421, 4.3.2, service not available, closing transmission channel
Posted on 2014-08-20
I have moved 4 servers from Inside to DMZ on my network. So, IP addresses have changed.
Two of the four servers we moved to DMZ from Inside network are application servers that use our exchange server as a relay to send automated notifications to members.
I have created new receive connector on the Exchange 2007 to reflect new IP addresses and created rule on DMZ interface of the firewall to have connectivity to exchange server via SMTP ( I added Telnet now for testing).
When app servers try to connect to exchange to send an email, we get this error:
"421 4.3.2, Service not available, closing transmission channel"
That possible indicates that app server does not have permissions to talk to exchange.
I tried manually connecting to exchange via telnet from app server on DMZ and got same result.
However, I do see that this SMTP rule is being used on the cisco ASA firewall.
I think I created Exchange Receive Connector properly and Firewall rule from DMZ to Inside is being used.
I am missing something.