一 监控原理
$ /bin/netstat -an|awk ‘/^tcp/{++S[$NF]}END{for(a in S) print a,S[a]}‘
TIME_WAIT 3464
FIN_WAIT1 31
FIN_WAIT2 3
ESTABLISHED 12
SYN_RECV 6
CLOSING 8
LISTEN 7
可以使用man netstat查看TCP的各种状态信息描述
ESTABLISHED socket已经建立连接
CLOSED socket没有被使用,无连接
CLOSING 服务器端和客户端都同时关闭连接
CLOSE_WAIT 等待关闭连接
TIME_WAIT The socket is waiting after close to handle packets still in the network. 表示收到了对方的FIN报文,并发送出了ACK报文,等待2MSL后就可回到CLOSED状态
LAST_ACK The remote end has shut down, and the socket is closed. Waiting for acknowledgement. 远端关闭,当前socket被动关闭后发送FIN报文,等待对方ACK报文
LISTEN 监听状态
SYN_RECV 接收到SYN报文
SYN_SENT 已经发送SYN报文
FIN_WAIT1 The socket is closed, and the connection is shutting down
FIN_WAIT2 Connection is closed, and the socket is waiting for a shutdown from the remote end.
2.监控脚本编写