squirrelmail/plugins/filters/README

Filters Plugin

ABOUT PLUGIN
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This plugin sorts messages in your inbox into different folders based upon 
given criteria. It is most useful for people who are subscribed to mailing 
lists to help organize their messages. The argument stands that filtering is 
not the place of the client, which is why this has been made a plugin for 
SquirrelMail. You may be better off using products such as Sieve, Maildrop or 
Procmail to do your filtering so it happens even when SquirrelMail isn't 
running.

IMPORTANT: At least one version of PHP has bugs in the checkdnsrr() function
that the SPAM filtering code RELIES ON. The PHP server that comes with Mandrake
8.1 has this problem -- checkdnsrr() NEVER finds the inaddr records, even the
ones that really exist.

This is a poor alternative to procmail or Elm's filter programs. This is a
pathetic replacement for good RBL mail scanning when you get the mail. This is
more for systems that can't/won't offer that kind of functionality and you 
still require it.

This is slow. Yep. Slow.

INSTALLATION
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Plugin is installed by enabling it in SquirrelMail configuration script. 
Plugin configuration can be changed with configuration files stored in 
config/filters_config.php or plugins/filters/config.php. Default configuration
values can be found in plugins/filters/config_default.php. If both 
configuration files are present, plugin uses file from config directory.

Main configuration option that must be changed is $SpamFilters_YourHop setting.
See comments about it in config_default.php. If $SpamFilters_YourHop uses 
default value, plugin will be unable to use RBL filtering correctly and 
warning message will is displayed to end user. If you don't want to use RBL 
filtering, you can disable it by setting $AllowSpamFilters option to false. If 
you can control your incoming SMTP server, it is recommended to turn RBL 
filtering on server.

If you use UW and if you encounter strange errors while using this plugin on
your system, edit configuration file and set $UseSeparateImapConnection to 
true. This may not solve the problem. One problem it might fix is if you run UW
2001 and if you don't see the number of unread messages in your left-hand 
folder pane, or if you see timeouts or IMAP server error messages. Turning on 
this feature may slow down the filters a bit more since it has to open a new 
connection.

Lastly, if there are some IPs that you want to refuse email from or some IPs 
you want to accept email from REGARDLESS of what the DNS databases say, you can
put in overrides in the SpamFilters_DNScache[] array. See the comments in 
config_default.php for more info on this.