Here is a list of the basics that every system administrator should implement:

1. Set your Reverse DNS. Don’t leave it empty.
2. Have geographically separated DNS servers
3. MTAs should have properly formed HELO names
4. rDNS should match the HELO on your MTA
5. HELO should resolve to your IP address
6. MX records must point to A records
7. Filter Bogons at the first opportunity in your network architecture and at appropriate routing points.
8. More to come

Posted by Brian Blood in General, Mail Server, Routers and Firewalls, Servers, Soap Box