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52 <h1 class="SECT1"><a name="GENERAL" id="GENERAL">1. General
56 <h3 class="SECT2"><a name="WHO-USES" id="WHO-USES">1.1. Who should give
57 <span class="APPLICATION">Privoxy</span> a try?</a></h3>
59 <p>Anyone who is interested in security, privacy, or in finer-grained
60 control over their web and Internet experience.</p>
64 <h3 class="SECT2"><a name="BESTCHOICE" id="BESTCHOICE">1.2. Is Privoxy
65 the best choice for me?</a></h3>
67 <p><span class="APPLICATION">Privoxy</span> is certainly a good choice,
68 especially for those who want more control and security. Those with the
69 willingness to read the documentation and the ability to fine-tune
70 their installation will benefit the most.</p>
72 <p>One of <span class="APPLICATION">Privoxy's</span> strengths is that
73 it is highly configurable giving you the ability to completely
74 personalize your installation. Being familiar with, or at least having
75 an interest in learning about <a href=
76 "http://en.wikipedia.org/wiki/Http" target="_top">HTTP</a> and other
77 networking protocols, <a href="http://en.wikipedia.org/wiki/Html"
78 target="_top">HTML</a>, and <a href=
79 "http://en.wikipedia.org/wiki/Regular_expressions" target=
80 "_top"><span class="QUOTE">"Regular Expressions"</span></a> will be a
81 big plus and will help you get the most out of <span class=
82 "APPLICATION">Privoxy</span>. A new installation just includes a very
83 basic configuration. The user should take this as a starting point
84 only, and enhance it as he or she sees fit. In fact, the user is
85 encouraged, and expected to, fine-tune the configuration.</p>
87 <p>Much of <span class="APPLICATION">Privoxy's</span> configuration can
88 be done with a <a href="http://en.wikipedia.org/wiki/Web_browser"
89 target="_top">Web browser</a>. But there are areas where configuration
90 is done using a <a href="http://en.wikipedia.org/wiki/Text_editors"
91 target="_top">text editor</a> to edit configuration files. Also note
92 that the web-based action editor doesn't use authentication and should
93 only be enabled in environments where all clients with access to
94 <span class="APPLICATION">Privoxy</span> listening port can be
99 <h3 class="SECT2"><a name="PROXYMORON" id="PROXYMORON">1.3. What is a
100 <span class="QUOTE">"proxy"</span>? How does Privoxy work?</a></h3>
102 <p>A <a href="http://en.wikipedia.org/wiki/Proxy_server" target=
103 "_top">web proxy</a> is a service, based on a software such as
104 <span class="APPLICATION">Privoxy</span>, that clients (i.e. browsers)
105 can use instead of connecting to web servers directly. The clients then
106 ask the proxy to request objects (web pages, images, movies etc) on
107 their behalf and to forward the data to the clients. It is a
108 <span class="QUOTE">"go-between"</span>. For details, see <a href=
109 "http://en.wikipedia.org/wiki/Proxy_server" target="_top">Wikipedia's
110 proxy definition</a>.</p>
112 <p>There are many reasons to use web proxies, such as security
113 (firewalling), efficiency (caching) and others, and there are any
114 number of proxies to accommodate those needs.</p>
116 <p><span class="APPLICATION">Privoxy</span> is a proxy that is
117 primarily focused on privacy enhancement, ad and junk elimination and
118 freeing the user from restrictions placed on his activities. Sitting
119 between your browser(s) and the Internet, it is in a perfect position
120 to filter outbound personal information that your browser is leaking,
121 as well as inbound junk. It uses a variety of techniques to do this,
122 all of which are under your complete control via the various
123 configuration files and options. Being a proxy also makes it easier to
124 share configurations among multiple browsers and/or users.</p>
128 <h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">1.4. Does
129 Privoxy do anything more than ad blocking?</a></h3>
131 <p>Yes, ad blocking is but one possible use. There are many, many ways
132 <span class="APPLICATION">Privoxy</span> can be used to sanitize and
133 customize web browsing.</p>
137 <h3 class="SECT2"><a name="NEWJB" id="NEWJB">1.5. What is this new
138 version of <span class="QUOTE">"Junkbuster"</span>?</a></h3>
140 <p>A long time ago, there was the <a href=
141 "http://www.junkbusters.com/ijb.html" target="_top"><span class=
142 "APPLICATION">Internet Junkbuster</span></a>, by Anonymous Coders and
143 <a href="http://www.junkbusters.com/" target="_top">Junkbusters
144 Corporation</a>. This saved many users a lot of pain in the early days
145 of web advertising and user tracking.</p>
147 <p>But the web, its protocols and standards, and with it, the
148 techniques for forcing ads on users, give up autonomy over their
149 browsing, and for tracking them, keeps evolving. Unfortunately, the
150 <span class="APPLICATION">Internet Junkbuster</span> did not. Version
151 2.0.2, published in 1998, was (and is) the last official <a href=
152 "http://www.junkbusters.com/ijbdist.html#release" target=
153 "_top">release</a> available from <a href="http://www.junkbusters.com"
154 target="_top">Junkbusters Corporation</a>. Fortunately, it had been
155 released under the GNU <a href=
156 "http://www.gnu.org/licenses/old-licenses/gpl-2.0.html" target=
157 "_top">GPL</a>, which allowed further development by others.</p>
159 <p>So Stefan Waldherr started maintaining an improved version of the
160 software, to which eventually a number of people contributed patches.
161 It could already replace banners with a transparent image, and had a
162 first version of pop-up killing, but it was still very closely based on
163 the original, with all its limitations, such as the lack of HTTP/1.1
164 support, flexible per-site configuration, or content modification. The
165 last release from this effort was version 2.0.2-10, published in
168 <p>Then, some <a href=
169 "http://www.privoxy.org/user-manual/copyright.html#AUTHORS" target=
170 "_top">developers</a> picked up the thread, and started turning the
171 software inside out, upside down, and then reassembled it, adding many
172 <a href="http://www.privoxy.org/user-manual/introduction.html#FEATURES"
173 target="_top">new features</a> along the way.</p>
175 <p>The result of this is <span class="APPLICATION">Privoxy</span>,
176 whose first stable version, 3.0, was released August, 2002.</p>
180 <h3 class="SECT2"><a name="AEN85" id="AEN85">1.6. Why <span class=
181 "QUOTE">"Privoxy"</span>? Why change the name from Junkbuster at
184 <p>Though outdated, <a href="http://junkbusters.com/" target=
185 "_top">Junkbusters Corporation</a> continues to offer their original
186 version of the <span class="APPLICATION">Internet Junkbuster</span>, so
187 publishing our <span class="APPLICATION">Junkbuster</span>-derived
188 software under the same name led to confusion.</p>
190 <p>There are also potential legal complications from our use of the
191 <span class="APPLICATION">Junkbuster</span> name, which is a registered
192 trademark of <a href="http://junkbusters.com/" target=
193 "_top">Junkbusters Corporation</a>. There are, however, no objections
194 from Junkbusters Corporation to the <span class=
195 "APPLICATION">Privoxy</span> project itself, and they, in fact, still
196 share our ideals and goals.</p>
198 <p>The developers also believed that there are so many improvements
199 over the original code, that it was time to make a clean break from the
200 past and make a name in their own right.</p>
202 <p><span class="APPLICATION">Privoxy</span> is the <span class=
203 "QUOTE">"<span class="emphasis EMPHASIS c2">Privacy Enhancing
204 Proxy</span>"</span>. Also, its content modification and junk
205 suppression gives <span class="emphasis EMPHASIS c2">you</span>, the
206 user, more control, more freedom, and allows you to browse your
207 personal and <span class="QUOTE">"<span class=
208 "emphasis EMPHASIS c2">private</span> edition"</span> of the web.</p>
212 <h3 class="SECT2"><a name="DIFFERS" id="DIFFERS">1.7. How does Privoxy
213 differ from the old Junkbuster?</a></h3>
215 <p><span class="APPLICATION">Privoxy</span> picks up where <span class=
216 "APPLICATION">Junkbuster</span> left off. The new <span class=
217 "APPLICATION">Privoxy</span> still blocks ads and banners, still
218 manages <a href="http://en.wikipedia.org/wiki/Browser_cookie" target=
219 "_top">cookies</a>, and still helps protect your privacy. But, most of
220 these features have been enhanced, and many new ones have been added,
221 all in the same vein.</p>
223 <p><span class="APPLICATION">Privoxy</span>'s new features include:</p>
227 <p>Supports "Connection: keep-alive". Outgoing connections can be
228 kept alive independently from the client.</p>
232 <p>Supports IPv6, provided the operating system does so too, and
233 the configure script detects it.</p>
237 <p>Supports tagging which allows to change the behaviour based on
238 client and server headers.</p>
242 <p>Can be run as an "intercepting" proxy, which obviates the need
243 to configure browsers individually.</p>
247 <p>Sophisticated actions and filters for manipulating both server
248 and client headers.</p>
252 <p>Can be chained with other proxies.</p>
256 <p>Integrated browser-based configuration and control utility at
257 <a href="http://config.privoxy.org/" target=
258 "_top">http://config.privoxy.org/</a> (shortcut: <a href=
259 "http://p.p/" target="_top">http://p.p/</a>). Browser-based tracing
260 of rule and filter effects. Remote toggling.</p>
264 <p>Web page filtering (text replacements, removes banners based on
265 size, invisible <span class="QUOTE">"web-bugs"</span> and HTML
266 annoyances, etc.)</p>
270 <p>Modularized configuration that allows for standard settings and
271 user settings to reside in separate files, so that installing
272 updated actions files won't overwrite individual user settings.</p>
276 <p>Support for Perl Compatible Regular Expressions in the
277 configuration files, and a more sophisticated and flexible
278 configuration syntax.</p>
282 <p>GIF de-animation.</p>
286 <p>Bypass many click-tracking scripts (avoids script
291 <p>User-customizable HTML templates for most proxy-generated pages
292 (e.g. "blocked" page).</p>
296 <p>Auto-detection and re-reading of config file changes.</p>
300 <p>Most features are controllable on a per-site or per-location
305 <p>Many smaller new features added, limitations and bugs
312 <h3 class="SECT2"><a name="WHATSANAD" id="WHATSANAD">1.8. How does
313 Privoxy know what is an ad, and what is not?</a></h3>
315 <p><span class="APPLICATION">Privoxy</span>'s approach to blocking ads
318 <p>First, there are certain patterns in the <span class=
319 "emphasis EMPHASIS c2">locations</span> (URLs) of banner images. This
320 applies to both the path (you wouldn't guess how many web sites serve
321 their banners from a directory called <span class=
322 "QUOTE">"banners"</span>!) and the host (blocking the big banner
323 hosting services like doublecklick.net already helps a lot).
324 <span class="APPLICATION">Privoxy</span> takes advantage of this fact
325 by using <a href="../user-manual/actions-file.html#AF-PATTERNS" target=
326 "_top">URL patterns</a> to sort out and block the requests for things
327 that sound like they would be ads or banners.</p>
329 <p>Second, banners tend to come in certain <span class=
330 "emphasis EMPHASIS c2">sizes</span>. But you can't tell the size of an
331 image by its URL without downloading it, and if you do, it's too late
332 to save bandwidth. Therefore, <span class="APPLICATION">Privoxy</span>
333 also inspects the HTML sources of web pages while they are loaded, and
334 replaces references to images with standard banner sizes by dummy
335 references, so that your browser doesn't request them anymore in the
338 <p>Both of this involves a certain amount of guesswork and is, of
339 course, freely and readily configurable.</p>
343 <h3 class="SECT2"><a name="AEN163" id="AEN163">1.9. Can Privoxy make
344 mistakes? This does not sound very scientific.</a></h3>
346 <p>Actually, it's a black art ;-) And yes, it is always possible to
347 have a broad rule accidentally block or change something by mistake.
348 You will almost surely run into such situations at some point. It is
349 tricky writing rules to cover every conceivable possibility, and not
350 occasionally get false positives.</p>
352 <p>But this should not be a big concern since the <span class=
353 "APPLICATION">Privoxy</span> configuration is very flexible, and
354 includes tools to help identify these types of situations so they can
355 be addressed as needed, allowing you to customize your installation.
356 (<a href="trouble.html#BADSITE">See the Troubleshooting section
361 <h3 class="SECT2"><a name="AEN169" id="AEN169">1.10. Will I have to
362 configure Privoxy before I can use it?</a></h3>
364 <p>That depends on your expectations. The default installation should
365 give you a good starting point, and block <span class=
366 "emphasis EMPHASIS c2">most</span> ads and unwanted content, but many
367 of the more advanced features are off by default, and require you to
370 <p>You do have to set up your browser to use <span class=
371 "APPLICATION">Privoxy</span> (see the <a href=
372 "installation.html#FIRSTSTEP">Installation section below</a>).</p>
374 <p>And you will certainly run into situations where there are false
375 positives, or ads not being blocked that you may not want to see. In
376 these cases, you would certainly benefit by customizing <span class=
377 "APPLICATION">Privoxy's</span> configuration to more closely match your
378 individual situation. And we encourage you to do this. This is where
379 the real power of <span class="APPLICATION">Privoxy</span> lies!</p>
383 <h3 class="SECT2"><a name="LAN" id="LAN">1.11. Can Privoxy run as a
384 server on a network?</a></h3>
386 <p>Yes, <span class="APPLICATION">Privoxy</span> runs as a server
387 already, and can easily be configured to <span class=
388 "QUOTE">"serve"</span> more than one client. See <a href=
389 "configuration.html#LANCONFIG">How can I set up Privoxy to act as a
390 proxy for my LAN</a> below.</p>
394 <h3 class="SECT2"><a name="BROWSERS2" id="BROWSERS2">1.12. My browser
395 does the same things as Privoxy. Why should I use Privoxy at
398 <p>Modern browsers do indeed have <span class=
399 "emphasis EMPHASIS c2">some</span> of the same functionality as
400 <span class="APPLICATION">Privoxy</span>. Maybe this is adequate for
401 you. But <span class="APPLICATION">Privoxy</span> is very versatile and
402 powerful, and can probably do a number of things your browser just
405 <p>In addition, a proxy is good choice if you use multiple browsers, or
406 have a LAN with multiple computers since <span class=
407 "APPLICATION">Privoxy</span> can run as a server application. This way
408 all the configuration is in one place, and you don't have to maintain a
409 similar configuration for possibly many browsers or users.</p>
411 <p>Note, however, that it's recommended to leverage both your browser's
412 and <span class="APPLICATION">Privoxy's</span> privacy enhancing
413 features at the same time. While your browser probably lacks some
414 features <span class="APPLICATION">Privoxy</span> offers, it should
415 also be able to do some things more reliable, for example restricting
416 and suppressing JavaScript.</p>
420 <h3 class="SECT2"><a name="WHYTRUST" id="WHYTRUST">1.13. Why should I
421 trust Privoxy?</a></h3>
423 <p>The most important reason is because you have access to <span class=
424 "emphasis EMPHASIS c2">everything</span>, and you can control
425 everything. You can check every line of every configuration file
426 yourself. You can check every last bit of source code should you
427 desire. And even if you can't read code, there should be some comfort
428 in knowing that other people can, and do read it. You can build the
429 software from scratch, if you want, so that you know the executable is
430 clean, and that it is <span class="emphasis EMPHASIS c2">yours</span>.
431 In fact, we encourage this level of scrutiny. It is one reason we use
432 <span class="APPLICATION">Privoxy</span> ourselves.</p>
436 <h3 class="SECT2"><a name="LICENSE" id="LICENSE">1.14. Is there is a
437 license or fee? What about a warranty? Registration?</a></h3>
439 <p><span class="APPLICATION">Privoxy</span> is free software and
440 licensed under the <a href=
441 "http://www.gnu.org/licenses/old-licenses/gpl-2.0.html" target=
442 "_top">GNU General Public License (GPL) version 2</a>. It is free to
443 use, copy, modify or distribute as you wish under the terms of this
444 license. Please see the <a href="copyright.html">Copyright</a> section
445 for more information on the license and copyright. Or the <tt class=
446 "FILENAME">LICENSE</tt> file that should be included.</p>
448 <p>There is <span class="emphasis EMPHASIS c2">no warranty</span> of
449 any kind, expressed, implied or otherwise. That is something that would
450 cost real money ;-) There is no registration either.</p>
454 <h3 class="SECT2"><a name="SPYWARE" id="SPYWARE">1.15. Can Privoxy
455 remove spyware? Adware? Viruses?</a></h3>
457 <p>No, at least not reliably enough to trust it. <span class=
458 "APPLICATION">Privoxy</span> is not designed to be a malware removal
459 tool and the default configuration doesn't even try to filter out any
462 <p><span class="APPLICATION">Privoxy</span> could help prevent contact
463 from (known) sites that use such tactics with appropriate configuration
464 rules, and thus could conceivably prevent contamination from such
465 sites. However, keeping such a configuration up to date would require a
466 lot of time and effort that would be better spend on keeping your
467 software itself up to date so it doesn't have known
472 <h3 class="SECT2"><a name="OTHERADS" id="OTHERADS">1.16. Can I use
473 Privoxy with other ad-blocking software?</a></h3>
475 <p><span class="APPLICATION">Privoxy</span> should work fine with other
476 proxies and other software in general.</p>
478 <p>But it is probably not necessary to use <span class=
479 "APPLICATION">Privoxy</span> in conjunction with other ad-blocking
480 products, and this could conceivably cause undesirable results. It
481 might be better to choose one software or the other and work a little
482 to tweak its configuration to your liking.</p>
484 <p>Note that this is an advice specific to ad blocking.</p>
488 <h3 class="SECT2"><a name="HELP-THE-DEVELOPERS" id=
489 "HELP-THE-DEVELOPERS">1.17. I would like to help you, what can I
493 <h4 class="SECT3"><a name="PARTICIPATE" id="PARTICIPATE">1.17.1.
494 Would you like to participate?</a></h4>
496 <p>Well, we <span class="emphasis EMPHASIS c2">always</span> need
497 help. There is something for everybody who wants to help us. We
498 welcome new developers, packagers, testers, documentation writers or
499 really anyone with a desire to help in any way. You <span class=
500 "emphasis EMPHASIS c2">DO NOT</span> need to be a <span class=
501 "QUOTE">"programmer"</span>. There are many other tasks available. In
502 fact, the programmers often can't spend as much time programming
503 because of some of the other, more mundane things that need to be
504 done, like checking the Tracker feedback sections or responding to
505 user questions on the mailing lists.</p>
507 <p>So first thing, subscribe to the <a href=
508 "https://lists.sourceforge.net/lists/listinfo/ijbswa-users" target=
509 "_top">Privoxy Users</a> or the <a href=
510 "https://lists.sourceforge.net/lists/listinfo/ijbswa-developers"
511 target="_top">Privoxy Developers</a> mailing list, join the
512 discussion, help out other users, provide general feedback or report
513 problems you noticed.</p>
515 <p>If you intend to help out with the trackers, you also might want
516 to <a href="https://sourceforge.net/account/register.php" target=
517 "_top">get an account on SourceForge.net</a> so we don't confuse you
518 with the other name-less users.</p>
520 <p>We also have a <a href="../developer-manual/index.html" target=
521 "_top">Developer's Manual</a>. While it is partly out of date, it's
522 still worth reading.</p>
525 "http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup"
526 target="_top">TODO list</a> may be of interest to you as well. Please
527 let us know if you want to work on one of the items listed.</p>
531 <h4 class="SECT3"><a name="DONATE" id="DONATE">1.17.2. Would you like
534 <p><span class="APPLICATION">Privoxy</span> is developed by unpaid
535 volunteers and thus our current running costs are pretty low.
536 Nevertheless, we have plans that will cost money in the future. They
537 include, but aren't limited to spending money on:</p>
541 <p>Hardware to help make sure <span class=
542 "APPLICATION">Privoxy</span> keeps running on platforms the
543 developers currently can't test on and can be ported to
548 <p>Technical books to educate our developers about said platforms
549 or to improve their knowledge in general.</p>
553 <p>More reliable hosting,</p>
557 <p>We would like to get this money through donations made by our
560 <p><span class="APPLICATION">Privoxy</span> has therefore become an
561 associated project of <a href=
562 "http://www.spi-inc.org/about-spi/about-spi" target="_top">Software
563 in the Public Interest (SPI)</a>, which allows us to receive
564 donations. In the United States they are tax-deductible, in a few
565 other western countries they might be tax-deductible in the
568 <p>If you read this section before you may notice that paying for the
569 project domain privoxy.org is no longer on the list. It has been
570 transferred to SPI is sponsored by Mythic Beasts Ltd.</p>
572 <p>If you enjoy our software and feel like helping out with a
573 donation, please have a look at <a href=
574 "http://www.spi-inc.org/donations" target="_top">SPI's donation
575 page</a> to see what the options are. If you have any questions
576 regarding donations please mail to either the public user mailing
577 list or, if it's a private matter, to <a href=
578 "mailto:fk@fabiankeil.de" target="_top">Fabian Keil</a> (Privoxy's
579 SPI liason) directly.</p>
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