Ok this is a weird one that started happening after a reboot.. I telnet into our Exchange 2007 CAS server with the following: telnet <IP of Exchange Server> 143 And this is what is returned: 220 <hostname> Microsoft ESMTP MAIL Service ready at Fri, 4 Dec 2009 10:53:05 -0600 Notice anything weird? Yea.. it's returning an SMTP header! What the heck. I ran port query and it just confirms this: TCP port 143 (imap service): LISTENING Data returned from port: 220 <hostname> Microsoft ESMTP MAIL Service ready at Fri, 4 Dec 2009 10:55:07 -0600 After running a "Netstat -a" it looks like maybe two connections are trying to use that port. I get two entries: TCP <hostname>:imap <hostname>:0 LISTENING TCP <hostname>:imap <hostname>:0 LISTENING Any Ideas on this one? I tried stopping the Exchange IMAP4 service and ran a telnet test, but still received a reply with the ESMTP header.

Ok ran a "netstat -a -b" to find what processes were using these ports: TCP <hostname>:imap <hostname>:0 LISTENING 5692 [Microsoft.Exchange.Imap4Service.exe] TCP <hostname>:imap <hostname>:0 LISTENING 3244 [edgetransport.exe] We do have a Receive Connector for Notifylink that pushes/pulls email to our blackberries, and that is set to receive mail on port 143. So that explains why two services are listening on the IMAP port. Still not sure why I still receive a SMTP header response on port 143 though, and why I still receive that response even after I've stopped the IMAP service on the Exchange server.

Can you paste the output of Get-ReceiveConnector here?Active Directory, 4th Edition - www.briandesmond.com/ad4/

Brian - I just sent using your websites contact page. It has internal server names on it, and I'd rather not post in a public forum. Let me know if it doesn't make it to you in a good format and I can resend another way. Thanks for the help Chris

Chris-Got it.Your problem here is that you have the "Internal Relay" Receive Connector bound to Port 143. If you pull up the properties of that and go on the Network tab you can change this.Active Directory, 4th Edition - www.briandesmond.com/ad4/

Ahh that was it. Awesome.. that one was throwing me for a loop! Thanks Brian! Chris