X-Git-Url: http://www.privoxy.org/gitweb/?a=blobdiff_plain;f=doc%2Fwebserver%2Ffaq%2Ftrouble.html;h=cab801a3ddbc05171d309d20b0e5e58726cbbf2f;hb=dc80a8219d68d1e25821219e0b3b5bcda5bae21e;hp=3fda0abff2c28afa128a0c0c8c018e820e6f7915;hpb=eaaad8fd2d3492c403ccf79a92ceff682bae6799;p=privoxy.git diff --git a/doc/webserver/faq/trouble.html b/doc/webserver/faq/trouble.html index 3fda0abf..cab801a3 100644 --- a/doc/webserver/faq/trouble.html +++ b/doc/webserver/faq/trouble.html @@ -1,239 +1,143 @@ - -
There are several possibilities:
Privoxy is not running. Solution: verify - that Privoxy is installed correctly, has not crashed, and is indeed running. - Turn on Privoxy's logging, and look at the logs to see what they say.
Or your browser is configured for a different port than what - Privoxy is using. Solution: verify that Privoxy - and your browser are set to the same port (listen-address).
Or if using a forwarding rule, you have a configuration problem or a - problem with a host in the forwarding chain. Solution: temporarily alter your - configuration and take the forwarders out of the equation.
Or you have a firewall that is interfering and blocking you. Solution: - try disabling or removing the firewall as a simple test. -
More than likely this is a problem with your TCP/IP networking. ZoneAlarm has - been reported to cause this symptom -- even if not running! The solution is - to either fight the ZA configuration, or uninstall ZoneAlarm, and then find - something better behaved in its place. Other personal firewall type products - may cause similar type problems if not configured correctly. -
If the ad had been displayed before you added its URL, it will probably be - held in the browser's cache for some time, so it will be displayed without - the need for any request to the server, and Privoxy - will not be involved. Flush the browser's caches, and then try again.
If this doesn't help, you probably have an error in the rule you - applied. Try pasting the full URL of the offending ad into http://config.privoxy.org/show-url-info - and see if it really matches your new rule. Blocking ads is like blocking - spam: a lot of tinkering is required to stay ahead of the game. And - remember you need to block the URL of the ad in question, which may be - entirely different from the site URL itself. Most ads are hosted on different - servers than the main site itself. If you right-click on the ad, you should - be able to get all the relevant information you need. Alternately, you can - find the correct URL by looking at Privoxy's logs - (you may need to enable logging in the main config file if its disabled).
Below is a slightly modified real-life log snippet that originates with one - requested URL: www.example.com (name of site was changed - for this example, the number of requests is real). You can see in this the - complexity of what goes into making up this one "page". There - are eight different domains involved here, with thirty two separate URLs - requested in all, making up all manner of images, Shockwave Flash, - JavaScript, CSS stylesheets, scripts, and other related content. Some of this - content is obviously "good" or "bad", but not all. - Many of the more questionable looking requests, are going to outside domains - that seem to be identifying themselves with suspicious looking names, making - our job a little easier. Privoxy has "crunched" (meaning caught - and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
Request: www.example.com/ + + + + ++ |
+
Despite 12 out of 32 requests being blocked, the page looked, and + seemed to behave perfectly "normal" (minus + some ads, of course).
+First verify that it is indeed a Privoxy problem, by toggling off Privoxy through http://config.privoxy.org/toggle (the toggle feature may + need to be enabled in the main config), and + then shift-reloading the problem page (i.e. holding down the shift key + while clicking reload. Alternatively, flush your browser's disk and + memory caches).
+ +If the problem went away, we know we have a configuration related + problem. Now go to http://config.privoxy.org/show-url-info and paste the + full URL of the page in question into the prompt. See which actions are + being applied to the URL, and which matches in which actions files are + responsible for that. It might be helpful also to look at your logs for + this site too, to see what else might be happening (note: logging may + need to be enabled in the main config file). Many sites are complex and + require a number of related pages to help present their content. Look + at what else might be used by the page in question, and what of that + might be required. Now, armed with this information, go to + http://config.privoxy.org/show-status and select the + appropriate actions files for editing.
+ +You can now either look for a section which disables the actions + that you suspect to cause the problem and add a pattern for your site + there, or make up a completely new section for your site. In any case, + the recommended way is to disable only the prime suspect, reload the + problem page, and only if the problem persists, disable more and more + actions until you have identified the culprit. You may or may not want + to turn the other actions on again. Remember to flush your browser's + caches in between any such changes!
+ +Alternately, if you are comfortable with a text editor, you can + accomplish the same thing by editing the appropriate actions file. + Probably the easiest way to deal with such problems when editing by + hand is to add your site to a { fragile } + section in user.action, which is an alias + that turns off most "dangerous" actions, but + is also likely to turn off more actions then needed, and thus lower + your privacy and protection more than necessary,
+ +Troubleshooting actions is discussed in more detail in the User Manual + appendix, Troubleshooting: the Anatomy of an Action. There is also + an actions tutorial with general configuration information and + examples.
+ +As a last resort, you can always see if your browser has a setting + that will bypass the proxy setting for selective sites. Modern browsers + can do this.
+This is a quirk that affects the installation of Privoxy, in conjunction with Internet Explorer and + Internet Connection Sharing on Windows 2000 and Windows XP. The + symptoms may appear to be corrupted or invalid DUN settings, or + passwords.
+ +When setting up an NT based Windows system with Privoxy you may find that things do not seem to be + doing what you expect. When you set your system up you will probably + have set up Internet Connection Sharing (ICS) with Dial up Networking + (DUN) when logged in with administrator privileges. You will probably + have made this DUN connection available to other accounts that you may + have set-up on your system. E.g. Mum or Dad sets up the system and + makes accounts suitably configured for the kids.
+ +When setting up Privoxy in this + environment you will have to alter the proxy set-up of Internet + Explorer (IE) for the specific DUN connection on which you wish to use + Privoxy. When you do this the ICS DUN + set-up becomes user specific. In this instance you will see no + difference if you change the DUN connection under the account used to + set-up the connection. However when you do this from another user you + will notice that the DUN connection changes to make available to "Me + only". You will also find that you have to store the password under + each different user!
+ +The reason for this is that each user's set-up for IE is user + specific. Each set-up DUN connection and each LAN connection in IE + store the settings for each user individually. As such this enforces + individual configurations rather than common ones. Hence the first time + you use a DUN connection after re-booting your system it may not + perform as you expect, and prompt you for the password. Just set and + save the password again and all should be OK.
+ +[Thanks to Ray Griffith for this submission.]
+Privoxy cannot act as a proxy for + FTP traffic, so do not configure your browser to use Privoxy as an FTP proxy. The same is true for + any protocol other than HTTP + or HTTPS (SSL).
+ +Most browsers understand FTP as well as HTTP. If you connect to a + site, with a URL like ftp://ftp.example.com, + your browser is making an FTP connection, and not a HTTP connection. So + while your browser may speak FTP, Privoxy does not, and cannot proxy such + traffic.
+ +To complicate matters, some systems may have a generic "proxy" setting, which will enable various protocols, + including both + HTTP and FTP proxying! So it is possible to accidentally enable FTP + proxying in these cases. And of course, if this happens, Privoxy will indeed cause problems since it does + not know FTP. Newer version will give a sane error message if a FTP + connection is attempted. Just disable the FTP setting and all will be + well again.
+ +Will Privoxy ever proxy FTP + traffic? Unlikely. There just is not much reason, and the work to make + this happen is more than it may seem.
+Microsoft Internet Explorer (in versions like 5.1) respects + system-wide network settings. In order to change the HTTP proxy, open + System Preferences, and click on the Network icon. In the settings pane + that comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" + checkbox is checked and enter 127.0.0.1 in the + entry field. Enter 8118 in the Port field. The + next time you start IE, it should reflect these values.
+Note: This ONLY applies to privoxy 3.0.6 and earlier.
+ +Just dragging the Privoxy folder to + the trash is not enough to delete it. Privoxy supplies an uninstall.command file that takes care of these + details. Open the trash, drag the uninstall.command file out of the trash and + double-click on it. You will be prompted for confirmation and the + administration password.
+ +The trash may still appear full after this command; emptying the + trash from the desktop should make it appear empty again.
+We believe this is due to an IPv6-related bug in Mac OS X, but don't + fully understand the issue yet. In any case, changing the proxy setting + to 127.0.0.1 instead of localhost works around the problem.
+The upgrade process to Mac OS X Mavericks (10.9) from an earlier + version of OS X deletes all user accounts that are either not part of + OS X itself or are not interactive user accounts (ones you log in + with). Since, for the sake of security, Privoxy runs as a non-privileged user that is + created by its installer (_privoxy), it can no longer start up once + that account gets deleted. The solution is to perform a complete + uninstall using the supplied uninstall.command script (either back up your + configuration files or select to not have the uninstaller remove them + when it prompts you) and then reinstall Privoxy using the installer package and merge in + your configuration.
+Chances are that the site suffers from a bug in PHP, which results in empty pages being sent + if the client explicitly requests an uncompressed page, like + Privoxy does. This bug has been fixed + in PHP 4.2.3.
+ +To find out if this is in fact the source of the problem, try adding + the site to a -prevent-compression section in + user.action:
+ +
+ + # Make exceptions for ill-behaved sites: + # + {-prevent-compression} + .example.com ++ |
+
If that works, you may also want to report the problem to the site's + webmasters, telling them to use zlib.output_compression instead of + ob_gzhandler in their PHP applications (workaround) or upgrade to PHP + 4.2.3 or later (fix).
+Privoxy tries to get the hostname + of the system its running on from the IP address of the system + interface it is bound to (from the config + file listen-address setting). If the system cannot + supply this information, Privoxy logs + this condition.
+ +Typically, this would be considered a minor system configuration + error. It is not a fatal error to Privoxy however, but may result in a much slower + response from Privoxy on some + platforms due to DNS timeouts.
+ +This can be caused by a problem with the local hosts file. If this file has been changed from the + original, try reverting it to see if that helps. Make sure whatever + name(s) are used for the local system, that they resolve both ways.
+ +You should also be able to work around the problem with the hostname + option.
+Port 8118 is Privoxy's default TCP + "listening" port. Typically this message + would mean that there is already one instance of Privoxy running, and your system is actually + trying to start a second Privoxy on + the same port, which will not work. (You can have multiple instances + but they must be assigned different ports.) How and why this might + happen varies from platform to platform, but you need to check your + installation and start-up procedures.
+This may be the result of an overly aggressive filter. The filters + that are enabled in the default configuration aren't expected to cause + problems like this. If you enabled the "demoronizer" filter, please try temporarily disabling + it.
+ +If that doesn't help, temporarily disable all filters to see if + another filter could be the culprit. If the problem disappears, enable + the filters one by one, until the problem reappears and the offending + filter is found.
+ +Once the problem-causing filter is known, it can be fixed or + disabled.
+ +Upgrading Privoxy, or going to the + most recent default.action file available + from SourceForge might be worth a try, too.
+This may also be caused by an (overly aggressive filter in conjunction + with a web server that is misreporting the content type. By default + binary files are exempted from Privoxy's filtering (unless the web server by + mistake says the file is something else).
+The original demoronizer was a Perl script that cleaned up HTML + pages which were created with certain Microsoft products. MS has used + proprietary extensions to standardized font encodings (ISO 8859-1), + which has caused problems for pages that are viewed with non-Microsoft + products (and are expecting to see a standard set of fonts). The + demoronizer corrected these errors so the pages displayed correctly. + Privoxy borrowed from this script, + introducing a filter based on the original demoronizer, which in turn + could correct these errors on the fly.
+ +But this is only needed in some situations, and will cause serious + problems in some other situations.
+ +If you are using Microsoft products, you do not need it. If you need + to view pages with UTF-8 characters (such as Cyrillic or Chinese), then + it will cause corruption of the fonts, and thus should not be on.
+ +On the other hand, if you use non-Microsoft products, and you + occasionally notice weird characters on pages, you might want to try + it.
+Privoxy is attempting to disable + malicious Javascript in this case, with the unsolicited-popups filter. Privoxy cannot tell very well "good" code snippets from "bad" code snippets.
+ +If you see this in HTML source, and the page displays without + problems, then this is good, and likely some pop-up window was + disabled. If you see this where it is causing a problem, such as a + downloaded program source code file, then you should set an exception + for this site or page such that the integrity of the page stays in tact + by disabling all filtering.
+There are potentially several factors here. First of all, the DNS + resolution is done by the underlying operating system -- not + Privoxy itself. Privoxy merely initiates the process and hands it + off, and then later reports whatever the outcome was and tries to give + a coherent message if there seems to be a problem. In some cases, this + might otherwise be mitigated by the browser itself which might try some + work-arounds and alternate approaches (e.g adding "www." to the URL).
+ +In other cases, if Privoxy is being + chained with another proxy, this could complicate the issue, and cause + undue delays and timeouts. In the case of a "socks4a" proxy, the socks server handles all the DNS. + Privoxy would just be the "messenger" which is reporting whatever problem occurred + downstream, and not the root cause of the error.
+ +In any case, versions newer than 3.0.3 include various improvements + to help Privoxy better handle these + cases.
+This is probably a manifestation of the "100% + cpu" problem that occurs on pages containing many (thousands + upon thousands) of blank lines. The blank lines are in the raw HTML + source of the page, and the browser just ignores them. But the pattern + matching in Privoxy's page filtering + mechanism is trying to match against absurdly long strings and this + becomes very CPU-intensive, taking a long, long time to complete.
+ +Until a better solution comes along, disable filtering on these + pages, particularly the js-annoyances and + unsolicited-popups filters. If you run into + this problem with a recent Privoxy + version, please send a problem report.
+This should not happen, and for the overwhelming number of users + world-wide, it does not happen. I would suspect some inadvertent + interaction of software components such as anti-virus software, spyware + protectors, personal firewalls or similar components. Try disabling (or + uninstalling) these one at a time and see if that helps. Either way, if + you are using a recent Privoxy + version, please report the problem.
+It's probably due to compression. It is a common practice for web + servers to send their content "compressed" + in order to speed things up, and then let the browser "uncompress" them. When compiled with zlib support + Privoxy can decompress content before + filtering, otherwise you may want to enable prevent-compression.
+ +As of Privoxy 3.0.9, zlib support + is enabled in the default builds.
+Probably the browser is requesting ads through HTTPS and + Privoxy is blocking the requests. + Privoxy's error messages are delivered unencrypted and while it's + obvious for the browser that the HTTPS request is already blocked by + the proxy, some warn about unauthenticated content anyway.
+ +To work around the problem you can redirect those requests to an + invalid local address instead of blocking them. While the redirects + aren't encrypted either, many browsers don't care. They simply follow + the redirect, fail to reach a server and display an error message + instead of the ad.
+ +To do that, enable logging to figure out which requests get blocked + by Privoxy and add the hosts (no path + patterns) to a section like this:
+ +
+ +{+redirect{http://127.0.0.1:0/} -block -limit-connect} +.ivwbox.de:443/ ++ |
+
Additionally you have to configure your browser to contact + "127.0.0.1:0" directly (instead of through + Privoxy).
+ +To add a proxy exception in Mozilla + Firefox open the "Preferences", click + the "Settings" button located on the + "Network" tab in the "Advanced" section, and add "127.0.0.1:0" in the "No Proxy + for:" field.
+Please report the problem to the creator of your selinux + policies.
+ +The problem is that some selinux policy writers aren't familiar with + the application they are trying to "secure" + and thus create policies that make no sense.
+ +In Privoxy's case the problem + usually is that the policy only allows outgoing connections for certain + destination ports (e.g. 80 and 443). While this may cover the standard + ports, websites occasionally use other ports as well. This isn't a + security problem and therefore Privoxy's default configuration doesn't block + these requests.
+ +If you really want to block these ports (and don't be able to load + websites that don't use standard ports), you should configure Privoxy + to block these ports as well, so it doesn't trigger the selinux + warnings.
+Probably you unintentionally compiled Privoxy without threading support in which case + requests have to be serialized and only one can be served at the same + time.
+ +Check your "USE" flags and make sure they + include "threads". If they don't, add the + flag and rebuild Privoxy.
+ +If you compiled Privoxy with + threading support (on POSIX-based systems), the "Conditional #defines" section on http://config.privoxy.org/show-status will list "FEATURE_PTHREAD" as "enabled".
+