I recently ran into an issue where the Microsoft Exchange FrontEnd Transport service refused to stay started. As a result, no external mail was being delivered to the Exchange server.
From the Services app, I could start the service, but it would stop within a couple of seconds.
When reviewing the Application logs in the Event Viewer I ran into a few separate errors with a source of MSExchangeFrontEndTransport. The first error was merely a symptom of a broken Front End Transport and not the root cause. We ignored this one and moved on.
Inbound direct trust authentication failed for certificate %1. The source IP address of the server that tried to authenticate to Microsoft Exchange is [%2]. Make sure EdgeSync is running properly.
The second error gave us the clue we needed. This error indicated something else was already listening to port 25.
The address is already in use. Binding: 0.0.0.0:25.[Read more…] about MSExchangeFrontEndTransport – The address is already in use