I am having an outbound email issue during the Exch 03 migration. Basically, we are migrating Exch03 to new hardware, both servers are Server 03 based.
Everything runs smooth while setting up and installing Exch 03 on the new box. Public folders are all replicated. My issues are shown below....
1) After starting to move users' mailboxes to new Exch 03, they receive some undeliverable mail and bounced back mail from some vendors, then I move few users back to test around, they have no problem at all after moving back to old Exch 03.
2) Another issue is our company has Blackberry users, we don't have BES. Under each user's mailboxes, we have forward rule setup, so that both user inbox and BB can receive email. User who is moved to the new Exch 03 server, they can only send email to the BB user's inbox, mail cannot be forwarded to BB at all, smtp queue stacks up and keep trying until the time is expired.
Since not all emails that the users send out from the new Exch have problem, I am not able to narrow down what is the issue here. Can anyone give me some ideas? Could this be MX record / Reversed DNS relate? Or firewall NAT rule setting? Thanks.