Question : Transition from Exchange 2003 to 2010

we want to install exchange 2010 in our organization.I know what should I do for setup exchange 2010 but I have some question about DNS and IP assignment. our current mail server public  DNS name is mail.externaldomain.com and internal DNS name is Exchange-server.internaldomain.com and we are using a PIX and NAT intenal IP to Public IP. if I install exchange 2010 on new server with internal name EX2010.internaldomain.com , when should I change mail.externaldomain.com IP address to new one and I want to know in internal networkwhat should our client to do to connect to new server? if they are connect to old server, will they redirected to new server or not?

Answer : Transition from Exchange 2003 to 2010

Follow this guide.http://petenetlive.com/KB/Article/0000234.htm

It follows everything you are talking about.

once your send/receive connectors to both 2003 and 2010 are up you will be golden.