I am working on a Exchange 2003 to 2010 transition and have a couple of questions.
Firstly, before I go ahead an install Exchange 2010, are there any DNS considerations I need to be aware of first? My concern is that the A record for the namespace points currently to 2003, as does the MX. One I introduce the 2010 server (all roles), will it ‘take over’ and therefore break client connectivity?
My understanding is that mailflow will then traverse the 2010 server once installed, but the DNS records point to 2003. I wanted to set up the Exchange 2010 server, configure it, and then move all mailboxes over a weekend together with updating the DNS records and firewall, and am concerned that something will break before I have the opportunity to do so.
Secondly, my 2003 server is in a different site to the 2010 server, will that be an issue at all?