Wednesday-April-02-2008 Reduce Email Spoofing with SPF Record
There is an open standard called SPF Records which is becoming more prevalent by DNS and Mail System Administrators to verify that the sender of a message is authorized to send for that domain.
Friday-November-12-2004 Setting up a White List for your Basic Spam filters
This article describes how to create a "White List" of valid email addresses that should not be caught in your basic spam filters. This does not apply to Premium Spam Filter customers.