Setting zimbra to only receive mail from single SN

[lctn]

I would like to set my Zimbra server to only allow smtp connections from my local LAN, so spammers cannot target my IP directly. I have a mailscanner set up that would receive all mail, and forward it to the Zimbra server

Any idea what to configure to accomplish this?

[uxbod]

Are you behind a firewall ? If so are you port-forwarding or NATing ?

[lctn]

My MX record is set so all mail for my local domain is supposed to go to our mailscanner, and then from the mailscanner to my Zimbra box. Spammers are hitting my IP, rathar than domain name, so my MX is useless. I port forward from one public IP to the mail scanner, and another public IP to my Zimbra box.

[uxbod]

Can you not just block port 25 from external to your ZCS server ? That way they would only get mail via your MS box.