Hi, We are a newbie in DNS and mail server. We have 2 mail server, both installed exchange server 5.5 sp3. We want to know, there is a domain aaa.com, if in the DNS record for aaa.com : MX 10 A.com MX 20 B.com and there is first mail server (A.com) with domain bbb.com and second mail server (B.com) with aaa.com. When an e-mail sent to domain aaa.com, what will happen with this e-mail ? Thanks. Regards, Sulis.