My SMTP gateway (installed on windows 2008 R2) is getting rejected by mx1.comcast.net .How do I enable SMTP logging so I can troubleshoot the issue?
1. mxtoolbox doesn't show any smpt errors on my domain
2. when I try to telnet mx1.comcast.net port 25 it will not connect , while connects fine to any other server
3. I also have 2003 based (second) SMTP gateway which connects fine to mx1.comcast.net 25
both SPF records are good