Amavisd Whitelists

[That Guy from that Place]

Anyone know how to whitelist a block of IPs in Amavisd? I found this article by phoenix, but I'm not sure how to do it with entire subnets rather than single IPs.

EDIT: What I'm trying to do is prevent outgoing mail (originating from local subnets) from being spam/virus scanned. Right now mail from local users to local users is being scanned twice: when it hits the outgoing queue, and when it hits the incoming queue. This is redundant and our Zimbra performance is not spectacular so we're trying to improve it. Disabling outgoing mail from being scanned will reduce unnecessary processes.