/proc/sys/net/ipv4/tcp_keepalive_time
/proc/sys/net/ipv4/tcp_keepalive_intvl
/proc/sys/net/ipv4/tcp_keepalive_probes
/proc/sys/net/ipv4/tcp_retries2

HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services: Tcpip Parameters

TcpInitialRTT: Defines what the initial time-out settings are for new connections. This number in seconds is doubled each time it retransmits before timing a connection out. Defaults to 3.

TcpMaxConnectRetransmissions: Defines the number of retransmissions before timing a connection out. Defaults to 5.