I'm hoping there are some Exchange experts out there that can help me understand an error I'm seeing and if it is an indication that the server is compromised. I've been administering Exchange servers since version 5 (I don't mean 2005) but I wear many hats and I rarely have to do much more than general user/mailbox administration so I am not an expert.
Anyway, I noticed in the Queue Viewer today an entry that was retrying because of this error:
Text
451 4.4.0 Primary target IP address responded with: "421 4.3.2 System not accepting network messages." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.That error is pretty self explanatory but when I look at the three messages in that queue, I see some unusual things that don't look right to me....