netstat是控制台命令,是一个监控TCP/IP网络的非常有用的工具，它可以显示路由表、实际的网络连接以及每一个网络接口设备的状态信息。Netstat用于显示与IP、TCP、UDP和ICMP协议相关的统计数据，一般用于检验本机各端口的网络连接情况。

常用选项

• -a (all)显示所有选项，默认不显示LISTEN相关
• -t (tcp)仅显示tcp相关选项
• -u (udp)仅显示udp相关选项
• -n 拒绝显示别名，能显示数字的全部转化成数字。
• -l 仅列出有在 Listen (监听) 的服務状态
• -p 显示建立相关链接的程序名
• -r 显示路由信息，路由表
• -e 显示扩展信息，例如uid等
• -s 按各个协议进行统计
• -c 每隔一个固定时间，执行该netstat命令。

示例

1. 列出所有的网络连接。

   ma@ma:~$ netstat -a | tail -10
   unix  3      [ ]         STREAM     CONNECTED     19834    
   unix  3      [ ]         STREAM     CONNECTED     29730    @/tmp/dbus-ZuLcXGJsqx
   unix  3      [ ]         STREAM     CONNECTED     28459    
   unix  3      [ ]         STREAM     CONNECTED     28134    
   unix  3      [ ]         STREAM     CONNECTED     85061    @/tmp/dbus-ZuLcXGJsqx
   unix  3      [ ]         STREAM     CONNECTED     28631    @/tmp/dbus-x79US7IeiT
   unix  3      [ ]         STREAM     CONNECTED     28484    
   unix  3      [ ]         STREAM     CONNECTED     25628    /var/run/dbus/system_bus_socket
   unix  3      [ ]         STREAM     CONNECTED     30171    @/tmp/.X11-unix/X0
   unix  3      [ ]         STREAM     CONNECTED     28364    

2. 列出监听中的连接。

   ma@ma:~$ netstat -l | tail -10
   unix  2      [ ACC ]     STREAM     LISTENING     19537    /run/acpid.socket
   unix  2      [ ACC ]     STREAM     LISTENING     19538    /var/run/avahi-daemon/socket
   unix  2      [ ACC ]     STREAM     LISTENING     19539    /var/run/dbus/system_bus_socket
   unix  2      [ ACC ]     STREAM     LISTENING     19540    /var/run/cups/cups.sock
   unix  2      [ ACC ]     STREAM     LISTENING     22992    /var/run/NetworkManager/private-dhcp
   unix  2      [ ACC ]     STREAM     LISTENING     22842    /tmp/.X11-unix/X0
   unix  2      [ ACC ]     STREAM     LISTENING     29201    /tmp/.ICE-unix/2496
   unix  2      [ ACC ]     STREAM     LISTENING     27712    @/tmp/dbus-ZuLcXGJsqx
   unix  2      [ ACC ]     STREAM     LISTENING     27642    @/com/ubuntu/upstart-session/1000/2243
   unix  2      [ ACC ]     STREAM     LISTENING     123399   /var/run/pcscd/pcscd.comm

3. 以IP地址列出所有的连接，并且显示连接的进程。

   ma@ma:~$ netstat -apn | tail -10
   (Not all processes could be identified, non-owned process info
   will not be shown, you would have to be root to see it all.)
   unix  3      [ ]         STREAM     CONNECTED     19834    -                   
   unix  3      [ ]         STREAM     CONNECTED     29730    2354/dbus-daemon    @/tmp/dbus-ZuLcXGJsqx
   unix  3      [ ]         STREAM     CONNECTED     28459    2564/indicator-sess 
   unix  3      [ ]         STREAM     CONNECTED     28134    2433/ibus-ui-gtk3   
   unix  3      [ ]         STREAM     CONNECTED     85061    2354/dbus-daemon    @/tmp/dbus-ZuLcXGJsqx
   unix  3      [ ]         STREAM     CONNECTED     28631    2467/dbus-daemon    @/tmp/dbus-x79US7IeiT
   unix  3      [ ]         STREAM     CONNECTED     28484    2571/dconf-service  
   unix  3      [ ]         STREAM     CONNECTED     25628    -                   /var/run/dbus/system_bus_socket
   unix  3      [ ]         STREAM     CONNECTED     30171    -                   @/tmp/.X11-unix/X0
   unix  3      [ ]         STREAM     CONNECTED     28364    2509/unity-panel-se 

4. 列出所有的udp连接。

   ma@ma:~$ netstat -aupn | tail -10
   (Not all processes could be identified, non-owned process info
   will not be shown, you would have to be root to see it all.)
   Active Internet connections (servers and established)
   Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
   udp        0      0 0.0.0.0:5353            0.0.0.0:*                           -               
   udp        0      0 0.0.0.0:55611           0.0.0.0:*                           -               
   udp        0      0 0.0.0.0:631             0.0.0.0:*                           -               
   udp        0      0 0.0.0.0:53301           0.0.0.0:*                           -               
   udp        0      0 127.0.1.1:53            0.0.0.0:*                           -               
   udp        0      0 0.0.0.0:68              0.0.0.0:*                           -               
   udp6       0      0 :::5353                 :::*                                -               
   udp6       0      0 :::43439                :::*                               -