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Linux命令学习之路---网络状态(netstat)命令

2015-07-20 09:37 645 查看


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


</pre></div></div><h2 style="margin: 10px 0px 3px; padding: 0px; line-height: 25.99431800842285px; font-size: 21px; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;"><a target=_blank name="t8" style="color: rgb(202, 0, 0);"></a><strong><span style="line-height: 1.5; font-size: 14pt;">3. 显示每个协议的统计信息</span></strong></h2><p style="margin: 10px auto; padding-top: 0px; padding-bottom: 0px; font-size: 13px; line-height: 19.5px; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;"><strong>  显示所有端口的统计信息 netstat -s</strong></p><div class="wp_syntax" style="font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: 13px; line-height: 19.5px;"><div class="code"><div class="cnblogs_code" style="background-color: rgb(245, 245, 245); border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; font-family: 'Courier New' !important; font-size: 12px !important;"><div class="cnblogs_code_toolbar" style="margin-top: 5px;"><span class="cnblogs_code_copy" style="padding-right: 5px; line-height: 1.5 !important;"><a target=_blank target="_blank" title="复制代码" style="color: navy; border: none !important;"><img src="http://common.cnblogs.com/images/copycode.gif" alt="复制代码" style="border: none !important; max-width: 100%;" /></a></span></div><pre style="white-space: pre-wrap; word-wrap: break-word; margin-top: 0px; margin-bottom: 0px; font-family: 'Courier New' !important;"># netstat -s
Ip:
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">11150</span> total packets received
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">1</span> with invalid addresses
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">0</span> forwarded
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">0</span> incoming packets discarded
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">11149</span> incoming packets delivered
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">11635</span> requests sent <span style="color: rgb(0, 0, 255); line-height: 1.5 !important;">out</span>
Icmp:
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">0</span> ICMP messages received
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">0</span> input ICMP message failed.
Tcp:
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">582</span> active connections openings
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> failed connection attempts
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">25</span> connection resets received
Udp:
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">1183</span> packets received
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">4</span> 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


</pre></div></div><h2 style="margin: 10px 0px 3px; padding: 0px; line-height: 25.99431800842285px; font-size: 21px; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;"><a target=_blank name="t11" style="color: rgb(202, 0, 0);"></a><strong><span style="line-height: 1.5; font-size: 14pt;">5. 在 netstat 输出中不显示主机,端口和用户名 (host, port or user)</span></strong></h2><p style="margin: 10px auto; padding-top: 0px; padding-bottom: 0px; font-size: 13px; line-height: 19.5px; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;">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。</p><p style="margin: 10px auto; padding-top: 0px; padding-bottom: 0px; font-size: 13px; line-height: 19.5px; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;">同样可以加速输出,因为不用进行比对查询。</p><div class="wp_syntax" style="font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: 13px; line-height: 19.5px;"><div class="code"><div class="cnblogs_code" style="background-color: rgb(245, 245, 245); border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; font-family: 'Courier New' !important; font-size: 12px !important;"><pre style="white-space: pre-wrap; word-wrap: break-word; margin-top: 0px; margin-bottom: 0px; font-family: 'Courier New' !important;"># 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


</pre><h2 style="margin: 10px 0px 3px; padding: 0px; font-size: 21px;"><a target=_blank name="t22" style="color: rgb(202, 0, 0);"></a><strong><span style="line-height: 1.5; font-size: 14pt;"> </span></strong></h2><h2 style="margin: 10px 0px 3px; padding: 0px; font-size: 21px;"><a target=_blank name="t23" style="color: rgb(202, 0, 0);"></a><strong><span style="line-height: 1.5; font-size: 14pt;">11. IP和TCP分析</span></strong></h2><p style="margin: 10px auto; padding-top: 0px; padding-bottom: 0px; line-height: 1.5;"><strong>  查看连接某服务端口最多的的IP地址</strong></p><div class="cnblogs_code" style="background-color: rgb(245, 245, 245); border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; font-family: 'Courier New' !important; font-size: 12px !important;"><div class="cnblogs_code_toolbar" style="margin-top: 5px;"><span class="cnblogs_code_copy" style="padding-right: 5px; line-height: 1.5 !important;"><a target=_blank target="_blank" title="复制代码" style="color: navy; border: none !important;"><img src="http://common.cnblogs.com/images/copycode.gif" alt="复制代码" style="border: none !important; max-width: 100%;" /></a></span></div><pre style="white-space: pre-wrap; word-wrap: break-word; margin-top: 0px; margin-bottom: 0px; font-family: 'Courier New' !important;">wss8848@ubuntu:~$ netstat -nat | grep <span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">"</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">192.168.1.15:22</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">"</span> |awk <span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">'</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">{print $5}</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">'</span>|awk -F: <span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">'</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">{print $1}</span><span style="color: rgb(128, 0, 0); line-height: 1.5 !important;">'</span>|sort|uniq -c|sort -nr|head -<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">20</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">18</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">221.136</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">168.36</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">3</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">154.74</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">45.242</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">78.173</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">31.236</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">62.183</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">207.98</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">192.168</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">1.14</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">182.48</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">111.215</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">124.193</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">219.34</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">119.145</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">41.2</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">2</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">114.255</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">41.30</span>
<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">1</span> <span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">75.102</span>.<span style="color: rgb(128, 0, 128); line-height: 1.5 !important;">11.99</span>


TCP各种状态列表

wss8848@ubuntu:~$ netstat -nat |awk '{print $6}'
established)
Foreign
LISTEN
TIME_WAIT
ESTABLISHED
TIME_WAIT
SYN_SENT


[php] view
plaincopyprint?

<span style="line-height:1.5; font-size:14px"> 先把状态全都取出来,然后使用uniq -c统计,之后再进行排序。</span>

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)


[php] view
plaincopyprint?

<span style="line-height:1.5; font-size:14px"> 最后的命令如下:</span>

netstat -nat |awk '{print $6}'|sort|uniq -c|sort -rn


[php] view
plaincopyprint?

<span style="line-height:1.5; font-size:14px"><strong>分析access.log获得访问前10位的ip地址</strong></span>

awk '{print $1}' access.log |sort|uniq -c|sort -nr|head -10
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