TCP Keep Alive

OS Configuration (Linux)

tcp_keepalive_time

Since Linux 2.2.

The number of seconds a connection needs to be idle before TCP begins sending out keep-alive probes.

(空闲时，启动探测间隔时间（秒）)

$ cat /proc/sys/net/ipv4/tcp_keepalive_time
7200
$ sysctl net.ipv4.tcp_keepalive_time
net.ipv4.tcp_keepalive_time = 7200

$ sudo sysctl -w net.ipv4.tcp_keepalive_time = 3600

See tcp_keepalive_time - tcp(7) - Debian Manpages.

tcp_keepalive_probes

Since Linux 2.2.

The maximum number of TCP keep-alive probes to send before giving up and killing the connection if no response is obtained from the other end.

(网络不可达时，重发探测次数)

$ cat /proc/sys/net/ipv4/tcp_keepalive_probes
9
$ sysctl net.ipv4.tcp_keepalive_probes
net.ipv4.tcp_keepalive_probes = 9

$ sudo sysctl -w net.ipv4.tcp_keepalive_probes = 9

See tcp_keepalive_probes - tcp(7) - Debian Manpages.

tcp_keepalive_intvl

Since Linux 2.4.

The number of seconds between TCP keep-alive probes.

(网络不可达时，重发探测间隔时间（秒）)

$ cat /proc/sys/net/ipv4/tcp_keepalive_intvl
75
$ sysctl net.ipv4.tcp_keepalive_intvl
net.ipv4.tcp_keepalive_intvl = 75

$ sudo sysctl -w net.ipv4.tcp_keepalive_intvl = 25

See tcp_keepalive_intvl - tcp(7) - Debian Manpages.

Python Recipes

References