This is the mail system at host thedude.zentela.com. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system : host mail.remotedomain.com[207.44.153.15] said: 554 This server requires PTR for unauthenticated connections. (in reply to RCPT TO command) Reporting-MTA: dns; thedude.mydomain.com X-Postfix-Queue-ID: 92DE23B00E X-Postfix-Sender: rfc822; brian@myOTHERdomain.com Arrival-Date: Mon, 24 Mar 2008 14:22:40 -0400 (EDT) Final-Recipient: rfc822; steve@remotedomain.com Original-Recipient: rfc822;steve@remotedomain.com Action: failed Status: 5.0.0 Remote-MTA: dns; mail.remotedomain.com Diagnostic-Code: smtp; 554 This server requires PTR for unauthenticated connections Pinging mydomain.com... PING mydomain.com (67.18.187.245) 56(84) bytes of data. 64 bytes from thedude.mydomain.com (67.18.187.245): icmp_seq=1 ttl=64 time=0.036 ms pinging myOTHERdomain.com... PING mydomain.com (67.18.187.245) 56(84) bytes of data. 64 bytes from thedude.mydomain.com (67.18.187.245): icmp_seq=1 ttl=64 time=0.036 ms pinging remotedomain.com... PING remotedomain.com (207.44.153.15) 56(84) bytes of data. 64 bytes from ev1s-207-44-153-15.ev1servers.net (207.44.153.15): icmp_seq=1 ttl=118 time=6.70 ms