-----Original Message----- From: Gary Gregg Sent: Saturday, March 16, 2002 12:15 PM To: 'exchangelist@xxxxxxxxxxxxx' Subject: email probs Hi all we have a small problem in our mail setup. We are running exchange 5.5 sp4 win2k box. We have 2 exchange servers in different locations both in the same organization the company is split into 2 locations one server at each site. Our server receives SMTP mail via our router; the other site uses pop accounts for email. For some reason our mail server is sending our domain name on all of the pop mail accounts and this is causing problems for the users. I get this message back A mail message was not sent due to a protocol error. 501 mail not accepted from blacklisted IP address The message that caused this notification was: To: <ole.christensen@xxxxxx> From: <IMCEAEX-_O=EXCEL_OU=XLTF_CN=RECIPIENTS_CN=OLE+20PETERC@xxxxxxxxxxx> Subject: testsdfsdfsdf Anyone got any ideas Thanks Gary