How to use multiplexing in SSH

Multiplexing allows a single SSH connection to be shared by multiple sessions. The connection could be set to persist for a set time and then reused for fast reconnection to the server.

Sharing SSH sessions in a single connection via multiplexing could be configured in the user's SSH client configuration file.

1. Launch terminal.
2. Open SSH client configuration file for your user using your preferred text editor.

   $ vi ~/.ssh/config

3. Select the host(s) that you want to implement multiplexing.

   host *

   * applies configuration for all hosts. Other possible host options:

   example.com *.example.com 192.168.100.10 192.168.100.*

4. Enable multiplexing for the selected host(s).

   host *     controlmaster auto

5. Set how long do you want the multiplexing session to persist.

   host *     controlmaster auto     controlpersist 10m

6. Set path and filename for controlmaster file.

   host *     controlmaster auto     controlpersist 10m     controlpath ~/.ssh/muxmasters/%C

   Create folder if doesn't exist.

   $ mkdir -p ~/.ssh/muxmasters

7. Check for existing control file on local host.

   $ ls ~/.ssh/muxmasters

8. Log in to a remote host.

   $ ssh 192.168.111.159 -- hostname user@192.168.111.159's password:  remotehost

9. Check for created control file to confirm.

   $ ls ~/.ssh/muxmasters 598a7155ff90f076057fb265730c6ffe5997d4bb

10. Log in again to the same host to test.

    $ ssh 192.168.111.159 -- hostname host

    Should be without password and very fast as long as you log in again within the controlpersist time value.