I have a client who get the messange below when ever he try to send an e-mail to the anyone@ISPdomain. The client domain is NOT blocked by the ISPdomain.
Note that sometimes he can send the mail to anyone@ISPdomain, some other times he can't: no change in configuration.
sending e-mails to other domains is ok. The client faceing the problem only with some domains including ISPdomain.
His server is exchange 2000, not open relay, nothing is filterd, and all is fine.
From: System Administrator
Sent: Thursday, October 28, 2004 11:14 AM
Subject: Undeliverable: xxx
Your message did not reach some or all of the intended recipients.
Sent: 10/28/2004 11:14 AM
The following recipient(s) could not be reached:
xxxx@ISPdomain on 10/28/2004 11:14 AM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<clientdomain #5.5.0 smtp;550 Denied by policy: Sender is listed on DNS-based RBL>