My exchange 2003 server is working fine. I now have to host another domain on this server. The MX record for this second domain points to a different IP. i.e domainA.com = 22.214.171.124 domainB.com =126.96.36.199 We own the IP's I have setup my firewall to for 1 to 1 NAT for the 188.8.131.52 and configured my exchange server with another private ip address of 192.168.1.2. I have also created a recipient policy with the new domain name and applied the policy to the users who need it, and i checked the box "this organization is responsible for" I then went to my default SMTP server, clicked the advanced tab, and added in the private ip 192.168.1.2 so it would listen on it.
When i try and send an email to user@domainB.com from an outside account I get a return message that says
Final-Recipient: RFC822; <user@domainB.com >
Diagnostic-Code: smtp; 550 5.7.1 Unable to relay for user@domainB.com
Am I on the right track here or way off?