Exchange 2003 Enterprise installed on Server 2003. Latest SP's etc. Dual homed. One nic (Nic1) on a DMZ ip mapped to the DNS MX record for our public domain. The other nic (Nic2) on the private LAN (several subnets) servicing our Windows 2000 Active Directory and providing our Exchange Server services. Default SMTP Virtual Server configured for Nic2 ip and Internet SMTP Virtual Server configure for Nic1 ip. Can properly service incoming SMTP, POP3, OWA, IMAP requests thru the MX record ip. The default gateway for the Exchange Server is the gateway for Nic2. This allows other private subnets to connect to the Exchange Server services. The Exchange Server sends all email from the default gateway nic (Nic2) which is delivered thru the firewall ip address (not the MX record ip address). The problem is some receiving email servers cannot resolve the DNS entry for our Exchange Server because it is identified coming from our firewall ip and not the MX record. The result is that some outgoing email is rejected as either spam or relayed email. If I set the default gateway to the Nic1 (the DMZ nic), all email is sent out with the MX record ip address and the problem is no longer. But this introduces the problem of not being able to route our Exchange Server services to the other private subnets. Would like suggestions on how to crack this catch-22 issue. Many thanks!