-<HTML
-><HEAD
-><TITLE
->Miscellaneous</TITLE
-><META
-NAME="GENERATOR"
-CONTENT="Modular DocBook HTML Stylesheet Version 1.64
-"><LINK
-REL="HOME"
-TITLE="Privoxy Frequently Asked Questions"
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-><BODY
-CLASS="SECT1"
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-><TH
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->Privoxy Frequently Asked Questions</TH
-></TR
-><TR
-><TD
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-VALIGN="bottom"
-><A
-HREF="configuration.html"
->Prev</A
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->Next</A
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-><HR
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-><DIV
-CLASS="SECT1"
-><H1
-CLASS="SECT1"
-><A
-NAME="MISC"
->4. Miscellaneous</A
-></H1
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN475"
->4.1. How much does <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> slow my browsing down? This
-has to add extra time to browsing.</A
-></H3
-><P
-> 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 being displayed.
- The actual processing time required by <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->
- 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.</P
-><P
-> <SPAN
-CLASS="QUOTE"
->"Filtering"</SPAN
-> via the <TT
-CLASS="FILENAME"
->filterfile</TT
->
- mechanism may cause a perceived slowdown, since the entire page is buffered
- before displaying. See below.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="LOADINGTIMES"
->4.2. I noticed considerable
-delays in page requests compared to the old Junkbuster. What's wrong?</A
-></H3
-><P
->Using the default filtering configuration, I noticed considerable delays in
-page requests compared to the old Junkbuster. Loading pages with large contents
-seemed to take forever, then suddenly delivering all the content at once.
- </P
-><P
->The whole content must be loaded in order to filter, and nothing is is
-sent to the browser during this time. The loading time does not really
-change 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".
- </P
-><P
->To modify the content of a page (i.e. make frames resizeable again, etc.) and
-not just replace ads, <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> needs to download the
-entire page first, do its content magic and then send the page to the browser.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="CONFIGURL"
->4.3. What is the "http://p.p/"?</A
-></H3
-><P
->Since <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> sits between your web browser and the Internet, it can be
-programmed to handle certain pages specially.</P
-><P
-> With recent versions of <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> (version 2.9.x and
- greater), you can get some information about
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> and change some settings by going to
- <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
-> or, equivalently, <A
-HREF="http://config.privoxy.org/"
-TARGET="_top"
->http://config.privoxy.org/</A
-> (Note
- that p.p is far easier to type but may not work in some configurations. With
- the name change to <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->, this is changed from
- the previous http://i.j.b/ and earlier 2.9.x versions).</P
-><P
-> These pages are <I
-CLASS="EMPHASIS"
->not</I
-> forwarded to a server on the
- Internet - instead they are handled by a special web server which is built in to
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->.</P
-><P
-> If you are not running <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->, then <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
-> will fail, and <A
-HREF="http://config.privoxy.org/"
-TARGET="_top"
->http://config.privoxy.org/</A
-> will
- return a web page telling you you're not running
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->.</P
-><P
-> If you have version 2.0.2, then the equivalent is
- http://example.com/show-proxy-args (but you get far less information, and
- you should really consider upgrading to 2.9.14).</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="BLOCKLIST"
->4.4. Do you still maintain the blocklists?</A
-></H3
-><P
-> No, not by this name. The format of the blocklists has changed
- significantly in versions 2.9.x and later. This functionality
- is done by the <SPAN
-CLASS="QUOTE"
->"actions"</SPAN
-> file now. See next question ...</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="NEWADS"
->4.5. How can I submit new ads?</A
-></H3
-><P
-> Beginning with <SPAN
-CLASS="APPLICATION"
->Privoxy v2.9.14</SPAN
->, missed ads and
- banners and other actions file problems, can be submitted by accessing
- <A
-HREF="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions','Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());"
-TARGET="_top"
-><SPAN
-CLASS="QUOTE"
->"actions file feedback system"</SPAN
-></A
->
- from <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
-></P
-><P
-> This process does not work with earlier versions of <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->
- or <SPAN
-CLASS="APPLICATION"
->Junkbuster</SPAN
->.</P
-><P
->
- There will soon be regularly updated actions files posted. These
- will be announced on the
- <A
-HREF="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce"
-TARGET="_top"
->ijbswa-announce</A
->
- list.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="IP"
->4.6. How can I hide my IP address?</A
-></H3
-><P
-> You cannot hide your IP address with <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> or any other software, since
-the server needs to know your IP address to send the answers back to you.</P
-><P
->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.</P
-><P
->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.</P
-><P
->You can find a list of anonymous public proxies at <A
-HREF="http://www.multiproxy.org/anon_list.htm"
-TARGET="_top"
->multiproxy.org</A
-> and many
-more through Google.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN532"
->4.7. Can <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> guarantee I am anonymous?</A
-></H3
-><P
-> 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.</P
-><P
-> <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> can remove various information about you,
- and allows <I
-CLASS="EMPHASIS"
->you</I
-> 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.</P
-><P
-> A few browsers disclose the user's email address in certain situations, such
- as when transferring a file by FTP. <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->
- 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 <SPAN
-CLASS="APPLICATION"
->NSClean</SPAN
->.</P
-><P
-> 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!</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN543"
->4.8. Might some things break because header information is
-being altered?</A
-></H3
-><P
-> 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.</P
-><P
-> <SPAN
-CLASS="QUOTE"
->"USER AGENT"</SPAN
-> in particular is often used in this way to identify
- the browser, and adjust content accordingly. Changing this now is not
- recommended, since so many sites do look for this. You may get undesirable
- results by changing this.</P
-><P
-> 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 <SPAN
-CLASS="QUOTE"
->"User Agent"</SPAN
-> 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
- <SPAN
-CLASS="QUOTE"
->"REFERER"</SPAN
-> header; they may fail or break if unavailable. The
- weather maps of Intellicast have been blocked by their server when no
- <SPAN
-CLASS="QUOTE"
->"REFERER"</SPAN
-> or cookie is provided, is another example. There are
- many, many other ways things can go wrong when trying to fool a web server.</P
-><P
-> 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.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN553"
->4.9. Can <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> act as a <SPAN
-CLASS="QUOTE"
->"caching"</SPAN
-> proxy to
-speed up web browsing?</A
-></H3
-><P
-> No, it does not have this ability at all. You want something like
- <A
-HREF="http://www.squid-cache.org/"
-TARGET="_top"
->Squid</A
-> for this. And, yes,
- before you ask, <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> can co-exist
- with other kinds of proxies like <SPAN
-CLASS="APPLICATION"
->Squid</SPAN
->.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN561"
->4.10. What about as a firewall? Can <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> protect me?</A
-></H3
-><P
-> Not in the way you mean, or in the way a true firewall can, or a proxy that
- has this specific capability. <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> can help
- protect your privacy, but not really protect you from intrusion attempts.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN566"
->4.11. The <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> logo that replaces ads is very blocky
-and ugly looking. Can't a better font be used?</A
-></H3
-><P
-> This is not a font problem. The logo is an image that is created by
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> 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
- <SPAN
-CLASS="QUOTE"
->"imageblock"</SPAN
-> directives: <I
-CLASS="EMPHASIS"
->pattern</I
->,
- <I
-CLASS="EMPHASIS"
->blank</I
->, or a URL of your choosing.</P
-><P
->Given the above problem, we have decided to remove the logo option entirely
-[as of v2.9.13].</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN575"
->4.12. I have large empty spaces now where ads used to be.
-Why?</A
-></H3
-><P
-> It would be easy enough to just eliminate this space altogether, rather than
- fill it with blank space. But, this would create problems with many pages
- that use the overall size of the ad to help organize the page layout and
- position the various components of the page where they were intended to be.
- It is best left this way.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN578"
->4.13. How can <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> filter Secure (HTTPS) URLs?</A
-></H3
-><P
-> This is a limitation since HTTPS transactions are encrypted SSL sessions
- between your browser and the secure site, and are meant to be reliably
- <I
-CLASS="EMPHASIS"
->secure</I
-> and private. This means that all cookies and HTTP
- header information are also encrypted from the time they leave your browser,
- to the site, and vice versa. <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> does not
- try to unencrypt this information, so it just passes through as is.
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> can still catch images and ads that
- are embedded in the SSL stream though.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN585"
->4.14. <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> runs as a <SPAN
-CLASS="QUOTE"
->"server"</SPAN
->. How
-secure is it? Do I need to take any special precautions?</A
-></H3
-><P
-> There are no known exploits that might effect
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->. On Unix-like systems,
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> can run as a non-privileged
- user, which is how we recommend it be run. Also, by default
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> only listens to requests
- from <SPAN
-CLASS="QUOTE"
->"localhost"</SPAN
->. The server aspect of
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> is not itself directly exposed to the
- Internet in this configuration. If you want to have
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> 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
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> config file. All LAN hosts can then use
- this as their proxy address in the browser proxy configuration. In this way,
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> will not listen on any external ports.
- Of course, a firewall is always good too. Better safe than sorry.</P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="TURNOFF"
->4.15. How can I temporarily disable <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->?</A
-></H3
-><P
-> The easiest way is to access <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> with your
- browser by using the special URL: <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
->
- and select "Toggle Privoxy on or off" from that page. </P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="SEEALSO"
->4.16. Where can I find more information about <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->
-and related issues?</A
-></H3
-><P
-> Other references and sites of interest to <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->
- users:</P
-><P
-> <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.privoxy.org/"
-TARGET="_top"
->http://www.privoxy.org/</A
->,
- The <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> Home page.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://sourceforge.net/projects/ijbswa"
-TARGET="_top"
->http://sourceforge.net/projects/ijbswa</A
->,
- the Project Page for <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> on
- <A
-HREF="http://sourceforge.net"
-TARGET="_top"
->Sourceforge</A
->.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
->, access
- <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> from your browser. Alternately,
- <A
-HREF="http://config.privoxy.org"
-TARGET="_top"
->http://config.privoxy.org</A
->
- may work in some situations where the first does not.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://p.p/"
-TARGET="_top"
->http://p.p/</A
->, and select <A
-HREF="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions','Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());"
-TARGET="_top"
-><SPAN
-CLASS="QUOTE"
->"actions file feedback system"</SPAN
-></A
->
- to submit <SPAN
-CLASS="QUOTE"
->"misses"</SPAN
-> to the developers.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.junkbusters.com/ht/en/cookies.html"
-TARGET="_top"
->http://www.junkbusters.com/ht/en/cookies.html</A
->
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.waldherr.org/junkbuster/"
-TARGET="_top"
->http://www.waldherr.org/junkbuster/</A
->
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://privacy.net/analyze/"
-TARGET="_top"
->http://privacy.net/analyze/</A
->
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.squid-cache.org/"
-TARGET="_top"
->http://www.squid-cache.org/</A
->
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
-> </P
-></DIV
-></DIV
-><DIV
-CLASS="NAVFOOTER"
-><HR
-ALIGN="LEFT"
-WIDTH="100%"><TABLE
-WIDTH="100%"
-BORDER="0"
-CELLPADDING="0"
-CELLSPACING="0"
-><TR
-><TD
-WIDTH="33%"
-ALIGN="left"
-VALIGN="top"
-><A
-HREF="configuration.html"
->Prev</A
-></TD
-><TD
-WIDTH="34%"
-ALIGN="center"
-VALIGN="top"
-><A
-HREF="index.html"
->Home</A
-></TD
-><TD
-WIDTH="33%"
-ALIGN="right"
-VALIGN="top"
-><A
-HREF="trouble.html"
->Next</A
-></TD
-></TR
-><TR
-><TD
-WIDTH="33%"
-ALIGN="left"
-VALIGN="top"
->Configuration</TD
-><TD
-WIDTH="34%"
-ALIGN="center"
-VALIGN="top"
-> </TD
-><TD
-WIDTH="33%"
-ALIGN="right"
-VALIGN="top"
->Troubleshooting</TD
-></TR
-></TABLE
-></DIV
-></BODY
-></HTML
->
\ No newline at end of file
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
+"http://www.w3.org/TR/html4/loose.dtd">
+
+<html>
+<head>
+ <title>Miscellaneous</title>
+ <meta name="GENERATOR" content=
+ "Modular DocBook HTML Stylesheet Version 1.79">
+ <link rel="HOME" title="Privoxy Frequently Asked Questions" href=
+ "index.html">
+ <link rel="PREVIOUS" title="Configuration" href="configuration.html">
+ <link rel="NEXT" title="Troubleshooting" href="trouble.html">
+ <link rel="STYLESHEET" type="text/css" href="../p_doc.css">
+ <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
+</head>
+
+<body class="SECT1" bgcolor="#EEEEEE" text="#000000" link="#0000FF" vlink=
+"#840084" alink="#0000FF">
+ <div class="NAVHEADER">
+ <table summary="Header navigation table" width="100%" border="0"
+ cellpadding="0" cellspacing="0">
+ <tr>
+ <th colspan="3" align="center">Privoxy Frequently Asked
+ Questions</th>
+ </tr>
+
+ <tr>
+ <td width="10%" align="left" valign="bottom"><a href=
+ "configuration.html" accesskey="P">Prev</a></td>
+
+ <td width="80%" align="center" valign="bottom"></td>
+
+ <td width="10%" align="right" valign="bottom"><a href="trouble.html"
+ accesskey="N">Next</a></td>
+ </tr>
+ </table>
+ <hr align="left" width="100%">
+ </div>
+
+ <div class="SECT1">
+ <h1 class="SECT1"><a name="MISC" id="MISC">4. Miscellaneous</a></h1>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SLOWSME" id="SLOWSME">4.1. How much does
+ Privoxy slow my browsing down? This has to add extra time to
+ browsing.</a></h3>
+
+ <p>How much of an impact depends on many things, including the CPU of
+ the host system, how aggressive the configuration is, which specific
+ actions are being triggered, the size of the page, the bandwidth of the
+ connection, etc.</p>
+
+ <p>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 retrieved and displayed. The actual processing time
+ required by <span class="APPLICATION">Privoxy</span> 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 and other junk content (if ad
+ blocking is being used).</p>
+
+ <p><span class="QUOTE">"Filtering"</span> content via the <tt class=
+ "LITERAL"><a href="../user-manual/actions-file.html#FILTER" target=
+ "_top">filter</a></tt> or <tt class="LITERAL"><a href=
+ "../user-manual/actions-file.html#DEANIMATE-GIFS" target=
+ "_top">deanimate-gifs</a></tt> actions may cause a perceived slowdown,
+ since the entire document needs to be buffered before displaying. And
+ on very large documents, filtering may have some measurable 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.</p>
+
+ <p>Also, when filtering is enabled but zlib support isn't available,
+ compression is often disabled (see <a href=
+ "../user-manual/actions-file.html#PREVENT-COMPRESSION" target=
+ "_top">prevent-compression</a>). This can have an impact on speed as
+ well, although it's probably smaller than you might think. Again, the
+ page size, etc. will determine how much of an impact.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="LOADINGTIMES" id="LOADINGTIMES">4.2. I
+ notice considerable delays in page requests. What's wrong?</a></h3>
+
+ <p>If you use any <tt class="LITERAL"><a href=
+ "../user-manual/actions-file.html#FILTER" target="_top">filter</a></tt>
+ action, such as filtering banners by size, web-bugs etc, or the
+ <tt class="LITERAL"><a href=
+ "../user-manual/actions-file.html#DEANIMATE-GIFS" target=
+ "_top">deanimate-gifs</a></tt> 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.</p>
+
+ <p>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 where there is filtering being done. But overall, the difference
+ should be very minimal. If there is a big impact, then probably some
+ other situation is contributing (like anti-virus software).</p>
+
+ <p>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. <span class=
+ "APPLICATION">Privoxy</span> 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.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="CONFIGURL" id="CONFIGURL">4.3. What are
+ "http://config.privoxy.org/" and "http://p.p/"?</a></h3>
+
+ <p><a href="http://config.privoxy.org/" target=
+ "_top">http://config.privoxy.org/</a> is the address of <span class=
+ "APPLICATION">Privoxy</span>'s built-in user interface, and <a href=
+ "http://p.p/" target="_top">http://p.p/</a> is a shortcut for it.</p>
+
+ <p>Since <span class="APPLICATION">Privoxy</span> sits between your web
+ browser and the Internet, it can simply intercept requests for these
+ addresses and answer them with its built-in <span class="QUOTE">"web
+ server"</span>.</p>
+
+ <p>This also makes for a good test for your browser configuration: If
+ entering the URL <a href="http://config.privoxy.org/" target=
+ "_top">http://config.privoxy.org/</a> takes you to a page saying
+ <span class="QUOTE">"This is Privoxy ..."</span>, everything is OK. If
+ you get a page saying <span class="QUOTE">"Privoxy is not
+ working"</span> instead, then your browser didn't use <span class=
+ "APPLICATION">Privoxy</span> for the request, hence it could not be
+ intercepted, and you have accessed the <span class="emphasis"><i class=
+ "EMPHASIS">real</i></span> web site at config.privoxy.org.</p>
+
+ <p>Note that config.privoxy.org resolves to a public IP address. If you
+ use config.privoxy.org as ping or traceroute target you will reach the
+ system on the Internet (Privoxy can't intercept ICMP requests). If you
+ want to ping the system Privoxy runs on, you should use its IP address
+ or local DNS name (if it has got one).</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="NEWADS" id="NEWADS">4.4. How can I submit
+ new ads, or report problems?</a></h3>
+
+ <p>Please see the <a href="contact.html">Contact section</a> for
+ various ways to interact with the developers.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="NEWADS2" id="NEWADS2">4.5. If I do submit
+ missed ads, will they be included in future updates?</a></h3>
+
+ <p>Whether such submissions are eventually included in the <tt class=
+ "FILENAME">default.action</tt> configuration file depends on how
+ significant the issue is. We of course want to address any potential
+ problem with major, high-profile sites such as <i class=
+ "CITETITLE">Google</i>, <i class="CITETITLE">Yahoo</i>, etc. Any site
+ with global or regional reach, has a good chance of being a candidate.
+ But at the other end of the spectrum are any number of smaller,
+ low-profile sites such as for local clubs or schools. Since their reach
+ and impact are much less, they are best handled by inclusion in the
+ user's <tt class="FILENAME">user.action</tt>, and thus would be
+ unlikely to be included.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="NOONECARES" id="NOONECARES">4.6. Why doesn't
+ anyone answer my support request?</a></h3>
+
+ <p>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 thoroughly, 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.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="IP" id="IP">4.7. How can I hide my IP
+ address?</a></h3>
+
+ <p>If you run both the browser and <span class=
+ "APPLICATION">Privoxy</span> locally, you cannot hide your IP address
+ with <span class="APPLICATION">Privoxy</span> or ultimately any other
+ software alone. The server needs to know your IP address so that it
+ knows where to send the responses back.</p>
+
+ <p>There are many publicly usable "anonymous" proxies out there, which
+ provide a further level of indirection between you and the web
+ server.</p>
+
+ <p>However, these proxies are called "anonymous" because you don't need
+ to authenticate, not because they would offer any real anonymity. Most
+ of them will log your IP address and make it available to the
+ authorities in case you violate the law of the country they run in. 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.</p>
+
+ <p>If you want to hide your IP address from most adversaries, you
+ should consider chaining <span class="APPLICATION">Privoxy</span> with
+ <a href="https://www.torproject.org/" target="_top">Tor</a>. The
+ configuration details can be found in <a href="#TOR" target="_top">How
+ do I use <span class="APPLICATION">Privoxy</span> together with
+ <span class="APPLICATION">Tor</span> section</a> just below.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="ANONFORSURE" id="ANONFORSURE">4.8. Can
+ Privoxy guarantee I am anonymous?</a></h3>
+
+ <p>No. Your chances of remaining anonymous are improved, but unless you
+ <a href="#TOR" target="_top">chain <span class=
+ "APPLICATION">Privoxy</span> with <span class=
+ "APPLICATION">Tor</span></a> or a similar proxy and know what you're
+ doing when it comes to configuring the rest of your system, you should
+ assume that everything you do on the Web can be traced back to you.</p>
+
+ <p><span class="APPLICATION">Privoxy</span> can remove various
+ information about you, and allows <span class="emphasis"><i class=
+ "EMPHASIS">you</i></span> more freedom to decide which sites you can
+ trust, and what details you want to reveal. But it neither hides your
+ IP address, nor can it guarantee that the rest of the system behaves
+ correctly. There are several possibilities how a web sites can find out
+ who you are, even if you are using a strict <span class=
+ "APPLICATION">Privoxy</span> configuration and chained it with
+ <span class="APPLICATION">Tor</span>.</p>
+
+ <p>Most of <span class="APPLICATION">Privoxy's</span> privacy-enhancing
+ features can be easily subverted by an insecure browser configuration,
+ therefore you should use a browser that can be configured to only
+ execute code from trusted sites, and be careful which sites you trust.
+ For example there is no point in having <span class=
+ "APPLICATION">Privoxy</span> modify the User-Agent header, if websites
+ can get all the information they want through JavaScript, ActiveX,
+ Flash, Java etc.</p>
+
+ <p>A few browsers disclose the user's email address in certain
+ situations, such as when transferring a file by FTP. <span class=
+ "APPLICATION">Privoxy</span> 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
+ <span class="APPLICATION">NSClean</span>.</p>
+
+ <p>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!</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="PROXYTEST" id="PROXYTEST">4.9. A test site
+ says I am not using a Proxy.</a></h3>
+
+ <p>Good! Actually, they are probably testing for some other kinds of
+ proxies. Hiding yourself completely would require additional steps.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="TOR" id="TOR">4.10. How do I use Privoxy
+ together with Tor?</a></h3>
+
+ <p>Before you configure <span class="APPLICATION">Privoxy</span> to use
+ <a href="https://www.torproject.org/" target="_top">Tor</a>, please
+ follow the <i class="CITETITLE">User Manual</i> chapters <a href=
+ "../user-manual/installation.html" target="_top">2. Installation</a>
+ and <a href="../user-manual/startup.html" target="_top">5. Startup</a>
+ to make sure <span class="APPLICATION">Privoxy</span> itself is setup
+ correctly.</p>
+
+ <p>If it is, refer to <a href=
+ "https://www.torproject.org/documentation.html" target="_top">Tor's
+ extensive documentation</a> to learn how to install <span class=
+ "APPLICATION">Tor</span>, and make sure <span class=
+ "APPLICATION">Tor</span>'s logfile says that <span class="QUOTE">"Tor
+ has successfully opened a circuit"</span> and it <span class=
+ "QUOTE">"looks like client functionality is working"</span>.</p>
+
+ <p>If either <span class="APPLICATION">Tor</span> or <span class=
+ "APPLICATION">Privoxy</span> isn't working, their combination most
+ likely will neither. Testing them on their own will also help you to
+ direct problem reports to the right audience. If <span class=
+ "APPLICATION">Privoxy</span> isn't working, don't bother the
+ <span class="APPLICATION">Tor</span> developers. If <span class=
+ "APPLICATION">Tor</span> isn't working, don't send bug reports to the
+ <span class="APPLICATION">Privoxy</span> Team.</p>
+
+ <p>If you verified that <span class="APPLICATION">Privoxy</span> and
+ <span class="APPLICATION">Tor</span> are working, it is time to connect
+ them. As far as <span class="APPLICATION">Privoxy</span> is concerned,
+ <span class="APPLICATION">Tor</span> is just another proxy that can be
+ reached by socks4, socks4a and socks5. Most likely you are interested
+ in <span class="APPLICATION">Tor</span> to increase your anonymity
+ level, therefore you should use socks5, to make sure DNS requests are
+ done through <span class="APPLICATION">Tor</span> and thus invisible to
+ your local network. Using socks4a would work too, but with socks5 you
+ get more precise error messages.</p>
+
+ <p><span class="APPLICATION">Privoxy's</span> <a href=
+ "../user-manual/config.html" target="_top">main configuration file</a>
+ is already prepared for <span class="APPLICATION">Tor</span>, if you
+ are using a default <span class="APPLICATION">Tor</span> configuration
+ and run it on the same system as <span class=
+ "APPLICATION">Privoxy</span>, you just have to edit the <a href=
+ "../user-manual/config.html#FORWARDING" target="_top">forwarding
+ section</a> and uncomment the line:</p>
+
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+ <pre class="SCREEN">
+# forward-socks5t / 127.0.0.1:9050 .
+
+</pre>
+ </td>
+ </tr>
+ </table>
+
+ <p>Note that if you got Tor through one of the bundles, you may have to
+ change the port from 9050 to 9150 (or even another one). For details,
+ please check the documentation on the <a href="https://torproject.org/"
+ target="_top">Tor website</a>.</p>
+
+ <p>This is enough to reach the Internet, but additionally you might
+ want to uncomment the following forward rules, to make sure your local
+ network is still reachable through Privoxy:</p>
+
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+ <pre class="SCREEN">
+# forward 192.168.*.*/ .
+# forward 10.*.*.*/ .
+# forward 127.*.*.*/ .
+
+</pre>
+ </td>
+ </tr>
+ </table>
+
+ <p>Unencrypted connections to systems in these address ranges will be
+ as (un)secure as the local network is, but the alternative is that your
+ browser can't reach the network at all. Then again, that may actually
+ be desired and if you don't know for sure that your browser has to be
+ able to reach the local network, there's no reason to allow it.</p>
+
+ <p>If you want your browser to be able to reach servers in your local
+ network by using their names, you will need additional exceptions that
+ look like this:</p>
+
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+ <pre class="SCREEN">
+# forward localhost/ .
+
+</pre>
+ </td>
+ </tr>
+ </table>
+
+ <p>Save the modified configuration file and open <a href=
+ "http://config.privoxy.org/show-status" target=
+ "_top">http://config.privoxy.org/show-status</a> in your browser,
+ confirm that <span class="APPLICATION">Privoxy</span> has reloaded its
+ configuration and that there are no other forward lines, unless you
+ know that you need them. If everything looks good, refer to <a href=
+ "https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate"
+ target="_top">Tor Faq 4.2</a> to learn how to verify that you are
+ really using <span class="APPLICATION">Tor</span>.</p>
+
+ <p>Afterward, please take the time to at least skim through the rest of
+ <span class="APPLICATION">Tor's</span> documentation. Make sure you
+ understand what <span class="APPLICATION">Tor</span> does, why it is no
+ replacement for application level security, and why you probably don't
+ want to use it for unencrypted logins.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SITEBREAK" id="SITEBREAK">4.11. Might some
+ things break because header information or content is being
+ altered?</a></h3>
+
+ <p>Definitely. It is common for sites to use browser type, browser
+ version, HTTP header content, and various other techniques in order to
+ dynamically decide what to display and how to display it. What you see,
+ and what I see, might be very different. There are many, many ways that
+ this can be handled, so having hard and fast rules, is tricky.</p>
+
+ <p>The <span class="QUOTE">"User-Agent"</span> is sometimes used in
+ this way to identify the browser, and adjust content accordingly.</p>
+
+ <p>Also, different browsers use different encodings of non-English
+ characters, certain web servers convert pages on-the-fly according to
+ the User Agent header. Giving a <span class="QUOTE">"User Agent"</span>
+ 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 <span class="QUOTE">"Referer"</span>
+ header; they may fail or break if unavailable. The weather maps of
+ Intellicast have been blocked by their server when no <span class=
+ "QUOTE">"Referer"</span> 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. The results of which could inadvertently cause pages to load
+ incorrectly, partially, or even not at all. And there may be no obvious
+ clues as to just what went wrong, or why. Nowhere will there be a
+ message that says <span class="QUOTE">"<span class="emphasis"><i class=
+ "EMPHASIS">Turn off <tt class="LITERAL">fast-redirects</tt> or
+ else!</i></span> "</span></p>
+
+ <p>Similar thoughts apply to modifying JavaScript, and, to a lesser
+ degree, HTML elements.</p>
+
+ <p>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.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="CACHING" id="CACHING">4.12. Can Privoxy act
+ as a <span class="QUOTE">"caching"</span> proxy to speed up web
+ browsing?</a></h3>
+
+ <p>No, it does not have this ability at all. You want something like
+ <a href="http://www.squid-cache.org/" target="_top">Squid</a> or
+ <a href="http://www.pps.jussieu.fr/~jch/software/polipo/" target=
+ "_top">Polipo</a> for this. And, yes, before you ask, <span class=
+ "APPLICATION">Privoxy</span> can co-exist with other kinds of proxies
+ like <span class="APPLICATION">Squid</span>. See the <a href=
+ "../user-manual/config.html#FORWARDING" target="_top">forwarding
+ chapter</a> in the <a href="../user-manual/index.html" target=
+ "_top">user manual</a> for details.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="FIREWALL" id="FIREWALL">4.13. What about as
+ a firewall? Can Privoxy protect me?</a></h3>
+
+ <p>Not in the way you mean, or in the way some firewall vendors claim
+ they can. <span class="APPLICATION">Privoxy</span> can help protect
+ your privacy, but can't protect your system from intrusion attempts. It
+ is, of course, perfectly possible to use <span class=
+ "emphasis"><i class="EMPHASIS">both</i></span>.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="WASTED" id="WASTED">4.14. I have large empty
+ spaces / a checkerboard pattern now where ads used to be. Why?</a></h3>
+
+ <p>It is technically possible to eliminate banners and ads in a way
+ that frees their allocated page space. This could easily be done by
+ blocking with <span class="APPLICATION">Privoxy's</span> filters, and
+ eliminating the <span class="emphasis"><i class=
+ "EMPHASIS">entire</i></span> image references from the HTML page
+ source.</p>
+
+ <p>But, this would consume considerably more CPU resources (IOW, slow
+ things down), would likely destroy the layout of some web pages which
+ rely on the banners utilizing a certain amount of page space, and might
+ fail in other cases, where the screen space is reserved (e.g. by HTML
+ tables for instance). Also, making ads and banners disappear without
+ any trace complicates troubleshooting, and would sooner or later be
+ problematic.</p>
+
+ <p>The better alternative is to instead let them stay, and block the
+ resulting requests for the banners themselves as is now the case. This
+ leaves either empty space, or the familiar checkerboard pattern.</p>
+
+ <p>So the developers won't support this in the default configuration,
+ but you can of course define appropriate filters yourself to achieve
+ this.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SSL" id="SSL">4.15. How can Privoxy filter
+ Secure (HTTPS) URLs?</a></h3>
+
+ <p>Since secure HTTP connections are encrypted SSL sessions between
+ your browser and the secure site, and are meant to be reliably
+ <span class="emphasis"><i class="EMPHASIS">secure</i></span>, there is
+ little that <span class="APPLICATION">Privoxy</span> can do but hand
+ the raw gibberish data though from one end to the other
+ unprocessed.</p>
+
+ <p>The only exception to this is blocking by host patterns, as the
+ client needs to tell <span class="APPLICATION">Privoxy</span> the name
+ of the remote server, so that <span class="APPLICATION">Privoxy</span>
+ can establish the connection. If that name matches a host-only pattern,
+ the connection will be blocked.</p>
+
+ <p>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 <span class="APPLICATION">Privoxy</span>'s ad
+ blocking.</p>
+
+ <p><span class="QUOTE">"Content cookies"</span> (those that are
+ embedded in the actual HTML or JS page content, see <tt class=
+ "LITERAL"><a href=
+ "../user-manual/actions-file.html#FILTER-CONTENT-COOKIES" target=
+ "_top">filter{content-cookies}</a></tt>), 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.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SECURE" id="SECURE">4.16. Privoxy runs as a
+ <span class="QUOTE">"server"</span>. How secure is it? Do I need to
+ take any special precautions?</a></h3>
+
+ <p>On Unix-like systems, <span class="APPLICATION">Privoxy</span> can
+ run as a non-privileged user, which is how we recommend it be run.
+ Also, by default <span class="APPLICATION">Privoxy</span> listens to
+ requests from <span class="QUOTE">"localhost"</span> only.</p>
+
+ <p>The server aspect of <span class="APPLICATION">Privoxy</span> is not
+ itself directly exposed to the Internet in this configuration. If you
+ want to have <span class="APPLICATION">Privoxy</span> 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 <span class="APPLICATION">Privoxy</span>
+ configuration file and check all <a href=
+ "../user-manual/config.html#ACCESS-CONTROL" target="_top">access
+ control and security options</a>. All LAN hosts can then use this as
+ their proxy address in the browser proxy configuration, but
+ <span class="APPLICATION">Privoxy</span> 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.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="TURNOFF" id="TURNOFF">4.17. Can I
+ temporarily disable Privoxy?</a></h3>
+
+ <p><span class="APPLICATION">Privoxy</span> doesn't have a transparent
+ proxy mode, but you can toggle off blocking and content filtering.</p>
+
+ <p>The easiest way to do that is to point your browser to the remote
+ toggle URL: <a href="http://config.privoxy.org/toggle" target=
+ "_top">http://config.privoxy.org/toggle</a>.</p>
+
+ <p>See the <a href="../user-manual/appendix.html#BOOKMARKLETS" target=
+ "_top">Bookmarklets section</a> of the <i class="CITETITLE">User
+ Manual</i> for an easy way to access this feature. Note that this is a
+ feature that may need to be enabled in the main <tt class=
+ "FILENAME">config</tt> file.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="REALLYOFF" id="REALLYOFF">4.18. When
+ <span class="QUOTE">"disabled"</span> is Privoxy totally out of the
+ picture?</a></h3>
+
+ <p>No, this just means all optional filtering and actions are disabled.
+ <span class="APPLICATION">Privoxy</span> is still acting as a proxy,
+ but just doing less of the things that <span class=
+ "APPLICATION">Privoxy</span> would normally be expected to do. It is
+ still a <span class="QUOTE">"middle-man"</span> in the interaction
+ between your browser and web sites. See below to bypass the proxy.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="TURNOFF2" id="TURNOFF2">4.19. How can I tell
+ Privoxy to totally ignore certain sites?</a></h3>
+
+ <p>Bypassing a proxy, or proxying based on arbitrary criteria, is
+ purely a browser configuration issue, not a <span class=
+ "APPLICATION">Privoxy</span> issue. Modern browsers typically do have
+ settings for not proxying certain sites. Check your browser's help
+ files.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="CRUNCH" id="CRUNCH">4.20. My logs show
+ Privoxy <span class="QUOTE">"crunches"</span> ads, but also its own
+ internal CGI pages. What is a <span class=
+ "QUOTE">"crunch"</span>?</a></h3>
+
+ <p>A <span class="QUOTE">"crunch"</span> simply means <span class=
+ "APPLICATION">Privoxy</span> intercepted <span class=
+ "emphasis"><i class="EMPHASIS">something</i></span>, nothing more.
+ Often this is indeed ads or banners, but <span class=
+ "APPLICATION">Privoxy</span> uses the same mechanism for trapping
+ requests for its own internal pages. For instance, a request for
+ <span class="APPLICATION">Privoxy's</span> configuration page at:
+ <a href="http://config.privoxy.org" target=
+ "_top">http://config.privoxy.org</a>, 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 <span class=
+ "QUOTE">"crunch"</span>.</p>
+
+ <p>Since version 3.0.7, Privoxy will also log the crunch reason. If you
+ are using an older version you might want to upgrade.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="DOWNLOADS" id="DOWNLOADS">4.21. Can Privoxy
+ affect files that I download from a webserver? FTP server?</a></h3>
+
+ <p>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 <span class="APPLICATION">Privoxy</span>. If there is a match
+ for a <tt class="LITERAL"><a href=
+ "../user-manual/actions-file.html#BLOCK" target="_top">block</a></tt>
+ pattern, it will still be blocked, and of course this is obvious.</p>
+
+ <p>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 advertisement, or Mr. Jimmy's latest/greatest
+ source code jewel. Of course, one of these presumably is <span class=
+ "QUOTE">"bad"</span> content that we don't want, and the other is
+ <span class="QUOTE">"good"</span> content that we do want. <span class=
+ "APPLICATION">Privoxy</span> is blind to the differences, and can only
+ distinguish <span class="QUOTE">"good from bad"</span> by the
+ configuration parameters <span class="emphasis"><i class=
+ "EMPHASIS">we</i></span> give it.</p>
+
+ <p><span class="APPLICATION">Privoxy</span> knows the differences in
+ files according to the <span class="QUOTE">"Content Type"</span> as
+ reported by the webserver. If this is reported accurately (e.g.
+ <span class="QUOTE">"application/zip"</span> for a zip archive), then
+ <span class="APPLICATION">Privoxy</span> knows to ignore these where
+ appropriate. <span class="APPLICATION">Privoxy</span> 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 <span class="QUOTE">"text/plain"</span>) 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.</p>
+
+ <p>Note that versions later than 3.0.2 do NOT filter document types
+ reported as <span class="QUOTE">"text/plain"</span>. Prior to this,
+ <span class="APPLICATION">Privoxy</span> did filter this document
+ type.</p>
+
+ <p>In short, filtering is <span class="QUOTE">"ON"</span> if a) the
+ content type as reported by the webserver is appropriate <span class=
+ "emphasis"><i class="EMPHASIS">and</i></span> 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 <span class="QUOTE">"good"</span>
+ and this is <span class="QUOTE">"bad"</span>. It's the configuration
+ that lets it all happen or not.</p>
+
+ <p>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
+ <tt class="FILENAME">user.action</tt> file. And also, for any site or
+ page where making <span class="emphasis"><i class=
+ "EMPHASIS">any</i></span> changes at all to the content is to be
+ avoided.</p>
+
+ <p><span class="APPLICATION">Privoxy</span> does not do FTP at all,
+ only HTTP and HTTPS (SSL) protocols.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="DOWNLOADS2" id="DOWNLOADS2">4.22. I just
+ downloaded a Perl script, and Privoxy altered it! Yikes, what is
+ wrong!</a></h3>
+
+ <p>Please read above.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="HOSTSFILE" id="HOSTSFILE">4.23. Should I
+ continue to use a <span class="QUOTE">"HOSTS"</span> file for
+ ad-blocking?</a></h3>
+
+ <p>One time-tested technique to defeat common ads is to trick the local
+ DNS system by giving a phony IP address for the ad generator in the
+ local <tt class="FILENAME">HOSTS</tt> file, typically using <tt class=
+ "LITERAL">127.0.0.1</tt>, aka <tt class="LITERAL">localhost</tt>. This
+ effectively blocks the ad.</p>
+
+ <p>There is no reason to use this technique in conjunction with
+ <span class="APPLICATION">Privoxy</span>. <span class=
+ "APPLICATION">Privoxy</span> does essentially the same thing, much more
+ elegantly and with much more flexibility. A large <tt class=
+ "FILENAME">HOSTS</tt> file, in fact, not only duplicates effort, but
+ may get in the way and seriously slow down your system. It is
+ recommended to remove such entries from your <tt class=
+ "FILENAME">HOSTS</tt> file. If you think your hosts list is neglected
+ by <span class="APPLICATION">Privoxy's</span> configuration, consider
+ adding your list to your <tt class="FILENAME">user.action</tt>
+ file:</p>
+
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+ <pre class="SCREEN">
+ { +block }
+ www.ad.example1.com
+ ad.example2.com
+ ads.galore.example.com
+ etc.example.com
+</pre>
+ </td>
+ </tr>
+ </table>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SEEALSO" id="SEEALSO">4.24. Where can I find
+ more information about Privoxy and related issues?</a></h3>
+
+ <p>Other references and sites of interest to <span class=
+ "APPLICATION">Privoxy</span> users:</p>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="https://www.privoxy.org/" target=
+ "_top">https://www.privoxy.org/</a>, the <span class=
+ "APPLICATION">Privoxy</span> Home page.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="https://www.privoxy.org/faq/" target=
+ "_top">https://www.privoxy.org/faq/</a>, the <span class=
+ "APPLICATION">Privoxy</span> FAQ.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="https://www.privoxy.org/developer-manual/" target=
+ "_top">https://www.privoxy.org/developer-manual/</a>, the
+ <span class="APPLICATION">Privoxy</span> developer manual.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="https://sourceforge.net/projects/ijbswa/" target=
+ "_top">https://sourceforge.net/projects/ijbswa/</a>, the Project
+ Page for <span class="APPLICATION">Privoxy</span> on <a href=
+ "http://sourceforge.net" target="_top">SourceForge</a>.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="http://config.privoxy.org/" target=
+ "_top">http://config.privoxy.org/</a>, the web-based user
+ interface. <span class="APPLICATION">Privoxy</span> must be
+ running for this to work. Shortcut: <a href="http://p.p/" target=
+ "_top">http://p.p/</a></td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href=
+ "https://sourceforge.net/tracker/?group_id=11118&atid=460288"
+ target=
+ "_top">https://sourceforge.net/tracker/?group_id=11118&atid=460288</a>,
+ to submit <span class="QUOTE">"misses"</span> and other
+ configuration related suggestions to the developers.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="http://www.squid-cache.org/" target=
+ "_top">http://www.squid-cache.org/</a>, a popular caching proxy,
+ which is often used together with <span class=
+ "APPLICATION">Privoxy</span>.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href=
+ "http://www.pps.univ-paris-diderot.fr/~jch/software/polipo/"
+ target=
+ "_top">http://www.pps.univ-paris-diderot.fr/~jch/software/polipo/</a>,
+ <span class="APPLICATION">Polipo</span> is a caching proxy with
+ advanced features like pipelining, multiplexing and caching of
+ partial instances. In many setups it can be used as <span class=
+ "APPLICATION">Squid</span> replacement.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td><a href="https://www.torproject.org/" target=
+ "_top">https://www.torproject.org/</a>, <span class=
+ "APPLICATION">Tor</span> can help anonymize web browsing, web
+ publishing, instant messaging, IRC, SSH, and other
+ applications.</td>
+ </tr>
+ </tbody>
+ </table>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="MICROSUCK" id="MICROSUCK">4.25. I've noticed
+ that Privoxy changes <span class="QUOTE">"Microsoft"</span> to
+ <span class="QUOTE">"MicroSuck"</span>! Why are you manipulating my
+ browsing?</a></h3>
+
+ <p>We're not. The text substitutions that you are seeing are disabled
+ in the default configuration as shipped. You have either manually
+ activated the <span class="QUOTE">"<tt class="LITERAL">fun</tt>"</span>
+ filter which is clearly labeled <span class="QUOTE">"Text replacements
+ for subversive browsing fun!"</span> or you are using an older Privoxy
+ version and have implicitly activated it by choosing the <span class=
+ "QUOTE">"Advanced"</span> profile in the web-based editor. Please
+ upgrade.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="VALID" id="VALID">4.26. Does Privoxy produce
+ <span class="QUOTE">"valid"</span> HTML (or XHTML)?</a></h3>
+
+ <p>Privoxy generates HTML in both its own <span class=
+ "QUOTE">"templates"</span>, and possibly whenever there are text
+ substitutions via a <span class="APPLICATION">Privoxy</span> filter.
+ While this should always conform to the HTML 4.01 specifications, it
+ has not been validated against this or any other standard.</p>
+ </div>
+
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SURPRISE-PRIVOXY" id=
+ "SURPRISE-PRIVOXY">4.27. How did you manage to get Privoxy on my
+ computer without my consent?</a></h3>
+
+ <p>We didn't. We make Privoxy available for download, but we don't go
+ around installing it on other people's systems behind their back. If
+ you discover Privoxy running on your system and are sure you didn't
+ install it yourself, somebody else did. You may not even be running the
+ real Privoxy, but maybe something else that only pretends to be
+ Privoxy, or maybe something that is based on the real Privoxy, but has
+ been modified.</p>
+
+ <p>Lately there have been reports of problems with some kind of
+ "parental control" software based on Privoxy that came preinstalled on
+ certain <a href="https://sourceforge.net/p/ijbswa/bugs/813/" target=
+ "_top">ASUS Netbooks</a>. The problems described are inconsistent with
+ the behaviour of official Privoxy versions, which suggests that the
+ preinstalled software may contain vendor modifications that we don't
+ know about and thus can't debug.</p>
+
+ <p>Privoxy's <a href="copyright.html">license</a> allows vendor
+ modifications, but the vendor has to comply with the license, which
+ involves informing the user about the changes and to make the changes
+ available under the same license as Privoxy itself.</p>
+
+ <p>If you are having trouble with a modified Privoxy version, please
+ try to talk to whoever made the modifications before reporting the
+ problem to us. Please also try to convince whoever made the
+ modifications to talk to us. If you think somebody gave you a modified
+ Privoxy version without complying to the license, please let us
+ know.</p>
+ </div>
+ </div>
+
+ <div class="NAVFOOTER">
+ <hr align="left" width="100%">
+
+ <table summary="Footer navigation table" width="100%" border="0"
+ cellpadding="0" cellspacing="0">
+ <tr>
+ <td width="33%" align="left" valign="top"><a href=
+ "configuration.html" accesskey="P">Prev</a></td>
+
+ <td width="34%" align="center" valign="top"><a href="index.html"
+ accesskey="H">Home</a></td>
+
+ <td width="33%" align="right" valign="top"><a href="trouble.html"
+ accesskey="N">Next</a></td>
+ </tr>
+
+ <tr>
+ <td width="33%" align="left" valign="top">Configuration</td>
+
+ <td width="34%" align="center" valign="top"> </td>
+
+ <td width="33%" align="right" valign="top">Troubleshooting</td>
+ </tr>
+ </table>
+ </div>
+</body>
+</html>
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