Exchange Server-side Security Improvements
Exchange Server 2003 has numerous product enhancements and new features including those that are security related. The following are some of the most notable server-level security features:
Distribution Lists Restricted to Authenticated Users You can allow only sending from authenticated users or specify which users can or cannot send mail to specified distribution lists.
Support of Real-Time Safe and Block Lists Reduce the amount of unsolicited mail delivered to your organization with connection filtering.
Inbound Recipient Filtering Reduce unsolicited email messages by filtering inbound messages based on the recipient. Messages that are addressed to users that are not found, or to whom the sender ...