Exchange 2010 cannot send mails to Exchange 2003 if it is not authorized to do so. In this case, the queue of the routing group fills up with the following error:
451 4.4.0 Primary target IP address responded with: "421 4.4.2 Connection dropped due to SocketError."
The problem can be solved by allowing the IP address of the Exchange 2010 server on the Exchange 2003 server:
As soon as the IP has been entered, the Exchange 2010 queue should empty and the messages should be delivered.
Hatten dank IPhone und Co leichtes Spiel beim Kunden.
Hast du es gut… :-)
Gut das die Kunden von uns schon 2007 oder 2010 haben und net von Urgestein migrieren müssen.