6.2 Spam-Checking During Local Delivery

The easiest way to add SpamAssassin to a Postfix system is to configure Postfix to use procmail as its local delivery agent, rather than the Postfix local program. Then add a procmail recipe for spam-tagging to /etc/procmailrc .

The advantages of this approach are:

• It's very easy to set up.

• You can run spamd , and the procmail recipe can use spamc for faster spam-checking.

• User preference files, autowhitelists, and Bayesian databases can be used.

However, Postfix runs a local delivery agent only for email destined for a local recipient. You cannot create a spam-checking gateway with this approach.

Instructions for configuring procmail for spam-checking can be found in Example 2-6 in Chapter 2. To configure Postfix to use procmail as the local delivery agent, use the mailbox_command directive in main.cf :

 mailbox_command = procmail -a "$EXTENSION" 

If you configure Postfix to use procmail as the local delivery agent, you must be sure that you have an alias for root in your aliases file (typically in /etc or /etx/postfix ). The alias should point to another local user. Without such an alias, Postfix may be unable to deliver mail to root using procmail.