I am in the process of planning our Windows/Exchange 2003 upgrade. Email delivery is very critical for our company and my goal is to minimize, if not eliminate, any potential loss of connectivity during the upgrade. I'll be purchasing new box which will replace our current Exchange 2000 server so I will have the luxury of running two Exchange boxes at the same time. See the bottom of this post for general environment info.
My questions are concerning Exchange's SMTP connector. When I build the new server with Windows 2003 and Exchange 2003, can I install a SMTP connector on that machine which will receive email for our domain, while there's a similar connector on our current Exchange box? (ie: run two SMTP connectors servicing the same domain simultaneously under the same Exchange organization?) My goal is to provide coverage when our ISP switches our MX record to point to the new Exchange 2003 box. It's conceivable that while the DNS change propagates we could recieve email directed to either Exchange box and I don't want to loose any emails.
Once I'm sure the new box is running correctly and all mail is coming to it and not the old Exchange box, I will follow the steps in Article 307917 to remove the Exchange 2000 server.
Windows 2000 (SP4) network with AD in native mode.
Single Exchange 2000 server, standard edition (SP3 & post SP3 rollup patch)
Goal is to upgrade all servers to Windows 2003 network with AD in 2003 native mode
Exchange 2003, Standard edition, will obviously be running on Windows 2003.