This option applies to protocol version 2 only. The default is 0, indicating that these messages will not be sent to the client. Sets a timeout interval in seconds after which if no data has been received from the client, sshd(8) will send a message through the encrypted channel to request a response from the client.

This could be helpful if you run the server yourself and don't want to customize all your clients. You can set a similar option on the server side in /etc/ssh/sshd_config. You can enable it for all host if you use a wildcard Host * If you want to send the signal every minute to the remote host, put the following in the configuration file: Host The configuration for this goes into $HOME/.ssh/config on the client. The default is 0, indicating that these messages will not be sent to the server. Sets a timeout interval in seconds after which if no data has been received from the server, ssh(1) will send a message through the encrypted channel to request a response from the server. When we log out of the session or the session times out after being idle for quite some time, the SIGHUP signal is send to the pseudo-terminal and all the jobs that have been run on that terminal, even the jobs that have their parent jobs being initiated on the pseudo-terminal are also sent the SIGHUP signal and are forced to terminate. If the server terminates the connection because the client was silent for too long, you can set the ServerAliveInterval (assuming you are using OpenSSH). 5 Ways to Keep SSH Sessions Running After Disconnection. Your post does not contain information why the connection timeout happens.

Ssh tunnel keep alive