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41 <h1 class="SECT1"><a name="CONFIGURATION" id="CONFIGURATION">3.
42 Configuration</a></h1>
45 <h3 class="SECT2"><a name="AEN369" id="AEN369">3.1. What exactly is an
46 <span class="QUOTE">"actions"</span> file?</a></h3>
48 <p><span class="APPLICATION">Privoxy</span> utilizes the concept of
49 <span class="QUOTE">" <a href=
50 "../user-manual/actions-file.html#ACTIONS" target=
51 "_top">actions</a>"</span> that are used to manipulate and control web
52 page data. <a href="../user-manual/actions-file.html" target=
53 "_top">Actions files</a> are where these <a href=
54 "../user-manual/actions-file.html#ACTIONS" target="_top">actions</a>
55 that <span class="APPLICATION">Privoxy</span> could take while
56 processing a certain request, are configured. Typically, you would
57 define a set of default actions that apply globally to all URLs, then
58 add exceptions to these defaults where needed. There is a wide array of
59 actions available that give the user a high degree of control and
60 flexibility on how to process each and every web page.</p>
62 <p>Actions can be defined on a <a href=
63 "../user-manual/actions-file.html#AF-PATTERNS" target="_top">URL
64 pattern</a> basis, i.e. for single URLs, whole web sites, groups or
65 parts thereof etc. Actions can also be grouped together and then
66 applied to requests matching one or more patterns. There are many
67 possible actions that might apply to any given site. As an example, if
68 you are blocking <a href="http://en.wikipedia.org/wiki/Browser_cookie"
69 target="_top">cookies</a> as one of your default actions, but need to
70 accept cookies from a given site, you would need to define an exception
71 for this site in one of your actions files, preferably in <tt class=
72 "FILENAME">user.action</tt>.</p>
76 <h3 class="SECT2"><a name="ACTIONSS" id="ACTIONSS">3.2. The
77 <span class="QUOTE">"actions"</span> concept confuses me. Please list
78 some of these <span class="QUOTE">"actions"</span>.</a></h3>
80 <p>For a comprehensive discussion of the actions concept, please refer
81 to the <a href="../user-manual/actions-file.html" target="_top">actions
82 file chapter</a> in the <a href="../user-manual/index.html" target=
83 "_top">User Manual</a>. It includes a <a href=
84 "../user-manual/actions-file.html#ACTIONS" target="_top">list of all
85 actions</a> and an <a href=
86 "../user-manual/actions-file.html#ACT-EXAMPLES" target="_top">actions
87 file tutorial</a> to get you started.</p>
91 <h3 class="SECT2"><a name="AEN392" id="AEN392">3.3. How are actions
92 files configured? What is the easiest way to do this?</a></h3>
94 <p>Actions files are just text files in a special syntax and can be
95 edited with a text editor. But probably the easiest way is to access
96 <span class="APPLICATION">Privoxy</span>'s user interface with your web
97 browser at <a href="http://config.privoxy.org/" target=
98 "_top">http://config.privoxy.org/</a> (Shortcut: <a href="http://p.p/"
99 target="_top">http://p.p/</a>) and then select <span class=
100 "QUOTE">"<a href="http://config.privoxy.org/show-status" target=
101 "_top">View & change the current configuration</a>"</span> from the
102 menu. Note that this feature must be explicitly enabled in the main
103 config file (see <a href=
104 "../user-manual/config.html#ENABLE-EDIT-ACTIONS" target=
105 "_top">enable-edit-actions</a>).</p>
109 <h3 class="SECT2"><a name="AEN401" id="AEN401">3.4. There are several
110 different <span class="QUOTE">"actions"</span> files. What are the
111 differences?</a></h3>
113 <p>Please have a look at the <a href="../user-manual/actions-file.html"
114 target="_top">the actions chapter</a> in the <a href=
115 "../user-manual/index.html" target="_top">User Manual</a> for a
116 detailed explanation.</p>
120 <h3 class="SECT2"><a name="GETUPDATES" id="GETUPDATES">3.5. Where can I
121 get updated Actions Files?</a></h3>
123 <p>Based on your feedback and the continuing development, updates of
124 <tt class="FILENAME">default.action</tt> will be made available from
125 time to time on the <a href=
126 "http://sourceforge.net/project/showfiles.php?group_id=11118" target=
127 "_top">files section</a> of our <a href=
128 "http://sf.net/projects/ijbswa/" target="_top">project page</a>.</p>
130 <p>If you wish to receive an email notification whenever we release
131 updates of <span class="APPLICATION">Privoxy</span> or the actions
133 "http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/" target=
134 "_top">subscribe to our announce mailing list</a>,
135 ijbswa-announce@lists.sourceforge.net.</p>
139 <h3 class="SECT2"><a name="NEWCONFIG" id="NEWCONFIG">3.6. Can I use my
140 old config files?</a></h3>
142 <p>The syntax and purpose of configuration files has remained roughly
143 the same throughout the 3.x series, but backwards compatibility is not
144 guaranteed. Also each release contains updated, <span class=
145 "QUOTE">"improved"</span> versions and it is therefore strongly
146 recommended to install the newer configuration files and merge back
147 your modifications.</p>
151 <h3 class="SECT2"><a name="DIFFICULT" id="DIFFICULT">3.7. Why is the
152 configuration so complicated?</a></h3>
154 <p><span class="QUOTE">"Complicated"</span> is in the eye of the
155 beholder. Those that are familiar with some of the underlying concepts,
156 such as regular expression syntax, take to it like a fish takes to
157 water. Also, software that tries hard to be <span class="QUOTE">"user
158 friendly"</span>, often lacks sophistication and flexibility. There is
159 always that trade-off there between power vs. easy-of-use. Furthermore,
160 anyone is welcome to contribute ideas and implementations to enhance
161 <span class="APPLICATION">Privoxy</span>.</p>
165 <h3 class="SECT2"><a name="YAHOO" id="YAHOO">3.8. How can I make my
166 Yahoo/Hotmail/Gmail account work?</a></h3>
168 <p>The default configuration shouldn't impact the usability of any of
169 these services. It may, however, make all <a href=
170 "http://en.wikipedia.org/wiki/Browser_cookie" target="_top">cookies</a>
171 temporary, so that your browser will forget your login credentials in
172 between browser sessions. If you would like not to have to log in
173 manually each time you access those websites, simply turn off all
174 cookie handling for them in the <tt class="FILENAME">user.action</tt>
175 file. An example for yahoo might look like:</p>
177 <table border="0" bgcolor="#E0E0E0" width="100%">
181 # Allow all cookies for Yahoo login:
183 { -<a href="../user-manual/actions-file.html#CRUNCH-INCOMING-COOKIES" target=
184 "_top">crunch-incoming-cookies</a> -<a href=
185 "../user-manual/actions-file.html#CRUNCH-OUTGOING-COOKIES" target=
186 "_top">crunch-outgoing-cookies</a> -<a href=
187 "../user-manual/actions-file.html#SESSION-COOKIES-ONLY" target=
188 "_top">session-cookies-only</a> }
195 <p>These kinds of sites are often quite complex and heavy with <a href=
196 "http://en.wikipedia.org/wiki/Javascript" target="_top">Javascript</a>
197 and thus <span class="QUOTE">"fragile"</span>. So if <span class=
198 "emphasis"><i class="EMPHASIS">still</i></span> a problem, we have an
199 <a href="../user-manual/actions-file.html#ALIASES" target=
200 "_top">alias</a> just for such sticky situations:</p>
202 <table border="0" bgcolor="#E0E0E0" width="100%">
206 # Gmail is a _fragile_ site:
208 { <tt class="LITERAL">fragile</tt> }
216 <p>Be sure to flush your browser's caches whenever making these kinds
217 of changes, just to make sure the changes <span class=
218 "QUOTE">"take"</span>.</p>
220 <p>Make sure the domain, host and path are appropriate as well. Your
221 browser can tell you where you are specifically and you should use that
222 information for your configuration settings. Note that above it is not
223 referenced as <tt class="LITERAL">gmail.com</tt>, which is a valid
228 <h3 class="SECT2"><a name="CONFIGFILES" id="CONFIGFILES">3.9. What's
229 the difference between the <span class="QUOTE">"Cautious"</span>,
230 <span class="QUOTE">"Medium"</span> and <span class=
231 "QUOTE">"Advanced"</span> defaults?</a></h3>
233 <p>Configuring <span class="APPLICATION">Privoxy</span> is not entirely
234 trivial. To help you get started, we provide you with three different
235 default action <span class="QUOTE">"profiles"</span> in the web based
236 actions file editor at <a href="http://config.privoxy.org/show-status"
237 target="_top">http://config.privoxy.org/show-status</a>. See the
238 <a href="../user-manual/actions-file.html" target="_top"><i class=
239 "CITETITLE">User Manual</i></a> for a list of actions, and how the
240 default profiles are set.</p>
242 <p>Where the defaults are likely to break some sites, exceptions for
243 known popular <span class="QUOTE">"problem"</span> sites are included,
244 but in general, the more aggressive your default settings are, the more
245 exceptions you will have to make later. New users are best to start off
246 in <span class="QUOTE">"Cautious"</span> setting. This is safest and
247 will have the fewest problems. See the <a href=
248 "../user-manual/index.html" target="_top"><i class="CITETITLE">User
249 Manual</i></a> for a more detailed discussion.</p>
251 <p>It should be noted that the <span class="QUOTE">"Advanced"</span>
252 profile (formerly known as the <span class=
253 "QUOTE">"Adventuresome"</span> profile) is more aggressive, and will
254 make use of some of <span class="APPLICATION">Privoxy's</span> advanced
255 features. Use at your own risk!</p>
259 <h3 class="SECT2"><a name="BROWSECONFIG" id="BROWSECONFIG">3.10. Why
260 can I change the configuration with a browser? Does that not raise
261 security issues?</a></h3>
263 <p>It may seem strange that regular users can edit the config files
264 with their browsers, although the whole <tt class=
265 "FILENAME">/etc/privoxy</tt> hierarchy belongs to the user <span class=
266 "QUOTE">"privoxy"</span>, with only 644 permissions.</p>
268 <p>When you use the browser-based editor, <span class=
269 "APPLICATION">Privoxy</span> itself is writing to the config files.
270 Because <span class="APPLICATION">Privoxy</span> is running as the user
271 <span class="QUOTE">"privoxy"</span>, it can update its own config
274 <p>If you run <span class="APPLICATION">Privoxy</span> for multiple
275 untrusted users (e.g. in a LAN) or aren't entirely in control of your
276 own browser, you will probably want to make sure that the web-based
277 editor and remote toggle features are <span class="QUOTE">"off"</span>
278 by setting <span class="QUOTE">"<tt class="LITERAL"><a href=
279 "../user-manual/config.html#ENABLE-EDIT-ACTIONS" target=
280 "_top">enable-edit-actions</a> 0</tt>"</span> and <span class=
281 "QUOTE">"<tt class="LITERAL"><a href=
282 "../user-manual/config.html#ENABLE-REMOTE-TOGGLE" target=
283 "_top">enable-remote-toggle</a> 0</tt>"</span> in the <a href=
284 "../user-manual/config.html" target="_top">main configuration
287 <p>As of <span class="APPLICATION">Privoxy</span> 3.0.7 these options
288 are disabled by default.</p>
292 <h3 class="SECT2"><a name="AEN489" id="AEN489">3.11. What is the
293 <tt class="FILENAME">default.filter</tt> file? What is a <span class=
294 "QUOTE">"filter"</span>?</a></h3>
296 <p>The <a href="../user-manual/filter-file.html" target=
297 "_top"><tt class="FILENAME">default.filter</tt></a> file is where
298 <span class="emphasis"><i class="EMPHASIS">filters</i></span> as
299 supplied by the developers are defined. Filters are a special subset of
300 actions that can be used to modify or remove web page content or
301 headers on the fly. Content filters can be applied to <span class=
302 "emphasis"><i class="EMPHASIS">anything</i></span> in the page source,
303 header filters can be applied to either server or client headers.
304 Regular expressions are used to accomplish this.</p>
306 <p>There are a number of pre-defined filters to deal with common
307 annoyances. The filters are only defined here, to invoke them, you need
308 to use the <a href="../user-manual/actions-file.html#FILTER" target=
309 "_top"><tt class="LITERAL">filter</tt> action</a> in one of the actions
310 files. Content filtering is automatically disabled for inappropriate
311 MIME types, but if you know better than Privoxy what should or should
312 not be filtered you can filter any content you like.</p>
314 <p>Filters should <span class="emphasis"><i class=
315 "EMPHASIS">not</i></span> be confused with <a href=
316 "../user-manual/actions-file.html#BLOCK" target="_top"><tt class=
317 "LITERAL">blocks</tt></a>, which is a completely different action, and
318 is more typically used to block ads and unwanted sites.</p>
320 <p>If you are familiar with regular expressions, and HTML, you can look
321 at the provided <tt class="FILENAME">default.filter</tt> with a text
322 editor and define your own filters. This is potentially a very powerful
323 feature, but requires some expertise in both regular expressions and
324 HTML/HTTP. You should place any modifications to the default filters,
325 or any new ones you create in a separate file, such as <tt class=
326 "FILENAME">user.filter</tt>, so they won't be overwritten during
327 upgrades. The ability to define multiple filter files in <tt class=
328 "FILENAME">config</tt> is a new feature as of v. 3.0.5.</p>
330 <p>There is no GUI editor option for this part of the configuration,
331 but you can disable/enable the various pre-defined filters of the
332 included <tt class="FILENAME">default.filter</tt> file with the
333 <a href="http://config.privoxy.org/show-status" target="_top">web-based
334 actions file editor</a>. Note that the custom actions editor must be
335 explicitly enabled in the main config file (see <a href=
336 "../user-manual/config.html#ENABLE-EDIT-ACTIONS" target=
337 "_top">enable-edit-actions</a>).</p>
339 <p>If you intend to develop your own filters, you might want to have a
340 look at <a href="http://www.fabiankeil.de/sourcecode/pft/" target=
341 "_top">Privoxy-Filter-Test</a>.</p>
345 <h3 class="SECT2"><a name="LANCONFIG" id="LANCONFIG">3.12. How can I
346 set up Privoxy to act as a proxy for my LAN?</a></h3>
348 <p>By default, <span class="APPLICATION">Privoxy</span> only responds
349 to requests from <tt class="LITERAL">127.0.0.1</tt> (localhost). To
350 have it act as a server for a network, this needs to be changed in the
351 <a href="../user-manual/config.html" target="_top">main configuration
352 file</a>. Look for the <tt class="LITERAL"><a href=
353 "../user-manual/config.html#LISTEN-ADDRESS" target=
354 "_top">listen-address</a></tt> option, which may be commented out with
355 a <span class="QUOTE">"#"</span> symbol. Make sure it is uncommented,
356 and assign it the address of the LAN gateway interface, and port number
357 to use. Assuming your LAN address is 192.168.1.1 and you wish to run
358 <span class="APPLICATION">Privoxy</span> on port 8118, this line should
361 <table border="0" bgcolor="#E0E0E0" width="100%">
365 listen-address 192.168.1.1:8118
371 <p>Save the file, and restart <span class="APPLICATION">Privoxy</span>.
372 Configure all browsers on the network then to use this address and port
375 <p>Alternately, you can have <span class="APPLICATION">Privoxy</span>
376 listen on all available interfaces:</p>
378 <table border="0" bgcolor="#E0E0E0" width="100%">
388 <p>And then use <span class="APPLICATION">Privoxy's</span> <a href=
389 "../user-manual/config.html#PERMIT-ACCESS" target=
390 "_top">permit-access</a> feature to limit connections. A firewall in
391 this situation is recommended as well.</p>
393 <p>The above steps should be the same for any TCP network, regardless
394 of operating system.</p>
396 <p>If you run <span class="APPLICATION">Privoxy</span> on a LAN with
397 untrusted users, we recommend that you double-check the <a href=
398 "../user-manual/config.html#ACCESS-CONTROL" target="_top">access
399 control and security</a> options!</p>
403 <h3 class="SECT2"><a name="AEN540" id="AEN540">3.13. Instead of ads,
404 now I get a checkerboard pattern. I don't want to see
407 <p>The replacement for blocked images can be controlled with the
408 <a href="../user-manual/actions-file.html#SET-IMAGE-BLOCKER" target=
409 "_top"><tt class="LITERAL">set-image-blocker</tt> action</a>. You have
410 the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka
411 <span class="QUOTE">"blank"</span>), or a redirect to a custom image of
412 your choice. Note that this choice only has effect for images which are
413 blocked as images, i.e. whose URLs match both a <tt class=
414 "LITERAL"><a href="../user-manual/actions-file.html#HANDLE-AS-IMAGE"
415 target="_top">handle-as-image</a></tt> <span class="emphasis"><i class=
416 "EMPHASIS">and</i></span> <tt class="LITERAL"><a href=
417 "../user-manual/actions-file.html#BLOCK" target="_top">block</a></tt>
420 <p>If you want to see nothing, then change the <a href=
421 "../user-manual/actions-file.html#SET-IMAGE-BLOCKER" target=
422 "_top"><tt class="LITERAL">set-image-blocker</tt> action</a> to
423 <span class="QUOTE">"blank"</span>. This can be done by editing the
424 <tt class="FILENAME">user.action</tt> file, or through the <a href=
425 "http://config.privoxy.org/show-status" target="_top">web-based actions
430 <h3 class="SECT2"><a name="AEN557" id="AEN557">3.14. Why would anybody
431 want to see a checkerboard pattern?</a></h3>
433 <p>Remember that <a href="general.html#WHATSANAD">telling which image
434 is an ad and which isn't</a>, is an educated guess. While we hope that
435 the standard configuration is rather smart, it will make occasional
436 mistakes. The checkerboard image is visually decent, and it shows you
437 where images have been blocked, which can be very helpful in case some
438 navigation aid or otherwise innocent image was erroneously blocked. It
439 is recommended for new users so they can <span class=
440 "QUOTE">"see"</span> what is happening. Some people might also enjoy
441 seeing how many banners they <span class="emphasis"><i class=
442 "EMPHASIS">don't</i></span> have to see.</p>
446 <h3 class="SECT2"><a name="AEN563" id="AEN563">3.15. I see some images
447 being replaced with text instead of the checkerboard image. Why and how
448 do I get rid of this?</a></h3>
450 <p>This happens when the banners are not embedded in the HTML code of
451 the page itself, but in separate HTML (sub)documents that are loaded
452 into (i)frames or (i)layers, and these external HTML documents are
453 blocked. Being non-images they get replaced by a substitute HTML page
454 rather than a substitute image, which wouldn't work out technically,
455 since the browser expects and accepts only HTML when it has requested
456 an HTML document.</p>
458 <p>The substitute page adapts to the available space and shows itself
459 as a miniature two-liner if loaded into small frames, or full-blown
460 with a large red "BLOCKED" banner if space allows.</p>
462 <p>If you prefer the banners to be blocked by images, you must see to
463 it that the HTML documents in which they are embedded are not blocked.
464 Clicking the <span class="QUOTE">"See why"</span> link offered in the
465 substitute page will show you which rule blocked the page. After
466 changing the rule and un-blocking the HTML documents, the browser will
467 try to load the actual banner images and the usual image blocking will
468 (hopefully!) kick in.</p>
472 <h3 class="SECT2"><a name="SRVANY" id="SRVANY">3.16. Can Privoxy run as
473 a service on Win2K/NT/XP?</a></h3>
475 <p>Yes. Version 3.0.5 introduces full <span class=
476 "APPLICATION">Windows</span> service functionality. See <a href=
477 "../user-manual/installation.html#installation-pack-win" target=
478 "_top">the <i class="CITETITLE">User Manual</i></a> for details on how
479 to install and configure <span class="APPLICATION">Privoxy</span> as a
482 <p>Earlier 3.x versions could run as a system service using <b class=
483 "COMMAND">srvany.exe</b>. See the discussion at <a href=
484 "http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118"
486 "_top">http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118</a>,
487 for details, and a sample configuration.</p>
491 <h3 class="SECT2"><a name="OTHERPROXY" id="OTHERPROXY">3.17. How can I
492 make Privoxy work with other proxies?</a></h3>
494 <p>This can be done and is often useful to combine the benefits of
495 <span class="APPLICATION">Privoxy</span> with those of a another proxy,
496 for example to cache content. See the <a href=
497 "../user-manual/config.html#FORWARDING" target="_top">forwarding
498 chapter</a> in the <a href="../user-manual/index.html" target=
499 "_top">User Manual</a> which describes how to do this. If you intend to
500 use Privoxy with Tor, please also have a look at <a href=
501 "misc.html#TOR">How do I use Privoxy together with Tor</a>.</p>
505 <h3 class="SECT2"><a name="PORT-80" id="PORT-80">3.18. Can I just set
506 Privoxy to use port 80 and thus avoid individual browser
507 configuration?</a></h3>
509 <p>No, its more complicated than that. This only works with special
510 kinds of proxies known as <span class="QUOTE">"intercepting"</span>
511 proxies (<a href="configuration.html#INTERCEPTING">see below</a>).</p>
515 <h3 class="SECT2"><a name="TRANSPARENT" id="TRANSPARENT">3.19. Can
516 Privoxy run as a <span class="QUOTE">"transparent"</span>
519 <p>The whole idea of Privoxy is to modify client requests and server
520 responses in all sorts of ways and therefore it's not a transparent
521 proxy as described in <a href="http://tools.ietf.org/html/rfc2616"
522 target="_top">RFC 2616</a>.</p>
524 <p>However, some people say <span class="QUOTE">"transparent
525 proxy"</span> when they mean <span class="QUOTE">"intercepting
526 proxy"</span>. If you are one of them, please read the <a href=
527 "configuration.html#INTERCEPTING">next entry</a>.</p>
531 <h3 class="SECT2"><a name="INTERCEPTING" id="INTERCEPTING">3.20. Can
532 Privoxy run as a <span class="QUOTE">"intercepting"</span>
535 <p><span class="APPLICATION">Privoxy</span> can't intercept traffic
536 itself, but it can handle requests that where intercepted and
537 redirected with a packet filter (like <span class=
538 "APPLICATION">PF</span> or <span class="APPLICATION">iptables</span>),
539 as long as the <tt class="LITERAL">Host</tt> header is present.</p>
541 <p>As the <tt class="LITERAL">Host</tt> header is required by HTTP/1.1
542 and as most web sites rely on it anyway, this limitation shouldn't be a
545 <p>Please refer to your packet filter's documentation to learn how to
546 intercept and redirect traffic into <span class=
547 "APPLICATION">Privoxy</span>. Afterward you just have to configure
548 <span class="APPLICATION">Privoxy</span> to <a href=
549 "../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS" target=
550 "_top">accept intercepted requests</a>.</p>
554 <h3 class="SECT2"><a name="OUTLOOK" id="OUTLOOK">3.21. How can I
555 configure Privoxy for use with Outlook?</a></h3>
557 <p>Versions of <span class="APPLICATION">Outlook</span> prior to Office
558 2007, use <span class="APPLICATION">Internet Explorer</span> components
559 to both render HTML, and fetch any HTTP requests that may be embedded
560 in an HTML email. So however you have <span class=
561 "APPLICATION">Privoxy</span> configured to work with IE, this
562 configuration should automatically be shared, at least with older
563 version of Internet Explorer.</p>
565 <p>Starting with Office 2007, Microsoft is instead using the MS-Word
566 rendering engine with Outlook. It is unknown whether this can be
567 configured to use a proxy.</p>
571 <h3 class="SECT2"><a name="OUTLOOK-MORE" id="OUTLOOK-MORE">3.22. How
572 can I have separate rules just for HTML mail?</a></h3>
574 <p>The short answer is, you can't. <span class=
575 "APPLICATION">Privoxy</span> has no way of knowing which particular
576 application makes a request, so there is no way to distinguish between
577 web pages and HTML mail. <span class="APPLICATION">Privoxy</span> just
578 blindly proxies all requests. In the case of <span class=
579 "APPLICATION">Outlook Express</span> (see above), OE uses IE anyway,
580 and there is no way for <span class="APPLICATION">Privoxy</span> to
581 ever be able to distinguish between them (nor could any other proxy
582 type application for that matter).</p>
584 <p>For a good discussion of some of the issues involved (including
585 privacy and security issues), see <a href=
586 "http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118"
588 "_top">http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</a>.</p>
592 <h3 class="SECT2"><a name="SNEAKY-COOKIES" id="SNEAKY-COOKIES">3.23. I
593 sometimes notice cookies sneaking through. How?</a></h3>
595 <p><a href="http://en.wikipedia.org/wiki/Browser_cookie" target=
596 "_top">Cookies</a> can be set in several ways. The classic method is
597 via the <tt class="LITERAL">Set-Cookie</tt> HTTP header. This is
598 straightforward, and an easy one to manipulate, such as the
599 <span class="APPLICATION">Privoxy</span> concept of <a href=
600 "../user-manual/actions-file.html#SESSION-COOKIES-ONLY" target=
601 "_top">session-cookies-only</a>. There is also the possibility of using
602 <a href="http://en.wikipedia.org/wiki/Javascript" target=
603 "_top">Javascript</a> to set cookies (<span class=
604 "APPLICATION">Privoxy</span> calls these <tt class=
605 "LITERAL">content-cookies</tt>). This is trickier because the syntax
606 can vary widely, and thus requires a certain amount of guesswork. It is
607 not realistic to catch all of these short of disabling Javascript,
608 which would break many sites. And lastly, if the cookies are embedded
609 in a HTTPS/SSL secure session via Javascript, they are beyond
610 <span class="APPLICATION">Privoxy's</span> reach.</p>
612 <p>All in all, <span class="APPLICATION">Privoxy</span> can help manage
613 cookies in general, can help minimize the loss of privacy posed by
614 cookies, but can't realistically stop all cookies.</p>
618 <h3 class="SECT2"><a name="EVIL-COOKIES" id="EVIL-COOKIES">3.24. Are
619 all cookies bad? Why?</a></h3>
621 <p>No, in fact there are many beneficial uses of <a href=
622 "http://en.wikipedia.org/wiki/Browser_cookie" target=
623 "_top">cookies</a>. Cookies are just a method that browsers can use to
624 store data between pages, or between browser sessions. Sometimes there
625 is a good reason for this, and the user's life is a bit easier as a
626 result. But there is a long history of some websites taking advantage
627 of this layer of trust, and using the data they glean from you and your
628 browsing habits for their own purposes, and maybe to your potential
629 detriment. Such sites are using you and storing their data on your
630 system. That is why the privacy conscious watch from whom those cookies
631 come, and why they really <span class="emphasis"><i class=
632 "EMPHASIS">need</i></span> to be there.</p>
634 <p>See the <a href="http://en.wikipedia.org/wiki/Browser_cookie"
635 target="_top">Wikipedia cookie definition</a> for more.</p>
639 <h3 class="SECT2"><a name="ALLOW-COOKIES" id="ALLOW-COOKIES">3.25. How
640 can I allow permanent cookies for my trusted sites?</a></h3>
642 <p>There are several actions that relate to cookies. The default
643 behavior is to allow only <span class="QUOTE">"session cookies"</span>,
644 which means the cookies only last for the current browser session. This
645 eliminates most kinds of abuse related to cookies. But there may be
646 cases where you want cookies to last.</p>
648 <p>To disable all cookie actions, so that cookies are allowed
649 unrestricted, both in and out, for <tt class=
650 "LITERAL">example.com</tt>:</p>
652 <table border="0" bgcolor="#E0E0E0" width="100%">
656 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
663 <p>Place the above in <tt class="FILENAME">user.action</tt>. Note that
664 some of these may be off by default anyway, so this might be redundant,
665 but there is no harm being explicit in what you want to happen.
666 <tt class="FILENAME">user.action</tt> includes an alias for this
667 situation, called <tt class="LITERAL">allow-all-cookies</tt>.</p>
671 <h3 class="SECT2"><a name="MULTIPLES" id="MULTIPLES">3.26. Can I have
672 separate configurations for different users?</a></h3>
674 <p>Each instance of <span class="APPLICATION">Privoxy</span> has its
675 own configuration, including such attributes as the TCP port that it
676 listens on. What you can do is run multiple instances of <span class=
677 "APPLICATION">Privoxy</span>, each with a unique <a href=
678 "../user-manual/config.html#LISTEN-ADDRESS" target=
679 "_top">listen-address</a> configuration setting, and configuration
680 path, and then each of these can have their own configurations. Think
681 of it as per-port configuration.</p>
683 <p>Simple enough for a few users, but for large installations, consider
684 having groups of users that might share like configurations.</p>
688 <h3 class="SECT2"><a name="WHITELISTS" id="WHITELISTS">3.27. Can I
689 set-up Privoxy as a whitelist of <span class="QUOTE">"good"</span>
692 <p>Sure. There are a couple of things you can do for simple
693 white-listing. Here's one real easy one:</p>
695 <table border="0" bgcolor="#E0E0E0" width="100%">
699 ############################################################
701 ############################################################
702 { <a href="../user-manual/actions-file.html#BLOCK" target=
706 ############################################################
708 ############################################################
709 { <a href="../user-manual/actions-file.html#BLOCK" target=
719 <p>This allows access to only those three sites by first blocking all
720 URLs, and then subsequently allowing three specific exceptions.</p>
722 <p>Another approach is <span class="APPLICATION">Privoxy's</span>
723 <tt class="LITERAL">trustfile</tt> concept, which incorporates the
724 notion of <span class="QUOTE">"trusted referrers"</span>. See the
725 <a href="../user-manual/config.html#TRUSTFILE" target="_top">Trust
726 documentation</a> for details.</p>
728 <p>These are fairly simple approaches and are not completely foolproof.
729 There are various other configuration options that should be disabled
730 (described elsewhere here and in <a href="../user-manual/" target=
731 "_top">the User Manual</a>) so that users can't modify their own
732 configuration and easily circumvent the whitelist.</p>
736 <h3 class="SECT2"><a name="NO-ADBLOCK" id="NO-ADBLOCK">3.28. How can I
737 turn off ad-blocking?</a></h3>
739 <p>Ad blocking is achieved through a complex application of various
740 <span class="APPLICATION">Privoxy</span> <a href=
741 "../user-manual/actions-file.html" target="_top">actions</a>. These
742 actions are deployed against simple images, banners, flash animations,
743 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as
744 simple as just turning one or two actions off. The various actions that
745 make up <span class="APPLICATION">Privoxy</span> ad blocking are
746 hard-coded into the default configuration files. It has been assumed
747 that everyone using <span class="APPLICATION">Privoxy</span> is
748 interested in this particular feature.</p>
750 <p>If you want to do without this, there are several approaches you can
751 take: You can manually undo the many block rules in <tt class=
752 "FILENAME">default.action</tt>. Or even easier, just create your own
753 <tt class="FILENAME">default.action</tt> file from scratch without the
754 many ad blocking rules, and corresponding exceptions. Or lastly, if you
755 are not concerned about the additional blocks that are done for privacy
756 reasons, you can very easily over-ride <span class="emphasis"><i class=
757 "EMPHASIS">all</i></span> blocking with the following very simple rule
758 in your <tt class="FILENAME">user.action</tt>:</p>
760 <table border="0" bgcolor="#E0E0E0" width="100%">
764 # Unblock everybody, everywhere
765 { <a href="../user-manual/actions-file.html#BLOCK" target=
767 / # UN-Block *all* URLs
773 <p>Or even a more comprehensive reversing of various ad related
776 <table border="0" bgcolor="#E0E0E0" width="100%">
780 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
781 { <a href="../user-manual/actions-file.html#BLOCK" target=
783 <a href="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE" target=
784 "_top">-filter{banners-by-size}</a> \
785 <a href="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK" target=
786 "_top">-filter{banners-by-link}</a> \
787 <tt class="LITERAL">allow-popups</tt> \
789 / # UN-Block *all* URLs and allow ads
795 <p>This last <span class="QUOTE">"action"</span> in this compound
796 statement, <tt class="LITERAL">allow-popups</tt>, is an <a href=
797 "../user-manual/actions-file.html#ALIASES" target="_top">alias</a> that
798 disables various pop-up blocking features.</p>
802 <h3 class="SECT2"><a name="TEMPLATES" id="TEMPLATES">3.29. How can I
803 have custom template pages, like the <span class="emphasis"><i class=
804 "EMPHASIS">BLOCKED</i></span> page?</a></h3>
806 <p><span class="APPLICATION">Privoxy</span> <span class=
807 "QUOTE">"templates"</span> are specialized text files utilized by
808 <span class="APPLICATION">Privoxy</span> for various purposes and can
809 easily be modified using any text editor. All the template pages are
810 installed in a sub-directory appropriately named: <tt class=
811 "FILENAME">templates</tt>. Knowing something about HTML syntax will of
812 course be helpful.</p>
814 <p>Be forewarned that the default templates are subject to being
815 overwritten during upgrades. You can, however, create completely new
816 templates, place them in another directory and specify the alternate
817 path in the main <tt class="FILENAME">config</tt>. For details, have a
818 look at the <a href="../user-manual/config.html#templdir" target=
819 "_top">templdir</a> option.</p>
823 <h3 class="SECT2"><a name="BLOCKALL" id="BLOCKALL">3.30. How can I
824 remove the <span class="QUOTE">"Go There Anyway"</span> link from the
825 <span class="emphasis"><i class="EMPHASIS">BLOCKED</i></span>
828 <p>There is more than one way to do it (although Perl is not
831 <p>Editing the BLOCKED template page (see above) may dissuade some
832 users, but this method is easily circumvented. Where you need this
833 level of control, you might want to build <span class=
834 "APPLICATION">Privoxy</span> from source, and disable various features
835 that are available as compile-time options. You should <b class=
836 "COMMAND">configure</b> the sources as follows:</p>
838 <table border="0" bgcolor="#E0E0E0" width="100%">
842 ./configure --disable-toggle --disable-editor --disable-force
848 <p>This will create an executable with hard-coded security features so
849 that <span class="APPLICATION">Privoxy</span> does not allow easy
850 bypassing of blocked sites, or changing the current configuration via
851 any connected user's web browser.</p>
853 <p>Finally, all of these features can also be toggled on/off via
854 options in <span class="APPLICATION">Privoxy's</span> main <a href=
855 "../user-manual/config.html#ACCESS-CONTROL" target="_top">config</a>
856 file which means you don't have to recompile anything.</p>
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