How to connect to MSSQL via SSH tunnel if there are 2 parts in the server name?

Question

SSH

There is a server called "MS-SQL009\SQL09" (inside the corporate network)
I try to connect / check the connection through the UDL file (on a working PC), it shows success.
telnet to 1433 fails to reach server MS-SQL009. ping is.
If you enter only "MS-SQL009" into the UDL file, then it will not work
. So what is this part of "\SQL09"?
And I'm still trying to connect via SSH tunnel to the "MS-SQL009" server on port 1433. But as I already said, there is no telneta even from the working machine and it's not clear where the udl file is connected.

Answer 1

SQL09- named instance. It was necessary to choose a default name.
Try making an alias for the server ( guide ).
From network: connection to MS SQL server via SSH tunnel .