We are in the process of migrating from 2007 to 2010 and currently have both in co-existence.
We had a problem where mail was not delivering from the Exchange 2010 to the 2007 server. All other mail was working ok (2010 to 2010, 2007 to 2007, external > Inbound etc..)
When I looked at the queues on the 2010 server I could see the mail being queued with the error -'451 4.4.0 Primary target IP address responded with: "451 5.7.3 Cannot achieve Exchange Server authentication
Next when inspecting the emails in the queue I see the following details:
Message Source Name: DSN
Source IP: 255.255.255.255
SCL: -1
Following on from this I added the 255.255.255.255 address to the newly created receive connector on the exchange 2007 server and the emails started flowing. If I remove the 255.255.255.255 address from the connector and add the servers actual IP the emails stall again.
My question is, why does Exchange 2010 list the source IP as 255.255.255.255 as opposed to the actual IP of 192.168.X.X?
Any suggestions appreciated.