System Setup: Exchange 2007 running on Server 2008 R2
This system was setup about a year and a half ago and has been running fine for the longest time. Nothing has changed, now suddenly I am getting intermittent times where outgoing email hangs to many different domains. For the most part, the email usually goes through, but not until after a very long delay, which is obviously hindering business.
When I check the Queue, I see the following messages:
451 4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or deliver failed to all alternate hosts.
This is a small setup (<10 mailboxes) and I have not changed a thing before this started happening.
Here are some examples when I do an NSLOOKUP from the command prompt on this machine:
nslookup cox.net
Server: Unknown
Address: ::1
Non-authoritative answer:
Name: cox.net
Address: 68.99.123.161
nslookup carilionclinic.org
Server: Unknown
Address: ::1
Non-authoritative answer:
Name: carilionclinic.org
Address: 184.73.245.212
They all pretty much do the exact same thing.
I have no idea what has caused this?
Mike