[plan9]

First of all, thank you for taking the time to address my question.

So a local DNS server is a requirement if I'm to send and receive messages external to my LAN?

Currently I'm running Exchange with no local DNS. I have port 25 on my router directed to my Exchange box. My Exchange machine has a local IP address (e.g., 192.168.2.10).

I must plead ignorance. I thought this would work the same for Zimbra or any other mail server for that matter. Am I simply wrong?