Exchange 5.5 An attempt to connect to host <hostname>.org failed.

[cmolnar]

Im running Exchange 5.5 Server Sp4, with the IMC installed. I just started having problems with users sending e-mail to one specific domain. I enabled all the advanced logging features for the IMC, and this is what i found. (edited out the actuall domain names and ip address)

When our server attempts to connect to the recipients server. Theese are the Event IDs logged.

EventID 3010 An attempt to connect to host <recipientdomain>.org failed.

and

A new TCP/IP SMTP connection has been made to host <edited out IP address> (for <recipientdomain>.org). Logfile: L0000000.LOG

here is the contents L000000.log

|
8/4/04 10:17:22 AM : <<< 220 <recipientdomain>.org ESMTP MDaemon 7.1.1; Wed, 04 Aug 2004 10:14:54 -0400
8/4/04 10:17:22 AM : >>> EHLO server1.<originatordomain>.org

8/4/04 10:17:23 AM : <<< IO: |451 <server1.<originatordomain>.org> is invalid or DNS says does not exist
|
8/4/04 10:17:23 AM : <<< 451 <server1.<originatordomain>.org> is invalid or DNS says does not exist

8/4/04 10:17:23 AM : >>> QUIT

8/4/04 10:17:23 AM : <<< IO: |221 See ya in cyberspace
|
8/4/04 10:17:23 AM : <<< 221 See ya in cyberspace
8/4/04 10:17:23 AM : 499 Host unreachable: <recipientdomain>.org. Message subject: ""test"". Rescheduling delivery for later.



The problem as i see it is the recipients server appears to be doing a reverse lookup on the us. BUT it is prefixing our actual netbios servername to our domain. which does not have an DNS entry..

this is the only domain we have troubles emailing.. other then this problem our server has been running fine for the last 4 years =) im not sure how to proceed from here..