The command fw ctl pstat can be used to verify the number of active concurrent connections on a gateway. This command displays various statistics about the firewall kernel, such as memory usage, CPU utilization, packet rates, and connection table information. The output of this command includes a line that shows the current number of connections and the peak number of connections since the last reboot. For example:

This means that there are currently 1234 active connections out of a maximum of 8192 connections, which is 15% of the connection table capacity. The peak number of connections since the last reboot was 2345.

https://sc1.checkpoint.com/documents/R81/WebAdminGuides/EN/CP_R81_NextGenSecurityGateway_Guide/Topics-FWG/CLI/fw-logswitch.htm

In Advanced Permanent Tunnel Configuration, the life_sign_timeout parameter sets the amount of time the tunnel test runs without a response before the peer host is declared 'down'. The life_sign_polling_interval parameter sets the interval between each tunnel test packet sent to the peer host.
Reference:
topic=documents/R77/CP_R77_VPN_AdminGuide/14018
Advanced Permanent Tunnel Configuration