The optional header checks table allows email to be redirected based on the contents of the message body. Each entry in the table has a POSIX regular expression on the left-hand side, and an action on the right.

The regular expression can be something like :
`/make.money.fast/`
to match messages containing the text 'make money fast'.

The action can be like :
`REJECT`
to simply reject mail matching the expression, or :
`REDIRECT spam@yourdomain.com`
To forward mail to another address.