TCPKEEPINTVL

TCPKEEPINTVL is a TCP (Transmission Control Protocol) kernel parameter that controls the interval between successive keepalive probes. When a TCP connection is established, it can optionally be configured to send keepalive probes. These probes are small packets sent to the remote host to verify that the connection is still active. If the remote host does not respond to a keepalive probe within a certain time, the connection is considered to be broken.

The TCPKEEPINTVL parameter specifically determines how long the system waits between sending these probes. For example, if TCPKEEPINTVL is set to 60 seconds, the system will send a keepalive probe every 60 seconds if no data has been exchanged on the connection. This parameter works in conjunction with other TCP keepalive settings, such as TCPKEEPCNT, which defines the maximum number of unacknowledged probes that can be sent before the connection is considered dead.

Adjusting TCPKEEPINTVL can be useful in situations where network latency is high or connections are expected to be idle for extended periods. A shorter interval can detect dead connections more quickly, but it also increases network traffic. Conversely, a longer interval reduces overhead but may lead to longer delays in recognizing a terminated connection. The default value for TCPKEEPINTVL varies across different operating systems.