How to stop multiplexing sessions in SSH

Stopping SSH multiplexing sessions is necessary when you need to close active connections or free up system resources. SSH multiplexing allows multiple sessions to share a single connection. However, you may need to terminate these sessions when they are no longer required.

In an SSH multiplexing setup, a control master process manages all multiplexed sessions. Stopping this process will terminate all related sessions. This is useful for resetting connections or maintaining security.

Exit command can be used to stop multiplexing sessions in SSH. The command ensures that all connections are properly closed and resources are freed.

1. Open the terminal on your local machine.

   $ ssh user@remotehost

2. Identify the control master process managing the multiplexed sessions.

   $ ps aux | grep ssh | grep -E 'master|mux'

3. Stop the multiplexing session by sending an exit command to the control master.

   $ ssh -O exit user@remotehost

   This command will close the control master and all related multiplexed sessions.

4. Verify that the control master process has stopped and the socket is removed.

   $ ls /tmp/ssh-* | grep -v "No such file or directory"

   If the socket is still present, the master session may still be active.

5. Ensure all multiplexed sessions are closed and no longer active.

   $ lsof -U | grep /tmp/ssh-*

   This command checks for any remaining active multiplexed connections.