Good morning, Please help!!! I tried to setup a spamsnake to filter all incoming mails before relaying to our Exchange server which are located behind a firewall. The Spamsnake is located in a DMZ subnet and my Exchange is located in other subnet. However I am unable to receive mail from external either I have set all port forwarding correctly as I am able to received test mails from Spamsnake. I am able to send out mail. Please see below schema for my setup Internet --> Router --> Firewall -->DMZ (Spamsnake 192.168.3.1)-->Exchange (192.168.0.23) In postfix I set relay_recipients, the transport_map, the relay_domains. I postmap all these files. Please help!!!