Various updates, including 7 or 8 new FAQs, and updates/changes to various

[privoxy.git] / doc / source / faq.sgml

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<!--
 File        :  $Source: /cvsroot/ijbswa/current/doc/source/faq.sgml,v $

 Purpose     :  FAQ
                This file belongs into
                ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
                
 $Id: faq.sgml,v 2.11 2006/07/18 14:48:50 david__schmidt Exp $

 Copyright (C) 2001-2006 Privoxy Developers <developers@privoxy.org>
 See LICENSE.

 Based partially on the Internet Junkbuster FAQ originally written by and
 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
 http://www.junkbusters.com/

 <Qandaset defaultlabel='qanda'>
  <QandAEntry>
   <question>
    <para> 
     How are you?
    </para>
   </question>
   <answer>
    <para> 
     Fine.
    </para>
   </answer>
  </QandAEntry>
 </QandASet>

 ========================================================================
 NOTE: Please read developer-manual/documentation.html before touching 
 this file!

 Please we keep the info in this file as version independent as possible 
 so we only have to maintain one FAQ. Where significant changes are 
 made to Privoxy configuration, please note the change in such a way that 
 it makes sense to both users of older and newer versions.
 ========================================================================


-->


<article id="index" class="faq">
<artheader>
<title>Privoxy Frequently Asked Questions</title>

<pubdate>
 <subscript>
<!-- Completely the wrong markup, but very little is allowed  -->
<!-- in this part of an article. FIXME -->
 <link linkend="copyright">Copyright</link> &my-copy; 2001-2006 by 
 <ulink url="http://www.privoxy.org">Privoxy Developers</ulink>
 </subscript>
</pubdate>

<pubdate>$Id: faq.sgml,v 2.11 2006/07/18 14:48:50 david__schmidt Exp $</pubdate>

<!--

Note: this should generate a separate page, and a live link to it. 
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Hal.

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 <para>
  text goes here ........
 </para>
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 <author>
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   <orgname>By: Privoxy Developers</orgname>
   </affiliation>
 </author>
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<abstract>
<![%dummy;[
<para>
 <comment>
  This is here to keep vim syntax file from breaking :/
  If I knew enough to fix it, I would.
  PLEASE DO NOT REMOVE! HB: hal@foobox.net
 </comment>
</para>
]]>
 <para>
 This FAQ gives quick answers to frequently asked  questions about
 <ulink url="http://www.privoxy.org/">Privoxy</ulink>.
 It can't and doesn't replace the
 <ulink url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>.
<!-- 
 This works, at least in some situtations:
 Test: <ulink url="privoxy-user-manual.pdf"><citetitle>User Manual</citetitle></ulink>.
--> 
 </para>

<!-- Include privoxy.sgml boilerplate: -->
 &p-intro;
<!-- end boilerplate -->

 <para>
  Please note that this document is a work in progress. This copy represents
  the state at the release of version &p-version;.
  You can find the latest version of the document at <ulink
  url="http://www.privoxy.org/faq/">http://www.privoxy.org/faq/</ulink>.
  Please see the <link linkend="contact">Contact section</link> if you want to
  contact the developers. 
 </para>

<!--   <para> -->
<!--    Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
<!--   </para> -->
</abstract>
</artheader>


<!--   ~~~~~       New section      ~~~~~     -->

<sect1 id="general"><title>General Information</title>

<sect2 renderas="sect3" id="newjb"><title>What is this new version of <application>Junkbuster</application>?</title>

<!-- Include history.sgml -->
 &history;
<!-- end -->

</sect2>


<sect2 renderas="sect3">
<title id="whyprivoxy">Why <quote>Privoxy</quote>? Why change the name from
<application>Junkbuster</application> at all?</title>
<para>
 <ulink url="http://junkbusters.com/">Junkbusters Corporation</ulink>
 continues to offer their original version of the <application>Internet
 Junkbuster</application>, so publishing our
 <application> Junkbuster</application>-derived software under the same name
 led to confusion.
</para>
<para>
 There are also potential legal complications from the continued use of the 
 <application>Junkbuster</application> name, which is a registered trademark of 
 <ulink url="http://junkbusters.com/">Junkbusters Corporation</ulink>.
 There are, however, no objections from Junkbusters Corporation to the 
 <application>Privoxy</application> project itself, and they, in fact, still
 share our ideals and goals.
</para>
<para>
 The developers also believed that there are so many improvements over the original 
 code, that it was time to make a clean break from the past and make 
 a name in their own right.
</para>
<para>
 <application>Privoxy</application> is the 
 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
 control, more freedom, and allows you to browse your personal and
 <quote><emphasis>private</emphasis> edition</quote> of the web.
</para>
</sect2>


<sect2 renderas="sect3" id="differs"><title>How does <application>Privoxy</application> differ
from the old <application>Junkbuster?</application></title> 
<para>
 <application>Privoxy</application> picks up where
 <application>Junkbuster</application> left off. All the old features remain.
 The new <application>Privoxy</application> still blocks ads and banners,
 still manages cookies, and still helps protect your privacy. But, these are
 all greatly enhanced, and many, many new features have been added, all in the same vein.
 </para>
 <para>
 The configuration has changed significantly as well. This is something that
 users will notice right off the bat if upgrading from 
 <application>Junkbuster</application> 2.0.x. The <quote>blocklist</quote>
 <quote>cookielist</quote>, <quote>imagelist</quote> and much more has been
 combined into the <quote>actions</quote> files, with a completely different
 syntax. See the <ulink url="../user-manual/whatsnew.html">What's New</ulink> 
 page for the latest updates.
</para>
<para>
 <application>Privoxy</application>'s new features include:
</para>

<!-- Include newfeatures.sgml: --> 
 &newfeatures;
<!-- end include -->

</sect2>

<sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
<application>Privoxy</application> work? </title>
 <para>
  A web proxy is a service, based on a software such as <application>Privoxy</application>,
  that clients (i.e. browsers) can use instead of connecting directly to the web
  servers on the Internet. The clients then ask the proxy to fetch the objects
  they need (web pages, images, movies etc) on their behalf, and when the proxy
  has done so, it hands the results back to the client.
 </para>
 <para>
  There are many reasons to use web proxies, such as security (firewalling),
  efficiency (caching) and others, and there are just as many different proxies
  to accommodate those needs.
 </para>
 <para>
  <application>Privoxy</application> is a proxy that is primarily focused on privacy
  protection, junk elimination and freeing the user from restrictions placed on his 
  activities. Sitting between your browser(s) and the Internet,
  it is in a perfect position to filter outbound personal information that your
  browser is leaking, as well as inbound junk. It uses a variety of techniques to do
  this, all of which are under your control via the various configuration
  files and options.
 </para>
</sect2>


<sect2 renderas="sect3" id="whatsanad">
<title id="knows">How does <application>Privoxy</application> know what is
an ad, and what is not?</title>
<para>
 <application>Privoxy</application>'s approach to blocking ads is twofold:
</para>
<para>
 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
 of banner images. This applies to both the path (you wouldn't guess how many
 web sites serve their banners from a directory called <quote>banners</quote>!)
 and the host (blocking the big banner hosting services like doublecklick.net
 already helps a lot). <application>Privoxy</application> takes advantage of this
 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
 patterns</ulink> to sort out and block the requests for banners.
</para>
<para>
 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
 can't tell the size of an image by its URL without downloading it, and if you
 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
 also inspects the HTML sources of web pages while they are loaded, and replaces
 references to images with standard banner sizes by dummy references, so that
 your browser doesn't request them anymore in the first place.
</para>
<para>
 Both of this involves a certain amount of guesswork and is, of course, freely
 configurable.
</para>
</sect2>

<sect2 renderas="sect3">
<title id="mistakes">Can <application>Privoxy</application> make mistakes? 
This does not sound very scientific.</title>
<para>
 Actually, it's a black art ;-) And yes, it is always possible to have a broad
 rule accidentally block or change something by mistake. You will almost surely
 run into such situations at some point. It is tricky writing rules to
 cover every conceivable possibility, and not occasionally get false positives.
</para>

<para>
 But this should not be a big concern since the
 <application>Privoxy</application> configuration is very flexible, and
 includes tools to help identify these types of situations so they can be
 addressed as needed, allowing you to customize your installation.
 (<link linkend="badsite">See the Troubleshooting section below</link>.)
</para>

</sect2>


<sect2 renderas="sect3">
<title id="configornot">Will I have to configure <application>Privoxy</application>
 before I can use it?</title>
<para>
 No, not really. The default installation should give you a good starting
 point, and block <emphasis>most</emphasis> unwanted content.
</para>
<para>
 But you will certainly run into situations where there are false positives,
 or ads not being blocked that you may not want to see. In these cases, you
 would certainly benefit by customizing <application>Privoxy's</application>
 configuration to more closely match your individual situation. And we would
 encourage you to do this. This is where the real power of
 <application>Privoxy</application> lies!
</para>

</sect2>

<sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
<application>Privoxy</application>. Why should I use
<application>Privoxy</application> at all?</title>
 <para>
  Modern browsers do indeed have <emphasis>some</emphasis> of the same
  functionality as <application>Privoxy</application>. Maybe this is
  adequate for you. But <application>Privoxy</application> is much more
  versatile and powerful, and can do a number of things that browsers just can't.
 </para>
 <para>
  In addition, a proxy is good choice if you use multiple browsers, or 
  have a LAN with multiple computers. This way all the configuration 
  is in one place, and you don't have to maintain a similar configuration 
  for possibly many browsers.
 </para>
</sect2>



<sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a 
warranty? Registration?</title>
 <para>
  <application>Privoxy</application> is licensed under the <ulink
  url="http://www.gnu.org/copyleft/gpl.html">GNU General Public License (GPL)</ulink>.
  It is free to use, copy, modify or distribute as you wish under the terms of this
  license.  Please see the <link linkend="copyright">Copyright</link> section for more
  information on the license and copyright. Or the <filename>LICENSE</filename> file 
  that should be included.
 </para>
 <para>
  There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
  That is something that would cost real money ;-) There is no registration either.
  <application>Privoxy</application> really is <emphasis>free</emphasis>
  in every respect!
 </para>

</sect2>

<sect2 renderas="sect3" id="jointeam"><title>I would like to help you, what do I do?</title>

<sect3 renderas="sect4" id="jointeam-money"><title>Contribute!</title>
<para>
 We, of course, welcome donations and could use money for domain registering,
 buying software to test <application>Privoxy</application> with, and, of course,
 for regular world-wide get-togethers (hahaha). If you enjoy the software and feel
 like helping us with a donation, just <ulink
 url="mailto: ijbswa-developers@lists.sourceforge.net">drop us a note</ulink>.
</para>
</sect3>

<sect3 renderas="sect4" id="jointeam-software"><title>Software</title>
<para>
 If you are a vendor of a web-related software like a browser, web server
 or proxy, and would like us to ensure that <application>Privoxy</application>
 runs smoothly with your product, you might consider supplying us with a
 copy or license. We can't, however, guarantee that we will fix all potential
 compatibility issues as a result.
</para>
</sect3>

<sect3 renderas="sect4" id="jointeam-work"><title>Would you like to participate?</title>
<para>
   Well, helping the team is always a good idea. We welcome new developers,
   packagers, testers, documentation writers or really anyone with a desire to help in 
   any way. You 
   <emphasis>DO NOT</emphasis> need to be a <quote>programmer</quote>. There
   are many other tasks available. In fact, the programmers often can't spend
   as much time programming because of some of the other, more mundane things
   that need to be done, like checking the Tracker feedback sections. 
 </para>
 <para>
  So first thing, <ulink
   url="https://sourceforge.net/account/register.php">get an account on SourceForge.net</ulink>
   and mail your id to the <ulink url="mailto:ijbswa-developers@lists.sourceforge.net">developers
   mailing list</ulink>. Then, please read the <ulink
   url="../developer-manual/index.html">Developer's Manual</ulink>, at least
   the pertinent sections.
</para>
<para>
 Once we have added you to the team, you'll have access to the <ulink
 url="http://sourceforge.net/cvs/?group_id=11118">CVS repository</ulink>, and
 together we'll find a suitable task for you.
</para>
</sect3>

</sect2>

</sect1>


<!--   ~~~~~       New section      ~~~~~     -->

<sect1  id="installation"><title>Installation</title>

<sect2 renderas="sect3" id="whichbrowsers">
<title>Which browsers are supported by <application>Privoxy</application>?</title>
<para>
 Any browser that can be configured to use a proxy, which 
 should be virtually all browsers. Direct browser support is not necessary
 since <application>Privoxy</application> runs as a separate application and
 talks to the browser in the standardized HTTP protocol, just like a web server
 does.
</para>
</sect2>

<sect2 renderas="sect3" id="whichos">
<title>Which operating systems are supported?</title>
<!--
Include supported.sgml here:
-->
&supported;
</sect2>

<sect2 renderas="sect3" id="email-client">
<title>Can I use <application>Privoxy</application> with my email client?</title>
<para>
 As long as there is some way to set a HTTP proxy for the client, then yes,
 any application can be used, whether it is strictly speaking a
 <quote>browser</quote> or not. Though this may not be the best approach for
 dealing with some of the common abuses of HTML in email. See <link
 linkend="outlook">How can I configure <application>Privoxy</application>
 with <application>Outlook Express</application>?</link> below for more on
 this. 
</para>
<para>
 Be aware that HTML email presents a number of unique security and privacy
 related issues, that can require advanced skills to overcome. The developers
 recommend using email clients that can be configured to convert HTML to plain
 text for these reasons.
</para>
</sect2>

<sect2 renderas="sect3" id="newinstall"><title>Can I install  
 <application>Privoxy</application> over <application>Junkbuster</application>?</title>
 <para>
   We recommend you un-install <application>Junkbuster</application>
   first to minimize conflicts and confusion. You may want to 
   save your old configuration files for future reference. The configuration
   files and syntax have substantially changed, so you will need to manually
   port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
   to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
   chapter</ulink> in the <ulink url="../user-manual/index.html">user manual</ulink>
   for details.
 </para>
 <para>
  Note: Some installers may automatically un-install
  <application>Junkbuster</application>, if present!
 </para>

</sect2>

<sect2 renderas="sect3">
<title id="firststep">I just installed <application>Privoxy</application>. Is there anything 
special I have to do now?</title>

<para>
 All browsers must be told to use <application>Privoxy</application> 
 as a proxy by specifying the correct proxy address and port number 
 in the appropriate configuration area for the browser. See below.
 You should also flush your browser's memory and disk cache to get rid of any
 cached junk items, and remove any stored cookies.

</para>

</sect2>


<sect2 renderas="sect3" id="localhost"><title>What is the proxy address of <application>Privoxy</application>?</title>
 <para>
  If you set up the <application>Privoxy</application> to run on
  the computer you browse from (rather than your ISP's server or some
  networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal> 
  (sometimes referred to as <quote>localhost</quote>,
  which is the special name used by every computer on the Internet to refer
  to itself) and the port will be 8118 (unless you have <application>Privoxy</application>
  to run on a different port with the <ulink
  url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink> config option). 
 </para>
 <para>
  When configuring your browser's proxy settings you typically enter
  the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
  in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
  then the number <quote>8118</quote> for <quote>port</quote>. 
  This tells your browser to send all web requests to <application>Privoxy</application>
  instead of directly to the Internet.
 </para>
 <para>
  <application>Privoxy</application> can also be used to proxy for 
  a Local Area Network. In this case, your would enter either the IP 
  address of the LAN host where <application>Privoxy</application> 
  is running, or the equivalent hostname. Port assignment would be 
  same as above. Note that <application>Privoxy</application> doesn't
  listen on any LAN interfaces by default.
 </para>
 <para>
  <application>Privoxy</application> does not currently handle
  any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc. 
 </para>
</sect2>

<sect2 renderas="sect3" id="nothing">
<title>I just installed <application>Privoxy</application>, and nothing is happening.
All the ads are there. What's wrong?</title>

<para>
 Did you configure your browser to use <application>Privoxy</application> 
 as a proxy? It does not sound like it. See above. You might also try flushing
 the browser's caches to force a full re-reading of pages. You can verify 
 that <application>Privoxy</application> is running, and your browser 
 is correctly configured by entering the special URL: 
 <ulink url="http://p.p/">http://p.p/</ulink>. 
 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
      of potential redirect caching problem (see next Q). -->
 This should take you to a page titled <quote>This is Privoxy..</quote> with
 access to <application>Privoxy's</application> internal configuration.
 If you see this, then you are good to go. If you receive a page saying 
 <quote>Privoxy is not running</quote>, then the browser is not set up to use
 your <application>Privoxy</application> installation.
 If you receive anything else (probably nothing at all), it could either
 be that the browser is not set up correctly, or that
 <application>Privoxy</application> is not running at all. Check the <ulink
 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
 on starting <application>Privoxy</application> and browser configuration,
 see the <ulink url="http://www.privoxy.org/user-manual/startup.html">chapter
 on starting <application>Privoxy</application></ulink> in the
 <ulink url="http://www.privoxy.org/user-manual/">user manual</ulink>.
</para>

</sect2>

<sect2 renderas="sect3" id="notused">
<title>I get a <quote>Privoxy is not being used</quote> dummy page although
<application>Privoxy</application> is running and being used.</title>

<para>
 First, make sure that Privoxy is <emphasis>really</emphasis> running and
 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
 should see the <application>Privoxy</application> main page. If not, see
 the <ulink url="http://www.privoxy.org/user-manual/startup.html">chapter
 on starting <application>Privoxy</application></ulink> in the
 <ulink url="http://www.privoxy.org/user-manual/">user manual</ulink>.
</para>

<para>
 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
 other parts of <application>Privoxy</application>'s web interface show
 the dummy page, your browser has cached a redirection it encountered before
 <application>Privoxy</application> was being used. You need to clear your
 browser's cache. Note that shift-reloading the dummy page won't help, since
 that'll only refresh the dummy page, not the redirection that lead you there.
</para>

<para>
 The procedure for clearing the cache varies from browser to browser. As an
 example, <application>Mozilla</application> users would click 
 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
</para>
</sect2>

</sect1>


<!--   ~~~~~       New section      ~~~~~     -->

<sect1 id="configuration"><title>Configuration</title>

<sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
 <para>
   Based on your feedback and the continuing development, updated actions files will be
   made available on the <ulink
  url="http://sourceforge.net/project/showfiles.php?group_id=11118">files section</ulink> of
  our <ulink url="http://sf.net/projects/ijbswa/">project page</ulink>.
 </para>

 <para>
  If you wish to receive an email notification whenever we release updates of
  <application>Privoxy</application> or the actions file, <ulink
  url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
  to our announce  mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
 </para>

</sect2>

<sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
 <para>
   The syntax, number, and purpose of configuration files has substantially
   changed from <application>Junkbuster</application> and early versions
   of <application>Privoxy</application>. The old files, like <filename>blocklist</filename>
   will not work at all. If you are upgrading from a 2.0.x version, you will
   need to port your configuration data to the new format. Note that even the
   pattern syntax has changed! Even configuration files from the 2.9.x versions
   will need to be adapted, as configuration syntax has been very much in flow
   in the 2.9.x series.
 </para>
 <para>
  Refer to the <ulink url="../user-manual/whatsnew.html">What's New</ulink> 
 page for information on configuration changes that may occur from one release to another.
 </para>
</sect2>

<sect2 renderas="sect3">
<title id="actionsfile">What is an <quote>actions</quote> file?</title>

<para>
 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
 are where various <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
 that <application>Privoxy</application> might take while processing a certain
 request, are configured. Typically, you would define a set of default actions
 that apply to all URLs, then add exceptions to these defaults where needed.
</para>
 
<para>
 Actions can be defined on a <ulink
 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
 grouped together and then applied to requests matching one or more patterns.
 There are many possible actions that might apply to any given site. As an example,
 if you are blocking cookies as one of your default actions, but need to accept
 cookies from a given site, you would need to define an exception for this
 site in one of your actions files, preferably in <filename>user.action</filename>.
</para>

</sect2>

<sect2 renderas="sect3" id="actionss">
<title>The <quote>actions</quote> concept confuses me. Please list 
some of these <quote>actions</quote>.</title>
<para>
 For a comprehensive discussion of the actions concept, please refer
 to the <ulink url="../user-manual/actions-file.html">actions file
 chapter</ulink> in the <ulink url="../user-manual/index.html">user
 manual</ulink>. It includes a <ulink
 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
 file tutorial</ulink> to get you started.
</para>
</sect2>


<sect2 renderas="sect3">
<title id="actconfig">How are actions files configured? What is the easiest
way to do this?</title> 

<para>
 Actions files are just text files in a special syntax and can be edited
 with a text editor. But probably the easiest way is to access
 <application>Privoxy</application>'s user interface with your web browser
 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
 <quote><ulink url="http://config.privoxy.org/show-status">View &
 change the current configuration</ulink></quote> from the menu.
</para>
</sect2>


<sect2 renderas="sect3">
<title>There are several different <quote>actions</quote> files. What are
the differences?</title>
<para>
 As of <application>Privoxy</application> v2.9.15, three actions files 
 are being included, to be used for 
 different purposes: These are 
 <filename>default.action</filename>, the <quote>main</quote> actions file
 which is actively maintained by the <application>Privoxy</application>
 developers, <filename>user.action</filename>, where users are encouraged
 to make their private customizations, and <filename>standard.action</filename>, 
 which is for internal <application>Privoxy</application> use only.
 Please see <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
 in the <ulink url="../user-manual/index.html">user manual</ulink> for a more
 detailed explanation.
</para>

<para>
 Earlier versions included three different versions of the 
 <filename>default.action</filename> file. The new scheme allows for 
 greater flexibility of local configuration, and for browser based 
 selection of pre-defined <quote>aggressiveness</quote> levels.
</para>

</sect2>

<sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
 <para>
  The default configuration shouldn't impact the usability of any of these services.
  It will, however, make all cookies temporary, so that your browser will forget your
  login credentials in between browser sessions. If you would like not to have to log
  in manually each time you access those websites, simply turn off all cookie handling
  for them in the <filename>user.action</filename> file. An example for yahoo might
  look like:
 </para>
 <para>
  <screen># Allow all cookies for Yahoo login:
#
{ -<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> }
.login.yahoo.com</screen>
 </para>

</sect2>

<sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
<quote>Cautious</quote>, <quote>Medium</quote> and <quote>Adventuresome</quote> defaults?</title>
 <para>
  Configuring <application>Privoxy</application> is not entirely trivial. To
  help you get started, we provide you with three different default action
  <quote>profiles</quote> in the web based actions file editor at <ulink
  url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
  See the <ulink url="../user-manual/actions-file.html"><citetitle>User
  Manual</citetitle></ulink> for a list of actions, and how the default 
  profiles are set.
 </para>

<para>
 Where the defaults are likely to break some sites, exceptions for
 known popular <quote>problem</quote> sites are included, but in
 general, the more aggressive your default settings are, the more exceptions
 you will have to make later. See the <ulink
 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
 for a more deatiled discussion.
</para>

<para>
 It should be noted that the <quote>Adventuresome</quote> profile (formerly known 
 as the <quote>Advanced</quote> profile) is not only more
 aggressive, but also includes fun and, extreme usage of most of
 <application>Privoxy's</application> features. Use at your own risk!
</para>

</sect2>

<sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration 
with a browser? Does that not raise security issues?</title>
 <para>
  It may seem strange that regular users can edit the config files with their
  browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
  belongs to the user <quote>privoxy</quote>, with only 644 permissions.
 </para>
 <para>
  When you use the browser-based editor, <application>Privoxy</application>
  itself is writing to the config files.  Because
  <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
  it can update the config files.
 </para>
 <para>
  If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
  a LAN), you will probably want to turn the web-based editor and remote toggle
  features off by setting <quote><literal><ulink
  url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
  0</literal></quote> and <quote><literal><ulink
  url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
  0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
 </para>
 <para>
  Note that in the default configuration, only local users (i.e. those on
  <quote>localhost</quote>) can connect to <application>Privoxy</application>,
  so this is not (normally) a security problem.
 </para>
</sect2>


<sect2 renderas="sect3">
<title id="filterfile">What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
<para>
 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
 file is where <emphasis>filters</emphasis> as supplied by the developers are defined. 
 Filters are a special subset of actions that can be used to modify or
 remove, web page content on the fly. Filters apply to <emphasis>anything</emphasis>
 in the page source (and optionally both client and server headers), including
 HTML tags, and JavaScript. Regular expressions are used to accomplish this.
 There are a number of pre-defined filters to deal with common annoyances. The
 filters are only defined here, to invoke them, you need to use the
 <ulink
 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
 action</ulink> in one of the actions files. Filtering is automatically
 disabled for inappropriate MIME types.
</para>

<para>
 If you are familiar with regular expressions, and HTML, you can look at 
 the provided <filename>default.filter</filename> with a text editor and define
 your own filters.  This is potentially a very powerful feature, but
 requires some expertise in both regular expressions and HTML/HTTP. You should 
 place any modifications to the default filters, or any new ones you create 
 in a separate file, such as <filename>user.filter</filename>, so they won't 
 be overwritten during upgrades. The ability to define multiple filter files 
 in <filename>config</filename> is a new feature as of v. 3.0.4.
</para>

<para>
 There is no GUI editor option for this part of the configuration, 
 but you can disable/enable the various pre-defined filters of the included 
 <filename>default.filter</filename> file with the <ulink
 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
</para>

</sect2>

<sect2 renderas="sect3">
<title id="lanconfig">How can I set up <application>Privoxy</application> to act as a proxy for my 
 LAN?</title>
<para>
 By default, <application>Privoxy</application> only responds to requests 
 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
 a network, this needs to be changed in the <ulink
 url="../user-manual/config.html">main configuration file</ulink>. Look for
 the <literal><ulink
 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
 option, which may be commented out with a <quote>#</quote> symbol. Make sure
 it is uncommented, and assign it the address of the LAN gateway interface,
 and port number to use. Assuming your LAN address is 192.168.1.1 and you
 wish to run <application>Privoxy</application> on port 8118, this line
 should look like:
</para>

<para>
 <screen>
  listen-address  192.168.1.1:8118</screen>
</para>

<para>
 Save the file, and restart <application>Privoxy</application>. Configure 
 all browsers on the network then to use this address and port number.
</para>

<para>
 Alternately, you can have <application>Privoxy</application> listen on 
 all available interfaces:
</para>

<para>
 <screen>
  listen-address    :8118</screen>
</para>

<para>
 And then use <application>Privoxy's</application> 
 <ulink
 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink> 
 feature to limit connections. A firewall in this situation is recommended 
 as well.
</para>

<para>
 The above steps should be the same for any TCP network, regardless of
 operating system.
</para>

<para>
 If you run <application>Privoxy</application> on a LAN with untrusted users,
 we recommend that you double-check the <ulink
 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
 options!
</para>

</sect2>


<sect2 renderas="sect3">
<title id="noseeum">Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
<para>
 The replacement for blocked images can be controlled with the <ulink
 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
 Note that this choice only has effect for images which are blocked as images, i.e.
 whose URLs match both a <literal><ulink
 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
 <emphasis>and</emphasis> <literal><ulink
 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
</para>
<para>
 If you want to see nothing, then change the <ulink
 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
 action</ulink> to <quote>blank</quote>. This can be done by editing the 
 <filename>default.action</filename> file, or trough the <ulink
 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
</para>

</sect2>

<sect2 renderas="sect3">
<title id="whyseeum">Why would anybody want to see a checkerboard pattern?</title>
<para>
 Remember that <link linkend="whatsanad">telling which image is an ad and which
 isn't</link>, is mostly guesswork. While we hope that the standard configuration
 is rather smart, it can and will make errors. The checkerboard image is visually
 decent, but it shows you that and where images were blocked, which can be very
 helpful in case some navigation aid or otherwise innocent image was
 erraneously blocked. Some people might also enjoy seeing how many banners
 they <emphasis>don't</emphasis> have to see..
</para>

</sect2>

<sect2 renderas="sect3">
<title id="blockedbytext">I see some images being replaced by a text
instead of the checkerboard image. Why and how do I get rid of this?</title>
<para>
 This happens when the banners are not embedded in the HTML code of the
 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
 or (i)layers, and these external HTML documents are blocked. Being non-images
 they get replaced by a substitute HTML page rather than a substitute image,
 which wouldn't work out technically, since the browser expects and accepts
 only HTML when it has requested an HTML document. 
</para>
<para>
 The substitute page adapts to the available space and shows itself as a
 miniature two-liner if loaded into small frames, or full-blown with a
 large red "BLOCKED" banner if space allows.
</para>
<para>
 If you prefer the banners to be blocked by images, you must see to it that
 the HTML documents in which they are embedded are not blocked. Clicking
 the <quote>See why</quote> link offered in the substitute page will show
 you which rule blocked the page. After changing the rule and un-blocking
 the HTML documents, the browser will try to load the actual banner images
 and the usual image blocking will (hopefully!) kick in.
</para>
</sect2>


<sect2 renderas="sect3" id="srvany">
<title>Can <application>Privoxy</application> run as a service 
on Win2K/NT?</title>
<para>
 Earlier versions could run as a system service using <command>srvany.exe</command>.
 See the discussion at <ulink
 url="http://sourceforge.net/tracker/?func=detail&#38;atid=361118&#38;aid=485617&#38;group_id=11118">http://sourceforge.net/tracker/?func=detail&#38;atid=361118&#38;aid=485617&#38;group_id=11118</ulink>,
 for details, and a sample configuration.
</para>
<para>
 Version 3.0.1 fixes the problem where the icon and menu where not available
 in the taskbar for this usage.
</para>
<para>
<!--
New check this hal
-->
 Version 3.0.4, introduces full Windows service functionality, thus elimating
 the <command>srvany.exe</command> requirement.
</para>
</sect2>


<sect2 renderas="sect3" id="otherproxy">
<title>How can I make <application>Privoxy</application> work with other 
proxies like <application>Squid</application> or <application>TOR</application>?</title>
<para>
 This can be done and is often useful to combine the benefits of
 <application>Privoxy</application> with those of a another proxy.
 See the <ulink
 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
 in the <ulink url="../user-manual/index.html">user manual</ulink> which
 describes how to do this.
</para>
</sect2>

<sect2 renderas="sect3" id="port-80">
<title>Can I just set <application>Privoxy</application> to use port 80
and thus avoid individual browser configuration?</title>

<para>
 No, its more complicated than that. This only works with special kinds 
 of proxies known as <quote>transparent</quote> proxies (see below).
</para>

</sect2>

<sect2 renderas="sect3" id="transparent">
<title>Can <application>Privoxy</application> run as a <quote>transparent
</quote> proxy?</title>
<para>
 No, <application>Privoxy</application> currently does not have this ability, 
 though it is planned for a future release. Transparent proxies require 
 special handling of the request headers beyond what
 <application>Privoxy</application> is now capable of.
</para>

<para>
 Chaining <application>Privoxy</application> behind another proxy that has 
 this ability should work though. 
 See the <ulink
 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
 in the <ulink url="../user-manual/index.html">user manual</ulink>. As
 a transparent proxy to be used for chaining we recommend Transproxy
 (<ulink url="http://www.transproxy.nlc.net.au/">http://www.transproxy.nlc.net.au/</ulink>).
</para>

</sect2>

<sect2 renderas="sect3" id="outlook">
<title>How can I configure <application>Privoxy</application> for use with <application>Outlook
 Express</application>?</title>
<para>
 <application>Outlook Express</application> uses <application>Internet Explorer</application> 
 components to both render HTML, and fetch any HTTP requests that may be embedded in an HTML email.
 So however you have <application>Privoxy</application> configured to work
 with IE, this configuration should automatically be shared.
</para>
</sect2>

<sect2 renderas="sect3" id="outlook-more">
<title>How can I have separate rules just for HTML mail?</title>
<para>
 The short answer is, you can't. <application>Privoxy</application> has no way
 of knowing which particular application makes a request, so there is no way to
 distinguish between web pages and HTML mail.
 <application>Privoxy</application> just blindly proxies all requests. In the
 case of <application>Outlook Express</application> (see above), OE uses 
 IE anyway, and there is no way for <application>Privoxy</application> to ever 
 be able to distinguish between them (nor could any other proxy type application for
 that matter).
</para>
<para>
 For a good discussion of some of the issues involved (including privacy and 
 security issues), see 
 <ulink url="http://sourceforge.net/tracker/?func=detail&#38;atid=211118&#38;aid=629518&#38;group_id=11118">http://sourceforge.net/tracker/?func=detail&#38;atid=211118&#38;aid=629518&#38;group_id=11118</ulink>.
</para>
</sect2>

<sect2 renderas="sect3" id="allow-cookies">
<title>How can I allow permanent cookies for my trusted sites?</title>

<para>
  There are several actions that relate to cookies. The default behavior is to 
  allow only <quote>session cookies</quote>, which means the cookies only last
  for the current browser session. This eliminates most kinds of abuse related 
  to cookies. But there may be cases where we want cookies to last.
</para>
<para>
  To disable all cookie actions, so that cookies are allowed unrestricted,
  both in and out, for <literal>example.com</literal>: 
</para>
<para>
 <screen>
 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
  .example.com</screen>
</para>
<para>
 Place the above in <filename>user.action</filename>. Note some of these may
 be off by default anyway, so this might be redundant, but there is no harm
 being explicit in what you want to happen. <filename>user.action</filename>
 includes an alias for this situation, called
 <literal>allow-all-cookies</literal>.
</para>
</sect2>

<sect2 renderas="sect3" id="multiples">
<title>Can I have separate configurations for different users?</title>
<para>
 Each instance of <application>Privoxy</application> has its own
 configuration, including such attributes as the TCP port that it listens on.
 What you can do is run multiple instances of <application>Privoxy</application>, each with 
 a unique <literal>listen-address</literal> and configuration path, and then
 each of these can have their own configurations. Think of it as per-port
 configuration.
</para>
<para> 
 Simple enough for a few users, but for large installations, consider having
 groups of users that might share like configurations.
</para>
</sect2>

<sect2 renderas="sect3" id="whitelists">
<title>Can I set-up <application>Privoxy</application> as a whitelist of
<quote>good</quote> sites?</title>
<para>
 Sure. There are a couple of things you can do for simple whitelisting.
 Here's one real easy one:
</para>
 <screen>
 ############################################################
 # Blacklist
 ############################################################
 { +block }
 / # Block *all* URLs
 
 ############################################################
 # Whitelist
 ############################################################
 { -block }
  kids.example.com
  toys.example.com
  games.example.com</screen>
<para>
 This allows access to only those three sites.
</para>
<para>
 A more interesting approach is <application>Privoxy's</application> 
 <literal>trustfile</literal> concept, which incorporates the notion of 
 <quote>trusted referrers</quote>. See the <ulink
 url="../user-manual/config.html#TRUSTFILE">User Manual Trust</ulink>
 documentation.
</para>
<para>
 These are fairly simple approaches and are not completely foolproof. There
 are various other configuration options that should be disabled (described
 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
 so that users can't modify their own configuration and easily circumvent the
 whitelist.
</para>
</sect2>

</sect1>

<!--  ~  End section  ~  -->


<!--   ~~~~~       New section      ~~~~~     -->

<sect1 id="misc"><title>Miscellaneous</title>

<sect2 renderas="sect3">
<title id="slowsme">How much does <application>Privoxy</application> slow my browsing down? This 
has to add extra time to browsing.</title>
<para>
 How much of an impact depends on many things, including the CPU of the host
 system, how agressive the configuration is, which specific actions are being triggered, etc.
</para>
<para>
 Overall, it should not slow you down any in real terms, and may actually help 
 speed things up since ads, banners and other junk are not typically being displayed.
 The actual processing time required by <application>Privoxy</application> 
 itself for each page, is relatively small in the overall scheme of things,
 and happens very quickly. This is typically more than offset by time saved
 not downloading and rendering ad images (if ad blocking is being used).
</para>

<para>
 <quote>Filtering</quote> content via the <literal><ulink
 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
 <literal><ulink
 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
 actions will cause a perceived slowdown, since the entire document needs to be buffered
 before displaying. On very large documents, there may be some impact. How
 much depends on the page size, the actual definition of the filter(s), etc. See below.
 Most other actions have little to no impact on speed.
</para>

</sect2>


<sect2 renderas="sect3" id="loadingtimes"><title>I noticed considerable
delays in page requests compared to the old Junkbuster. What's wrong?</title>
<para>
 If you use any <literal><ulink
 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
 such as filtering banners by size, web-bugs etc, or the <literal><ulink
 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
 action, the entire document must be loaded into memory in order for the filtering 
 mechanism to work, and nothing is sent to the browser during this time.
</para>
<para>
 The loading time typically does not really change much in real numbers, but
 the feeling is different, because most browsers are able to start rendering
 incomplete content, giving the user a feeling of "it works". This effect is
 more noticeable on slower dialup connections. Extremely large documents
 may have some impact on the time to load the page. But the overall difference
 should be very minimal. If there is a big impact, then probably some other
 problem is contributing.
 </para>
<para>
 Filtering is automatically disabled for inappropriate MIME types. But note 
 that if the web server mis-reports the MIME type, then content that should
 not be filtered, could be. <application>Privoxy</application> only knows how
 to differentiate filterable content because of the MIME type as reported by
 the server, or because of some configuration setting that enables/disables
 filtering.

</para>
</sect2>

<sect2 renderas="sect3" id="slowcrawl">
<title>I just installed <application>Privoxy</application>, and all my
browsing has slowed to a crawl. What gives? </title>
<para>
 This should not happen, and for the overwhelming number of users world-wide,
 it does not happen. I would suspect some inadvertent interaction of software
 components such as anti-virus software, spyware protectors, personal
 firewalls or similar components. Try disabling (or uninstalling) these one
 at a time and see if that helps.
</para>
</sect2>

<sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
"http://p.p/"?</title>
<para>
 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
 address of <application>Privoxy</application>'s built-in user interface, and 
 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
</para>
<para>
 Since <application>Privoxy</application> sits between your web browser and the Internet, 
 it can simply intercept requests for these addresses and answer them with its built-in
 <quote>web server</quote>.
</para>
<para>
 This also makes for a good test for your browser configuration: If entering the
 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
 If you get a page saying <quote>Privoxy is not working</quote> instead, then
 your browser didn't use <application>Privoxy</application> for the request,
 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
 web site at config.privoxy.org.
</para>
<para>
 With recent versions of <application>Privoxy</application> (version 2.9.x and
 later), the user interface features information on the run time status, the
 configuration, and even a built-in editor for the <ulink
 url="../user-manual/actions-file.html">actions files</ulink>.
</para>

<para>
 Note that the built-in URLs from earlier versions of <application>Junkbuster</application>
 / <application>Privoxy</application>, http://example.com/show-proxy-args and http://i.j.b/,
 are no longer supported. If you still use such an old version, you should really consider
 upgrading to &p-version;.
</para>
</sect2>

<!--
 out of date 09/02/06 HB
<sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
 <para>
  No. The patterns for blocking now reside (among other things) in the <ulink
  url="../user-manual/actions-file.html">actions files</ulink>, which are 
  actively maintained instead. See next question ...
</para>
</sect2>
-->
<sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
problems?</title>
<para>
Please see the <link linkend="contact">Contact section</link> for
various ways to interact with the developers.
</para>

</sect2>

<sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support 
request?</title>
<para>
Rest assured that it has been read and considered. Why it is not answered,
could be for various reasons, including no one has a good answer for it, no
one has had time to yet investigate it thorougly, it has been reported
numerous times already, or because not enough information was provided to help
us help you. Your efforts are not wasted, and we do appreciate them.
</para>

</sect2>


<sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
<para>
 If you run both the browser and the proxy locally, you cannot hide your IP
 address with <application>Privoxy</application> or ultimately any other
 software. The server needs to know your IP address to send the answers back
 to you. 
</para>
<para>
 Fortunately there are many publicly usable anonymous proxies out there, which
 solve the problem by providing a further level of indirection between you and
 the web server, shared by many people, and thus letting your requests "drown"
 in white noise of unrelated requests as far as user tracking is concerned.
</para>
<para>
 Most of them will, however, log your IP address and make it available to the
 authorities in case you abuse that anonymity for criminal purposes. In fact
 you can't even rule out that some of them only exist to *collect* information
 on (those suspicious) people with a more than average preference for privacy.
</para>
<para>
 You can find a list of anonymous public proxies at <ulink
 url="http://www.multiproxy.org/anon_proxy.htm">multiproxy.org</ulink> and many
 more through Google. A particularly interesting project is the JAP service
 offered by the Technical University of Dresden (<ulink
 url="http://anon.inf.tu-dresden.de/index_en.html">http://anon.inf.tu-dresden.de/index_en.html</ulink>).
</para>
<para>
 There is, however, even in the single-machine case the possibility to make the
 server believe that your machine is in fact a shared proxy serving a large
 LAN, and we are looking into that.
</para>
</sect2>

<sect2 renderas="sect3">
<title id="anonforsure">Can <application>Privoxy</application> guarantee I am anonymous?</title>
<para>
 No. Your chances of remaining anonymous are greatly improved, but unless you
 are an expert on Internet security it would be safest to assume that
 everything you do on the Web can be traced back to you.
</para>
<para>
 <application>Privoxy</application> can remove various information about you,
 and allows <emphasis>you</emphasis> more freedom  to decide which sites 
 you can trust, and what details you want to reveal. But it's still possible
 that web sites can find out who you are. Here's one way this can happen.
</para>
<para>
 A few browsers disclose the user's email address in certain situations, such
 as when transferring a file by FTP. <application>Privoxy</application>
 does not filter FTP. If you need this feature, or are concerned about the
 mail handler of your browser disclosing your email address, you might
 consider products such as <application>NSClean</application>.
</para>
<para>
 Browsers available only as binaries could use non-standard headers to give
 out any information they can have access to: see the manufacturer's license
 agreement. It's impossible to anticipate and prevent every breach of privacy
 that might occur. The professionally paranoid prefer browsers available as
 source code, because anticipating their behavior is easier. Trust the source,
 Luke!
</para>

</sect2>

<sect2 renderas="sect3">
<title id="sitebreak">Might some things break because header information or
content is being altered?</title>

<para>
 Definitely. More and more sites use HTTP header content to decide what to
 display and how to display it. There is many ways that this can be handled, 
 so having hard and fast rules, is tricky.
</para>

<para>
 <quote>User-Agent</quote> in particular is often used in this way to identify
 the browser, and adjust content accordingly. Changing this now (at least not
 further than removing the OS information) is not recommended, since so many
 sites do look for it. You may get undesirable results by changing this.
</para>

<para>
 For instance, different browsers use different encodings of Russian and Czech
 characters, certain web servers convert pages on-the-fly according to the
 User Agent header. Giving a <quote>User Agent</quote> with the wrong
 operating system or browser manufacturer causes some sites in these languages
 to be garbled; Surfers to Eastern European sites should change it to
 something closer. And then some page access counters work by looking at the
 <quote>Referer</quote> header; they may fail or break if unavailable. The
 weather maps of Intellicast have been blocked by their server when no
 <quote>Referer</quote> or cookie is provided, is another example. (But you
 can forge both headers without giving information away). There are
 many other ways things can go wrong when trying to fool a web server.
</para>

<para>
 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
 HTML elements.
</para>

<para>
 If you have problems with a site, you will have to adjust your configuration 
 accordingly. Cookies are probably the most likely adjustment that may 
 be required, but by no means the only one.
</para>

</sect2>


<sect2 renderas="sect3">
<title id="caching">Can <application>Privoxy</application> act as a <quote>caching</quote> proxy to 
speed up web browsing?</title>
<para>
 No, it does not have this ability at all. You want something like 
 <ulink url="http://www.squid-cache.org/">Squid</ulink> for this. And, yes, 
 before you ask, <application>Privoxy</application> can co-exist 
 with other kinds of proxies like <application>Squid</application>.
 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
 chapter</ulink> in the <ulink url="../user-manual/index.html">user
 manual</ulink> for details.
</para>
</sect2>

<sect2 renderas="sect3">
<title id="firewall">What about as a firewall? Can <application>Privoxy</application> protect me?</title>
<para>
 Not in the way you mean, or in the way a true firewall can. 
 <application>Privoxy</application> can help protect your privacy, but not
 protect you from intrusion attempts. It is, of course, perfectly possible
 and recommended to use <emphasis>both</emphasis>.
</para>
</sect2>

<!-- No longer needed
<sect2 renderas="sect3">
<title id="logo">The <application>Privoxy</application> logo that replaces ads is very blocky 
and ugly looking. Can't a better font be used?</title>

<para>
 This is not a font problem. The logo is an image that is created by 
 <application>Privoxy</application> on the fly. So as to not waste 
 memory, the image is rather small. The blockiness comes when the 
 image is scaled to fill a largish area. There is not much to be done 
 about this, other than to use one of the other
 <quote>imageblock</quote> directives: <emphasis>pattern</emphasis>, 
 <emphasis>blank</emphasis>, or a URL of your choosing.
</para>
<para>
Given the above problem, we have decided to remove the logo option entirely 
[as of v2.9.13].
</para>
</sect2>
-->

<sect2 renderas="sect3">
<title id="wasted">I have large empty spaces / a checkerboard pattern now where
ads used to be. Why?</title>
<para>
 It would be technically possible eliminate the banners in a way that frees
 their screen estate in many cases, by doing all banner blocking with filters,
 i.e. eliminating the whole image references from the HTML pages instead
 of letting them stay in, and blocking the resulting requests for the
 banners themselves.
</para>
<para>
 But this would consume considerable CPU resources, would likely destroy
 the layout of many web pages which rely on the banners consuming a certain
 amount of screen space, and would fail in other cases, where the screen space
 is reserved e.g. by tables anyway. Also, making the banners disappear without
 a visual trace complicates troubleshooting.
</para>
<para>
 So we won't support this in the default configuration, but you can of course
 define appropriate filters yourself.
</para>
</sect2>

<sect2 renderas="sect3">
<title id="ssl">How can <application>Privoxy</application> filter Secure (HTTPS) URLs?</title>
<para>
 Since secure HTTP connections are encrypted SSL sessions between your browser
 and the secure site, and are meant to be reliably <emphasis>secure</emphasis>,
 there is little that <application>Privoxy</application> can do but hand the raw
 gibberish data though from one end to the other unprocessed.
</para>
<para>
 The only exception to this is blocking by host patterns, as the client needs
 to tell <application>Privoxy</application> the name of the remote server,
 so that <application>Privoxy</application> can establish the connection.
 If that name matches a host-only pattern, the connection will be blocked.
</para>
<para>
 As far as ad blocking is concerned, this is less of a restriction than it may
 seem, since ad sources are often identifiable by the host name, and often
 the banners to be placed in an encrypted page come unencrypted nonetheless
 for efficiency reasons, which exposes them to the full power of 
 <application>Privoxy</application>'s ad blocking.
</para>
<para>
 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
 JS page content, see <literal><ulink
 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>), 
 in an SSL transaction will be impossible to block under these conditions. 
 Fortunately, this does not seem to be a very common scenario since most 
 cookies come by traditional means.
</para>

</sect2>

<sect2 renderas="sect3">
<title id="secure"><application>Privoxy</application> runs as a <quote>server</quote>. How 
secure is it? Do I need to take any special precautions?</title>
<para>
 There are no known exploits that might affect
 <application>Privoxy</application>. On Unix-like systems, 
 <application>Privoxy</application> can run as a non-privileged 
 user, which is how we recommend it be run. Also, by default 
 <application>Privoxy</application> only listens to requests 
 from <quote>localhost</quote> only. The server aspect of
 <application>Privoxy</application> is not itself directly exposed to the
 Internet in this configuration. If you want to have
 <application>Privoxy</application> serve as a LAN proxy, this will have to
 be opened up to allow for LAN requests. In this case, we'd recommend
 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main 
 <application>Privoxy</application> configuration file and check all <ulink
 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
 options</ulink>. All LAN hosts can then use this as their proxy address
 in the browser proxy configuration, but <application>Privoxy</application>
 will not listen on any external interfaces. ACLs can be defined in addition,
 and using a firewall is always good too. Better safe than sorry.
</para>

</sect2>

<sect2 renderas="sect3" id="turnoff">
<title>How can I temporarily disable <application>Privoxy</application>?</title>
<para>
 The easiest way is to access <application>Privoxy</application> with your 
 browser by using the remote toggle URL: <ulink
 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink> 
 of the <citetitle>User Manual</citetitle> for an easy way to access this 
 feature.
</para>
</sect2>

<sect2 renderas="sect3" id="reallyoff">
<title>When <quote>disabled</quote> is <application>Privoxy</application> totally 
out of the picture?</title>
<para>
 No, this just means all filtering and actions are disabled.
 <application>Privoxy</application> is still acting as a proxy, but just not 
 doing any of the things that <application>Privoxy</application> would
 normally be expected to do. It is still a <quote>middle-man</quote> in 
 the interaction between your browser and web sites.
</para>
</sect2>

<sect2 renderas="sect3" id="crunch">
<title>My logs show <application>Privoxy</application> <quote>crunches</quote> 
ads, but also its own CGI pages. What is a <quote>crunch</quote>?</title>
<para>
 A <quote>crunch</quote> simply means <application>Privoxy</application> intercepted 
 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
 banners, but <application>Privoxy</application> uses the same mechanism for
 trapping requests for its own internal pages. For instance, a request for
 <application>Privoxy's</application> configuration page at: <ulink
 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
 configuration is returned to the browser, and the log consequently will show
 a <quote>crunch</quote>.
</para>
</sect2>

<sect2 renderas="sect3" id="downloads">
<title>Can <application>Privoxy</application> effect files that I download
from a webserver? FTP server?</title>
<para>
 From the webserver's perspective, there is no difference between
 viewing a document (i.e. a page), and downloading a file. The same is true of
 <application>Privoxy</application>. If there is a match for a <literal><ulink
 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
 it will still be blocked, and of course this is obvious. 
 </para>
 <para>
 Filtering is potentially more of a concern since the results are not always
 so obvious, and the effects of filtering are there whether the file is simply
 viewed, or downloaded. And potentially whether the content is some obnoxious
 advertizement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
 one of these presumably is <quote>bad</quote> content that we don't want, and
 the other is <quote>good</quote> content that we do want.
 <application>Privoxy</application> is blind to the differences, and can only
 distinguish <quote>good from bad</quote> by the configuration parameters
 <emphasis>we</emphasis> give it.
</para>
<para>
 <application>Privoxy</application> knows the differences in files according
 to the <quote>Document Type</quote> as reported by the webserver. If this is
 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
 then <application>Privoxy</application> knows to ignore these where
 appropriate. <application>Privoxy</application> potentially can filter HTML
 as well as plain text documents, subject to configuration parameters of
 course. Also, documents that are of an unknown type (generally assumed to be
 <quote>text/plain</quote>) can be filtered, as will those that might be
 incorrectly reported by the webserver. If such a file is a downloaded file
 that is intended to be saved to disk, then any content that might have been
 altered by filtering, will be saved too, for these (probably rare) cases.
</para>
<para>
 Note that versions later than 3.0.2 do NOT filter document types of
 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
 did filter this document type.
</para>
<para>
 In short, filtering is <quote>ON</quote> if a) the Document Type as reported
 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
 allows it (or at least does not disallow it). That's it. There is no magic
 cookie anywhere to say this is <quote>good</quote> and this is
 <quote>bad</quote>. It's the configuration that let's it all happen or not.
</para>
<para>
 If you download text files, you probably do not want these to be filtered,
 particularly if the content is source code, or other critical content. Source
 code sometimes might be mistaken for Javascript (i.e. the kind that might
 open a pop-up window). It is recommended to turn off filtering for download
 sites (particularly if the content may be plain text files and you are using
 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
 also, for any site or page where making <emphasis>any</emphasis> changes at
 all to the content is to be avoided.
</para>
<para>
 <application>Privoxy</application> does not do FTP at all, only HTTP 
  protocols, so please don't even try.
</para>
</sect2>

<sect2 renderas="sect3" id="downloads2">
<title>I just downloaded a Perl script, and <application>Privoxy</application>
altered it! Yikes, what is wrong!</title>
<para>
 Please read above.
</para>
</sect2>


<sect2 renderas="sect3" id="seealso">
<title>Where can I find more information about <application>Privoxy</application>
and related issues?</title>
<!-- Include seealso.sgml boilerplate: -->
 &seealso;
<!-- end boilerplate -->

<!--
<para>
 Please see the 
 <ulink url="../user-manual/seealso.html">user-manual</ulink> for 
 others references.
</para>
-->
</sect2>

<sect2 renderas="sect3" id="microsuck">
<title>I've noticed that Privoxy changes <quote>Microsoft</quote> to 
<quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>

<para>
 We're not. The text substitutions that you are seeing are disabled
 in the default configuration as shipped. You have either manually
 activated the <quote><literal>fun</literal></quote> filter which
 is clearly labeled <quote>Text replacements for subversive browsing
 fun!</quote> or you have implicitly activated it by choosing the
 <quote>Adventuresome</quote> profile in the web-based editor (formerly known 
 as the <application>Advanced</application> profile).
</para>
</sect2>

</sect1>


<!--   ~~~~~       New section      ~~~~~     -->

<sect1 id="trouble">
<title>Troubleshooting</title>

<sect2 renderas="sect3">
<title id="refused">I am getting <quote>connection refused</quote>
with every web page?</title>
<para>
 Either <application>Privoxy</application> is not running, or your 
 browser is configured for a different port than what
 <application>Privoxy</application> is using.
</para>

<para>
 Early <application>Privoxy</application> versions (and also
 <application>Junkbuster</application>) used port 8000 by 
 default. This has been changed to port 8118 now, due to a conflict 
 with NAS (Network Audio Service), which uses port 8000. If you haven't, 
 you need to change your browser to the new port number, or alternately 
 change the <ulink
 url="../user-manual/config.html#LISTEN-ADDRESS"><literal>listen-address</literal>
 option</ulink> in <application>Privoxy's</application> <ulink
 url="../user-manual/config.html">main configuration file</ulink>.
</para>

</sect2>

<sect2 renderas="sect3">
<title id="flushit">I just added a new rule, but the steenkin ad is 
still getting through. How?</title>
<para>
 If the ad had been displayed before you added its URL, it will probably be
 held in the browser's cache for some time, so it will be displayed without
 the need for any request to the server, and <application>Privoxy</application>
 will not be in the picture. The best thing to do is try flushing the browser's
 caches. And then try again.
</para>

<para>
 If this doesn't help, you probably have an error in the rule you
 applied. Try pasting the full URL of the offending ad into <ulink
 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
 and see if it really matches your new rule. Blocking ads is like blocking
 spam: a lot of tinkering is required to stay ahead of the game.
</para>

</sect2>

<sect2 id="badsite" renderas="sect3">
<title >One of my favorite sites does not work with <application>Privoxy</application>.
What can I do?</title>

<para>
 First verify that it is indeed a <application>Privoxy</application> problem, 
 by toggling off <application>Privoxy</application> through <ulink
 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>,
 and then shift-reloading the problem page (i.e. holding down the shift key
 while clicking reload. Alternatively, flush your browser's disk and memory
 caches).
</para>

<para>
 If still a problem, go to <ulink
 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
 and paste the full URL of the page in question into the prompt. See which actions
 are being applied to the URL, and which matches in which actions files are
 responsible for that. Now, armed with this information, go to <ulink
 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
 and select the appropriate actions files for editing.
</para>
<para>
 You can now either look for a section which disables the actions that
 you suspect to cause the problem and add a pattern for your site there,
 or make up a completely new section for your site. In any case, the recommended
 way is to disable only the prime suspect, reload the problem page, and only
 if the problem persists, disable more and more actions until you have
 identified the culprit. You may or may not want to turn the other actions
 on again. Remember to flush your browser's caches in between any such changes!
</para>
<para>
 Alternately, if you are comfortable with a text editor, you can accomplish 
 the same thing by editing the appropriate actions file. Probably the easiest 
 way to deal with such problems when editing by hand is to add your
 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
 which is an alias that turns off most <quote>dangerous</quote>
 actions, but is also likely to turn off more actions then needed, and thus lower
 your privacy and protection more than necessary, 
</para>
<para>
 Troubleshooting actions is discussed in more detail in the <ulink
 url="../user-manual/appendix.html#ACTIONSANAT">user-manual appendix</ulink>.
 There is also an <ulink
 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>.
</para>

</sect2>


<!--   ~~~~~       New section      ~~~~~     -->
<sect2 id="dun" renderas="sect3">
<title>After installing <application>Privoxy</application>, I have to log in
every time I start IE. What gives?</title>

<para>
 This is a quirk that effects the installation of
 <application>Privoxy</application>, in conjunction with Internet Explorer and
 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
 appear to be corrupted or invalid DUN settings, or passwords.
</para>

<para>
 When setting up an NT based Windows system with
 <application>Privoxy</application> you may find that things do not seem to be
 doing what you expect. When you set your system up you will probably have set
 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
 logged in with administrator privileges. You will probably have made this DUN
 connection available to other accounts that you may have set-up on your
 system. E.g. Mum or Dad sets up the system and makes accounts suitably
 configured for the kids.
</para>

<para>
 When setting up <application>Privoxy</application> in this environment you
 will have to alter the proxy set-up of Internet Explorer (IE) for the
 specific DUN connection on which you wish to use
 <application>Privoxy</application>. When you do this the ICS DUN set-up
 becomes user specific. In this instance you will see no difference if you
 change the DUN connection under the account used to set-up the connection.
 However when you do this from another user you will notice that the DUN
 connection changes to make available to "Me only". You will also find that
 you have to store the password under each different user!
</para>

<para>
 The reason for this is that each user's set-up for IE is user specific. Each
 set-up DUN connection and each LAN connection in IE store the settings for
 each user individually. As such this enforces individual configurations
 rather than common ones. Hence the first time you use a DUN connection after
 re-booting your system it may not perform as you expect, and prompt you for 
 the password. Just set and save the password again and all should be OK.
</para>

<para>
[Thanks to Ray Griffith for this submission.]
</para>
</sect2>


<!--   ~~~~~       New section      ~~~~~     -->
<sect2 id="ftp" renderas="sect3">
<title>I cannot connect to any FTP sites. <application>Privoxy</application>
 seems to be blocking me.</title>
 <para>
  <application>Privoxy</application> cannot act as a proxy for FTP traffic, 
  so do not configure your browser to use <application>Privoxy</application>
  as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
  or HTTPS</emphasis>. 
 </para>
 <para>
  Most browsers understand FTP as well as HTTP. If you connect to a site, with
  a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
  an FTP connection, and not a HTTP connection. So while your browser may 
  speak FTP, <application>Privoxy</application> does not, and cannot proxy 
  such traffic.
 </para>
 <para>
  To complicate matters, some systems may have a generic <quote>proxy</quote>
  setting, which will silently enable <emphasis>both</emphasis> HTTP and FTP
  proxying! So it is possible to accidentally enable FTP proxying in these
  cases. And of course, if this happens, <application>Privoxy</application>
  will indeed cause problems since it does not know FTP.
 </para>
 <para>
  Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
  There just is not much reason, and the work to make this happen is more than
  it may seem.
 </para>
</sect2>

<!--   ~~~~~       New section      ~~~~~     -->
<sect2 id="osxie" renderas="sect3">
<title>In Mac OSX, I can't configure Microsoft Internet Explorer to use 
 <application>Privoxy</application> as the HTTP proxy.</title>
 <para>
  Microsoft Internet Explorer (in versions like 5.1) respects system-wide
  network settings.  In order to change the HTTP proxy, open System
  Preferences, and click on the Network icon.  In the settings pane that
  comes up, click on the Proxies tab.  Ensure the "Web Proxy (HTTP)" checkbox 
  is checked and enter <literal>127.0.0.1</literal> in the entry field.  
  Enter <literal>8118</literal> in the Port field.  The next time you start
  IE, it should reflect these values.
 </para>
</sect2>

<!--   ~~~~~       New section      ~~~~~     -->
<sect2 renderas="sect3" id="osxuninstall">
<title>In Mac OSX, I dragged the Privoxy folder to the trash in order to 
 uninstall it.  Now the finder tells me I don't have sufficient privileges to
 empty the trash.</title>
 <para>
  Just dragging the <application>Privoxy</application> folder to the trash is
  not enough to delete it.  <application>Privoxy</application> supplies an
  <application>uninstall.command</application> file that takes care of
  these details.  Open the trash, drag the <application>uninstall.command</application>
  file out of the trash and double-click on it.  You will be prompted for
  confirmation and the administration password.
 </para> 
 <para>
  The trash may still appear full after this command; emptying the trash 
  from the desktop should make it appear empty again.
 </para>
</sect2>


<!--   ~~~~~       New section      ~~~~~     -->
<sect2 renderas="sect3" id="osximages">
<title>In Mac OSX Panther (10.3), images often fail to load and/or I
 experience random delays in page loading. I'm using
 <literal>localhost</literal> as my browser's proxy setting.</title>
 <para>
  We believe this is due to an IPv6-related bug in OSX, but don't fully
  understand the issue yet. In any case, changing the proxy setting to 
  <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
  works around the problem.
 </para>
</sect2>

<!--   ~~~~~       New section      ~~~~~     -->
<sect2 renderas="sect3" id="blankpage">
<title>I get a completely blank page at one site. <quote>View Source</quote>
 shows only: <markup><![CDATA[<html><body></body></html>]]></markup>. Without
 <application>Privoxy</application> the page loads fine.</title>
 <para>
  Chances are that the site suffers from a bug in
  <ulink url="http://www.php.net/"><application>PHP</application></ulink>,
  which results in empty pages being sent if the client explicitly requests
  an uncompressed page, like <application>Privoxy</application> does.
  This bug has been fixed in PHP 4.2.3.
 </para>
 <para>
  To find out if this is in fact the source of the problem, try adding
  the site to a <literal>-prevent-compression</literal> section in
  <filename>user.action</filename>:
 </para>
 <screen>
   # Make exceptions for ill-behaved sites:                                     
   #                                                                    
   {-prevent-compression}                                               
    .example.com</screen>
 <para>
  If that works, you may also want to report the problem to the
  site's webmasters, telling them to use zlib.output_compression
  instead of ob_gzhandler in their PHP applications (workaround)
  or upgrade to PHP 4.2.3 or later (fix).
 </para>
</sect2>

<!--   ~~~~~       New section      ~~~~~     -->
<sect2 renderas="sect3" id="error503">
<title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
 <para>
  More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
  been reported to cause this symptom -- even if not running. The solution is
  to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
  something better behaved in its place. Other personal firewall type products
  may cause similar type problems if not configured correctly.
 </para>
</sect2>

<sect2 renderas="sect3" id="nohostname">
<title>My logs show many <quote>Unable to get my own hostname</quote> lines.
Why?</title>
<para>
 <application>Privoxy</application> tries to get the hostname of the system
 its running on from the IP address of the system interface it is bound to
 (from the <filename>config</filename> file
 <emphasis>listen-address</emphasis> setting). If the system cannot supply
 this information, <application>Privoxy</application> logs this condition. 
</para>
<para>
 Typically, this would be considered a minor system configuration error. It is
 not a fatal error to <application>Privoxy</application> however, but may
 result in a much slower response from <application>Privoxy</application> on
 some platforms due to DNS timeouts.
</para>
</sect2>

<sect2 renderas="sect3" id="inuse">
<title>When I try to launch <application>Privoxy</application>, I get an 
error message <quote>port 8118 is already in use</quote> (or similar wording).
Why?</title>
<para>
 Port 8118 is <application>Privoxy's</application> default TCP 
 <quote>listening</quote> port. Typically this message would mean that there
 is already one instance of <application>Privoxy</application> running, and
 you are actually trying to start a second <application>Privoxy</application> 
 on the same port, which will not work. (You can have multiple instances but
 they must be assigned different ports.) How and why this might happen varies
 from platform to platform, but you need to check your installation and
 start-up procedures.
</para>
</sect2>

<sect2 renderas="sect3" id="demoronizer">
<title>
 Pages with UTF-8 fonts are garbled.
</title>
<para>
 This is caused by the <quote>demoronizer</quote> filter. You should either
 upgrade <application>Privoxy</application>, or at least upgrade to the most
 recent <filename>default.action</filename> file available from <ulink
 url="http://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>.
 Or you can simply disable the demoronizer filter.
</para>
</sect2>

<sect2 renderas="sect3" id="demoronizer2">
<title>
 Why are binary files (such as images) corrupted when <application>Privoxy</application>
 is used?
</title>
<para>
 This may also be caused by the <quote>demoronizer</quote> filter, 
 in conjunction with a web server that is misreporting a file type. Binary 
 files are exempted from <application>Privoxy's</application> filtering
 (unless the web server by mistake says the file is something else). Either
 upgrade <application>Privoxy</application>, or go to the most recent
 <filename>default.action</filename> file available from <ulink
 url="http://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>.
</para>
</sect2>

<sect2 renderas="sect3" id="demoronizer3">
<title>
 What is the <quote>demoronizer</quote> and why is it there?
</title>
<para>
 The original demoronizer was a Perl script that cleaned up HTML pages which 
 were created with certain Microsoft products. MS has used proprietary extensions 
 to standardized font encodings (ISO 8859-1), which has caused problems for pages
 that are viewed with non-Microsoft products (and are expecting to see a
 standard set of fonts). The demoronizer corrected these errors so the pages
 displayed correctly. <application>Privoxy</application> borrowed from this
 script, introducing a filter based on the original demoronizer, which in turn could
 correct these errors on the fly. 
</para>
<para>
 But this is only needed in some situations, and will cause serious problems in some 
 other situations.
</para>
<para>
 If you are using Microsoft products, you do not need it. If you need to view 
 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will 
 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
</para>
<para>
 On the other hand, if you use non-Microsoft products, and you occasionally 
 notice wierd characters on pages, you might want to try it.
</para>
</sect2>

<sect2 renderas="sect3" id="windowopen">
<title>
 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
</title>
<para>
 <application>Privoxy</application> is attempting to disable malicious 
 Javascript in this case, with the <literal>unsolicited-popups</literal>
 filter. <application>Privoxy</application> cannot tell very well 
 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
</para>
<para>
 If you see this in HTML source, and the page displays without problems, then 
 this is good, and likely some pop-up window was disabled. If you see this 
 where it is causing a problem, such as a downloaded program source code file, 
 then you should set an exception for this site or page such that the
 integrity of the page stays in tact by disabling all filtering.
</para>
</sect2>

<sect2 renderas="sect3" id="dnserrors">
<title>
 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
 can't <application>Privoxy</application> do this better?
</title>
<para>
 There are potentially several factors here. First of all, the DNS resolution
 is done by the underlying operating system -- not
 <application>Privoxy</application> itself. <application>Privoxy</application>
 merely initiates the process and hands it off, and then later reports
 whatever the outcome was. And tries to give a coherent message if there seems
 to be a problem. In some cases, this might otherwise be mitigated by the
 browser itself which might try some work-arounds and alernate approaches (e.g
 adding <quote>www.</quote> to the URL). In other cases, if
 <application>Privoxy</application> is being chained with another proxy, this
 could complicate the issue, and cause undue
 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
 server handles all the DNS.  <application>Privoxy</application> would just be
 the <quote>messenger</quote> which is reporting whatever problem occurred
 downstream, and not the root cause of the error.
</para>
<para>
 In any case, v. 3.0.4 includes various improvements to help
 <application>Privoxy</application> better handle these cases.
</para>
</sect2>

<sect2 renderas="sect3" id="allcpu">
<title>
 At one site <application>Privoxy</application> just hangs, and starts taking 
 all CPU. Why is this?
</title>
<para>
 This is probably a manifestation of the <quote>100% cpu</quote> problem that
 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines 
 are in the raw HTML source of the page, and the browser just ignores them. But the 
 pattern matching in <application>Privoxy's</application> page filtering
 mechanism is trying to match against absurdly long strings and this becomes
 very CPU-intensive, taking a long, long time to complete. Until a better
 solution comes along, disable filtering on these pages, particularly the
 <literal>js-annoyances</literal> and <literal>unsolicited-popups</literal>
 filters.
</para>
</sect2>



</sect1>

  <!--   ~~~~~       New section      ~~~~~     -->
  <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
<!-- Include contacting.sgml  -->
 &contacting;
<!-- end contacting -->
  </sect1>
  
<!--   ~~~~~       New section      ~~~~~     -->
<sect1 id="copyright"><title>Privoxy Copyright, License and History</title>

 <!-- Include copyright.sgml -->
  &copyright;
 <!-- end -->
  

  <para>
   Portions of this document are <quote>borrowed</quote> from the original
   <application>Junkbuster</application> (tm) FAQ, and modified as 
   appropriate for <application>Privoxy</application>.
  </para>

 <!--   ~~~~~       New section      ~~~~~     -->
 <sect2><title>License</title>
 <!-- Include copyright.sgml: -->
  &license;
 <!-- end copyright -->
 </sect2>
 <!--  ~  End section  ~  -->

 <!--   ~~~~~       New section      ~~~~~     -->
 <sect2><title>History</title>
 <!-- Include history.sgml -->
  &history;
 <!-- end -->
 </sect2>

 </sect1>
 <!--  ~  End section  ~  -->
 
  
<!--   ~~~~~       New section      ~~~~~     -->
<!--
<sect1 id="seealso"><title>See also</title>
-->
<!-- Include seealso.sgml -->
<!--
 &see;
-->
<!-- end  -->
<!--
</sect1>
-->

<!-- hhmts end -->
 <!--
 Tue 09/11/01 06:38:14 PM EST: Test SGML doc by Hal Burgiss.
 
 This program is free software; you can redistribute it 
 and/or modify it under the terms of the GNU General
 Public License as published by the Free Software
 Foundation; either version 2 of the License, or (at
 your option) any later version.

 This program is distributed in the hope that it will
 be useful, but WITHOUT ANY WARRANTY; without even the
 implied warranty of MERCHANTABILITY or FITNESS FOR A
 PARTICULAR PURPOSE.  See the GNU General Public
 License for more details.

 The GNU General Public License should be included with
 this file.  If not, you can view it at
 http://www.gnu.org/copyleft/gpl.html
 or write to the Free Software Foundation, Inc., 59
 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

$Log: faq.sgml,v $
Revision 2.11  2006/07/18 14:48:50  david__schmidt
Reorganizing the repository: swapping out what was HEAD (the old 3.1 branch)
with what was really the latest development (the v_3_0_branch branch)

Revision 1.61.2.41  2004/04/05 13:44:05  oes
Fixed allow-all-cookies alias name; closes SR #929746

Revision 1.61.2.40  2004/01/30 17:00:33  oes
Added OSX Panther problem

Revision 1.61.2.39  2004/01/29 22:53:08  hal9
Minor changes for exempting docs of text/plain. Change copyright date.

Revision 1.61.2.38  2003/12/10 03:39:45  hal9
Added FAQs for: demoronizer, related problems and why its included. Also,
port 8118 already in use questions, and PrivoxyWindowOpen() questions. All in
troubleshooting section.

Revision 1.61.2.37  2003/10/17 11:01:50  oes
Added Q&A for "not being used" page problem

Revision 1.61.2.36  2003/06/26 23:49:20  hal9
More on the filter/source code problem.

Revision 1.61.2.35  2003/06/26 13:38:08  hal9
Add FAQ on whether configuring Privoxy is necessary or not.

Revision 1.61.2.34  2003/06/26 03:00:03  hal9
Sorry, found another copyright date.

Revision 1.61.2.33  2003/06/26 02:57:05  hal9
Fix typo (finally!) and very minor modifications.

Revision 1.61.2.32  2003/06/26 02:52:04  hal9
Test, no changes.

Revision 1.61.2.31  2003/06/25 01:27:51  hal9
Fix copyright, and a few nits.

Revision 1.61.2.30  2003/06/25 01:13:52  hal9
Add:

 - FAQ on "Unable to get my own hostname"
 - Another one on filtering effects on text files.

Revision 1.61.2.29  2003/06/15 21:32:58  hal9
Add to the 4.17 (filtering effects on downloaded files).

Revision 1.61.2.28  2003/03/18 19:37:21  oes
s/Advanced|Radical/Adventuresome/g to avoid complaints re fun filter

Revision 1.61.2.27  2002/12/01 06:31:58  hal9
Add faq on win32 error 503 due to ZoneAlarm.

Revision 1.61.2.26  2002/11/17 06:41:06  hal9
Move default profiles table from FAQ to U-M, and other minor related changes.
Add faq on cookies.

Revision 1.61.2.25  2002/10/29 03:21:50  hal9
Add 3 Q/A's relating to HTML in email. Other minor touchups.

Revision 1.61.2.24  2002/10/15 12:50:22  oes
s/Advanced/Radical/ (stupid me)

Revision 1.61.2.23  2002/10/15 12:38:56  oes
Added Microsuck faq; more detail for PHP problem

Revision 1.61.2.22  2002/10/12 01:13:13  hal9
Updates for demoronizer, more commentary on Radical profile, and update on
the srvany.exe/icon fix.

Revision 1.61.2.21  2002/10/10 04:09:35  hal9
s/Advanced/Radical/ and added very brief note.

Revision 1.61.2.20  2002/09/26 01:22:45  hal9
Small additions for LAN setup, content-cookies/SSL, and FTP non-support.

Revision 1.61.2.19  2002/08/25 23:31:56  hal9
Fix one grammatical error. Add brief FAQ relating to tranparent proxies (ie
port 80 setting). Add FAQ on effects of Privoxy on downloaded files
(especially filtering).

Revision 1.61.2.18  2002/08/14 16:39:37  hal9
Fix wrong tag on FAQ addition.

Revision 1.61.2.17  2002/08/14 00:01:18  hal9
Add a crunch FAQ.

Revision 1.61.2.16  2002/08/13 00:10:38  hal9
Add faq to troubleshooting re: blank page syndrome, ie {-prevent-compression}.

Revision 1.61.2.15  2002/08/10 11:34:22  oes
Add disclaimer about probably being out-of-date

Revision 1.61.2.14  2002/08/07 02:53:43  hal9
Fix some minor markup errors, and move one OSX Q/A to troubleshooting section.

Revision 1.61.2.13  2002/08/06 11:55:32  oes
Added missing close tag

Revision 1.61.2.12  2002/08/06 11:43:46  david__schmidt
Updated OSX uninstall FAQ... we have an uninstall script now.

Revision 1.61.2.11  2002/08/06 08:54:03  oes
Style police: Fixed formatting details

Revision 1.61.2.10  2002/08/02 14:00:25  david__schmidt
Made the OSX removal commands far less dangerous

Revision 1.61.2.9  2002/08/02 13:14:45  oes
Added warning about sudo rm -r for Mac OSX deinstallation; moved this item to install section

Revision 1.61.2.8  2002/08/02 02:01:42  david__schmidt
Add FAQ item for MSIE on OSX HTTP proxy confusion

Revision 1.61.2.7  2002/08/02 01:46:01  david__schmidt
Added FAQ item for Mac OSX uninstall woes

Revision 1.61.2.6  2002/07/30 20:04:56  hal9
Fix typo: 'schould'.

Revision 1.61.2.5  2002/07/26 15:22:58  oes
- Updated to reflect changes in standard.action
- Added info on where to get updated actions files

Revision 1.61.2.4  2002/07/25 21:42:29  hal9
Add brief notes on not proxying non-HTTP protocols.

Revision 1.61.2.3  2002/06/09 16:36:33  hal9
Clarifications on filtering and MIME. Hardcode 'latest release' in index.html.

Revision 1.61.2.2  2002/06/06 02:51:34  hal9
Fix typo in URL http:/config.privoxy.org

Revision 1.61.2.1  2002/06/05 23:10:43  hal9
Add new FAQ re: DUN/IE. Change release date from May to June :)

Revision 1.61  2002/05/25 12:37:25  hal9
Various minor changes and edits.

Revision 1.60  2002/05/22 17:17:48  oes
Proofread & added more links into u-m

Revision 1.59  2002/05/15 04:03:30  hal9
Fix ulink -> link markup.

Revision 1.58  2002/05/10 01:48:20  hal9
This is mostly proposed copyright/licensing additions and changes. Docs
are still GPL, but licensing and copyright are more visible. Also, copyright
changed in doc header comments (eliminate references to JB except FAQ).

Revision 1.57  2002/05/05 20:26:02  hal9
Sorting out license vs copyright in these docs.

Revision 1.56  2002/05/04 08:44:44  swa
bumped version

Revision 1.55  2002/05/04 00:41:56  hal9
-Remove TOC/first page kludge in favor of proper handling via dsl file.

Revision 1.54  2002/05/03 05:06:44  hal9
Add brief Q/A on transparent proxies.

Revision 1.53  2002/05/03 01:34:52  hal9
Fix section numbering for new sections (due to TOC kludge).

Revision 1.52  2002/04/29 03:08:43  hal9
-Added new Q/A on new actions file set up (pointer to u-m)
-Fixed a few broken links and converted old actions as a result of
 recent changes.

Revision 1.51  2002/04/26 17:24:31  swa
bookmarks cleaned, changed structure of user manual, screen and programlisting cleanups, and numerous other changes that I forgot

Revision 1.50  2002/04/26 05:25:23  hal9
Mass commit to catch a few scattered fixes.

Revision 1.49  2002/04/12 10:10:18  swa
version update

Revision 1.48  2002/04/10 18:45:15  swa
generated

Revision 1.47  2002/04/10 04:05:32  hal9
More on BML, etc.

Revision 1.45  2002/04/08 22:59:26  hal9
Version update. Spell chkconfig correctly :)

Revision 1.44  2002/04/07 21:24:29  hal9
Touch up on name change.

Revision 1.43  2002/04/04 21:59:53  hal9
Added NT/W2K service/icon situation.

Revision 1.42  2002/04/04 18:46:47  swa
consistent look. reuse of copyright, history et. al.

Revision 1.41  2002/04/04 06:48:37  hal9
Structural changes to allow for conditional inclusion/exclusion of content
based on entity toggles, e.g. 'entity % p-not-stable  "INCLUDE"'. And
definition of internal entities, e.g. 'entity p-version "2.9.13"' that will
eventually be set by Makefile.
More boilerplate text for use across multiple docs.

Revision 1.40  2002/04/03 04:22:03  hal9
Fixed several typos.

Revision 1.39  2002/04/03 03:53:03  hal9
Revert some changes, and then make some news, to layout, and appearance.

Revision 1.38  2002/04/02 03:49:10  hal9
Major changes to doc structure and layout. Sections are not automatically
numbered now. TOC is on page by itself.

Revision 1.37  2002/04/01 16:24:07  hal9
-Rework of supported Q/A.
-Set up entities to include boilerplate text.

Revision 1.36  2002/03/31 23:18:47  hal9
More on dealing with BLOCKED.

Revision 1.35  2002/03/30 04:14:19  hal9
Fix privoxy.org/config links.

Revision 1.34  2002/03/29 04:35:56  hal9
Touch ups.

Revision 1.33  2002/03/29 01:31:48  hal9
Several new Q/A's and other touch ups.

Revision 1.32  2002/03/27 00:57:03  hal9
Touch ups for name change.

Revision 1.31  2002/03/26 22:29:55  swa
we have a new homepage!

Revision 1.30  2002/03/25 16:39:22  hal9
A few new sections. Made all links relative to user-manual.

Revision 1.29  2002/03/25 05:23:57  hal9
Moved section, and touch ups.

Revision 1.28  2002/03/25 04:27:33  hal9
New section related to name change.

Revision 1.25  2002/03/24 16:08:08  swa
we are too lazy to make a block-built
privoxy logo. hence removed the option.

Revision 1.24  2002/03/24 15:46:20  swa
name change related issue.

Revision 1.23  2002/03/24 12:33:01  swa
more additions.

Revision 1.22  2002/03/24 11:51:00  swa
name change. changed filenames.

Revision 1.21  2002/03/24 11:01:06  swa
name change

Revision 1.20  2002/03/23 15:13:11  swa
renamed every reference to the old name with foobar.
fixed "application foobar application" tag, fixed
"the foobar" with "foobar". left junkbustser in cvs
comments and remarks to history untouched.

Revision 1.19  2002/03/21 17:01:54  hal9
Some touch ups.

Revision 1.18  2002/03/18 16:40:31  hal9
More additions.

Revision 1.17  2002/03/18 03:53:53  hal9
Some new additions.

Revision 1.16  2002/03/17 21:32:56  hal9
A few more additions.

Revision 1.15  2002/03/17 07:25:59  hal9
Correcting some of my typos, and some additions.

Revision 1.14  2002/03/17 02:39:13  hal9
A little more added ...

Revision 1.13  2002/03/17 00:22:20  hal9
Adding new stuff, and trying to incorporate stuff from old faq.

Revision 1.12  2002/03/11 20:13:21  swa
typo

Revision 1.11  2002/03/11 18:42:27  swa
new section

Revision 1.10  2002/03/11 13:13:27  swa
correct feedback channels

Revision 1.9  2002/03/10 23:34:04  swa
more info on not hiding ip address

Revision 1.8  2002/03/09 15:55:48  swa
added default config section

Revision 1.7  2002/03/07 18:16:55  swa
looks better

Revision 1.6  2002/03/07 13:16:31  oes
Committing changes by Stefan

Revision 1.5  2002/03/02 15:50:04  swa
2.9.11 version. more input for docs.

Revision 1.4  2002/02/24 14:34:24  jongfoster
Formatting changes.  Now changing the doctype to DocBook XML 4.1
will work - no other changes are needed.

Revision 1.3  2001/09/23 10:13:48  swa
upload process established. run make webserver and
the documentation is moved to the webserver. documents
are now linked correctly.

Revision 1.2  2001/09/13 15:20:17  swa
merged standards into developer manual

Revision 1.1  2001/09/12 15:36:41  swa
source files for junkbuster documentation

Revision 1.3  2001/09/10 17:43:59  swa
first proposal of a structure.

Revision 1.2  2001/06/13 14:28:31  swa
docs should have an author.

Revision 1.1  2001/06/13 14:20:37  swa
first import of project's documentation for the webserver.

-->

</article>