We have one Exchange 2000 mail server at our location. On our private network the IP Address 192.168.1.x. We have a valid routable IP Address on the Internet. We are using NAT on our router to translate our public IP to our private IP. Our internal domain name is xyz.com and our external domain name is abc.xyz.com. We can send internet e-mail with a return address of email@example.com. When recipients try to reply to our e-mail they receive an error message "unknown user at abc.xyz.com. External users can telnet into our Exchange Server on port 25. Does anyone know how to configure exchange to allow e-mail addressed to my internal users using naming convention firstname.lastname@example.org?
Yes, I have created Recipient Policy for both abc.xyz.com and xyx.com. I am still not receiving external e-mail.