tcp_keepalive_intvl

file: /proc/sys/net/ipv4/tcp_keepalive_intvl
variable: net.ipv4.tcp_keepalive_intvl
Official reference

How frequently the probes are send out. Multiplied by tcp_keepalive_probes it is time to kill not responding connection, after probes started. Default value: 75sec i.e. connection will be aborted after ~11 minutes of retries.

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