Scenario: I have existing Exchange 2013 server that has issues with database corruption and it won't update. I have installed a 2nd Exchange 2013 server and service packed etc and with new databases. I have migrated a test mailbox to the new server and can send mail out without a problem. However I cannot receive mail from the internet or from users on the old server. My intention is to decommission the old server, no NLB or DAG required. Sure i'm missing something obvious, just not sure what.
Additional info. If I look in the queues I have an entry for 'unreachable domain' and error message on a message in that queue; "There is currently no route to the mailbox database.;2;EXH02DB01;0"