netstat
netstat -nt —>>>查看tcp连接
netstat -nua —>>>查看udp连接
[root@dbserver ~]# netstat -nt --->>>查看tcp连接
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 52 192.168.80.187:22 192.168.80.1:54458 ESTABLISHED
tcp 0 0 192.168.80.187:22 192.168.80.1:54455 ESTABLISHED
tcp 0 0 192.168.80.187:22 192.168.80.1:52256 ESTABLISHED
tcp 0 0 192.168.80.187:22 192.168.80.1:52264 ESTABLISHED
tcp 0 0 192.168.80.187:7432 192.168.80.1:54515 ESTABLISHED
[root@dbserver ~]# netstat -nua --->>>查看udp连接
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 0.0.0.0:5353 0.0.0.0:*
udp 0 0 0.0.0.0:41277 0.0.0.0:*
udp 0 0 127.0.0.1:323 0.0.0.0:*
udp 0 0 0.0.0.0:978 0.0.0.0:*
udp 0 0 192.168.122.1:53 0.0.0.0:*
udp 0 0 0.0.0.0:67 0.0.0.0:*
udp 0 0 0.0.0.0:111 0.0.0.0:*
udp6 0 0 ::1:323 :::*
udp6 0 0 ::1:61020 ::1:61020 ESTABLISHED
udp6 0 0 :::978 :::*
udp6 0 0 :::111 :::*
[root@dbserver ~]#
如下取自man netstat的结果：
Recv-Q
Established: The count of bytes not copied by the user program connected to this socket.
Listening: Since Kernel 2.6.18 this column contains the current syn backlog.
Send-Q
Established: The count of bytes not acknowledged by the remote host.
Listening: Since Kernel 2.6.18 this column contains the maximum size of the syn backlog.
