netstat命令

netstat
              -t：tcp协议相关
              -a：所有状态
              -n：以数字显示IP和端口
              -u：udp相关协议
              -l：处于监听状态
              -p：显示相关进程以及PID

# netstat -tan
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:2222                0.0.0.0:*                   LISTEN      
tcp        0      0 127.0.0.1:25                0.0.0.0:*                   LISTEN

# netstat -uan
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
udp        0      0 172.17.42.1:123             0.0.0.0:*                               
udp        0      0 172.16.173.245:123          0.0.0.0:*                               
udp        0      0 127.0.0.1:123               0.0.0.0:*

# netstat -tnl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:2222                0.0.0.0:*                   LISTEN      
tcp        0      0 127.0.0.1:25                0.0.0.0:*                   LISTEN

# netstat -tnlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name   
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      3868/mysqld         
tcp        0      0 0.0.0.0:2222                0.0.0.0:*                   LISTEN      1632/sshd           
tcp        0      0 127.0.0.1:25                0.0.0.0:*                   LISTEN      2010/master