Linux netstat命令详解
简介
Netstat 命令用于显示各种网络相关信息，如网络连接，路由表，接口状态 (Interface Statistics)，masquerade 连接，多播成员 (Multicast Memberships) 等等。
输出信息含义
执行netstat后，其输出结果为
Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 2 210.34.6.89:telnet 210.34.6.96:2873 ESTABLISHED tcp 296 0 210.34.6.89:1165 210.34.6.84:netbios-ssn ESTABLISHED tcp 0 0 localhost.localdom:9001 localhost.localdom:1162 ESTABLISHED tcp 0 0 localhost.localdom:1162 localhost.localdom:9001 ESTABLISHED tcp 0 80 210.34.6.89:1161 210.34.6.10:netbios-ssn CLOSE
Active UNIX domain sockets (w/o servers) Proto RefCnt Flags Type State I-Node Path unix 1 [ ] STREAM CONNECTED 16178 @000000dd unix 1 [ ] STREAM CONNECTED 16176 @000000dc unix 9 [ ] DGRAM 5292 /dev/log unix 1 [ ] STREAM CONNECTED 16182 @000000df
从整体上看，netstat的输出结果可以分为两个部分：
一个是Active Internet connections，称为有源TCP连接，其中"Recv-Q"和"Send-Q"指%0A的是接收队列和发送队列。这些数字一般都应该是0。如果不是则表示软件包正在队列中堆积。这种情况只能在非常少的情况见到。
另一个是Active UNIX domain sockets，称为有源Unix域套接口(和网络套接字一样，但是只能用于本机通信，性能可以提高一倍)。 Proto显示连接使用的协议,RefCnt表示连接到本套接口上的进程号,Types显示套接口的类型,State显示套接口当前的状态,Path表示连接到套接口的其它进程使用的路径名。
常见参数
-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。
提示：LISTEN和LISTENING的状态只有用-a或者-l才能看到
实用命令实例
1. 列出所有端口 (包括监听和未监听的)
列出所有端口 netstat -a
# netstat -a | more ?Active Internet connections (servers and established) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?tcp ???????0 ?????0 localhost:30037 ????????*:* ????????????????????LISTEN ?udp ???????0 ?????0 *:bootpc ???????????????*:* ??Active UNIX domain sockets (servers and established) ?Proto RefCnt Flags ??????Type ??????State ????????I-Node ??Path ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????6135 ????/tmp/.X11-unix/X0 ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????5140 ????/var/run/acpid.socket
列出所有 tcp 端口 netstat -at
# netstat -at ?Active Internet connections (servers and established) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?tcp ???????0 ?????0 localhost:30037 ????????*:* ????????????????????LISTEN ?tcp ???????0 ?????0 localhost:ipp ??????????*:* ????????????????????LISTEN ?tcp ???????0 ?????0 *:smtp ?????????????????*:* ????????????????????LISTEN ?tcp6 ??????0 ?????0 localhost:ipp ??????????[::]:* ?????????????????LISTEN
列出所有 udp 端口 netstat -au
# netstat -au ?Active Internet connections (servers and established) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?udp ???????0 ?????0 *:bootpc ???????????????*:* ?udp ???????0 ?????0 *:49119 ????????????????*:* ?udp ???????0 ?????0 *:mdns ?????????????????*:*
2. 列出所有处于监听状态的 Sockets
只显示监听端口 netstat -l
# netstat -l ?Active Internet connections (only servers) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?tcp ???????0 ?????0 localhost:ipp ??????????*:* ????????????????????LISTEN ?tcp6 ??????0 ?????0 localhost:ipp ??????????[::]:* ?????????????????LISTEN ?udp ???????0 ?????0 *:49119 ????????????????*:*
只列出所有监听 tcp 端口 netstat -lt
# netstat -lt ?Active Internet connections (only servers) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?tcp ???????0 ?????0 localhost:30037 ????????*:* ????????????????????LISTEN ?tcp ???????0 ?????0 *:smtp ?????????????????*:* ????????????????????LISTEN ?tcp6 ??????0 ?????0 localhost:ipp ??????????[::]:* ?????????????????LISTEN
只列出所有监听 udp 端口 netstat -lu
# netstat -lu ?Active Internet connections (only servers) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?udp ???????0 ?????0 *:49119 ????????????????*:* ?udp ???????0 ?????0 *:mdns ?????????????????*:*
只列出所有监听 UNIX 端口 netstat -lx
# netstat -lx ?Active UNIX domain sockets (only servers) ?Proto RefCnt Flags ??????Type ??????State ????????I-Node ??Path ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????6294 ????private/maildrop ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????6203 ????public/cleanup ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????6302 ????private/ifmail ?unix ?2 ?????[ ACC ] ????STREAM ????LISTENING ????6306 ????private/bsmtp
3. 显示每个协议的统计信息
显示所有端口的统计信息 netstat -s
# netstat -s ?Ip: ?11150 total packets received ?1 with invalid addresses ?0 forwarded ?0 incoming packets discarded ?11149 incoming packets delivered ?11635 requests sent out ?Icmp: ?0 ICMP messages received ?0 input ICMP message failed. ?Tcp: ?582 active connections openings ?2 failed connection attempts ?25 connection resets received ?Udp: ?1183 packets received ?4 packets to unknown port received. ?.....
显示 TCP 或 UDP 端口的统计信息 netstat -st 或 -su
# netstat -st ?# netstat -su
4. 在 netstat 输出中显示 PID 和进程名称 netstat -p
netstat -p 可以与其它开关一起使用，就可以添加 “PID/进程名称” 到 netstat 输出中，这样 debugging 的时候可以很方便的发现特定端口运行的程序。
# netstat -pt ?Active Internet connections (w/o servers) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ??????PID/Program name ?tcp ???????1 ?????0 ramesh-laptop.loc:47212 192.168.185.75:www ???????CLOSE_WAIT ?2109/firefox ?tcp ???????0 ?????0 ramesh-laptop.loc:52750 lax:www ESTABLISHED 2109/firefox
5. 在 netstat 输出中不显示主机，端口和用户名 (host, port or user)
当你不想让主机，端口和用户名显示，使用 netstat -n。将会使用数字代替那些名称。
同样可以加速输出，因为不用进行比对查询。
# netstat -an
如果只是不想让这三个名称中的一个被显示，使用以下命令
# netsat -a --numeric-ports # netsat -a --numeric-hosts # netsat -a --numeric-users
6. 持续输出 netstat 信息
netstat 将每隔一秒输出网络信息。
# netstat -c ?Active Internet connections (w/o servers) ?Proto Recv-Q Send-Q Local Address ??????????Foreign Address ????????State ?tcp ???????0 ?????0 ramesh-laptop.loc:36130 101-101-181-225.ama:www ESTABLISHED ?tcp ???????1 ?????1 ramesh-laptop.loc:52564 101.11.169.230:www ?????CLOSING ?tcp ???????0 ?????0 ramesh-laptop.loc:43758 server-101-101-43-2:www ESTABLISHED ?tcp ???????1 ?????1 ramesh-laptop.loc:42367 101.101.34.101:www ?????CLOSING ?^C
7. 显示系统不支持的地址族 (Address Families)
netstat --verbose
在输出的末尾，会有如下的信息
netstat: no support for `AF IPX‘ on this system. netstat: no support for `AF AX25‘ on this system. netstat: no support for `AF X25‘ on this system. netstat: no support for `AF NETROM‘ on this system.
8. 显示核心路由信息 netstat -r
# netstat -r ?Kernel IP routing table ?Destination ????Gateway ????????Genmask ????????Flags ??MSS Window ?irtt Iface ?192.168.1.0 ????* ??????????????255.255.255.0 ??U ????????0 0 ?????????0 eth2 ?link-local ?????* ??????????????255.255.0.0 ????U ????????0 0 ?????????0 eth2 ?default ????????192.168.1.1 ????0.0.0.0 ????????UG ???????0 0 ?????????0 eth2
注意： 使用 netstat -rn 显示数字格式，不查询主机名称。
9. 找出程序运行的端口
并不是所有的进程都能找到，没有权限的会不显示，使用 root 权限查看所有的信息。
# netstat -ap | grep ssh ?tcp ???????1 ?????0 dev-db:ssh ??????????101.174.100.22:39213 ???????CLOSE_WAIT ?- ?tcp ???????1 ?????0 dev-db:ssh ??????????101.174.100.22:57643 ???????CLOSE_WAIT ?-
找出运行在指定端口的进程
# netstat -an | grep ‘:80‘
10. 显示网络接口列表
# netstat -i ?Kernel Interface table ?Iface ??MTU Met ??RX-OK RX-ERR RX-DRP RX-OVR ???TX-OK TX-ERR TX-DRP TX-OVR Flg ?eth0 ??????1500 0 ????????0 ?????0 ?????0 0 ????????????0 ?????0 ?????0 ?????0 BMU ?eth2 ??????1500 0 ????26196 ?????0 ?????0 0 ????????26883 ?????6 ?????0 ?????0 BMRU ?lo ???????16436 0 ????????4 ?????0 ?????0 0 ????????????4 ?????0 ?????0 ?????0 LRU
显示详细信息，像是 ifconfig 使用 netstat -ie:
# netstat -ie ?Kernel Interface table ?eth0 ?????Link encap:Ethernet ?HWaddr 00:10:40:11:11:11 ?UP BROADCAST MULTICAST ?MTU:1500 ?Metric:1 ?RX packets:0 errors:0 dropped:0 overruns:0 frame:0 ?TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 ?collisions:0 txqueuelen:1000 ?RX bytes:0 (0.0 B) ?TX bytes:0 (0.0 B) ?Memory:f6ae0000-f6b00000
11. IP和TCP分析
查看连接某服务端口最多的的IP地址
wss8848@ubuntu:~$ netstat -nat | grep "192.168.1.15:22" |awk ‘{print $5}‘|awk -F: ‘{print $1}‘|sort|uniq -c|sort -nr|head -20 18 221.136.168.36 3 154.74.45.242 2 78.173.31.236 2 62.183.207.98 2 192.168.1.14 2 182.48.111.215 2 124.193.219.34 2 119.145.41.2 2 114.255.41.30 1 75.102.11.99TCP各种状态列表
wss8848@ubuntu:~$ netstat -nat |awk ‘{print $6}‘ established) Foreign LISTEN TIME_WAIT ESTABLISHED TIME_WAIT SYN_SENT?先把状态全都取出来,然后使用uniq -c统计，之后再进行排序。
wss8848@ubuntu:~$ netstat -nat |awk ‘{print $6}‘|sort|uniq -c 143 ESTABLISHED 1 FIN_WAIT1 1 Foreign 1 LAST_ACK 36 LISTEN 6 SYN_SENT 113 TIME_WAIT 1 established)?最后的命令如下:
netstat -nat |awk ‘{print $6}‘|sort|uniq -c|sort -rn分析access.log获得访问前10位的ip地址
awk ‘{print $1}‘ access.log |sort|uniq -c|sort -nr|head -10参考资料:http://blog.maxiang.net/10-netstat-command-examples/139/
http://www.ipcpu.com/2011/07/netstat-linux/
Linux netstat命令详解
原文地址：http://www.cnblogs.com/justuntil/p/7895016.html