This module checks the Subject header of a message and ensures that it starts (modulo an initial Re:) with a valid keyword. By default, the following keyword formats are supported:


If multiple keywords are given, they all have to be valid. Keywords are checked against a list given in a file and are case-insensitive.

This module takes one optional argument, a reference to a sub which, if given a subject line, returns a list of all the keywords present. This can be used to override the default patterns listed above.

There is one required configuration file directive:

keywords FILENAME

Specifies the file from which the list of valid keywords will be read. The file should list all valid keywords, one per line.

Two failure messages are possible:

No keywords found

There were no keywords in the subject header of the message.

Invalid keyword '%s'

A keyword was found that wasn't in the list of valid keywords.