linux命令之ifconfig

 在windows系统中，ipconfig命令行工具被用来获取网络接口配置信息并对此进行修改。Linux系统拥有一个类似的工具，也就是ifconfig(interfaces config)。

 

    (1)用法:

    用法:  ifconfig [网络设备] [参数]

 

    (2)功能:

    功能:  ifconfig命令用来查看和配置网络设备，当网络环境发生改变时可通过此命令对网络进行相应的配置。

    注意:  用ifconfig命令配置的网卡信息，在网卡重启后机器重启后，配置就不存在。要想将上述的配置信息永远的存在电脑里，那就要修改网卡的配置文件了。

 

    (3)选项参数:

      1)  up 　　　　     　　启动指定网络设备/网卡。

      2)  down 　　      　　 关闭指定网络设备/网卡。该参数可以有效地阻止通过指定接口的IP信息流，如果想永久地关闭一个接口，我们还需要从核心路由表中将该接口的路由信息全部删除。

      3) -a　　　　　　 　　 无论是否激活，显示所有配置的网络接口。

      4) add 　　　　  　　 给指定网卡配置IPv6地址

　　5) del　　　　　　　　  删除指定网卡的IPv6地址

      6) arp|-arp　　　 　　  打开或关闭支持ARP协议

      7) mtu<字节数>  　　  设置网卡的最大传输单元

      8) netmask<子网掩码> 设置网卡的子网掩码

 

    (4)实例:

      1)[sunjimeng@localhost ~]$ ifconfig　　　　　　　　

[sunjimeng@localhost ~]$ ifconfig 　　　　　　　　//未联网时的参数eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 1914  bytes 174936 (170.8 KiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 0  bytes 0 (0.0 B)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 3246  bytes 281472 (274.8 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 3246  bytes 281472 (274.8 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[sunjimeng@localhost ~]$ ifconfig                   //连接到有线网时的参数eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500                //mtu表示最大传输单元        inet 192.168.117.128  netmask 255.255.255.0  broadcast 192.168.117.255        inet6 fe80::20c:29ff:fe4d:a3cc  prefixlen 64  scopeid 0x20<link>        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 1969  bytes 181974 (177.7 KiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 48  bytes 6324 (6.1 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 3590  bytes 310452 (303.1 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 3590  bytes 310452 (303.1 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    说明:

　　1）etn(Number)指的是网卡，可以看到目前这个网卡的物理地址(MAC地址）是 00:0c:29:4d:a3:cc。

      2）inet后表示ip地址，此网卡的ip地址是192.168.117.128，广播地址是192.168.117.255，掩码地址为255.255.255.0。

      3）lo是表示主机的回坏地址，这个一般是用来测试一个网络程序，但又不想让局域网或外网的用户能够查看，只能在此台主机上运行和查看所用的网络接口。

　　比如把 http服务器指定到回环地址，在浏览器输入127.0.0.1就能看到你所架WEB网站了。但只是您能看得到，局域网的其它主机或用户无从知道。

    2)[root@localhost sunjimeng]# ifconfig eno16777736 down　　　　打开和关闭指定网卡

[sunjimeng@localhost ~]$ ifconfig eno16777736 down　　　　　　//必须是root权限才可以SIOCSIFFLAGS: 不允许的操作[sunjimeng@localhost ~]$ su root密码：[root@localhost sunjimeng]# ifconfig eno16777736 down[root@localhost sunjimeng]# ifconfiglo: 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 0  (Local Loopback)        RX packets 3598  bytes 311224 (303.9 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 3598  bytes 311224 (303.9 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0[root@localhost sunjimeng]# ifconfig eno16777736 up[root@localhost sunjimeng]# ifconfigeno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 2013  bytes 185705 (181.3 KiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 88  bytes 9726 (9.4 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 3602  bytes 311520 (304.2 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 3602  bytes 311520 (304.2 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      注意：ssh登陆linux服务器，关闭了网卡就不能开启了，除非你有多网卡。

      3)[root@localhost sunjimeng]# ifconfig -a　　　　　　无论是否激活，显示所有配置的网络接口，不带参数的只显示已激活的网络接口

[root@localhost sunjimeng]# ifconfig -aeno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 2016  bytes 185981 (181.6 KiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 88  bytes 9726 (9.4 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 3602  bytes 311520 (304.2 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 3602  bytes 311520 (304.2 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      4)启用或关闭支持ARP协议

[root@localhost sunjimeng]# ifconfig eno16777736 arp[root@localhost sunjimeng]# ifconfig eno16777736 -arp

      5)[root@localhost sunjimeng]# ifconfig eno16777736 mtu 2000　　　　设置网络设备传输的最大单元

[root@localhost sunjimeng]# ifconfigeno16777736: flags=4291<UP,BROADCAST,RUNNING,NOARP,MULTICAST>  mtu 1500        inet 192.168.117.128  netmask 255.255.255.0  broadcast 192.168.117.255        inet6 fe80::20c:29ff:fe4d:a3cc  prefixlen 64  scopeid 0x20<link>        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 75518  bytes 108412465 (103.3 MiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 20662  bytes 1263791 (1.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 4381  bytes 364888 (356.3 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 4381  bytes 364888 (356.3 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0[root@localhost sunjimeng]# ifconfig eno16777736 mtu 2000[root@localhost sunjimeng]# ifconfigeno16777736: flags=4291<UP,BROADCAST,RUNNING,NOARP,MULTICAST>  mtu 2000        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 99762  bytes 145117330 (138.3 MiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 20663  bytes 1263851 (1.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 5243  bytes 424328 (414.3 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 5243  bytes 424328 (414.3 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      6)[root@localhost sunjimeng]# ifconfig eno16777736 hw ether 00:0c:29:4d:a3:dd　　　　设置网卡的mac地址

[root@localhost sunjimeng]# ifconfigeno16777736: flags=4291<UP,BROADCAST,RUNNING,NOARP,MULTICAST>  mtu 2000        inet 0.0.0.64  netmask 0.0.0.0  broadcast 255.255.255.255        ether 00:0c:29:4d:a3:cc  txqueuelen 1000  (Ethernet)        RX packets 109425  bytes 159195954 (151.8 MiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 20668  bytes 1264151 (1.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 33371  bytes 2821752 (2.6 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 33371  bytes 2821752 (2.6 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0[root@localhost sunjimeng]# ifconfig eno16777736 hw ether 00:0c:29:4d:a3:dd[root@localhost sunjimeng]# ifconfigeno16777736: flags=4291<UP,BROADCAST,RUNNING,NOARP,MULTICAST>  mtu 2000        inet 0.0.0.64  netmask 0.0.0.0  broadcast 255.255.255.255        ether 00:0c:29:4d:a3:dd  txqueuelen 1000  (Ethernet)        RX packets 109434  bytes 159196494 (151.8 MiB)        RX errors 0  dropped 36  overruns 0  frame 0        TX packets 20668  bytes 1264151 (1.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: 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 0  (Local Loopback)        RX packets 34011  bytes 2876296 (2.7 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 34011  bytes 2876296 (2.7 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0