linux netstat 命令详解

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linux netstat 命令详解

科技探索者 2017-11-12 12:26:00 浏览839
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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


[root@localhost net]# netstat 
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0     52 localhost.localdoma:ssh 192.168.1.120:56520     ESTABLISHED
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ]         DGRAM                    8805     /run/systemd/notify
unix  2      [ ]         DGRAM                    8807     /run/systemd/cgroups-agent
unix  5      [ ]         DGRAM                    8825     /run/systemd/journal/socket


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)

[root@localhost net]# netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp        0      0 localhost:smtp          0.0.0.0:*               LISTEN     
tcp        0     52 localhost.localdoma:ssh 192.168.1.120:56520     ESTABLISHED
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     
tcp6       0      0 localhost:smtp          [::]:*                  LISTEN     
raw6       0      0 [::]:ipv6-icmp          [::]:*                  7          
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ]         DGRAM                    8805     /run/systemd/notify
unix  2      [ ]         DGRAM                    8807     /run/systemd/cgroups-agent
unix  2      [ ACC ]     STREAM     LISTENING     11629    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     20594    /var/run/NetworkManager/private-dhcp
unix  2      [ ACC ]     SEQPACKET  LISTENING     11638    /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     8822     /run/systemd/journal/stdout
unix  5      [ ]         DGRAM                    8825     /run/systemd/journal/socket
unix  13     [ ]         DGRAM                    8827     /dev/log
unix  2      [ ACC ]     STREAM     LISTENING     12163    /var/run/dbus/system_bus_socket
unix  2      [ ]         DGRAM                    11669    /run/systemd/shutdownd
unix  2      [ ACC ]     STREAM     LISTENING     18008    public/pickup
unix  2      [ ACC ]     STREAM     LISTENING     18012    public/cleanup
unix  2      [ ACC ]     STREAM     LISTENING     18015    public/qmgr
unix  2      [ ACC ]     STREAM     LISTENING     18019    private/tlsmgr
unix  2      [ ACC ]     STREAM     LISTENING     18022    private/rewrite
unix  2      [ ACC ]     STREAM     LISTENING     18025    private/bounce


列出所有 tcp 端口 netstat -at


[root@localhost net]# netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp        0      0 localhost:smtp          0.0.0.0:*               LISTEN     
tcp        0     52 localhost.localdoma:ssh 192.168.1.120:56520     ESTABLISHED
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     
tcp6       0      0 localhost:smtp          [::]:*                  LISTEN  


列出所有 udp 端口 netstat -au


[root@localhost net]# netstat -au
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State 

2. 列出所有处于监听状态的 Sockets

只显示监听端口 netstat -l


[root@localhost net]# netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp        0      0 localhost:smtp          0.0.0.0:*               LISTEN     
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     
tcp6       0      0 localhost:smtp          [::]:*                  LISTEN     
raw6       0      0 [::]:ipv6-icmp          [::]:*                  7          
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     11629    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     20594    /var/run/NetworkManager/private-dhcp
unix  2      [ ACC ]     SEQPACKET  LISTENING     11638    /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     8822     /run/systemd/journal/stdout
unix  2      [ ACC ]     STREAM     LISTENING     12163    /var/run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     18008    public/pickup
unix  2      [ ACC ]     STREAM     LISTENING     18012    public/cleanup
unix  2      [ ACC ]     STREAM     LISTENING     18015    public/qmgr
unix  2      [ ACC ]     STREAM     LISTENING     18019    private/tlsmgr
unix  2      [ ACC ]     STREAM     LISTENING     18022    private/rewrite
unix  2      [ ACC ]     STREAM     LISTENING     18025    private/bounce
unix  2      [ ACC ]     STREAM     LISTENING     18028    private/defer
unix  2      [ ACC ]     STREAM     LISTENING     18031    private/trace
unix  2      [ ACC ]     STREAM     LISTENING     18034    private/verify
unix  2      [ ACC ]     STREAM     LISTENING     18037    public/flush
unix  2      [ ACC ]     STREAM     LISTENING     18040    private/proxymap
unix  2      [ ACC ]     STREAM     LISTENING     18043    private/proxywrite
unix  2      [ ACC ]     STREAM     LISTENING     18046    private/smtp
unix  2      [ ACC ]     STREAM     LISTENING     18049    private/relay
unix  2      [ ACC ]     STREAM     LISTENING     18052    public/showq
unix  2      [ ACC ]     STREAM     LISTENING     18055    private/error
unix  2      [ ACC ]     STREAM     LISTENING     18058    private/retry
unix  2      [ ACC ]     STREAM     LISTENING     18061    private/discard
unix  2      [ ACC ]     STREAM     LISTENING     18064    private/local
unix  2      [ ACC ]     STREAM     LISTENING     18067    private/virtual
unix  2      [ ACC ]     STREAM     LISTENING     18070    private/lmtp
unix  2      [ ACC ]     STREAM     LISTENING     18073    private/anvil
unix  2      [ ACC ]     STREAM     LISTENING     18076    private/scache


只列出所有监听 tcp 端口 netstat -lt


[root@localhost net]# netstat -lt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp        0      0 localhost:smtp          0.0.0.0:*               LISTEN     
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     
tcp6       0      0 localhost:smtp          [::]:*                  LISTEN 


只列出所有监听 udp 端口 netstat -lu


[root@localhost net]# netstat -lu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State 


只列出所有监听 UNIX 端口 netstat -lx


[root@localhost net]# netstat -lx
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     11629    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     20594    /var/run/NetworkManager/private-dhcp
unix  2      [ ACC ]     SEQPACKET  LISTENING     11638    /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     8822     /run/systemd/journal/stdout
unix  2      [ ACC ]     STREAM     LISTENING     12163    /var/run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     18008    public/pickup
unix  2      [ ACC ]     STREAM     LISTENING     18012    public/cleanup
unix  2      [ ACC ]     STREAM     LISTENING     18015    public/qmgr
unix  2      [ ACC ]     STREAM     LISTENING     18019    private/tlsmgr
unix  2      [ ACC ]     STREAM     LISTENING     18022    private/rewrite
unix  2      [ ACC ]     STREAM     LISTENING     18025    private/bounce
unix  2      [ ACC ]     STREAM     LISTENING     18028    private/defer
unix  2      [ ACC ]     STREAM     LISTENING     18031    private/trace
unix  2      [ ACC ]     STREAM     LISTENING     18034    private/verify
unix  2      [ ACC ]     STREAM     LISTENING     18037    public/flush
unix  2      [ ACC ]     STREAM     LISTENING     18040    private/proxymap
unix  2      [ ACC ]     STREAM     LISTENING     18043    private/proxywrite
unix  2      [ ACC ]     STREAM     LISTENING     18046    private/smtp
unix  2      [ ACC ]     STREAM     LISTENING     18049    private/relay
unix  2      [ ACC ]     STREAM     LISTENING     18052    public/showq
unix  2      [ ACC ]     STREAM     LISTENING     18055    private/error
unix  2      [ ACC ]     STREAM     LISTENING     18058    private/retry
unix  2      [ ACC ]     STREAM     LISTENING     18061    private/discard
unix  2      [ ACC ]     STREAM     LISTENING     18064    private/local
unix  2      [ ACC ]     STREAM     LISTENING     18067    private/virtual
unix  2      [ ACC ]     STREAM     LISTENING     18070    private/lmtp
unix  2      [ ACC ]     STREAM     LISTENING     18073    private/anvil
unix  2      [ ACC ]     STREAM     LISTENING     18076    private/scache

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


[root@localhost net]# netstat -s
Ip:
    9682 total packets received
    0 forwarded
    0 incoming packets discarded
    9669 incoming packets delivered
    1675 requests sent out
Icmp:
    33 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 31
        echo replies: 2
    37 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 31
        echo request: 6
IcmpMsg:
        InType0: 2
        InType3: 31
        OutType3: 31
        OutType8: 6
Tcp:
    0 active connections openings
    1 passive connection openings
    0 failed connection attempts
    0 connection resets received
    1 connections established
    2517 segments received
    1723 segments send out
    0 segments retransmited
    0 bad segments received.
    0 resets sent
Udp:
    0 packets received
    30 packets to unknown port received.
    0 packet receive errors
    30 packets sent
    0 receive buffer errors
    0 send buffer errors
UdpLite:
TcpExt:
    29 delayed acks sent
    1 packets directly queued to recvmsg prequeue.
    746 packet headers predicted
    396 acknowledgments not containing data payload received
    918 predicted acknowledgments
    IPReversePathFilter: 3
    TCPRcvCoalesce: 1
    TCPAutoCorking: 5
    TCPOrigDataSent: 1644
IpExt:
    InNoRoutes: 10
    InBcastPkts: 7089
    InOctets: 838424
    OutOctets: 526211
    InBcastOctets: 653606
    InNoECTPkts: 9682

显示 TCP 或 UDP 端口的统计信息 netstat -st 或 -su


[root@localhost net]# netstat -st
IcmpMsg:
    InType0: 2
    InType3: 31
    OutType3: 31
    OutType8: 6
Tcp:
    0 active connections openings
    1 passive connection openings
    0 failed connection attempts
    0 connection resets received
    1 connections established
    2625 segments received
    1801 segments send out
    0 segments retransmited
    0 bad segments received.
    0 resets sent
UdpLite:
TcpExt:
    32 delayed acks sent
    1 packets directly queued to recvmsg prequeue.
    790 packet headers predicted
    410 acknowledgments not containing data payload received
    966 predicted acknowledgments
    IPReversePathFilter: 3
    TCPRcvCoalesce: 1
    TCPAutoCorking: 5
    TCPOrigDataSent: 1716
IpExt:
    InNoRoutes: 10
    InBcastPkts: 7400
    InOctets: 874918
    OutOctets: 535207
    InBcastOctets: 681848
    InNoECTPkts: 10101

[root@localhost net]# netstat -su
IcmpMsg:
    InType0: 2
    InType3: 31
    OutType3: 31
    OutType8: 6
Udp:
    0 packets received
    30 packets to unknown port received.
    0 packet receive errors
    30 packets sent
    0 receive buffer errors
    0 send buffer errors
UdpLite:
IpExt:
    InNoRoutes: 10
    InBcastPkts: 7540
    InOctets: 895035
    OutOctets: 541059
    InBcastOctets: 694911
    InNoECTPkts: 10343


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。


[root@localhost net]# netstat -pt
'Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0     52 localhost.localdoma:ssh 192.168.1.120:56520     ESTABLISHED 3047/sshd: root@pts



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。


[root@localhost net]# netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN     
tcp        0     52 192.168.1.205:22        192.168.1.120:56520     ESTABLISHED
tcp6       0      0 :::22                   :::*                    LISTEN     
tcp6       0      0 ::1:25                  :::*                    LISTEN     
raw6       0      0 :::58                   :::*                    7          
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ]         DGRAM                    8805     /run/systemd/notify
unix  2      [ ]         DGRAM                    8807     /run/systemd/cgroups-agent
unix  2      [ ACC ]     STREAM     LISTENING     11629    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     20594    /var/run/NetworkManager/private-dhcp
unix  2      [ ACC ]     SEQPACKET  LISTENING     11638    /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     8822     /run/systemd/journal/stdout
unix  5      [ ]         DGRAM                    8825     /run/systemd/journal/socket
unix  13     [ ]         DGRAM                    8827     /dev/log
unix  2      [ ACC ]     STREAM     LISTENING     12163    /var/run/dbus/system_bus_socket
unix  2      [ ]         DGRAM                    11669    /run/systemd/shutdownd
unix  2      [ ACC ]     STREAM     LISTENING     18008    public/pickup
unix  2      [ ACC ]     STREAM     LISTENING     18012    public/cleanup
unix  2      [ ACC ]     STREAM     LISTENING     18015    public/qmgr
unix  2      [ ACC ]     STREAM     LISTENING     18019    private/tlsmgr
unix  2      [ ACC ]     STREAM     LISTENING     18022    private/rewrite
unix  2      [ ACC ]     STREAM     LISTENING     18025    private/bounce
unix  2      [ ACC ]     STREAM     LISTENING     18028    private/defer
unix  2      [ ACC ]     STREAM     LISTENING     18031    private/trace
unix  2      [ ACC ]     STREAM     LISTENING     18034    private/verify
unix  2      [ ACC ]     STREAM     LISTENING     18037    public/flush
unix  2      [ ACC ]     STREAM     LISTENING     18040    private/proxymap
unix  2      [ ACC ]     STREAM     LISTENING     18043    private/proxywrite
unix  2      [ ACC ]     STREAM     LISTENING     18046    private/smtp
unix  2      [ ACC ]     STREAM     LISTENING     18049    private/relay
unix  2      [ ACC ]     STREAM     LISTENING     18052    public/showq
unix  2      [ ACC ]     STREAM     LISTENING     18055    private/error
unix  2      [ ACC ]     STREAM     LISTENING     18058    private/retry
unix  2      [ ACC ]     STREAM     LISTENING     18061    private/discard
unix  2      [ ACC ]     STREAM     LISTENING     18064    private/local
unix  2      [ ACC ]     STREAM     LISTENING     18067    private/virtual
unix  2      [ ACC ]     STREAM     LISTENING     18070    private/lmtp
unix  2      [ ACC ]     STREAM     LISTENING     18073    private/anvil
unix  2      [ ACC ]     STREAM     LISTENING     18076    private/scache
unix  3      [ ]         STREAM     CONNECTED     18024    
unix  3      [ ]         STREAM     CONNECTED     18006    
unix  2      [ ]         DGRAM                    15804    
unix  3      [ ]         STREAM     CONNECTED     13803    
unix  3      [ ]         STREAM     CONNECTED     18010    
unix  3      [ ]         STREAM     CONNECTED     18021    
unix  3      [ ]         STREAM     CONNECTED     16073    /var/run/dbus/system_bus_socket
unix  3      [ ]         STREAM     CONNECTED     18013    
unix  3      [ ]         STREAM     CONNECTED     13854    
unix  2      [ ]         DGRAM                    18705    
unix  2      [ ]         DGRAM                    13801    
unix  3      [ ]         STREAM     CONNECTED     18017    
unix  2      [ ]         DGRAM                    18713    
unix  3      [ ]         STREAM     CONNECTED     12169    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     13842    
unix  3      [ ]         STREAM     CONNECTED     18009    
unix  3      [ ]         STREAM     CONNECTED     14985    
unix  3      [ ]         STREAM     CONNECTED     18027    
unix  3      [ ]         STREAM     CONNECTED     18026    
unix  3      [ ]         STREAM     CONNECTED     15079    
unix  3      [ ]         STREAM     CONNECTED     18633    
unix  3      [ ]         STREAM     CONNECTED     13802    
unix  3      [ ]         STREAM     CONNECTED     15026    
unix  3      [ ]         STREAM     CONNECTED     18020    
unix  3      [ ]         STREAM     CONNECTED     12166    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     18016    
unix  3      [ ]         STREAM     CONNECTED     13855    /var/run/dbus/system_bus_socket
unix  3      [ ]         STREAM     CONNECTED     18007    
unix  3      [ ]         STREAM     CONNECTED     13853    
unix  3      [ ]         STREAM     CONNECTED     18023    
unix  3      [ ]         STREAM     CONNECTED     18029    
unix  3      [ ]         STREAM     CONNECTED     12869    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     18014    
unix  2      [ ]         DGRAM                    13112    
unix  2      [ ]         DGRAM                    13966    
unix  3      [ ]         STREAM     CONNECTED     12867    
unix  3      [ ]         STREAM     CONNECTED     18074    
unix  3      [ ]         STREAM     CONNECTED     12954    /run/systemd/journal/stdout
unix  2      [ ]         DGRAM                    15028    
unix  2      [ ]         DGRAM                    17279    
unix  3      [ ]         STREAM     CONNECTED     18053    
unix  3      [ ]         STREAM     CONNECTED     18048    
unix  3      [ ]         STREAM     CONNECTED     18075    
unix  3      [ ]         STREAM     CONNECTED     18033    
unix  3      [ ]         STREAM     CONNECTED     18078    
unix  3      [ ]         STREAM     CONNECTED     13856    /var/run/dbus/system_bus_socket
unix  3      [ ]         STREAM     CONNECTED     18077    
unix  3      [ ]         STREAM     CONNECTED     18032    
unix  3      [ ]         STREAM     CONNECTED     18030    
unix  3      [ ]         STREAM     CONNECTED     12286    
unix  3      [ ]         DGRAM                    14562    
unix  3      [ ]         STREAM     CONNECTED     12287    /var/run/dbus/system_bus_socket
unix  2      [ ]         DGRAM                    20340    
unix  2      [ ]         DGRAM                    15161    
unix  3      [ ]         STREAM     CONNECTED     18035    
unix  2      [ ]         DGRAM                    15152    
unix  3      [ ]         STREAM     CONNECTED     12288    /var/run/dbus/system_bus_socket
unix  3      [ ]         STREAM     CONNECTED     13113    
unix  3      [ ]         STREAM     CONNECTED     12167    /run/systemd/journal/stdout
unix  2      [ ]         DGRAM                    23685    
unix  3      [ ]         STREAM     CONNECTED     18054    
unix  3      [ ]         STREAM     CONNECTED     18036    
unix  3      [ ]         STREAM     CONNECTED     12953    
unix  3      [ ]         STREAM     CONNECTED     17038    
unix  2      [ ]         DGRAM                    14548    
unix  3      [ ]         STREAM     CONNECTED     18039    
unix  3      [ ]         STREAM     CONNECTED     13105    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     18057    
unix  3      [ ]         STREAM     CONNECTED     18038    
unix  3      [ ]         STREAM     CONNECTED     15421    
unix  3      [ ]         STREAM     CONNECTED     18044    
unix  3      [ ]         STREAM     CONNECTED     18060    
unix  3      [ ]         STREAM     CONNECTED     12501    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     18059    
unix  3      [ ]         STREAM     CONNECTED     18047    
unix  3      [ ]         STREAM     CONNECTED     18062    
unix  3      [ ]         STREAM     CONNECTED     18050    
unix  3      [ ]         STREAM     CONNECTED     15711    /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     14546    
unix  3      [ ]         STREAM     CONNECTED     18063    
unix  3      [ ]         STREAM     CONNECTED     18066    
unix  3      [ ]         STREAM     CONNECTED     18042    
unix  3      [ ]         STREAM     CONNECTED     18065    
unix  3      [ ]         STREAM     CONNECTED     18041    
unix  3      [ ]         DGRAM                    14561    
unix  3      [ ]         STREAM     CONNECTED     18068    
unix  3      [ ]         STREAM     CONNECTED     15038    
unix  3      [ ]         STREAM     CONNECTED     13104    
unix  3      [ ]         STREAM     CONNECTED     15169    /var/run/dbus/system_bus_socket
unix  2      [ ]         DGRAM                    12394    
unix  3      [ ]         STREAM     CONNECTED     18056    
unix  3      [ ]         STREAM     CONNECTED     18045    
unix  3      [ ]         STREAM     CONNECTED     18069    
unix  3      [ ]         STREAM     CONNECTED     18072    
unix  3      [ ]         STREAM     CONNECTED     18051    
unix  3      [ ]         STREAM     CONNECTED     18071    

6. 持续输出 netstat 信息

netstat 将每隔一秒输出网络信息。


[root@localhost net]# netstat -c


7. 显示核心路由信息 netstat -r

[root@localhost net]# netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         gateway         0.0.0.0         UG        0 0          0 bond0
192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 bond0

8. 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。


[root@localhost net]# netstat -ap|grep ssh
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN      1073/sshd           
tcp        0     52 localhost.localdoma:ssh 192.168.1.120:56520     ESTABLISHED 3047/sshd: root@pts 
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN      1073/sshd           
unix  2      [ ]         DGRAM                    20340    3047/sshd: root@pts  

找出运行在指定端口的进程


[root@localhost net]# netstat -an|grep 22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0     52 192.168.1.205:22        192.168.1.120:56520     ESTABLISHED
tcp6       0      0 :::22               


9. 显示网络接口列表

[root@localhost net]# netstat -i
Kernel Interface table
Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
bond0     1500    34778      0      0 0          2279      0      0      0 BMmRU
ens33     1500    19106      0      0 0          2293      0      0      0 BMsRU
ens34     1500    15778      0      0 0             5      0      0      0 BMsRU
lo       65536      105      0      0 0           105      0      0      0 LRU


显示详细信息,像是 ifconfig 使用 netstat -ie:


[root@localhost net]# netstat -ie
Kernel Interface table
bond0: flags=5187<UP,BROADCAST,RUNNING,MASTER,MULTICAST>  mtu 1500
        inet 192.168.1.205  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::b296:1197:e1d4:6b6  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:61:cf:79  txqueuelen 1000  (Ethernet)
        RX packets 35278  bytes 3126800 (2.9 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2288  bytes 858051 (837.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST>  mtu 1500
        ether 00:0c:29:61:cf:79  txqueuelen 1000  (Ethernet)
        RX packets 19361  bytes 1708695 (1.6 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2302  bytes 859421 (839.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens34: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST>  mtu 1500
        ether 00:0c:29:61:cf:79  txqueuelen 1000  (Ethernet)
        RX packets 16023  bytes 1428346 (1.3 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5  bytes 660 (660.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1  (Local Loopback)
        RX packets 105  bytes 9048 (8.8 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 105  bytes 9048 (8.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

本文转自服务器运维博客51CTO博客,原文链接http://blog.51cto.com/shamereedwine/1981183如需转载请自行联系原作者

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