Here are the steps to increase ssh timeout at the server level on Linux OS:

These steps are performed on CentOS:

Modify the following directives by editing the sshd config file: /etc/ssh/sshd_config

TCPKeepAlive yes
ClientAliveInterval 30
ClientAliveCountMax 99999


Restart SSH Demon after modifying the config file:

[root@mars ~]# service sshd restart
Stopping sshd: [ OK ]
Starting sshd: [ OK ]

Caution: only recommended in development environment.