+><P
+> And then use <SPAN
+CLASS="APPLICATION"
+>Privoxy's</SPAN
+>
+ <A
+HREF="../user-manual/config.html#PERMIT-ACCESS"
+TARGET="_top"
+>permit-access</A
+>
+ feature to limit connections. A firewall in this situation is recommended
+ as well.</P
+><P
+> The above steps should be the same for any TCP network, regardless of
+ operating system.</P
+><P
+> If you run <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> on a LAN with untrusted users,
+ we recommend that you double-check the <A
+HREF="../user-manual/config.html#ACCESS-CONTROL"
+TARGET="_top"
+>access control and security</A
+>
+ options!</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="AEN531"
+>3.13. Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</A
+></H3
+><P
+> The replacement for blocked images can be controlled with the <A
+HREF="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"
+TARGET="_top"
+><TT
+CLASS="LITERAL"
+>set-image-blocker</TT
+>
+ action</A
+>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
+ image (aka <SPAN
+CLASS="QUOTE"
+>"blank"</SPAN
+>), or a redirect to a custom image of your choice.
+ Note that this choice only has effect for images which are blocked as images, i.e.
+ whose URLs match both a <TT
+CLASS="LITERAL"
+><A
+HREF="../user-manual/actions-file.html#HANDLE-AS-IMAGE"
+TARGET="_top"
+>handle-as-image</A
+></TT
+>
+ <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>and</I
+></SPAN
+> <TT
+CLASS="LITERAL"
+><A
+HREF="../user-manual/actions-file.html#BLOCK"
+TARGET="_top"
+>block</A
+></TT
+> action.</P
+><P
+> If you want to see nothing, then change the <A
+HREF="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"
+TARGET="_top"
+><TT
+CLASS="LITERAL"
+>set-image-blocker</TT
+>
+ action</A
+> to <SPAN
+CLASS="QUOTE"
+>"blank"</SPAN
+>. This can be done by editing the
+ <TT
+CLASS="FILENAME"
+>user.action</TT
+> file, or through the <A
+HREF="http://config.privoxy.org/show-status"
+TARGET="_top"
+>web-based actions file editor</A
+>.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="AEN548"
+>3.14. Why would anybody want to see a checkerboard pattern?</A
+></H3
+><P
+> Remember that <A
+HREF="general.html#WHATSANAD"
+>telling which image is an ad and which
+ isn't</A
+>, is an educated guess. While we hope that the standard configuration
+ is rather smart, it will make occasional mistakes. The checkerboard image is visually
+ decent, and it shows you where images have been blocked, which can be very
+ helpful in case some navigation aid or otherwise innocent image was
+ erroneously blocked. It is recommended for new users so they can
+ <SPAN
+CLASS="QUOTE"
+>"see"</SPAN
+> what is happening. Some people might also enjoy seeing how
+ many banners they <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>don't</I
+></SPAN
+> have to see.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="AEN554"
+>3.15. I see some images being replaced with text
+instead of the checkerboard image. Why and how do I get rid of this?</A
+></H3
+><P
+> This happens when the banners are not embedded in the HTML code of the
+ page itself, but in separate HTML (sub)documents that are loaded into (i)frames
+ or (i)layers, and these external HTML documents are blocked. Being non-images
+ they get replaced by a substitute HTML page rather than a substitute image,
+ which wouldn't work out technically, since the browser expects and accepts
+ only HTML when it has requested an HTML document. </P
+><P
+> The substitute page adapts to the available space and shows itself as a
+ miniature two-liner if loaded into small frames, or full-blown with a
+ large red "BLOCKED" banner if space allows.</P
+><P
+> If you prefer the banners to be blocked by images, you must see to it that
+ the HTML documents in which they are embedded are not blocked. Clicking
+ the <SPAN
+CLASS="QUOTE"
+>"See why"</SPAN
+> link offered in the substitute page will show
+ you which rule blocked the page. After changing the rule and un-blocking
+ the HTML documents, the browser will try to load the actual banner images
+ and the usual image blocking will (hopefully!) kick in.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="SRVANY"
+>3.16. Can Privoxy run as a service
+on Win2K/NT/XP?</A
+></H3
+><P
+> Yes. Version 3.0.5 introduces full <SPAN
+CLASS="APPLICATION"
+>Windows</SPAN
+> service
+ functionality. See <A
+HREF="../user-manual/installation.html#installation-pack-win"
+TARGET="_top"
+> the <I
+CLASS="CITETITLE"
+>User Manual</I
+></A
+> for details on how to install and configure
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> as a service.</P
+><P
+> Earlier 3.x versions could run as a system service using <B
+CLASS="COMMAND"
+>srvany.exe</B
+>.
+ See the discussion at <A
+HREF="http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118"
+TARGET="_top"
+>http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</A
+>,
+ for details, and a sample configuration.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="OTHERPROXY"
+>3.17. How can I make Privoxy work with other
+proxies like Squid or Tor?</A
+></H3
+><P
+> This can be done and is often useful to combine the benefits of
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> with those of a another proxy.
+ 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
+> which
+ describes how to do this, and the <A
+HREF="misc.html#TOR"
+> How do I use Privoxy together with
+ Tor</A
+> section below.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="PORT-80"
+>3.18. Can I just set Privoxy to use port 80
+and thus avoid individual browser configuration?</A
+></H3
+><P
+> No, its more complicated than that. This only works with special kinds
+ of proxies known as <SPAN
+CLASS="QUOTE"
+>"intercepting"</SPAN
+> proxies (see below).</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="TRANSPARENT"
+>3.19. Can Privoxy run as a <SPAN
+CLASS="QUOTE"
+>"transparent"</SPAN
+> proxy?</A
+></H3
+><P
+> The whole idea of Privoxy is to modify client requests
+ and server responses in all sorts of ways and therefore
+ it's not a transparent proxy as described in
+ <A
+HREF="http://tools.ietf.org/html/rfc2616"
+TARGET="_top"
+>RFC 2616</A
+>.</P
+><P
+> However, some people say <SPAN
+CLASS="QUOTE"
+>"transparent proxy"</SPAN
+> when they
+ mean <SPAN
+CLASS="QUOTE"
+>"intercepting proxy"</SPAN
+>. If you are one of them,
+ please read the <A
+HREF="#intercepting"
+TARGET="_top"
+>next entry</A
+>.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="INTERCEPTING"
+>3.20. Can Privoxy run as a <SPAN
+CLASS="QUOTE"
+>"intercepting"</SPAN
+> proxy?</A
+></H3
+><P
+> <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> can't intercept traffic itself,
+ but it can handle requests that where intercepted and redirected
+ with a packet filter (like <SPAN
+CLASS="APPLICATION"
+>PF</SPAN
+> or
+ <SPAN
+CLASS="APPLICATION"
+>iptables</SPAN
+>), as long as the <TT
+CLASS="LITERAL"
+>Host</TT
+>
+ header is present.
+ </P
+><P
+> As the <TT
+CLASS="LITERAL"
+>Host</TT
+> header is required by HTTP/1.1 and as most
+ web sites rely on it anyway, this limitation shouldn't be a problem.</P
+><P
+> Please refer to your packet filter's documentation to learn how to
+ intercept and redirect traffic into <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+>.
+ Afterward you just have to configure <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> to
+ <A
+HREF="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS"
+TARGET="_top"
+>accept
+ intercepted requests</A
+>.</P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="OUTLOOK"
+>3.21. How can I configure Privoxy for use with Outlook?</A
+></H3
+><P
+> Versions of <SPAN
+CLASS="APPLICATION"
+>Outlook</SPAN
+> prior to Office 2007, use
+ <SPAN
+CLASS="APPLICATION"
+>Internet Explorer</SPAN
+> components to both render HTML,
+ and fetch any HTTP requests that may be embedded in an HTML email. So however
+ you have <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> configured to work with IE, this
+ configuration should automatically be shared, at least with older version of
+ Internet Explorer.</P
+><P
+> Starting with Office 2007, Microsoft is instead using the MS-Word rendering
+ engine with Outlook. It is unknown whether this can be configured to use a
+ proxy.
+ </P
+></DIV
+><DIV
+CLASS="SECT2"
+><H3
+CLASS="SECT2"
+><A
+NAME="OUTLOOK-MORE"
+>3.22. How can I have separate rules just for HTML mail?</A
+></H3
+><P
+> The short answer is, you can't. <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> has no way
+ of knowing which particular application makes a request, so there is no way to
+ distinguish between web pages and HTML mail.
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> just blindly proxies all requests. In the
+ case of <SPAN
+CLASS="APPLICATION"
+>Outlook Express</SPAN
+> (see above), OE uses
+ IE anyway, and there is no way for <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> to ever
+ be able to distinguish between them (nor could any other proxy type application for
+ that matter).</P
+><P
+> For a good discussion of some of the issues involved (including privacy and
+ security issues), see
+ <A
+HREF="http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118"
+TARGET="_top"
+>http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</A
+>.</P