the prompt. See which actions are
1323 being applied to the URL. Now, armed with this information, go to <quote>Edit
1324 the actions list</quote>. Here you should see various sections that have
1325 various <application>Privoxy</application> features disabled for specific
1326 sites. Disabled <quote>actions</quote> will have a <quote>-</quote> (minus
1327 sign) in front of them. Add your problem page URL to one of these sections
1328 that looks like it is disabling the feature that is causing the
1329 problem. Re-try the page. There might be some trial and error involved. This
1330 is discussed in a little more detail in the
1331 <ulink url="../user-manual/appendix.html#ACTIONSANAT">user-manual
1337 Alternately, if you are comfortable with a text editor, you can accomplish
1338 the same thing by editing the appropriate <quote>actions</quote> file.
1344 <title>Where and how do I submit bug reports? Feature Requests? Etc?</title>
1346 Feedback is encouraged, whether good, bad or ugly. Please see the contact
1347 page in the <ulink url="../user-manual/contact.html">user-manual</ulink> for
1355 <title id="time">What time is it?</title>
1366 <!-- ~~~~~ New section ~~~~~ -->
1368 FIXME: Commented out until we have something to put here. HB 03/18/02.
1369 <sect1 id="knownissues"><title>Known Issues</title>
1376 <!-- ~~~~~ New section ~~~~~ -->
1379 This is referenced in the doc header already. HB 03/25/02
1381 <sect1 id="contact"><title>Contact the developers</title>
1382 <para>Please see the user manual for information on how to contact the developers.
1386 <!-- ~~~~~ New section ~~~~~ -->
1387 <sect1 id="copyright"><title>Copyright and History</title>
1390 <ulink url="../user-manual/copyright.html#HISTORY">user-manual</ulink> for
1391 information on Copyright and History.
1395 <!-- ~~~~~ New section ~~~~~ -->
1396 <sect1 id="seealso"><title>See also</title>
1399 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
1406 Tue 09/11/01 06:38:14 PM EST: Test SGML doc by Hal Burgiss.
1408 Last modified: Mon Sep 10 19:22:09 CEST 2001
1410 This program is free software; you can redistribute it
1411 and/or modify it under the terms of the GNU General
1412 Public License as published by the Free Software
1413 Foundation; either version 2 of the License, or (at
1414 your option) any later version.
1416 This program is distributed in the hope that it will
1417 be useful, but WITHOUT ANY WARRANTY; without even the
1418 implied warranty of MERCHANTABILITY or FITNESS FOR A
1419 PARTICULAR PURPOSE. See the GNU General Public
1420 License for more details.
1422 The GNU General Public License should be included with
1423 this file. If not, you can view it at
1424 http://www.gnu.org/copyleft/gpl.html
1425 or write to the Free Software Foundation, Inc., 59
1426 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
1429 Revision 1.32 2002/03/27 00:57:03 hal9
1430 Touch ups for name change.
1432 Revision 1.31 2002/03/26 22:29:55 swa
1433 we have a new homepage!
1435 Revision 1.30 2002/03/25 16:39:22 hal9
1436 A few new sections. Made all links relative to user-manual.
1438 Revision 1.29 2002/03/25 05:23:57 hal9
1439 Moved section, and touch ups.
1441 Revision 1.28 2002/03/25 04:27:33 hal9
1442 New section related to name change.
1444 Revision 1.25 2002/03/24 16:08:08 swa
1445 we are too lazy to make a block-built
1446 privoxy logo. hence removed the option.
1448 Revision 1.24 2002/03/24 15:46:20 swa
1449 name change related issue.
1451 Revision 1.23 2002/03/24 12:33:01 swa
1454 Revision 1.22 2002/03/24 11:51:00 swa
1455 name change. changed filenames.
1457 Revision 1.21 2002/03/24 11:01:06 swa
1460 Revision 1.20 2002/03/23 15:13:11 swa
1461 renamed every reference to the old name with foobar.
1462 fixed "application foobar application" tag, fixed
1463 "the foobar" with "foobar". left junkbustser in cvs
1464 comments and remarks to history untouched.
1466 Revision 1.19 2002/03/21 17:01:54 hal9
1469 Revision 1.18 2002/03/18 16:40:31 hal9
1472 Revision 1.17 2002/03/18 03:53:53 hal9
1475 Revision 1.16 2002/03/17 21:32:56 hal9
1476 A few more additions.
1478 Revision 1.15 2002/03/17 07:25:59 hal9
1479 Correcting some of my typos, and some additions.
1481 Revision 1.14 2002/03/17 02:39:13 hal9
1482 A little more added ...
1484 Revision 1.13 2002/03/17 00:22:20 hal9
1485 Adding new stuff, and trying to incorporate stuff from old faq.
1487 Revision 1.12 2002/03/11 20:13:21 swa
1490 Revision 1.11 2002/03/11 18:42:27 swa
1493 Revision 1.10 2002/03/11 13:13:27 swa
1494 correct feedback channels
1496 Revision 1.9 2002/03/10 23:34:04 swa
1497 more info on not hiding ip address
1499 Revision 1.8 2002/03/09 15:55:48 swa
1500 added default config section
1502 Revision 1.7 2002/03/07 18:16:55 swa
1505 Revision 1.6 2002/03/07 13:16:31 oes
1506 Committing changes by Stefan
1508 Revision 1.5 2002/03/02 15:50:04 swa
1509 2.9.11 version. more input for docs.
1511 Revision 1.4 2002/02/24 14:34:24 jongfoster
1512 Formatting changes. Now changing the doctype to DocBook XML 4.1
1513 will work - no other changes are needed.
1515 Revision 1.3 2001/09/23 10:13:48 swa
1516 upload process established. run make webserver and
1517 the documentation is moved to the webserver. documents
1518 are now linked correctly.
1520 Revision 1.2 2001/09/13 15:20:17 swa
1521 merged standards into developer manual
1523 Revision 1.1 2001/09/12 15:36:41 swa
1524 source files for junkbuster documentation
1526 Revision 1.3 2001/09/10 17:43:59 swa
1527 first proposal of a structure.
1529 Revision 1.2 2001/06/13 14:28:31 swa
1530 docs should have an author.
1532 Revision 1.1 2001/06/13 14:20:37 swa
1533 first import of project's documentation for the webserver.