I have a strange Exchange 2007 issue.
Config:
SBS2008
Exchange 2007 (Version 8.1 (Build 240.6))
Symantec Endpoint Protection Including Exchange Spam/Virus filtering
Cisco ASA 5501 is redirecting Port 25 to server's IP address
Issue:
Can send to any other domain on the internet except one specific credit union. Anytime a user at my location tries to send to this domain, it fails within 3 seconds.
Trouble shooting:
Sent test from client in HTML: Send Fails
Sent test from client in ASCII: Send Fails
Sent Test via telnet to por 25: Send WORKS!!
MXToolbox shows MX record correctly (my side)
MXToolbox shows no Blacklist issues. (myside)
MXToolbox SMTP test shows only one warning: Warning - Does not support TLS. (my side)
Their Side:
Exchange 2007
MXToolbox shows MX record correctly
MXToolbox shows no Blacklist issues.
MXToolbox SMTP test shows two warnings:
Warning - Does not support TLS.
Warning - Reverse DNS does not match SMTP Banner
Now I can send from a different domain to their server. This issue just appears to be between THIS office and the other side.