I have been receiving the following bounced messages. I believe the problem is at the remote site I'm sending too. But, I need some clarification. I changed the usernames and hostnames for privacy.
Final-Recipient: rfc822; user@destination_host_name
Remote-MTA: dns; destination_host_name
Diagnostic-Code: smtp; 451 4.1.8 <list_name@myhost>... Domain of sender address list_name@myhost does not resolve
Last-Attempt-Date: Mon, 19 Mar 2001 08:11:52 -0500 (EST)
As clarification I did an nslookup on myhost and it resolves fine.