I think you're referring to the OS sending its own TCP keepalive probes - as configured by sysctls like net.ipv4.tcp_keepalive_(intvl|probes|time)
TCP keepalive messages are what the kernel uses, and not what circumvents the kernel's own probes.
Applications can also implementation their own layers of 'are you alive?'/'yes I am' type messages on top. SSH has its own messages (see the ServerAliveInterval/ServerAliveCountMax config keys)
TCP keepalive messages are what the kernel uses, and not what circumvents the kernel's own probes.
Applications can also implementation their own layers of 'are you alive?'/'yes I am' type messages on top. SSH has its own messages (see the ServerAliveInterval/ServerAliveCountMax config keys)