https://blog.csdn.net/asty9000/article/details/81536441
sysctl -a |grep keepalive
发现为默认的配置
net.ipv4.tcp_keepalive_time = 7200 net.ipv4.tcp_keepalive_probes = 9 net.ipv4.tcp_keepalive_intvl = 75
默认情况下在连接空闲7200秒即2个小时后才会发送keepalive探测包来确认连接情况。
解决：通过修改keepalive配置为合适的值（如改为200秒）可以快速释放端口连接。
临时修改，通过echo设置tcp_keepalive_time。
echo "200" > /proc/sys/net/ipv4/tcp_keepalive_time
永久生效，编辑/etc/sysctl.conf，新增或修改为
net.ipv4.tcp_keepalive_time = 200
然后执行命令使修改后的配置生效
sysctl -p标签：sysctl,断开,time,tcp,TCP,Linux,net,ipv4,keepalive From： https://www.cnblogs.com/x666-6/p/17006201.html