We have a SQL Server Cluster with a number of named instances for production, dev and test). We have an application which needs to utilise a static port, the port that is used in SQL is then entered into the application.
We tried changing the port to one that sits outside the range that is used for dynamic port allocation and the SQL would not come back online.
The errors in application and system logs:
- APP: Server TCP provider failed to listen on [ 10.150.x.y <ipv4> 49152]. Tcp port is already in use.
- APP: TDSSNIClient initialization failed with error 0x271d, status code 0xa. Reason: Unable to initialize the TCP/IP listener. An attempt was made to access a socket in a way forbidden by its access permissions.
- SYS: The SQL Server (PROD) service terminated with service-specific error An attempt was made to access a socket in a way forbidden by its access permissions..
I assume from this we've just picked a port that is allocated or listening already. Two questions:
- Is picking a free static port trial and error or is there a best practice to allocating ports to named instances?
- What would be the impact of using port 1433 which is usually associated with the default instance which in this case we don't utilise? Btw, port 1433 works on this named instance.
Many thanks.