Hello:
I am curious about general workings of a SMTP E-mail Server behind Gnatbox, NAT type firewall. My GB100 allows the server to connect anywhere on port 25. IP address is then NATed so it looks as if the SMTP/25 connection is coming from GB100's external and published Internet address. As you can see from the partial SMTP e-mail dialog, my internal system name is used along with the Gnatbox's external name. Everything works fine, but what prevents the other SMTP server from doing RDNS or Spam-IP check on the internal system name? How does it know which name to do the check? Is this normal? .. Trying alltrista.com (0) Connect alltrista.com [209.224.158.197:25] (1) 220 imail.alltrista.com ESMTP Server (5.5.2653.13) ready EHLO nt5svre.pmxcr.com (** MY Internal System Name **) 250-imail.alltrista.com Hello [ntmail.ipmx.com] (** External Gnatbox name **) 250-XEXCH50 250-HELP 250-ETRN 250-DSN .. SO ON .. Also, Gnatbox E-mail proxy supports only SMTP and not the newer E-SMTP. Will E-SMTP functionality help to stop/prevent Spam relay(bounced SMTP)? Thanks Suresh Ganu PMX Industries, Inc.
