$cat /proc/sys/net/ipv4/tcp_keepalive_intvl 75 $ tcp_keepalive_intvl the interval between subsequential keepalive probes, regardless of what the connection has exchanged in the meantime linux/net/ipv4/tcp.c – 8 identical 368: * MUST default to no keep-alives. (does) 369: * MUST make keep-alive interval configurable. (does) 370: * MUST make default keep-alive interval > 2 hours. (does) tcp_timer.c – 3 …