Gentlemen, I have mail server presently sending and receving e-mail for two public domains (batman.com & robin.com), with users each having an address for each domain: batman.com mailserver IN A 33.44.55.66 IN MX 10 mailserver.batman.com IN MX 50 mailserver.ISP.com robin.com IN MX 10 mailserver.batman.com IN MX 50 mailserver.ISP.com I want to swap the A record from batman to robin like this: batman.com IN MX 10 mailserver.robin.com IN MX 50 mailserver.ISP.com robin.com mailserver IN A 33.44.55.66 IN MX 10 mailserver.robin.com IN MX 50 mailserver.ISP.com If I have the ISP make this change, do I need to make any changes on the Exchange Server side? Note that I am running Exchange Server 5.5 SP4 on Windows NT 4 Server SP5 and that the mailserver can already send and receive for both robin.com and batman.com domains. Thank you.