-----Original Message----- From: Greg Hermida [mailto:ghermida@xxxxxxxxxxxxxxx] Sent: Tuesday, May 04, 2004 5:09 PM To: [ExchangeList] Subject: [exchangelist] Outbound emails http://www.MSExchange.org/ I am running an Exchange 5.5 Enterprise with sp4 on a win2k server. It is a single site, single exchange server in a mixed mode NT4 domain. I usually have a bunch of outbound messages stuck in the "Outbound awaiting delivery" with no Originator header going towards various spam related websites. I manually delete hundreds of these out of the que several times a day. Is there a way to configure the exchange server not to accept any email which has no Originator information? I have relaying shut down tight. I assume that these emails are the result of either a virus on an infected pc here on our network or pc's with spyware loaded accidentally on them or something of this nature. If there was a way to lock down the exchange server, is there a downside to this action? thanks, Greg My guess is that you are seeing NDRs from <> because Exchange accepts the message then verifies that there is a valid email address. The fix is to reject during the SMTP for invalid users but in the Exchange Family only 2003 has that ability natively. I use an LDAP lookup from my Linux box running my filtering software CanIt-Pro http://www.canit.ca. John