Troubleshooting

Troubleshooting
Privoxy Frequently Asked Questions
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5. Troubleshooting
5.1. I cannot connect to any websites. Or, I am getting
"connection refused"
message with every web page. Why?
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.
5.2. Why am I getting a 503 Error (WSAECONNREFUSED) on every
page?
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.
5.3. I just added a new rule, but the steenkin ad is still
getting through. How?
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
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/
Request: www.example.com/favicon.ico
Request: img.example.com/main.css
Request: img.example.com/sr.js
Request: example.betamarker.com/example.html
Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
Request: img.example.com/pb.png
Request: www.google-analytics.com/urchin.js crunch! (Blocked)
Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
Request: img.example.com/p.gif
Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
Request: www.adtrak.net/adx.js crunch! (Blocked)
Request: img.example.com/hbg.gif
Request: img.example.com/example.jpg
Request: img.example.com/mt.png
Request: img.example.com/mm.png
Request: img.example.com/mb.png
Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
Request: www.example.com/tracker.js
Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
Request: 66.70.21.80/img/pixel.gif
Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
Despite 12 out of 32 requests being blocked, the page looked, and seemed to behave perfectly
"normal"
(minus some ads, of course).
5.4. One of my favorite sites does not work with Privoxy. What
can I do?
First verify that it is indeed a
Privoxy
problem, by toggling off
Privoxy
through
(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
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
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.
5.5. After installing Privoxy, I have to log in every time I start IE.
What gives?
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.]
5.6. I cannot connect to any FTP sites. Privoxy is blocking me.
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.
5.7. In Mac OS X, I can't configure Microsoft Internet
Explorer to use Privoxy as the HTTP proxy.
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.
5.8. In Mac OS X, I dragged the Privoxy folder
to the trash in order to uninstall it. Now the finder tells me I don't have sufficient privileges to empty the
trash.
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.
5.9. In Mac OS X Panther (10.3), images often fail to
load and/or I experience random delays in page loading. I'm using
localhost
as my
browser's proxy setting.
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.
5.10. I just upgraded to Mac OS X
10.9 (Mavericks) and now
Privoxy
has stopped working.
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.
5.11. My logs show many
"Unable to get
my own hostname"
lines. Why?
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
5.12. When I try to launch Privoxy, I get an error message
"port 8118 is already in use"
(or similar wording). Why?
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.
5.13. Pages with UTF-8 fonts are garbled.
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
git
might be worth a try, too.
5.14. Why are binary files (such as images) corrupted
when Privoxy is used?
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).
5.15. What is the
"demoronizer"
and why is it there?
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.
5.16. Why do I keep seeing
"PrivoxyWindowOpen()"
in raw source code?
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.
5.17. I am getting too many DNS errors like
"404 No Such Domain"
. Why can't Privoxy do this better?
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.
5.18. At one site Privoxy just hangs, and starts taking all CPU.
Why is this?
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.
5.19. I just installed Privoxy, and all my browsing has
slowed to a crawl. What gives?
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.
5.20. Why do my filters work on some sites but not on
others?
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.
5.21. On some HTTPS sites my browser warns me about
unauthenticated content, the URL bar doesn't get highlighted and the lock symbol appears to be broken. What's
going on?
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.
You can also prevent the problem by enabling
https-inspection
in which case Privoxy's error messages are delivered encrypted.
5.22. I get selinux error messages. How can I fix
this?
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.
5.23. I compiled
Privoxy
with Gentoo's portage and it appears to be very slow. Why?
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
will list
"FEATURE_PTHREAD"
as
"enabled"
5.24. What are tainted sockets and how do I
prevent them?
Privoxy
marks sockets as tainted when it can't use them to serve additional
requests. This does not necessarily mean that something went wrong and information about tainted sockets is only
logged if connection debugging is enabled (debug 2).
For example server sockets that were used for CONNECT requests (which are used to tunnel https:// requests)
are considered tainted once the client closed its connection to
Privoxy
Technically
Privoxy
could keep the connection to the server open, but the server
would not accept requests that do not belong to the previous TLS/SSL session (and the client may even have
terminated the session).
Server sockets are also marked tainted when a client requests a resource, but closes the connection before
Privoxy
has completely received (and forwarded) the resource to the client. In
this case the server would (probably) accept additional requests, but
Privoxy
could not get the response without completely reading the leftovers from the previous response.
These are just two examples, there are currently a bit more than 25 scenarios in which a socket is considered
tainted.
While sockets can also be marked tainted as a result of a technical problem that may be worth fixing, the
problem will be explicitly logged as error.
5.25. After adding my custom filters,
Privoxy
crashes when visitting certain websites
This can happen if your custom filters require more memory than
Privoxy
is
allowed to use. Usually the problem is that the operating system enforces a stack size limit that isn't
sufficient.
Unless the problem occurs with the filters available in the default configuration, this is not considered a
Privoxy bug.
To prevent the crashes you can rewrite your filter to use less resources, increase the relevant memory limit
or recompile pcre to use less stack space. For details please see the
pcrestack man page
and the documentation of
your operating system.
5.26. What to do if editing the config file of
privoxy is access denied?
Your userid probably isn't allowed to edit the file. On Windows you can use the windows equivalent of
sudo:
runas /user:administrator "notepad \privoxy\config.txt"
or fix the file permissions:
C:\Privoxy>icacls config.txt
config.txt BUILTIN\Administrators:(I)(F)
NT AUTHORITY\SYSTEM:(I)(F)
BUILTIN\Users:(I)(RX)
NT AUTHORITY\Authenticated Users:(I)(M)

Successfully processed 1 files; Failed processing 0 files

C:\Privoxy>icacls config.txt /grant Lee:F
processed file: config.txt
Successfully processed 1 files; Failed processing 0 files

C:\Privoxy>icacls config.txt
config.txt I3668\Lee:(F)
BUILTIN\Administrators:(I)(F)
NT AUTHORITY\SYSTEM:(I)(F)
BUILTIN\Users:(I)(RX)
NT AUTHORITY\Authenticated Users:(I)(M)

Successfully processed 1 files; Failed processing 0 files

C:\Privoxy>
or try to point-n-click your way through adjusting the file permissions in windows explorer.
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