I am in the process of migrating to Exchange 2010 from 2003.
After moving over all the mailboxes and public folders. I went ahead and reconfigured my firewall to point SMTP and SSL to the new Exchange 2010 box.
I realized that mail flow wasn't coming in/out. I checked the EMC in 2003 and found the relaying was not allowed. I allowed relaying from the new Exchange 2010 to the 2003 box and mail flow started to work again. The only issue at this time is, email destined for 'outside' end up sitting in the 'routing queue' on the 2003 for a few minutes before going out.
1) Any ideas why it would route right away (like it used to)??
2) Why is the mail still being router thru the 2003 box at this point?
3) How can I be sure that Exchange 2010 is fully in control of all the roles, so I can go ahead and uninstall 2003?
4) Do I 'need' to uninstall 2003? or can I just unplug the 2003 box when I'm done removing all my other stuff from it?