Increase SSH Connection Timeout

SSH timeouts as a result of inactivity can be quite irritating. This usually compels you to reinitiate the connection and start all over again.

Thankfully, you can easily increase the SSH timeout limit and keep your SSH session alive even after some inactivity. This happens when either the server or the client sends null packets to the other system to keep the session alive.

Increase SSH Connection Timeout Steps

On the server, head over to the /etc/ssh/sshd_config configuration file.

sudo nano /etc/ssh/sshd_config

Scroll and locate the following parameters:

#ClientAliveInterval
#ClientAliveCountMax

The ClientAliveInterval parameter specifies the time in seconds that the server will wait before sending a null packet to the client system to keep the connection alive.

On the other hand, the ClientAliveCountMax parameter defines the number of client alive messages which are sent without getting any messages from the client. If this limit is reached while the messages are being sent, the sshd daemon will drop the session, effectively terminating the ssh session.

The timeout value is given by the product of the above parameters i.e.

For example, let’s say you have defined your parameters as shown:

ClientAliveInterval  1200
ClientAliveCountMax 3
TCPKeepAlive yes

Once done, reload the OpenSSH daemon for the changes to come into effect

sudo systemctl reload sshd