Check if SSH tunnel is still running

Listening ports can only been seen from the machine that initiated the SSH Tunnel. Your command logs you into the remote system interactively. Consider the command following for better visibility:

ssh -nNf [email protected] -L 9999:10.238.93.43:8991

Once the tunnel is up, then execute the following command from client machine that initiated the tunnel:

netstat -tulpn | grep -i listen

You should get something like this:

tcp     0    0 127.0.0.1:9999       0.0.0.0:*      LISTEN      1286/ssh
tcp     0    0 ::1:9999              :::*           LISTEN      1286/ssh

Both lines in the results show 9999 as the listening port from client side. You will not be able to get same results from the server side.