This past month I setup a new Windows 2008 R2 server with Exchange 2010 and added it to our environment along with our old Server 2003 server running Exchange 2003.
I was able to get all of the mail boxes moved over and was able to verify that all the users where pointing to the new server, I was able to get all of the users sending and receiving e-mail without much hassle however I have several integrated systems that we have here and they are now broke.
I still have the old 2003 up and running and the hub transport is in place to the best of my knowledge. We have uptime and it still points to the old server by IP address which is still sending mail just fine. However our most important system is current not able to send any mail and is receiving an error in the code.
"The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure"
The program we use is developed in house and I am sure we could change all the code to the new server but right now thats not an option. The old server to the best of my knowledge is still allowing mail to flow so this should still work. Like I said my Up.Time is configured to point to the old server and if I send a report it goes through just fine.
This is from Up.Time to show you how its configured and working correctly
"Attempting to send message to up.time Administrator - **MASKED**@**MASKED**.com
Test message from up.time Monitoring Station
SMTP Server: 10.31.2.10
SMTP Port: 25
SMTP Sender: "uptime Monitoring Station" <uptime@**MASKED**>
SMTP Helo String: uptimesoftware.com
Message sent successfully."
I dont know if I need to enable the mail relay to certain IP's which is how its setup on the old server or if I should be looking into something else.