Ok i found out abt the MX records implementation. I learnt that 2 MX records can exist one for each machine having exchange 2000 configured to receive email for the 2 domains. Both will have some cost issue involved which will set the priority. I got all that. What confused me now is that how will both the MAIL SERVERS replicate data amongst one another. Both should contain the same mailboxes right to be able to replace each other...plz drop in some ideas... Umar