Linux netstat详解

骑猪看日落 2022-04-06 10:23 150阅读 0赞

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#### 一、netstat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。

#### 二、netstat使用 ####

*  **1、命令的一般格式**
    
        netstat [选项]
 *  **2、参数介绍**
    
        -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
 *  **3、实例**
    
     *  A、列出所有端口
        
         *  列出所有端口
            
                root@iZ235ubl1arZ:/home/yanmin/blog# netstat -a | more
                Active Internet connections (servers and established)
                Proto Recv-Q Send-Q Local Address           Foreign Address         State
                tcp        0      0 *:http                  *:*                     LISTEN
                tcp        0      0 *:ssh                   *:*                     LISTEN
         *  列出所有tcp端口
            
                root@iZ235ubl1arZ:/home/yanmin/blog# netstat -at
                Active Internet connections (servers and established)
                Proto Recv-Q Send-Q Local Address           Foreign Address         State
                tcp        0      0 *:http                  *:*                     LISTEN
                tcp        0      0 *:ssh                   *:*                     LISTEN
                tcp        0      0 121.41.120.65:http      140.205.201.20:35425    TIME_WAIT
         *  列出所有udp端口
            
                root@iZ235ubl1arZ:/home/yanmin/blog# netstat -au
                Active Internet connections (servers and established)
                Proto Recv-Q Send-Q Local Address           Foreign Address         State
                udp        0      0 121.41.120.65:ntp       *:*
                udp        0      0 iZ235ubl1arZ:ntp        *:*
                udp        0      0 localhost:ntp           *:*
                udp        0      0 *:ntp                   *:*
                udp6       0      0 [::]:ntp                [::]:*
 *  B、列出所有处于监听状态的Sockets
    
     *  只显示监听端口netstat -l
        
            root@iZ235ubl1arZ:/home/yanmin/blog# netstat -l
            Active Internet connections (only servers)
            Proto Recv-Q Send-Q Local Address           Foreign Address         State
            tcp        0      0 *:http                  *:*                     LISTEN
            tcp        0      0 *:ssh                   *:*                     LISTEN
            udp        0      0 121.41.120.65:ntp       *:*
            udp        0      0 iZ235ubl1arZ:ntp        *:*
            udp        0      0 localhost:ntp           *:*
     *  只列出所有监听tcp端口netstat -lt
        
            root@iZ235ubl1arZ:/home/yanmin/blog# netstat -lt
            Active Internet connections (only servers)
            Proto Recv-Q Send-Q Local Address           Foreign Address         State
            tcp        0      0 *:http                  *:*                     LISTEN
            tcp        0      0 *:ssh                   *:*                     LISTEN
     *  只列出所有监听udp端口 netstat -lu
        
            root@iZ235ubl1arZ:/home/yanmin/blog# netstat -lu
            Active Internet connections (only servers)
            Proto Recv-Q Send-Q Local Address           Foreign Address         State
            udp        0      0 121.41.120.65:ntp       *:*
            udp        0      0 iZ235ubl1arZ:ntp        *:*
            udp        0      0 localhost:ntp           *:*
            udp        0      0 *:ntp                   *:*
            udp6       0      0 [::]:ntp                [::]:*
     *  只列出所有监听UNIX端口 netstat -lx
        
            root@iZ235ubl1arZ:/home/yanmin/blog# netstat -lx
            Active UNIX domain sockets (only servers)
            Proto RefCnt Flags       Type       State         I-Node   Path
            unix  2      [ ACC ]     STREAM     LISTENING     9506     /var/run/nscd/socket
            unix  2      [ ACC ]     STREAM     LISTENING     8267     /var/run/dbus/system_bus_socket
            unix  2      [ ACC ]     SEQPACKET  LISTENING     7769     /run/udev/control
            unix  2      [ ACC ]     STREAM     LISTENING     7592     @/com/ubuntu/upstart
 *  C、在netstat 输出中显示PID和进程名称netstat -p
    
        root@iZ235ubl1arZ:/home/yanmin/blog# netstat -p
        Active Internet connections (w/o servers)
        Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
        tcp        0    316 121.41.120.65:ssh       58.246.62.146:54175     ESTABLISHED 17558/sshd: yanmin
        tcp        0      0 121.41.120.65:ssh       58.246.62.146:52592     ESTABLISHED 14538/sshd: yanmin
        Active UNIX domain sockets (w/o servers)
        Proto RefCnt Flags       Type       State         I-Node   PID/Program name    Path
        unix  10     [ ]         DGRAM                    8286     682/rsyslogd        /dev/log
        unix  3      [ ]         STREAM     CONNECTED     307127   17558/sshd: yanmin
 *  D、显示核心路由信息 netstat -r
    
        yanmin:blog yanmin$ netstat -r
        Routing tables
        
        Internet:
        Destination        Gateway            Flags        Refs      Use   Netif Expire
        default 10.96.150.1 UGSc 21 0 en0
        10.16/14           10.254.254.81      UGSc            0        0   utun1
        10.16.0.222/32     10.254.254.81      UGSc            1        0   utun1

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