-<!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=ISO-8859-1"></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"
->4. Miscellaneous</A
-></H1
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="AEN728"
->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"
->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"
->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
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="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"
->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"
->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"
->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="AEN793"
->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="AEN811"
->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"
->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 or socks4a. Most likely you are interested in <SPAN
-CLASS="APPLICATION"
->Tor</SPAN
->
- to increase your anonymity level, therefore you should use socks4a, to make sure DNS requests are
- done through <SPAN
-CLASS="APPLICATION"
->Tor</SPAN
-> and thus invisible to your local network.</P
-><P
-> Since <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> 3.0.5, its
- <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
-><P
-> <TABLE
-BORDER="0"
-BGCOLOR="#E0E0E0"
-WIDTH="100%"
-><TR
-><TD
-><PRE
-CLASS="SCREEN"
-># forward-socks5 / 127.0.0.1:9050 .
- </PRE
-></TD
-></TR
-></TABLE
-></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
-><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
-><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
-><P
-> <TABLE
-BORDER="0"
-BGCOLOR="#E0E0E0"
-WIDTH="100%"
-><TR
-><TD
-><PRE
-CLASS="SCREEN"
-># forward localhost/ .
- </PRE
-></TD
-></TR
-></TABLE
-></P
-><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="AEN867"
->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="AEN881"
->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="AEN891"
->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="AEN896"
->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="AEN904"
->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="AEN918"
->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"
->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"
->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"
->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"
->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"
->4.21. Can Privoxy effect 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"
->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"
->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
-><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
-></P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="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
-><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://www.privoxy.org/faq/"
-TARGET="_top"
->http://www.privoxy.org/faq/</A
->,
- the <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> FAQ.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.privoxy.org/developer-manual/"
-TARGET="_top"
->http://www.privoxy.org/developer-manual/</A
->,
- the <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
-> developer manual.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><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
-><P
-></P
->
- <P
-></P
-><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
-><P
-></P
->
- <P
-></P
-><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
-><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
->,
- an explanation how cookies are used to track web users.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.junkbusters.com/ijb.html"
-TARGET="_top"
->http://www.junkbusters.com/ijb.html</A
->,
- the original Internet Junkbuster.
- </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
->, a popular
- caching proxy, which is often used together with <SPAN
-CLASS="APPLICATION"
->Privoxy</SPAN
->.
- </TD
-></TR
-></TBODY
-></TABLE
-><P
-></P
->
- <P
-></P
-><TABLE
-BORDER="0"
-><TBODY
-><TR
-><TD
-> <A
-HREF="http://www.pps.jussieu.fr/~jch/software/polipo/"
-TARGET="_top"
->http://www.pps.jussieu.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
-><P
-></P
->
- <P
-></P
-><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
-><P
-></P
->
- </P
-></DIV
-><DIV
-CLASS="SECT2"
-><H3
-CLASS="SECT2"
-><A
-NAME="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"
->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"
->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
- Privoxy versions that come preinstalled on some Netbooks.
- Some of 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
->
+<!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=iso-8859-1">
+</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="https://www.irif.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>If you enable <a href="../user-manual/actions-file.html#HTTPS-INSPECTION" target="_top">https-inspection</a>
+ <span class="APPLICATION">Privoxy</span> will impersonate the destination server and can thus filter encrypted
+ requests and responses as well.</p>
+ <p>Without <a href="../user-manual/actions-file.html#HTTPS-INSPECTION" target="_top">https-inspection</a> secure
+ HTTP connections are encrypted SSL sessions between your browser and the secure site, and 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="HTTP2" id="HTTP2">4.16. Does Privoxy support HTTP/2?</a></h3>
+ <p>Privoxy currently doesn't parse HTTP/2 but applications can tunnel HTTP/2 through Privoxy if Privoxy is
+ configured to allow CONNECT requests (default) which are also used for HTTPS.</p>
+ <p>Adding HTTP/2 support is on the <a href=
+ "https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD" target="_top">TODO</a> list but
+ currently nobody is known to work on it.</p>
+ </div>
+ <div class="SECT2">
+ <h3 class="SECT2"><a name="SECURE" id="SECURE">4.17. 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">4.18. 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">4.19. 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">4.20. 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">4.21. 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> 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">4.22. 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">4.23. 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">4.24. 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">4.25. 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="https://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/p/ijbswa/actionsfile-feedback/" target=
+ "_top">https://sourceforge.net/p/ijbswa/actionsfile-feedback/</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="https://www.irif.fr/~jch/software/polipo/" target=
+ "_top">https://www.irif.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">4.26. 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">4.27. 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">4.28. 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>
projects / privoxy.git / blobdiff