We have 2 domain names that share an Exchnage 2003 server, (i.e. dom1.com and dom2.com). I want to setup one domain to route SMTP traffic on one public IP address/MX record (i.e. 1.2.3.4) and the scond to route on public IP/MX record (i.e. 1.2.3.5). I want to do ths becuase we are using one of the domain names to send bulk email (not spam) to our customers. The other domain is used strictly for typicall buisness email. I have seen several questions about this and the experts recomend using the same public IP address/MX record for multiple domains. The issue with this solution is that the public IP adress has/can be blacklisted and ultiamatly afftect the important business email. I want the "biulk" domain assocaited with a different Public IP address. Many of the experts have suggested that you cannot have Exchange specify which IP address to send out on. I have setup my firewall with a 1to1 NAT to route the incoming SMTP pubilc IP traffc to two different internal private IP addresses, both on the Exchnage server. I am looking for a way to setup Exchange to accept the SMTP traffic indpendently and send email out the correct public IP address. Is this possible? Any help would be appreciated.

Hi, I suggest you refer to following two articles regarding the issue: SMTP Virtual Server Myths Exposed http://social.technet.microsoft.com/Forums/en-US/exchangesvrgeneral/thread/db54118d-b3f4-4b84-960e-c859bf186382 Source IP address selection on a Multi-Homed Windows Computer http://blogs.technet.com/networking/archive/2009/04/24/source-ip-address-selection-on-a-multi-homed-windows-computer.aspx According the above articles, the Exchange does not provide a source IP address to use, and as such, you will notice that the source IP address assigned by Windows will be based on the Windows routing table, not taking into consideration the IP of the SMTP VSI that is delivering the message. Mike Shen TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com