Changing the Keep Alive timer

This covers how to change the Keep Alive timer in the Opengear console servers. The purpose of this is to allow for greater flexibility in various environments. 

By default the timers are set as follows: 

# cat /proc/sys/net/ipv4/tcp_keepalive_time
7200

# cat /proc/sys/net/ipv4/tcp_keepalive_intvl
75

# cat /proc/sys/net/ipv4/tcp_keepalive_probes
9
7200 = 2 Hours by default, this may too long for some clients using Windows Winsock. For best results to keep sessions open using Windows clients (PuTTY, SecureCRT, Command) it is recommended to reduce the time to 15 minutes - 900.

You can adjust the keep alive timer via the cli interface by entering this syntax:
# echo 600 > /proc/sys/net/ipv4/tcp_keepalive_time 900

To verify:

# cat /proc/sys/net/ipv4/tcp_keepalive_time

This won’t be persistent across reboots, for that you would need to add this line to the startup script:

/etc/config/rc.local

# echo 600 > /proc/sys/net/ipv4/tcp_keepalive_time 900