From Bryan Hughes, Tue Feb 28 13:44:10 2006
To use forwarding with spam filtering a user will need to be using their own procmailrc with spam filtering rules (not the one we soft link for them).
At the very end of .procmailrc they will need to add the lines:
:0 ! addresstoforwardto@someMTA.com
if they also want a local copy also delivered they need to add "c" to the first line like so:
:0c ! addresstoforwardto@someMTA.com