X-Git-Url: http://www.privoxy.org/gitweb/?p=privoxy.git;a=blobdiff_plain;f=doc%2Fwebserver%2Ffaq%2Fconfiguration.html;h=b9f387004519a659a4cee856728a7135b0e7718c;hp=3f1c67a0b5941056539a8c774d687685a8f5c1f5;hb=3e837e6e9561de90b1db799199f8036977cb36b0;hpb=6de6bda5b29cbb5a8aef6863c1b5ca999ab4887b diff --git a/doc/webserver/faq/configuration.html b/doc/webserver/faq/configuration.html index 3f1c67a0..b9f38700 100644 --- a/doc/webserver/faq/configuration.html +++ b/doc/webserver/faq/configuration.html @@ -1,754 +1,1757 @@ - - - - Configuration - - - - - - - - - -
-

3. - Configuration

-
-

3.1. What - exactly is an "actions" file?

-

Privoxy utilizes the concept of - " actions" that are used to manipulate and control web - page data. Actions files are where these actions - that Privoxy could take while - processing a certain request, are configured. Typically, you would - define a set of default actions that apply globally to all URLs, then - add exceptions to these defaults where needed. There is a wide array of - actions available that give the user a high degree of control and - flexibility on how to process each and every web page.

-

Actions can be defined on a URL - pattern basis, i.e. for single URLs, whole web sites, groups or - parts thereof etc. Actions can also be grouped together and then - applied to requests matching one or more patterns. There are many - possible actions that might apply to any given site. As an example, if - you are blocking cookies as one of your default actions, but need to - accept cookies from a given site, you would need to define an exception - for this site in one of your actions files, preferably in user.action.

-
-
-

3.2. The - "actions" concept confuses me. Please list - some of these "actions".

-

For a comprehensive discussion of the actions concept, please refer - to the actions - file chapter in the User Manual. It includes a list of all - actions and an actions - file tutorial to get you started.

-
-
-

3.3. How are - actions files configured? What is the easiest way to do this?

-

Actions files are just text files in a special syntax and can be - edited with a text editor. But probably the easiest way is to access - Privoxy's user interface with your web - browser at http://config.privoxy.org/ (Shortcut: http://p.p/) and then select "View & change the current configuration" from the - menu. Note that this feature must be explicitly enabled in the main - config file (see enable-edit-actions).

-
-
-

3.4. There are several - different "actions" files. What are the - differences?

-

Please have a look at the the actions chapter in the User Manual for a - detailed explanation.

-
-
-

3.5. Where can I - get updated Actions Files?

-

Based on your feedback and the continuing development, updates of - default.action will be made available from - time to time on the files section of our project - page.

-

If you wish to receive an email notification whenever we release - updates of Privoxy or the actions - file, subscribe to our announce mailing list, - privoxy-announce@lists.privoxy.org.

-
-
-

3.6. Can I use my - old config files?

-

The syntax and purpose of configuration files has remained roughly - the same throughout the 3.x series, but backwards compatibility is not - guaranteed. Also each release contains updated, "improved" versions and it is therefore strongly - recommended to install the newer configuration files and merge back - your modifications.

-
-
-

3.7. Why is the - configuration so complicated?

-

"Complicated" is in the eye of the - beholder.

-

Privoxy is currently mainly written by and for people who are - already familiar with the underlying concepts like regular expressions, - HTTP and HTML, or are willing to become familiar with them to be able - to get the most out of a powerful and flexible tool such as - Privoxy.

-

While everybody is expected to be able to get a Privoxy default - installation up and running, fine-tuning requires a certain amount of - background information and Privoxy's documentation mainly concentrates - on the Privoxy-specific parts while only providing references to the - rest.

-

If you or anyone you know has the skills, time and energy to reduce - the barrier of entry, please get - involved.

-
-
-

3.8. How can I make my - Yahoo/Hotmail/Gmail account work?

-

The default configuration shouldn't impact the usability of any of - these services. It may, however, make all cookies - temporary, so that your browser will forget your login credentials in - between browser sessions. If you would like not to have to log in - manually each time you access those websites, simply turn off all - cookie handling for them in the user.action - file. An example for yahoo might look like:

- - -
-
# Allow all cookies for Yahoo login:
+
+Configuration
Privoxy Frequently Asked Questions
PrevNext

3. Configuration

3.1. What exactly is an "actions" file?

Privoxy utilizes the concept of " actions" + that are used to manipulate and control web page data. + Actions files + are where these actions + that Privoxy could take while processing a certain + request, are configured. Typically, you would define a set of default actions + that apply globally to all URLs, then add exceptions to these defaults where needed. + There is a wide array of actions available that give the user a high degree + of control and flexibility on how to process each and every web page.

Actions can be defined on a URL pattern basis, i.e. + for single URLs, whole web sites, groups or parts thereof etc. Actions can also be + grouped together and then applied to requests matching one or more patterns. + There are many possible actions that might apply to any given site. As an example, + if you are blocking cookies + as one of your default actions, but need to accept cookies from a given site, + you would need to define an exception for this site in one of your actions + files, preferably in user.action.

3.2. The "actions" concept confuses me. Please list +some of these "actions".

For a comprehensive discussion of the actions concept, please refer + to the actions file + chapter in the User + Manual. It includes a list of all actions + and an actions + file tutorial to get you started.

3.3. How are actions files configured? What is the easiest +way to do this?

Actions files are just text files in a special syntax and can be edited + with a text editor. But probably the easiest way is to access + Privoxy's user interface with your web browser + at http://config.privoxy.org/ + (Shortcut: http://p.p/) and then select + "View & + change the current configuration" from the menu. Note + that this feature must be explicitly enabled in the main config file + (see enable-edit-actions).

3.5. Where can I get updated Actions Files?

Based on your feedback and the continuing development, updates of + default.action will be + made available from time to time on the files section of + our project page. +

If you wish to receive an email notification whenever we release updates of + Privoxy or the actions file, subscribe + to our announce mailing list, privoxy-announce@lists.privoxy.org. +

3.6. Can I use my old config files?

The syntax and purpose of configuration files has remained roughly the + same throughout the 3.x series, but backwards compatibility is not guaranteed. + Also each release contains updated, "improved" versions and it is + therefore strongly recommended to install the newer configuration files + and merge back your modifications. +

3.7. Why is the configuration so complicated?

"Complicated" is in the eye of the beholder. +

Privoxy is currently mainly written by and for people who are already + familiar with the underlying concepts like regular expressions, HTTP and HTML, + or are willing to become familiar with them to be able to get the most + out of a powerful and flexible tool such as Privoxy. +

While everybody is expected to be able to get a Privoxy default installation + up and running, fine-tuning requires a certain amount of background + information and Privoxy's documentation mainly concentrates on the + Privoxy-specific parts while only providing references to the rest. +

If you or anyone you know has the skills, time and energy to + reduce the barrier of entry, please get involved. +

3.8. How can I make my Yahoo/Hotmail/Gmail account work?

The default configuration shouldn't impact the usability of any of these services. + It may, however, make all cookies + temporary, so that your browser will forget your + login credentials in between browser sessions. If you would like not to have to log + in manually each time you access those websites, simply turn off all cookie handling + for them in the user.action file. An example for yahoo might + look like: +

- -
# Allow all cookies for Yahoo login:
 #
-{ -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only }
-.login.yahoo.com
-
-

These kinds of sites are often quite complex and heavy with Javascript - and thus "fragile". So if still a problem, we have an - alias just for such sticky situations:

- - -
-
# Gmail is a _fragile_ site:
+{ -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only }
+.login.yahoo.com

These kinds of sites are often quite complex and heavy with + Javascript and + thus "fragile". So if still a problem, + we have an alias just for such + sticky situations: +

- -
# Gmail is a _fragile_ site:
 #
-{ fragile }
+{ fragile }
  # Gmail is ...
- mail.google.com
-
-

Be sure to flush your browser's caches whenever making these kinds - of changes, just to make sure the changes "take".

-

Make sure the domain, host and path are appropriate as well. Your - browser can tell you where you are specifically and you should use that - information for your configuration settings. Note that above it is not - referenced as gmail.com, which is a valid - domain name.

-
-
-

3.9. What's - the difference between the "Cautious", - "Medium" and "Advanced" defaults?

-

Configuring Privoxy is not entirely - trivial. To help you get started, we provide you with three different - default action "profiles" in the web based - actions file editor at http://config.privoxy.org/show-status. See the - User Manual for a list of actions, and how the - default profiles are set.

-

Where the defaults are likely to break some sites, exceptions for - known popular "problem" sites are included, - but in general, the more aggressive your default settings are, the more - exceptions you will have to make later. New users are best to start off - in "Cautious" setting. This is safest and - will have the fewest problems. See the User - Manual for a more detailed discussion.

-

It should be noted that the "Advanced" - profile (formerly known as the "Adventuresome" profile) is more aggressive, and will - make use of some of Privoxy's advanced - features. Use at your own risk!

-
-
-

3.10. Why - can I change the configuration with a browser? Does that not raise - security issues?

-

It may seem strange that regular users can edit the config files - with their browsers, although the whole /etc/privoxy hierarchy belongs to the user "privoxy", with only 644 permissions.

-

When you use the browser-based editor, Privoxy itself is writing to the config files. - Because Privoxy is running as the user - "privoxy", it can update its own config - files.

-

If you run Privoxy for multiple - untrusted users (e.g. in a LAN) or aren't entirely in control of your - own browser, you will probably want to make sure that the web-based - editor and remote toggle features are "off" - by setting "enable-edit-actions 0" and "enable-remote-toggle 0" in the main configuration - file.

-

As of Privoxy 3.0.7 these options - are disabled by default.

-
-
-

3.11. What is - the default.filter file? What is a - "filter"?

-

The default.filter file is where - filters as - supplied by the developers are defined. Filters are a special subset of - actions that can be used to modify or remove web page content or - headers on the fly. Content filters can be applied to anything in the page source, - header filters can be applied to either server or client headers. - Regular expressions are used to accomplish this.

-

There are a number of pre-defined filters to deal with common - annoyances. The filters are only defined here, to invoke them, you need - to use the filter action in one of the actions - files. Content filtering is automatically disabled for inappropriate - MIME types, but if you know better than Privoxy what should or should - not be filtered you can filter any content you like.

-

Filters should not be confused with blocks, which is a completely different action, and - is more typically used to block ads and unwanted sites.

-

If you are familiar with regular expressions, and HTML, you can look - at the provided default.filter with a text - editor and define your own filters. This is potentially a very powerful - feature, but requires some expertise in both regular expressions and - HTML/HTTP. You should place any modifications to the default filters, - or any new ones you create in a separate file, such as user.filter, so they won't be overwritten during - upgrades. The ability to define multiple filter files in config is a new feature as of v. 3.0.5.

-

There is no GUI editor option for this part of the configuration, - but you can disable/enable the various pre-defined filters of the - included default.filter file with the - web-based - actions file editor. Note that the custom actions editor must be - explicitly enabled in the main config file (see enable-edit-actions).

-

If you intend to develop your own filters, you might want to have a - look at Privoxy-Filter-Test.

-
-
-

3.12. How can I - set up Privoxy to act as a proxy for my LAN?

-

By default, Privoxy only responds - to requests from 127.0.0.1 (localhost). To - have it act as a server for a network, this needs to be changed in the - main configuration - file. Look for the listen-address option, which may be commented out with - a "#" symbol. Make sure it is uncommented, - and assign it the address of the LAN gateway interface, and port number - to use. Assuming your LAN address is 192.168.1.1 and you wish to run - Privoxy on port 8118, this line should - look like:

- - - - -
-
  listen-address  192.168.1.1:8118
-
-

Save the file, and restart Privoxy. - Configure all browsers on the network then to use this address and port - number.

-

Alternately, you can have Privoxy - listen on all available interfaces:

- - - - -
-
  listen-address    :8118
-
-

And then use Privoxy's permit-access feature to limit connections. A firewall in - this situation is recommended as well.

-

The above steps should be the same for any TCP network, regardless - of operating system.

-

If you run Privoxy on a LAN with - untrusted users, we recommend that you double-check the access - control and security options!

-
-
-

3.13. Instead of ads, - now I get a checkerboard pattern. I don't want to see - anything.

-

The replacement for blocked images can be controlled with the - set-image-blocker action. You have - the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka - "blank"), or a redirect to a custom image of - your choice. Note that this choice only has effect for images which are - blocked as images, i.e. whose URLs match both a handle-as-image and block - action.

-

If you want to see nothing, then change the set-image-blocker action to - "blank". This can be done by editing the - user.action file, or through the web-based actions - file editor.

-
-
-

3.14. Why would - anybody want to see a checkerboard pattern?

-

Remember that telling which image - is an ad and which isn't, is an educated guess. While we hope that - the standard configuration is rather smart, it will make occasional - mistakes. The checkerboard image is visually decent, and it shows you - where images have been blocked, which can be very helpful in case some - navigation aid or otherwise innocent image was erroneously blocked. It - is recommended for new users so they can "see" what is happening. Some people might also enjoy - seeing how many banners they don't have to see.

-
-
-

3.15. I - see some images being replaced with text instead of the checkerboard - image. Why and how do I get rid of this?

-

This happens when the banners are not embedded in the HTML code of - the page itself, but in separate HTML (sub)documents that are loaded - into (i)frames or (i)layers, and these external HTML documents are - blocked. Being non-images they get replaced by a substitute HTML page - rather than a substitute image, which wouldn't work out technically, - since the browser expects and accepts only HTML when it has requested - an HTML document.

-

The substitute page adapts to the available space and shows itself - as a miniature two-liner if loaded into small frames, or full-blown - with a large red "BLOCKED" banner if space allows.

-

If you prefer the banners to be blocked by images, you must see to - it that the HTML documents in which they are embedded are not blocked. - Clicking the "See why" link offered in the - substitute page will show you which rule blocked the page. After - changing the rule and un-blocking the HTML documents, the browser will - try to load the actual banner images and the usual image blocking will - (hopefully!) kick in.

-
-
-

3.16. Can Privoxy run as - a service on Win2K/NT/XP?

-

Yes. Version 3.0.5 introduces full Windows service functionality. See the User Manual for details on how - to install and configure Privoxy as a - service.

-

Earlier 3.x versions could run as a system service using srvany.exe. See the discussion at https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, - for details, and a sample configuration.

-
-
-

3.17. How can I - make Privoxy work with other proxies?

-

This can be done and is often useful to combine the benefits of - Privoxy with those of a another proxy, - for example to cache content. See the forwarding - chapter in the User Manual which describes how to do this. If you intend to - use Privoxy with Tor, please also have a look at How do I use Privoxy together with Tor.

-
-
-

3.18. Can I just set - Privoxy to use port 80 and thus avoid individual browser - configuration?

-

No, its more complicated than that. This only works with special - kinds of proxies known as "intercepting" - proxies (see below).

-
-
-

3.19. Can - Privoxy run as a "transparent" - proxy?

-

The whole idea of Privoxy is to modify client requests and server - responses in all sorts of ways and therefore it's not a transparent - proxy as described in RFC 2616.

-

However, some people say "transparent - proxy" when they mean "intercepting - proxy". If you are one of them, please read the next entry.

-
-
-

3.20. Can - Privoxy run as a "intercepting" - proxy?

-

Privoxy can't intercept traffic - itself, but it can handle requests that where intercepted and - redirected with a packet filter (like PF or iptables), - as long as the Host header is present.

-

As the Host header is required by HTTP/1.1 - and as most web sites rely on it anyway, this limitation shouldn't be a - problem.

-

Please refer to your packet filter's documentation to learn how to - intercept and redirect traffic into Privoxy. Afterward you just have to configure - Privoxy to accept intercepted requests.

-
-
-

3.21. How can I - configure Privoxy for use with Outlook?

-

Versions of Outlook prior to Office - 2007, use Internet Explorer components - to both render HTML, and fetch any HTTP requests that may be embedded - in an HTML email. So however you have Privoxy configured to work with IE, this - configuration should automatically be shared, at least with older - version of Internet Explorer.

-

Starting with Office 2007, Microsoft is instead using the MS-Word - rendering engine with Outlook. It is unknown whether this can be - configured to use a proxy.

-
-
-

3.22. How - can I have separate rules just for HTML mail?

-

The short answer is, you can't. Privoxy has no way of knowing which particular - application makes a request, so there is no way to distinguish between - web pages and HTML mail. Privoxy just - blindly proxies all requests. In the case of Outlook Express (see above), OE uses IE anyway, - and there is no way for Privoxy to - ever be able to distinguish between them (nor could any other proxy - type application for that matter).

-

For a good discussion of some of the issues involved (including - privacy and security issues), see https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118.

-
-
-

3.23. I - sometimes notice cookies sneaking through. How?

-

Cookies can be set in several ways. The classic method is - via the Set-Cookie HTTP header. This is - straightforward, and an easy one to manipulate, such as the - Privoxy concept of session-cookies-only. There is also the possibility of using - Javascript to set cookies (Privoxy calls these content-cookies). This is trickier because the syntax - can vary widely, and thus requires a certain amount of guesswork. It is - not realistic to catch all of these short of disabling Javascript, - which would break many sites. And lastly, if the cookies are embedded - in a HTTPS/SSL secure session via Javascript, they are beyond - Privoxy's reach.

-

All in all, Privoxy can help manage - cookies in general, can help minimize the loss of privacy posed by - cookies, but can't realistically stop all cookies.

-
-
-

3.24. Are - all cookies bad? Why?

-

No, in fact there are many beneficial uses of cookies. Cookies are just a method that browsers can use to - store data between pages, or between browser sessions. Sometimes there - is a good reason for this, and the user's life is a bit easier as a - result. But there is a long history of some websites taking advantage - of this layer of trust, and using the data they glean from you and your - browsing habits for their own purposes, and maybe to your potential - detriment. Such sites are using you and storing their data on your - system. That is why the privacy conscious watch from whom those cookies - come, and why they really need to be there.

-

See the Wikipedia cookie definition for more.

-
-
-

3.25. How - can I allow permanent cookies for my trusted sites?

-

There are several actions that relate to cookies. The default - behavior is to allow only "session cookies", - which means the cookies only last for the current browser session. This - eliminates most kinds of abuse related to cookies. But there may be - cases where you want cookies to last.

-

To disable all cookie actions, so that cookies are allowed - unrestricted, both in and out, for example.com:

- - - - -
-
-            { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
-  .example.com
-
-

Place the above in user.action. Note that - some of these may be off by default anyway, so this might be redundant, - but there is no harm being explicit in what you want to happen. - user.action includes an alias for this - situation, called allow-all-cookies.

-
-
-

3.26. Can I have - separate configurations for different users?

-

Each instance of Privoxy has its - own configuration, including such attributes as the TCP port that it - listens on. What you can do is run multiple instances of Privoxy, each with a unique listen-address configuration setting, and configuration - path, and then each of these can have their own configurations. Think - of it as per-port configuration.

-

Simple enough for a few users, but for large installations, consider - having groups of users that might share like configurations.

-
-
-

3.27. Can I - set-up Privoxy as a whitelist of "good" - sites?

-

Sure. There are a couple of things you can do for simple - white-listing. Here's one real easy one:

- - -
-
-            ############################################################
+ mail.google.com

Be sure to flush your browser's caches whenever making these kinds of + changes, just to make sure the changes "take". +

Make sure the domain, host and path are appropriate as well. Your browser can + tell you where you are specifically and you should use that information for + your configuration settings. Note that above it is not referenced as + gmail.com, which is a valid domain name. +

3.9. What's the difference between the +"Cautious", "Medium" and "Advanced" defaults?

Configuring Privoxy is not entirely trivial. To + help you get started, we provide you with three different default action + "profiles" in the web based actions file editor at http://config.privoxy.org/show-status. + See the User + Manual for a list of actions, and how the default + profiles are set. +

Where the defaults are likely to break some sites, exceptions for + known popular "problem" sites are included, but in + general, the more aggressive your default settings are, the more exceptions + you will have to make later. New users are best to start off in + "Cautious" setting. This is safest and will have the fewest + problems. See the User Manual + for a more detailed discussion.

It should be noted that the "Advanced" profile (formerly known + as the "Adventuresome" profile) is more + aggressive, and will make use of some of + Privoxy's advanced features. Use at your own risk!

3.10. Why can I change the configuration +with a browser? Does that not raise security issues?

It may seem strange that regular users can edit the config files with their + browsers, although the whole /etc/privoxy hierarchy + belongs to the user "privoxy", with only 644 permissions. +

When you use the browser-based editor, Privoxy + itself is writing to the config files. Because + Privoxy is running as the user "privoxy", + it can update its own config files. +

If you run Privoxy for multiple untrusted users (e.g. in + a LAN) or aren't entirely in control of your own browser, you will probably want + to make sure that the web-based editor and remote toggle features are + "off" by setting "enable-edit-actions + 0" and "enable-remote-toggle + 0" in the main configuration file. +

As of Privoxy 3.0.7 these options are disabled by default. +

3.11. What is the default.filter file? What is a "filter"?

The default.filter + file is where filters as supplied by the developers are defined. + Filters are a special subset of actions that can be used to modify or + remove web page content or headers on the fly. Content filters can + be applied to anything in the page source, + header filters can be applied to either server or client headers. + Regular expressions are used to accomplish this.

There are a number of pre-defined filters to deal with common annoyances. The + filters are only defined here, to invoke them, you need to use the + filter + action in one of the actions files. Content filtering is automatically + disabled for inappropriate MIME types, but if you know better than Privoxy + what should or should not be filtered you can filter any content you like.

Filters should + not be confused with blocks, which + is a completely different action, and is more typically used to block ads and + unwanted sites.

If you are familiar with regular expressions, and HTML, you can look at + the provided default.filter with a text editor and define + your own filters. This is potentially a very powerful feature, but + requires some expertise in both regular expressions and HTML/HTTP. + You should + place any modifications to the default filters, or any new ones you create + in a separate file, such as user.filter, so they won't + be overwritten during upgrades. + The ability to define multiple filter files + in config is a new feature as of v. 3.0.5.

There is no GUI editor option for this part of the configuration, + but you can disable/enable the various pre-defined filters of the included + default.filter file with the web-based actions file editor. + Note that the custom actions editor must be explicitly enabled in + the main config file (see enable-edit-actions).

If you intend to develop your own filters, you might want to have a look at + Privoxy-Filter-Test.

3.12. How can I set up Privoxy to act as a proxy for my + LAN?

By default, Privoxy only responds to requests + from 127.0.0.1 (localhost). To have it act as a server for + a network, this needs to be changed in the main configuration file. Look for + the listen-address + option, which may be commented out with a "#" symbol. Make sure + it is uncommented, and assign it the address of the LAN gateway interface, + and port number to use. Assuming your LAN address is 192.168.1.1 and you + wish to run Privoxy on port 8118, this line + should look like:

  listen-address  192.168.1.1:8118

Save the file, and restart Privoxy. Configure + all browsers on the network then to use this address and port number.

Alternately, you can have Privoxy listen on + all available interfaces:

  listen-address    :8118

And then use Privoxy's + permit-access + feature to limit connections. A firewall in this situation is recommended + as well.

The above steps should be the same for any TCP network, regardless of + operating system.

If you run Privoxy on a LAN with untrusted users, + we recommend that you double-check the access control and security + options!

3.13. Instead of ads, now I get a checkerboard pattern. I don't want to see anything.

The replacement for blocked images can be controlled with the set-image-blocker + action. You have the choice of a checkerboard pattern, a transparent 1x1 GIF + image (aka "blank"), or a redirect to a custom image of your choice. + Note that this choice only has effect for images which are blocked as images, i.e. + whose URLs match both a handle-as-image + and block action.

If you want to see nothing, then change the set-image-blocker + action to "blank". This can be done by editing the + user.action file, or through the web-based actions file editor.

3.14. Why would anybody want to see a checkerboard pattern?

Remember that telling which image is an ad and which + isn't, is an educated guess. While we hope that the standard configuration + is rather smart, it will make occasional mistakes. The checkerboard image is visually + decent, and it shows you where images have been blocked, which can be very + helpful in case some navigation aid or otherwise innocent image was + erroneously blocked. It is recommended for new users so they can + "see" what is happening. Some people might also enjoy seeing how + many banners they don't have to see.

3.15. I see some images being replaced with text +instead of the checkerboard image. Why and how do I get rid of this?

This happens when the banners are not embedded in the HTML code of the + page itself, but in separate HTML (sub)documents that are loaded into (i)frames + or (i)layers, and these external HTML documents are blocked. Being non-images + they get replaced by a substitute HTML page rather than a substitute image, + which wouldn't work out technically, since the browser expects and accepts + only HTML when it has requested an HTML document.

The substitute page adapts to the available space and shows itself as a + miniature two-liner if loaded into small frames, or full-blown with a + large red "BLOCKED" banner if space allows.

If you prefer the banners to be blocked by images, you must see to it that + the HTML documents in which they are embedded are not blocked. Clicking + the "See why" link offered in the substitute page will show + you which rule blocked the page. After changing the rule and un-blocking + the HTML documents, the browser will try to load the actual banner images + and the usual image blocking will (hopefully!) kick in.

3.16. Can Privoxy run as a service +on Win2K/NT/XP?

Yes. Version 3.0.5 introduces full Windows service + functionality. See the User Manual for details on how to install and configure + Privoxy as a service.

Earlier 3.x versions could run as a system service using srvany.exe. + See the discussion at https://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, + for details, and a sample configuration.

3.17. How can I make Privoxy work with other proxies?

This can be done and is often useful to combine the benefits of + Privoxy with those of a another proxy, + for example to cache content. + See the forwarding chapter + in the User Manual which + describes how to do this. If you intend to use Privoxy with Tor, + please also have a look at + How do I use Privoxy together with Tor.

3.18. Can I just set Privoxy to use port 80 +and thus avoid individual browser configuration?

No, its more complicated than that. This only works with special kinds + of proxies known as "intercepting" proxies + (see below).

3.19. Can Privoxy run as a "transparent" proxy?

The whole idea of Privoxy is to modify client requests + and server responses in all sorts of ways and therefore + it's not a transparent proxy as described in + RFC 2616.

However, some people say "transparent proxy" when they + mean "intercepting proxy". If you are one of them, + please read the next entry.

3.20. Can Privoxy run as a "intercepting" proxy?

Privoxy can't intercept traffic itself, + but it can handle requests that where intercepted and redirected + with a packet filter (like PF or + iptables), as long as the Host + header is present. +

As the Host header is required by HTTP/1.1 and as most + web sites rely on it anyway, this limitation shouldn't be a problem.

Please refer to your packet filter's documentation to learn how to + intercept and redirect traffic into Privoxy. + Afterward you just have to configure Privoxy to + accept + intercepted requests.

3.21. How can I configure Privoxy for use with Outlook?

Versions of Outlook prior to Office 2007, use + Internet Explorer components to both render HTML, + and fetch any HTTP requests that may be embedded in an HTML email. So however + you have Privoxy configured to work with IE, this + configuration should automatically be shared, at least with older version of + Internet Explorer.

Starting with Office 2007, Microsoft is instead using the MS-Word rendering + engine with Outlook. It is unknown whether this can be configured to use a + proxy. +

3.22. How can I have separate rules just for HTML mail?

The short answer is, you can't. Privoxy has no way + of knowing which particular application makes a request, so there is no way to + distinguish between web pages and HTML mail. + Privoxy just blindly proxies all requests. In the + case of Outlook Express (see above), OE uses + IE anyway, and there is no way for Privoxy to ever + be able to distinguish between them (nor could any other proxy type application for + that matter).

For a good discussion of some of the issues involved (including privacy and + security issues), see + https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118.

3.23. I sometimes notice cookies sneaking through. How?

Cookies can be + set in several ways. The classic method is via the + Set-Cookie HTTP header. This is straightforward, and an + easy one to manipulate, such as the Privoxy concept of + session-cookies-only. + There is also the possibility of using + Javascript to + set cookies (Privoxy calls these content-cookies). This + is trickier because the syntax can vary widely, and thus requires a certain + amount of guesswork. It is not realistic to catch all of these short of + disabling Javascript, which would break many sites. And lastly, if the + cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond + Privoxy's reach.

All in all, Privoxy can help manage cookies in general, can help minimize + the loss of privacy posed by cookies, but can't realistically stop all + cookies.

3.24. Are all cookies bad? Why?

No, in fact there are many beneficial uses of + cookies. Cookies are just a + method that browsers can use to store data between pages, or between browser + sessions. Sometimes there is a good reason for this, and the user's life is a + bit easier as a result. But there is a long history of some websites taking + advantage of this layer of trust, and using the data they glean from you and + your browsing habits for their own purposes, and maybe to your potential + detriment. Such sites are using you and storing their data on your system. + That is why the privacy conscious watch from whom those cookies come, and why + they really need to be there.

See the + Wikipedia cookie + definition for more.

3.25. How can I allow permanent cookies for my trusted sites?

There are several actions that relate to cookies. The default behavior is to + allow only "session cookies", which means the cookies only last + for the current browser session. This eliminates most kinds of abuse related + to cookies. But there may be cases where you want cookies to last.

To disable all cookie actions, so that cookies are allowed unrestricted, + both in and out, for example.com:

 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
+  .example.com

Place the above in user.action. Note that some of these may + be off by default anyway, so this might be redundant, but there is no harm + being explicit in what you want to happen. user.action + includes an alias for this situation, called + allow-all-cookies.

3.26. Can I have separate configurations for different users?

Each instance of Privoxy has its own + configuration, including such attributes as the TCP port that it listens on. + What you can do is run multiple instances of Privoxy, each with + a unique + listen-address + configuration setting, and configuration path, and then + each of these can have their own configurations. Think of it as per-port + configuration.

Simple enough for a few users, but for large installations, consider having + groups of users that might share like configurations.

3.27. Can I set-up Privoxy as a whitelist of +"good" sites?

Sure. There are a couple of things you can do for simple white-listing. + Here's one real easy one:

- -
 ############################################################
  # Blacklist
  ############################################################
- { +block }
+ { +block }
  / # Block *all* URLs
 
  ############################################################
  # Whitelist
  ############################################################
- { -block }
+ { -block }
   kids.example.com
   toys.example.com
-  games.example.com
-
-

This allows access to only those three sites by first blocking all - URLs, and then subsequently allowing three specific exceptions.

-

Another approach is Privoxy's - trustfile concept, which incorporates the - notion of "trusted referrers". See the - Trust - documentation for details.

-

These are fairly simple approaches and are not completely foolproof. - There are various other configuration options that should be disabled - (described elsewhere here and in the User Manual) so that users can't modify their own - configuration and easily circumvent the whitelist.

-
-
-

3.28. How can I - turn off ad-blocking?

-

Ad blocking is achieved through a complex application of various - Privoxy actions. These - actions are deployed against simple images, banners, flash animations, - text pages, JavaScript, pop-ups and pop-unders, etc., so its not as - simple as just turning one or two actions off. The various actions that - make up Privoxy ad blocking are - hard-coded into the default configuration files. It has been assumed - that everyone using Privoxy is - interested in this particular feature.

-

If you want to do without this, there are several approaches you can - take: You can manually undo the many block rules in default.action. Or even easier, just create your own - default.action file from scratch without the - many ad blocking rules, and corresponding exceptions. Or lastly, if you - are not concerned about the additional blocks that are done for privacy - reasons, you can very easily over-ride all blocking with the following very simple rule - in your user.action:

- - - - -
-
 # Unblock everybody, everywhere
- { -block }
- / # UN-Block *all* URLs
-
-

Or even a more comprehensive reversing of various ad related - actions:

- - -
-
-            # Unblock everybody, everywhere, and turn off appropriate filtering, etc
- { -block \
-  -filter{banners-by-size} \
-  -filter{banners-by-link} \
-  allow-popups \
+  games.example.com

This allows access to only those three sites by first blocking all URLs, and + then subsequently allowing three specific exceptions.

Another approach is Privoxy's + trustfile concept, which incorporates the notion of + "trusted referrers". See the Trust documentation + for details.

These are fairly simple approaches and are not completely foolproof. There + are various other configuration options that should be disabled (described + elsewhere here and in the User Manual) + so that users can't modify their own configuration and easily circumvent the + whitelist.

3.28. How can I turn off ad-blocking?

Ad blocking is achieved through a complex application of various Privoxy + actions. These + actions are deployed against simple images, banners, flash animations, + text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as + just turning one or two actions off. The various actions that make up + Privoxy ad blocking are hard-coded into the default configuration files. It + has been assumed that everyone using Privoxy is interested in this + particular feature. +

If you want to do without this, there are several approaches you can take: + You can manually undo the many block rules in + default.action. Or even easier, just create your own + default.action file from scratch without the many ad + blocking rules, and corresponding exceptions. Or lastly, if you are not + concerned about the additional blocks that are done for privacy reasons, you + can very easily over-ride all blocking with the + following very simple rule in your user.action: +

 # Unblock everybody, everywhere
+ { -block }
+ / # UN-Block *all* URLs

Or even a more comprehensive reversing of various ad related actions:

- -
 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
+ { -block \
+  -filter{banners-by-size} \
+  -filter{banners-by-link} \
+  allow-popups \
  }
- / # UN-Block *all* URLs and allow ads
-
-

This last "action" in this compound - statement, allow-popups, is an alias that - disables various pop-up blocking features.

-
-
-

3.29. How can I - have custom template pages, like the BLOCKED page?

-

Privoxy "templates" are specialized text files utilized by - Privoxy for various purposes and can - easily be modified using any text editor. All the template pages are - installed in a sub-directory appropriately named: templates. Knowing something about HTML syntax will of - course be helpful.

-

Be forewarned that the default templates are subject to being - overwritten during upgrades. You can, however, create completely new - templates, place them in another directory and specify the alternate - path in the main config. For details, have a - look at the templdir option.

-
-
-

3.30. How can I - remove the "Go There Anyway" link from the - BLOCKED - page?

-

There is more than one way to do it (although Perl is not - involved).

-

Editing the BLOCKED template page (see above) may dissuade some - users, but this method is easily circumvented. Where you need this - level of control, you might want to build Privoxy from source, and disable various features - that are available as compile-time options. You should configure the sources as follows:

- - - - -
-
-            ./configure  --disable-toggle  --disable-editor  --disable-force
-
-

This will create an executable with hard-coded security features so - that Privoxy does not allow easy - bypassing of blocked sites, or changing the current configuration via - any connected user's web browser.

-

Finally, all of these features can also be toggled on/off via - options in Privoxy's main config - file which means you don't have to recompile anything.

-
-
- - - + / # UN-Block *all* URLs and allow ads

This last "action" in this compound statement, + allow-popups, is an alias that disables + various pop-up blocking features.

3.29. How can I have custom template pages, like the +BLOCKED page?

Privoxy "templates" are specialized text files utilized by + Privoxy for various purposes and can easily be modified using any text + editor. All the template pages are installed in a sub-directory appropriately + named: templates. Knowing something about HTML syntax + will of course be helpful.

Be forewarned that the default templates are subject to being overwritten + during upgrades. You can, however, create completely new templates, + place them in another directory and specify the alternate path in the main + config. For details, have a look at the templdir option.

3.30. How can I remove the "Go There Anyway" link from +the BLOCKED page?

There is more than one way to do it (although Perl is not involved).

Editing the BLOCKED template page (see above) may dissuade some users, but + this method is easily circumvented. Where you need this level of control, you + might want to build Privoxy from source, and disable various features that are + available as compile-time options. You should + configure the sources as follows:

 ./configure  --disable-toggle  --disable-editor  --disable-force

This will create an executable with hard-coded security features so that + Privoxy does not allow easy bypassing of blocked sites, or changing the + current configuration via any connected user's web browser.

Finally, all of these features can also be toggled on/off via options in + Privoxy's main config file which + means you don't have to recompile anything.


PrevHomeNext
Installation Miscellaneous
\ No newline at end of file