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39 >Privoxy Frequently Asked Questions</TH
47 HREF="configuration.html"
82 >4.1. How much does <SPAN
85 > slow my browsing down? This
86 has to add extra time to browsing.</A
89 > It should not slow you down any in real terms, and may actually help
90 speed things up since ads, banners and other junk are not being displayed.
91 The actual processing time required by <SPAN
95 itself for each page, is relatively small in the overall scheme of things,
96 and happens very quickly. This is typically more than offset by time saved
97 not downloading and rendering ad images.</P
106 mechanism may cause a perceived slowdown, since the entire page is buffered
107 before displaying. See below.</P
115 >4.2. I noticed considerable
116 delays in page requests compared to the old Junkbuster. What's wrong?</A
119 >Using the default filtering configuration, I noticed considerable delays in
120 page requests compared to the old Junkbuster. Loading pages with large contents
121 seemed to take forever, then suddenly delivering all the content at once.
124 >The whole content must be loaded in order to filter, and nothing is is
125 sent to the browser during this time. The loading time does not really
126 change in real numbers, but the feeling is different, because most
127 browsers are able to start rendering incomplete content, giving the
128 user a feeling of "it works".
131 >To modify the content of a page (i.e. make frames resizeable again, etc.) and
132 not just replace ads, <SPAN
135 > needs to download the
136 entire page first, do its content magic and then send the page to the browser.</P
144 >4.3. What is the "http://p.p/"?</A
150 > sits between your web browser and the Internet, it can be
151 programmed to handle certain pages specially.</P
153 >With recent versions of <SPAN
156 > (version 2.9.x), you can get some
157 information about <SPAN
160 > and change some settings by going to
165 > or, equivalently, <A
166 HREF="http://config.privoxy.org/"
168 >http://config.privoxy.org/</A
170 (Note that p.p is far easier to type but may not work in some
171 configurations. With the name change to <SPAN
175 this is changed from the previous http://i.j.b/ or earlier 2.9.x versions).</P
180 > forwarded to a server on the Internet
181 - instead they are handled by a special web server which is built in to
187 >If you are not running <SPAN
195 HREF="http://config.privoxy.org/"
197 >http://config.privoxy.org/</A
199 return a web page telling you you're not running
205 >If you have version 2.0.2, then the equivalent is
206 http://example.com/show-proxy-args (but you get far less information, and you
207 should really consider upgrading to 2.9.14).</P
215 >4.4. Do you still maintain the blocklists?</A
218 > No. The format of the blocklists has changed significantly in versions
219 2.9.x and later. Once we have released the new stable
220 version, v3.0, there will again be blocklists that you can update
229 >4.5. How can I submit new ads?</A
232 > As of now, please discontinue to submit new ad blocking infos. Once we
233 have released the new version, there will again be a form on the website,
234 which you can use to contribute new ads.</P
242 >4.6. How can I hide my IP address?</A
245 > You cannot hide your IP address with <SPAN
248 > or any other software, since
249 the server needs to know your IP address to send the answer to you.</P
251 >Fortunately there are many publicly usable anonymous proxies out there, which
252 solve the problem by providing a further level of indirection between you and
253 the web server, shared by many people and thus letting your requests "drown"
254 in white noise of unrelated requests as far as user tracking is concerned.</P
256 >Most of them will, however, log your IP address and make it available to the
257 authorities in case you abuse that anonymity for criminal purposes. In fact
258 you can't even rule out that some of them only exist to *collect* information
259 on (those suspicious) people with a more than average preference for privacy.</P
261 >You can find a list of anonymous public proxies at <A
262 HREF="http://www.multiproxy.org/anon_list.htm"
266 more through Google.</P
277 > guarantee I am anonymous?</A
280 > No. Your chances of remaining anonymous are greatly improved, but unless you
281 are an expert on Internet security it would be safest to assume that
282 everything you do on the Web can be traced back to you.</P
287 > can remove various information about you,
291 > more freedom to decide which sites
292 you can trust, and what details you want to reveal. But it's still possible
293 that web sites can find out who you are. Here's one way this can happen.</P
295 > A few browsers disclose the user's email address in certain situations, such
296 as when transferring a file by FTP. <SPAN
300 does not filter FTP. If you need this feature, or are concerned about the
301 mail handler of your browser disclosing your email address, you might
302 consider products such as <SPAN
307 > Browsers available only as binaries could use non-standard headers to give
308 out any information they can have access to: see the manufacturer's license
309 agreement. It's impossible to anticipate and prevent every breach of privacy
310 that might occur. The professionally paranoid prefer browsers available as
311 source code, because anticipating their behavior is easier. Trust the source,
320 >4.8. Might some things break because header information is
324 > Definitely. More and more sites use HTTP header content to decide what to
325 display and how to display it. There is many ways that this can be handled,
326 so having hard and fast rules, is tricky.</P
331 > in particular is often used in this way to identify
332 the browser, and adjust content accordingly. Changing this now is not
333 recommended, since so many sites do look for this. You may get undesirable
334 results by changing this.</P
336 > For instance, different browsers use different encodings of Russian and Czech
337 characters, certain web servers convert pages on-the-fly according to the
338 User Agent header. Giving a <SPAN
342 operating system or browser manufacturer causes some sites in these languages
343 to be garbled; Surfers to Eastern European sites should change it to
344 something closer. And then some page access counters work by looking at the
348 > header; they may fail or break if unavailable. The
349 weather maps of Intellicast have been blocked by their server when no
353 > or cookie is provided, is another example. There are
354 many, many other ways things can go wrong when trying to fool a web server.</P
356 > If you have problems with a site, you will have to adjust your configuration
357 accordingly. Cookies are probably the most likely adjustment that may
358 be required, but by no means the only one.</P
373 speed up web browsing?</A
376 > No, it does not have this ability at all. You want something like
378 HREF="http://www.squid-cache.org/"
381 > for this. And, yes,
382 before you ask, <SPAN
386 with other kinds of proxies like <SPAN
397 >4.10. What about as a firewall? Can <SPAN
403 > Not in the way you mean, or in the way a true firewall can, or a proxy that
404 has this specific capability. <SPAN
408 protect your privacy, but not really protect you from intrusion attempts.</P
419 > logo that replaces ads is very blocky
420 and ugly looking. Can't a better font be used?</A
423 > This is not a font problem. The logo is an image that is created by
427 > on the fly. So as to not waste
428 memory, the image is rather small. The blockiness comes when the
429 image is scaled to fill a largish area. There is not much to be done
430 about this, other than to use one of the other
441 >, or a URL of your choosing.</P
443 >Given the above problem, we have decided to remove the logo option entirely
452 >4.12. I have large empty spaces now where ads used to be.
456 > It would be easy enough to just eliminate this space altogether, rather than
457 fill it with blank space. But, this would create problems with many pages
458 that use the overall size of the ad to help organize the page layout and
459 position the various components of the page where they were intended to be.
460 It is best left this way.</P
471 > filter Secure (HTTPS) URLs?</A
474 > This is a limitation since HTTPS transactions are encrypted SSL sessions
475 between your browser and the secure site, and are meant to be reliably
479 > and private. This means that all cookies and HTTP
480 header information are also encrypted from the time they leave your browser,
481 to the site, and vice versa. <SPAN
485 try to unencrypt this information, so it just passes through as is.
489 > can still catch images and ads that
490 are embedded in the SSL stream though.</P
505 secure is it? Do I need to take any special precautions?</A
508 > There are no known exploits that might effect
512 >. On Unix-like systems,
516 > can run as a non-privileged
517 user, which is how we recommend it be run. Also, by default
521 > only listens to requests
525 >. The server aspect of
529 > is not itself directly exposed to the
530 Internet in this configuration. If you want to have
534 > serve as a LAN proxy, this will have to
535 be opened up to allow for LAN requests. In this case, we'd recommend
536 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
540 > config file. All LAN hosts can then use
541 this as their proxy address in the browser proxy configuration. In this way,
545 > will not listen on any external ports.
546 Of course, a firewall is always good too. Better safe than sorry.</P
554 >4.15. How can I temporarily disable <SPAN
560 > The easiest way is to access <SPAN
564 browser by using the special URL: <A
569 and select "Toggle Privoxy on or off" from that page. </P
577 >4.16. Where can I find more information about <SPAN
581 and related issues?</A
584 > Other references and sites of interest to <SPAN
598 HREF="http://www.privoxy.org/"
600 >http://www.privoxy.org/</A
621 HREF="http://sourceforge.net/projects/ijbswa"
623 >http://sourceforge.net/projects/ijbswa</A
625 the Project Page for <SPAN
630 HREF="http://sourceforge.net"
656 > from your browser. Alternately,
658 HREF="http://config.privoxy.org"
660 >http://config.privoxy.org</A
662 may work in some situations where the first does not.
678 HREF="http://www.junkbusters.com/ht/en/cookies.html"
680 >http://www.junkbusters.com/ht/en/cookies.html</A
697 HREF="http://www.waldherr.org/junkbuster/"
699 >http://www.waldherr.org/junkbuster/</A
716 HREF="http://privacy.net/analyze/"
718 >http://privacy.net/analyze/</A
735 HREF="http://www.squid-cache.org/"
737 >http://www.squid-cache.org/</A
763 HREF="configuration.html"