Strange DNS/SMTP related messages

Hello all,

We've seen these types of messages in our Domino server's log going
back in history and have never really had a problem apparent with them, but
are trying to get them cleaned up and fix whatever the root issue is. Just
a few weeks ago, I realized what was occurring - you will notice that the
host name appears to get truncated for some reason in each instance.

Our setup is as follows, we relay our outgoing mail to MessageLabs via the
hostname 'cluster2out.us.messagelabs.com', which is handled by a cluster of
servers on their end. NSLOOKUP (from an i5/OS prompt) for that host name
will return a number of IP addresses. If a NSLOOKUP is done on those
particular IPs that are returned, they all resolve to valid/complete
hostnames (mail73.messagelabs.com for instance).

We cannot figure out why when we resolve cluster2out.us.messagelabs.com we
are getting these incomplete hostnames back (that then fail to resolve).
Anyone seen this or have any ideas?



12/06/2007 12:21:04 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail73.MESSAGELAB) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 12:34:53 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail196.MESSAGELABS) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 12:36:23 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail53.MESSAGEL) via SMTP: The remote
server is not a known TCP/IP host.

12/06/2007 12:52:04 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail197.MESSAGELAB) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 13:00:16 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail196.MESSAGELABS) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 13:01:33 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail197.MESSAGELAB) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 13:06:06 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail64.MESSAGELA) via SMTP: The remote
server is not a known TCP/IP host.

12/06/2007 13:19:44 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail129.MESSAGELABS.C) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 13:25:56 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail167.MESSAGELABS.C) via SMTP: The
remote server is not a known TCP/IP host.

12/06/2007 13:29:03 Router: No messages transferred to
CLUSTER2OUT.US.MESSAGELABS.COM (host mail196.MESSAGELABS) via SMTP: The
remote server is not a known TCP/IP host.