1)Dealing with the client side

First of all, to deal on the client side /etc/ssh/ssh_configor ~/.ssh/configto describe the contents of two following.

$ vim ~/.ssh/config

ServerAliveInterval 15
ServerAliveCountMax 10

With this setting, we send an acknowledgment ten times to the server every 15 seconds, and
if there is no response timeout occurs.

2)Dealing with the server side

Next, on the server side, there is a corresponding way, but /etc/ssh/sshd_configto

$ vim / etc / ssh / sshd_config

ClientAliveInterval 30
ClientAliveCountMax 5

If you write it, it sends an acknowledgment five times to the client every 30 seconds,
but if there is no response it will time out.

reference:

https://qiita.com/ysk24ok/items/2f4ced5edf306fdd9dfb