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43 <h1 class="SECT1"><a name="TROUBLE" id="TROUBLE">5.
44 Troubleshooting</a></h1>
47 <h3 class="SECT2"><a name="REFUSED" id="REFUSED">5.1. I cannot connect
48 to any websites. Or, I am getting <span class="QUOTE">"connection
49 refused"</span> message with every web page. Why?</a></h3>
51 <p>There are several possibilities:</p>
55 <p><span class="APPLICATION">Privoxy</span> is not running.
56 Solution: verify that <span class="APPLICATION">Privoxy</span> is
57 installed correctly, has not crashed, and is indeed running. Turn
58 on <span class="APPLICATION">Privoxy's</span> logging, and look at
59 the logs to see what they say.</p>
63 <p>Or your browser is configured for a different port than what
64 <span class="APPLICATION">Privoxy</span> is using. Solution: verify
65 that <span class="APPLICATION">Privoxy</span> and your browser are
66 set to the same port (<tt class="LITERAL">listen-address</tt>).</p>
70 <p>Or if using a forwarding rule, you have a configuration problem
71 or a problem with a host in the forwarding chain. Solution:
72 temporarily alter your configuration and take the forwarders out of
77 <p>Or you have a firewall that is interfering and blocking you.
78 Solution: try disabling or removing the firewall as a simple
85 <h3 class="SECT2"><a name="ERROR503" id="ERROR503">5.2. Why am I
86 getting a 503 Error (WSAECONNREFUSED) on every page?</a></h3>
88 <p>More than likely this is a problem with your TCP/IP networking.
89 ZoneAlarm has been reported to cause this symptom -- even if not
90 running! The solution is to either fight the ZA configuration, or
91 uninstall ZoneAlarm, and then find something better behaved in its
92 place. Other personal firewall type products may cause similar type
93 problems if not configured correctly.</p>
97 <h3 class="SECT2"><a name="FLUSHIT" id="FLUSHIT">5.3. I just added a
98 new rule, but the steenkin ad is still getting through. How?</a></h3>
100 <p>If the ad had been displayed before you added its URL, it will
101 probably be held in the browser's cache for some time, so it will be
102 displayed without the need for any request to the server, and
103 <span class="APPLICATION">Privoxy</span> will not be involved. Flush
104 the browser's caches, and then try again.</p>
106 <p>If this doesn't help, you probably have an error in the rule you
107 applied. Try pasting the full URL of the offending ad into <a href=
108 "http://config.privoxy.org/show-url-info" target=
109 "_top">http://config.privoxy.org/show-url-info</a> and see if it really
110 matches your new rule. Blocking ads is like blocking spam: a lot of
111 tinkering is required to stay ahead of the game. And remember you need
112 to block the URL of the ad in question, which may be entirely different
113 from the site URL itself. Most ads are hosted on different servers than
114 the main site itself. If you right-click on the ad, you should be able
115 to get all the relevant information you need. Alternately, you can find
116 the correct URL by looking at <span class=
117 "APPLICATION">Privoxy's</span> logs (you may need to enable logging in
118 the main config file if its disabled).</p>
120 <p>Below is a slightly modified real-life log snippet that originates
121 with one requested URL: <tt class="LITERAL">www.example.com</tt> (name
122 of site was changed for this example, the number of requests is real).
123 You can see in this the complexity of what goes into making up this one
124 <span class="QUOTE">"page"</span>. There are eight different domains
125 involved here, with thirty two separate URLs requested in all, making
126 up all manner of images, Shockwave Flash, JavaScript, CSS stylesheets,
127 scripts, and other related content. Some of this content is obviously
128 <span class="QUOTE">"good"</span> or <span class="QUOTE">"bad"</span>,
129 but not all. Many of the more questionable looking requests, are going
130 to outside domains that seem to be identifying themselves with
131 suspicious looking names, making our job a little easier. <span class=
132 "APPLICATION">Privoxy</span> has <span class="QUOTE">"crunched"</span>
133 (meaning caught and BLOCKED) quite a few items in this example, but
134 perhaps missed a few as well.</p>
136 <table border="0" bgcolor="#E0E0E0" width="100%">
140 Request: www.example.com/
141 Request: www.example.com/favicon.ico
142 Request: img.example.com/main.css
143 Request: img.example.com/sr.js
144 Request: example.betamarker.com/example.html
145 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
146 Request: img.example.com/pb.png
147 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
148 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
149 Request: img.example.com/p.gif
150 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
151 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
152 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
153 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
154 Request: www.adtrak.net/adx.js crunch! (Blocked)
155 Request: img.example.com/hbg.gif
156 Request: img.example.com/example.jpg
157 Request: img.example.com/mt.png
158 Request: img.example.com/mm.png
159 Request: img.example.com/mb.png
160 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
161 Request: www.example.com/tracker.js
162 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
163 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
164 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
165 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
166 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
167 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
168 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
169 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
170 Request: 66.70.21.80/img/pixel.gif
171 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
172 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
178 <p>Despite 12 out of 32 requests being blocked, the page looked, and
179 seemed to behave perfectly <span class="QUOTE">"normal"</span> (minus
180 some ads, of course).</p>
184 <h3 class="SECT2"><a name="BADSITE" id="BADSITE">5.4. One of my
185 favorite sites does not work with Privoxy. What can I do?</a></h3>
187 <p>First verify that it is indeed a <span class=
188 "APPLICATION">Privoxy</span> problem, by toggling off <span class=
189 "APPLICATION">Privoxy</span> through <a href=
190 "http://config.privoxy.org/toggle" target=
191 "_top">http://config.privoxy.org/toggle</a> (the toggle feature may
192 need to be enabled in the main <tt class="FILENAME">config</tt>), and
193 then shift-reloading the problem page (i.e. holding down the shift key
194 while clicking reload. Alternatively, flush your browser's disk and
197 <p>If the problem went away, we know we have a configuration related
198 problem. Now go to <a href="http://config.privoxy.org/show-url-info"
199 target="_top">http://config.privoxy.org/show-url-info</a> and paste the
200 full URL of the page in question into the prompt. See which actions are
201 being applied to the URL, and which matches in which actions files are
202 responsible for that. It might be helpful also to look at your logs for
203 this site too, to see what else might be happening (note: logging may
204 need to be enabled in the main config file). Many sites are complex and
205 require a number of related pages to help present their content. Look
206 at what else might be used by the page in question, and what of that
207 might be <span class="emphasis"><i class=
208 "EMPHASIS">required</i></span>. Now, armed with this information, go to
209 <a href="http://config.privoxy.org/show-status" target=
210 "_top">http://config.privoxy.org/show-status</a> and select the
211 appropriate actions files for editing.</p>
213 <p>You can now either look for a section which disables the actions
214 that you suspect to cause the problem and add a pattern for your site
215 there, or make up a completely new section for your site. In any case,
216 the recommended way is to disable only the prime suspect, reload the
217 problem page, and only if the problem persists, disable more and more
218 actions until you have identified the culprit. You may or may not want
219 to turn the other actions on again. Remember to flush your browser's
220 caches in between any such changes!</p>
222 <p>Alternately, if you are comfortable with a text editor, you can
223 accomplish the same thing by editing the appropriate actions file.
224 Probably the easiest way to deal with such problems when editing by
225 hand is to add your site to a <tt class="LITERAL">{ fragile }</tt>
226 section in <tt class="FILENAME">user.action</tt>, which is an alias
227 that turns off most <span class="QUOTE">"dangerous"</span> actions, but
228 is also likely to turn off more actions then needed, and thus lower
229 your privacy and protection more than necessary,</p>
231 <p>Troubleshooting actions is discussed in more detail in the <a href=
232 "../user-manual/appendix.html#ACTIONSANAT" target="_top">User Manual
233 appendix, Troubleshooting: the Anatomy of an Action</a>. There is also
234 an <a href="../user-manual/actions-file.html#ACT-EXAMPLES" target=
235 "_top">actions tutorial</a> with general configuration information and
238 <p>As a last resort, you can always see if your browser has a setting
239 that will bypass the proxy setting for selective sites. Modern browsers
244 <h3 class="SECT2"><a name="DUN" id="DUN">5.5. After installing Privoxy,
245 I have to log in every time I start IE. What gives?</a></h3>
247 <p>This is a quirk that affects the installation of <span class=
248 "APPLICATION">Privoxy</span>, in conjunction with Internet Explorer and
249 Internet Connection Sharing on Windows 2000 and Windows XP. The
250 symptoms may appear to be corrupted or invalid DUN settings, or
253 <p>When setting up an NT based Windows system with <span class=
254 "APPLICATION">Privoxy</span> you may find that things do not seem to be
255 doing what you expect. When you set your system up you will probably
256 have set up Internet Connection Sharing (ICS) with Dial up Networking
257 (DUN) when logged in with administrator privileges. You will probably
258 have made this DUN connection available to other accounts that you may
259 have set-up on your system. E.g. Mum or Dad sets up the system and
260 makes accounts suitably configured for the kids.</p>
262 <p>When setting up <span class="APPLICATION">Privoxy</span> in this
263 environment you will have to alter the proxy set-up of Internet
264 Explorer (IE) for the specific DUN connection on which you wish to use
265 <span class="APPLICATION">Privoxy</span>. When you do this the ICS DUN
266 set-up becomes user specific. In this instance you will see no
267 difference if you change the DUN connection under the account used to
268 set-up the connection. However when you do this from another user you
269 will notice that the DUN connection changes to make available to "Me
270 only". You will also find that you have to store the password under
271 each different user!</p>
273 <p>The reason for this is that each user's set-up for IE is user
274 specific. Each set-up DUN connection and each LAN connection in IE
275 store the settings for each user individually. As such this enforces
276 individual configurations rather than common ones. Hence the first time
277 you use a DUN connection after re-booting your system it may not
278 perform as you expect, and prompt you for the password. Just set and
279 save the password again and all should be OK.</p>
281 <p>[Thanks to Ray Griffith for this submission.]</p>
285 <h3 class="SECT2"><a name="FTP" id="FTP">5.6. I cannot connect to any
286 FTP sites. Privoxy is blocking me.</a></h3>
288 <p><span class="APPLICATION">Privoxy</span> cannot act as a proxy for
289 FTP traffic, so do not configure your browser to use <span class=
290 "APPLICATION">Privoxy</span> as an FTP proxy. The same is true for
291 <span class="emphasis"><i class="EMPHASIS">any protocol other than HTTP
292 or HTTPS (SSL)</i></span>.</p>
294 <p>Most browsers understand FTP as well as HTTP. If you connect to a
295 site, with a URL like <tt class="LITERAL">ftp://ftp.example.com</tt>,
296 your browser is making an FTP connection, and not a HTTP connection. So
297 while your browser may speak FTP, <span class=
298 "APPLICATION">Privoxy</span> does not, and cannot proxy such
301 <p>To complicate matters, some systems may have a generic <span class=
302 "QUOTE">"proxy"</span> setting, which will enable various protocols,
303 including <span class="emphasis"><i class="EMPHASIS">both</i></span>
304 HTTP and FTP proxying! So it is possible to accidentally enable FTP
305 proxying in these cases. And of course, if this happens, <span class=
306 "APPLICATION">Privoxy</span> will indeed cause problems since it does
307 not know FTP. Newer version will give a sane error message if a FTP
308 connection is attempted. Just disable the FTP setting and all will be
311 <p>Will <span class="APPLICATION">Privoxy</span> ever proxy FTP
312 traffic? Unlikely. There just is not much reason, and the work to make
313 this happen is more than it may seem.</p>
317 <h3 class="SECT2"><a name="MACOSXIE" id="MACOSXIE">5.7. In Mac OS X, I
318 can't configure Microsoft Internet Explorer to use Privoxy as the HTTP
321 <p>Microsoft Internet Explorer (in versions like 5.1) respects
322 system-wide network settings. In order to change the HTTP proxy, open
323 System Preferences, and click on the Network icon. In the settings pane
324 that comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)"
325 checkbox is checked and enter <tt class="LITERAL">127.0.0.1</tt> in the
326 entry field. Enter <tt class="LITERAL">8118</tt> in the Port field. The
327 next time you start IE, it should reflect these values.</p>
331 <h3 class="SECT2"><a name="MACOSXUNINSTALL" id="MACOSXUNINSTALL">5.8.
332 In Mac OS X, I dragged the Privoxy folder to the trash in order to
333 uninstall it. Now the finder tells me I don't have sufficient
334 privileges to empty the trash.</a></h3>
336 <p>Note: This ONLY applies to privoxy 3.0.6 and earlier.</p>
338 <p>Just dragging the <span class="APPLICATION">Privoxy</span> folder to
339 the trash is not enough to delete it. <span class=
340 "APPLICATION">Privoxy</span> supplies an <span class=
341 "APPLICATION">uninstall.command</span> file that takes care of these
342 details. Open the trash, drag the <span class=
343 "APPLICATION">uninstall.command</span> file out of the trash and
344 double-click on it. You will be prompted for confirmation and the
345 administration password.</p>
347 <p>The trash may still appear full after this command; emptying the
348 trash from the desktop should make it appear empty again.</p>
352 <h3 class="SECT2"><a name="MACOSXIMAGES" id="MACOSXIMAGES">5.9. In Mac
353 OS X Panther (10.3), images often fail to load and/or I experience
354 random delays in page loading. I'm using <tt class=
355 "LITERAL">localhost</tt> as my browser's proxy setting.</a></h3>
357 <p>We believe this is due to an IPv6-related bug in Mac OS X, but don't
358 fully understand the issue yet. In any case, changing the proxy setting
359 to <tt class="LITERAL">127.0.0.1</tt> instead of <tt class=
360 "LITERAL">localhost</tt> works around the problem.</p>
364 <h3 class="SECT2"><a name="MACOSXACCOUNTDELETION" id=
365 "MACOSXACCOUNTDELETION">5.10. I just upgraded to Mac OS X 10.9
366 (Mavericks) and now <span class="APPLICATION">Privoxy</span> has
367 stopped working.</a></h3>
369 <p>The upgrade process to Mac OS X Mavericks (10.9) from an earlier
370 version of OS X deletes all user accounts that are either not part of
371 OS X itself or are not interactive user accounts (ones you log in
372 with). Since, for the sake of security, <span class=
373 "APPLICATION">Privoxy</span> runs as a non-privileged user that is
374 created by its installer (_privoxy), it can no longer start up once
375 that account gets deleted. The solution is to perform a complete
376 uninstall using the supplied <span class=
377 "APPLICATION">uninstall.command</span> script (either back up your
378 configuration files or select to not have the uninstaller remove them
379 when it prompts you) and then reinstall <span class=
380 "APPLICATION">Privoxy</span> using the installer package and merge in
381 your configuration.</p>
385 <h3 class="SECT2"><a name="NOHOSTNAME" id="NOHOSTNAME">5.11. My logs
386 show many <span class="QUOTE">"Unable to get my own hostname"</span>
389 <p><span class="APPLICATION">Privoxy</span> tries to get the hostname
390 of the system its running on from the IP address of the system
391 interface it is bound to (from the <tt class="FILENAME">config</tt>
392 file <span class="emphasis"><i class=
393 "EMPHASIS">listen-address</i></span> setting). If the system cannot
394 supply this information, <span class="APPLICATION">Privoxy</span> logs
397 <p>Typically, this would be considered a minor system configuration
398 error. It is not a fatal error to <span class=
399 "APPLICATION">Privoxy</span> however, but may result in a much slower
400 response from <span class="APPLICATION">Privoxy</span> on some
401 platforms due to DNS timeouts.</p>
403 <p>This can be caused by a problem with the local <tt class=
404 "FILENAME">hosts</tt> file. If this file has been changed from the
405 original, try reverting it to see if that helps. Make sure whatever
406 name(s) are used for the local system, that they resolve both ways.</p>
408 <p>You should also be able to work around the problem with the <a href=
409 "../user-manual/config.html#HOSTNAME" target="_top">hostname
414 <h3 class="SECT2"><a name="INUSE" id="INUSE">5.12. When I try to launch
415 Privoxy, I get an error message <span class="QUOTE">"port 8118 is
416 already in use"</span> (or similar wording). Why?</a></h3>
418 <p>Port 8118 is <span class="APPLICATION">Privoxy's</span> default TCP
419 <span class="QUOTE">"listening"</span> port. Typically this message
420 would mean that there is already one instance of <span class=
421 "APPLICATION">Privoxy</span> running, and your system is actually
422 trying to start a second <span class="APPLICATION">Privoxy</span> on
423 the same port, which will not work. (You can have multiple instances
424 but they must be assigned different ports.) How and why this might
425 happen varies from platform to platform, but you need to check your
426 installation and start-up procedures.</p>
430 <h3 class="SECT2"><a name="DEMORONIZER" id="DEMORONIZER">5.13. Pages
431 with UTF-8 fonts are garbled.</a></h3>
433 <p>This may be the result of an overly aggressive filter. The filters
434 that are enabled in the default configuration aren't expected to cause
435 problems like this. If you enabled the <span class=
436 "QUOTE">"demoronizer"</span> filter, please try temporarily disabling
439 <p>If that doesn't help, temporarily disable all filters to see if
440 another filter could be the culprit. If the problem disappears, enable
441 the filters one by one, until the problem reappears and the offending
444 <p>Once the problem-causing filter is known, it can be fixed or
447 <p>Upgrading <span class="APPLICATION">Privoxy</span>, or going to the
448 most recent <tt class="FILENAME">default.action</tt> file available
450 "https://sourceforge.net/project/showfiles.php?group_id=11118" target=
451 "_top">SourceForge</a> might be worth a try, too.</p>
455 <h3 class="SECT2"><a name="DEMORONIZER2" id="DEMORONIZER2">5.14. Why
456 are binary files (such as images) corrupted when Privoxy is
459 <p>This may also be caused by an (<a href=
460 "trouble.html#DEMORONIZER">overly aggressive filter</a> in conjunction
461 with a web server that is misreporting the content type. By default
462 binary files are exempted from <span class=
463 "APPLICATION">Privoxy's</span> filtering (unless the web server by
464 mistake says the file is something else).</p>
468 <h3 class="SECT2"><a name="DEMORONIZER3" id="DEMORONIZER3">5.15. What
469 is the <span class="QUOTE">"demoronizer"</span> and why is it
472 <p>The original demoronizer was a Perl script that cleaned up HTML
473 pages which were created with certain Microsoft products. MS has used
474 proprietary extensions to standardized font encodings (ISO 8859-1),
475 which has caused problems for pages that are viewed with non-Microsoft
476 products (and are expecting to see a standard set of fonts). The
477 demoronizer corrected these errors so the pages displayed correctly.
478 <span class="APPLICATION">Privoxy</span> borrowed from this script,
479 introducing a filter based on the original demoronizer, which in turn
480 could correct these errors on the fly.</p>
482 <p>But this is only needed in some situations, and will cause serious
483 problems in some other situations.</p>
485 <p>If you are using Microsoft products, you do not need it. If you need
486 to view pages with UTF-8 characters (such as Cyrillic or Chinese), then
487 it will cause corruption of the fonts, and thus <span class=
488 "emphasis"><i class="EMPHASIS">should not be on</i></span>.</p>
490 <p>On the other hand, if you use non-Microsoft products, and you
491 occasionally notice weird characters on pages, you might want to try
496 <h3 class="SECT2"><a name="WINDOWOPEN" id="WINDOWOPEN">5.16. Why do I
497 keep seeing <span class="QUOTE">"PrivoxyWindowOpen()"</span> in raw
498 source code?</a></h3>
500 <p><span class="APPLICATION">Privoxy</span> is attempting to disable
501 malicious <a href="http://en.wikipedia.org/wiki/Javascript" target=
502 "_top">Javascript</a> in this case, with the <tt class=
503 "LITERAL">unsolicited-popups</tt> filter. <span class=
504 "APPLICATION">Privoxy</span> cannot tell very well <span class=
505 "QUOTE">"good"</span> code snippets from <span class=
506 "QUOTE">"bad"</span> code snippets.</p>
508 <p>If you see this in HTML source, and the page displays without
509 problems, then this is good, and likely some pop-up window was
510 disabled. If you see this where it is causing a problem, such as a
511 downloaded program source code file, then you should set an exception
512 for this site or page such that the integrity of the page stays in tact
513 by disabling all filtering.</p>
517 <h3 class="SECT2"><a name="DNSERRORS" id="DNSERRORS">5.17. I am getting
518 too many DNS errors like <span class="QUOTE">"404 No Such
519 Domain"</span>. Why can't Privoxy do this better?</a></h3>
521 <p>There are potentially several factors here. First of all, the DNS
522 resolution is done by the underlying operating system -- not
523 <span class="APPLICATION">Privoxy</span> itself. <span class=
524 "APPLICATION">Privoxy</span> merely initiates the process and hands it
525 off, and then later reports whatever the outcome was and tries to give
526 a coherent message if there seems to be a problem. In some cases, this
527 might otherwise be mitigated by the browser itself which might try some
528 work-arounds and alternate approaches (e.g adding <span class=
529 "QUOTE">"www."</span> to the URL).</p>
531 <p>In other cases, if <span class="APPLICATION">Privoxy</span> is being
532 chained with another proxy, this could complicate the issue, and cause
533 undue delays and timeouts. In the case of a <span class=
534 "QUOTE">"socks4a"</span> proxy, the socks server handles all the DNS.
535 <span class="APPLICATION">Privoxy</span> would just be the <span class=
536 "QUOTE">"messenger"</span> which is reporting whatever problem occurred
537 downstream, and not the root cause of the error.</p>
539 <p>In any case, versions newer than 3.0.3 include various improvements
540 to help <span class="APPLICATION">Privoxy</span> better handle these
545 <h3 class="SECT2"><a name="ALLCPU" id="ALLCPU">5.18. At one site
546 Privoxy just hangs, and starts taking all CPU. Why is this?</a></h3>
548 <p>This is probably a manifestation of the <span class="QUOTE">"100%
549 cpu"</span> problem that occurs on pages containing many (thousands
550 upon thousands) of blank lines. The blank lines are in the raw HTML
551 source of the page, and the browser just ignores them. But the pattern
552 matching in <span class="APPLICATION">Privoxy's</span> page filtering
553 mechanism is trying to match against absurdly long strings and this
554 becomes very CPU-intensive, taking a long, long time to complete.</p>
556 <p>Until a better solution comes along, disable filtering on these
557 pages, particularly the <tt class="LITERAL">js-annoyances</tt> and
558 <tt class="LITERAL">unsolicited-popups</tt> filters. If you run into
559 this problem with a recent <span class="APPLICATION">Privoxy</span>
560 version, please send a problem report.</p>
564 <h3 class="SECT2"><a name="SLOWCRAWL" id="SLOWCRAWL">5.19. I just
565 installed Privoxy, and all my browsing has slowed to a crawl. What
568 <p>This should not happen, and for the overwhelming number of users
569 world-wide, it does not happen. I would suspect some inadvertent
570 interaction of software components such as anti-virus software, spyware
571 protectors, personal firewalls or similar components. Try disabling (or
572 uninstalling) these one at a time and see if that helps. Either way, if
573 you are using a recent <span class="APPLICATION">Privoxy</span>
574 version, please report the problem.</p>
578 <h3 class="SECT2"><a name="PREVENTCOMP" id="PREVENTCOMP">5.20. Why do
579 my filters work on some sites but not on others?</a></h3>
581 <p>It's probably due to compression. It is a common practice for web
582 servers to send their content <span class="QUOTE">"compressed"</span>
583 in order to speed things up, and then let the browser <span class=
584 "QUOTE">"uncompress"</span> them. When compiled with zlib support
585 <span class="APPLICATION">Privoxy</span> can decompress content before
586 filtering, otherwise you may want to enable <a href=
587 "../user-manual/actions-file.html#PREVENT-COMPRESSION" target=
588 "_top">prevent-compression</a>.</p>
590 <p>As of <span class="APPLICATION">Privoxy</span> 3.0.9, zlib support
591 is enabled in the default builds.</p>
595 <h3 class="SECT2"><a name="SSL-WARNINGS" id="SSL-WARNINGS">5.21. On
596 some HTTPS sites my browser warns me about unauthenticated content, the
597 URL bar doesn't get highlighted and the lock symbol appears to be
598 broken. What's going on?</a></h3>
600 <p>Probably the browser is requesting ads through HTTPS and
601 <span class="APPLICATION">Privoxy</span> is blocking the requests.
602 Privoxy's error messages are delivered unencrypted and while it's
603 obvious for the browser that the HTTPS request is already blocked by
604 the proxy, some warn about unauthenticated content anyway.</p>
606 <p>To work around the problem you can redirect those requests to an
607 invalid local address instead of blocking them. While the redirects
608 aren't encrypted either, many browsers don't care. They simply follow
609 the redirect, fail to reach a server and display an error message
610 instead of the ad.</p>
612 <p>To do that, enable logging to figure out which requests get blocked
613 by <span class="APPLICATION">Privoxy</span> and add the hosts (no path
614 patterns) to a section like this:</p>
616 <table border="0" bgcolor="#E0E0E0" width="100%">
620 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
627 <p>Additionally you have to configure your browser to contact
628 <span class="QUOTE">"127.0.0.1:0"</span> directly (instead of through
629 <span class="APPLICATION">Privoxy</span>).</p>
631 <p>To add a proxy exception in <span class="APPLICATION">Mozilla
632 Firefox</span> open the <span class="QUOTE">"Preferences"</span>, click
633 the <span class="QUOTE">"Settings"</span> button located on the
634 <span class="QUOTE">"Network"</span> tab in the <span class=
635 "QUOTE">"Advanced"</span> section, and add <span class=
636 "QUOTE">"127.0.0.1:0"</span> in the <span class="QUOTE">"No Proxy
637 for:"</span> field.</p>
641 <h3 class="SECT2"><a name="SE-LINUX" id="SE-LINUX">5.22. I get selinux
642 error messages. How can I fix this?</a></h3>
644 <p>Please report the problem to the creator of your selinux
647 <p>The problem is that some selinux policy writers aren't familiar with
648 the application they are trying to <span class="QUOTE">"secure"</span>
649 and thus create policies that make no sense.</p>
651 <p>In <span class="APPLICATION">Privoxy's</span> case the problem
652 usually is that the policy only allows outgoing connections for certain
653 destination ports (e.g. 80 and 443). While this may cover the standard
654 ports, websites occasionally use other ports as well. This isn't a
655 security problem and therefore <span class=
656 "APPLICATION">Privoxy's</span> default configuration doesn't block
659 <p>If you really want to block these ports (and don't be able to load
660 websites that don't use standard ports), you should configure Privoxy
661 to block these ports as well, so it doesn't trigger the selinux
666 <h3 class="SECT2"><a name="GENTOO-RICERS" id="GENTOO-RICERS">5.23. I
667 compiled <span class="APPLICATION">Privoxy</span> with Gentoo's portage
668 and it appears to be very slow. Why?</a></h3>
670 <p>Probably you unintentionally compiled <span class=
671 "APPLICATION">Privoxy</span> without threading support in which case
672 requests have to be serialized and only one can be served at the same
675 <p>Check your <span class="QUOTE">"USE"</span> flags and make sure they
676 include <span class="QUOTE">"threads"</span>. If they don't, add the
677 flag and rebuild <span class="APPLICATION">Privoxy</span>.</p>
679 <p>If you compiled <span class="APPLICATION">Privoxy</span> with
680 threading support (on POSIX-based systems), the <span class=
681 "QUOTE">"Conditional #defines"</span> section on <a href=
682 "http://config.privoxy.org/show-status" target=
683 "_top">http://config.privoxy.org/show-status</a> will list <span class=
684 "QUOTE">"FEATURE_PTHREAD"</span> as <span class=
685 "QUOTE">"enabled"</span>.</p>
689 <h3 class="SECT2"><a name="TAINTED-SOCKETS" id="TAINTED-SOCKETS">5.24.
690 What are tainted sockets and how do I prevent them?</a></h3>
692 <p><span class="APPLICATION">Privoxy</span> marks sockets as tainted
693 when it can't use them to serve additional requests. This does not
694 necessarily mean that something went wrong and information about
695 tainted sockets is only logged if connection debugging is enabled
698 <p>For example server sockets that were used for CONNECT requests
699 (which are used to tunnel https:// requests) are considered tainted
700 once the client closed its connection to <span class=
701 "APPLICATION">Privoxy</span>. Technically <span class=
702 "APPLICATION">Privoxy</span> could keep the connection to the server
703 open, but the server would not accept requests that do not belong to
704 the previous TLS/SSL session (and the client may even have terminated
707 <p>Server sockets are also marked tainted when a client requests a
708 resource, but closes the connection before <span class=
709 "APPLICATION">Privoxy</span> has completely received (and forwarded)
710 the resource to the client. In this case the server would (probably)
711 accept additional requests, but <span class=
712 "APPLICATION">Privoxy</span> could not get the response without
713 completely reading the leftovers from the previous response.</p>
715 <p>These are just two examples, there are currently a bit more than 25
716 scenarios in which a socket is considered tainted.</p>
718 <p>While sockets can also be marked tainted as a result of a technical
719 problem that may be worth fixing, the problem will be explicitly logged
724 <h3 class="SECT2"><a name="PCRE-STACK-LIMIT" id=
725 "PCRE-STACK-LIMIT">5.25. After adding my custom filters, <span class=
726 "APPLICATION">Privoxy</span> crashes when visitting certain
729 <p>This can happen if your custom filters require more memory than
730 <span class="APPLICATION">Privoxy</span> is allowed to use. Usually the
731 problem is that the operating system enforces a stack size limit that
732 isn't sufficient.</p>
734 <p>Unless the problem occurs with the filters available in the default
735 configuration, this is not considered a Privoxy bug.</p>
737 <p>To prevent the crashes you can rewrite your filter to use less
738 ressources, increase the relevant memory limit or recompile pcre to use
739 less stack space. For details please see the <a href=
740 "http://pcre.org/original/doc/html/pcrestack.html" target=
741 "_top">pcrestack man page</a> and the documentation of your operating
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