It appears Bellsouth.net (aka Att.net) has made some further adjustments to their mail security that are causing more a few of my clients to have mail bounceback issues. These are not new installs, One exchange server has been up for 4 years with no changes of note.
We are not receiving a specific error message in return to help obtain the exact issue. Currently the affected clients are all on Exchange 2003, REV DNS is configured, No special firewall router/spam filtering.
Error message is as follows
Delivery to the following recipients has been delayed
Final-Recipient: accountID ;firstname.lastname@example.org
Will-Retry-Until: Thu, 7 Feb 2008 10:35:36 -0500
X-Display-Name: User Name(email@example.com)