SQL server did not listen to port 1433

[suedixon]

Hi,
We have SQL server 2005 installed in our production environment.

During a maintenace change when we changed the SQL Server Agent service account, when the SQL was started it did not listen to port 1433. There is one more port in use 1434. Every time SQL server start it Listens to both the ports except this only time.

On next morning when the SQL server was started again it started with out any issue this time correctly listening to port 1433 as well as 1434.

Can any one come up with any reason why a SQL server might not listen to port 1433 (TCP/IP) on startup? We are just after the root cause of this issue for our future reference. The SQL Server is working fine without any issue now.

[rmiao]

Did you see any related message in sql server log and windows event logs? Ensure no any other process on the server uses that port.

[skhanal]

When it is not listening on 1433, run netstat command to see what other service is using that port. It sounds like something started before SQL server and is configured to use 1433.

[suedixon]

Thanks for your response. There is nothing else configured to use that port. Also that problem was just that one time. After that it is listening to that port everytime without any issue.