As the title suggests, I have a block of IP addresses in which I have sat a number of servers running Exchange Server, of various versions.
They are all servers I am hosting for clients, and my Exchange Server is in the same block of IPs.
Each Exchange Server is for a different Internet domain, and works as expected, except one.
My server cannot send mail to one of the others. Investigation has found that it will not accept mail from any of the four other Exchange Servers on that block of IPs, either.
If I log on to any of the other Exchange Servers via RDP and Telnet to the rogue server (SBS 2008, Exchange 2007) on port 25 I get:
421 4.3.2 Service not available, closing transmission channel
I figured I would add all the IPs in the block to the Network tab of the default Receive Connector. After doing so I can Telent from any of the server in the IP block to the problem child on port 25 and it opens a connection.
But, mail does not get through, and I get a message that it is queued for a later delivery attempt.
What else should I do?