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=<UP,BROADCAST,RUNNING,MULTICAST> mtu
ether :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (170.8 KiB)
RX errors dropped overruns frame
TX packets bytes (0.0 B)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (274.8 KiB)
RX errors dropped overruns frame
TX packets bytes (274.8 KiB)
TX errors dropped overruns carrier collisions
[sunjimeng@localhost ~]$ ifconfig //连接到有线网时的参数
eno16777736: flags=<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 :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (177.7 KiB)
RX errors dropped overruns frame
TX packets bytes (6.1 KiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (303.1 KiB)
RX errors dropped overruns frame
TX packets bytes (303.1 KiB)
TX errors dropped overruns carrier collisions
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]# ifconfig
lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (303.9 KiB)
RX errors dropped overruns frame
TX packets bytes (303.9 KiB)
TX errors dropped overruns carrier collisions
[root@localhost sunjimeng]# ifconfig eno16777736 up
[root@localhost sunjimeng]# ifconfig
eno16777736: flags=<UP,BROADCAST,RUNNING,MULTICAST> mtu
ether :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (181.3 KiB)
RX errors dropped overruns frame
TX packets bytes (9.4 KiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (304.2 KiB)
RX errors dropped overruns frame
TX packets bytes (304.2 KiB)
TX errors dropped overruns carrier collisions
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 -a
eno16777736: flags=<UP,BROADCAST,RUNNING,MULTICAST> mtu
ether :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (181.6 KiB)
RX errors dropped overruns frame
TX packets bytes (9.4 KiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (304.2 KiB)
RX errors dropped overruns frame
TX packets bytes (304.2 KiB)
TX errors dropped overruns carrier collisions
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]# ifconfig
eno16777736: flags=<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 scopeid 0x20<link>
ether :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (103.3 MiB)
RX errors dropped overruns frame
TX packets bytes (1.2 MiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (356.3 KiB)
RX errors dropped overruns frame
TX packets bytes (356.3 KiB)
TX errors dropped overruns carrier collisions [root@localhost sunjimeng]# ifconfig eno16777736 mtu
[root@localhost sunjimeng]# ifconfig
eno16777736: flags=<UP,BROADCAST,RUNNING,NOARP,MULTICAST> mtu
ether :0c::4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (138.3 MiB)
RX errors dropped overruns frame
TX packets bytes (1.2 MiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (414.3 KiB)
RX errors dropped overruns frame
TX packets bytes (414.3 KiB)
TX errors dropped overruns carrier collisions
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]# ifconfig
eno16777736: flags=<UP,BROADCAST,RUNNING,NOARP,MULTICAST> mtu
inet 0.0.0.64 netmask 0.0.0.0 broadcast 255.255.255.255
ether 00:0c:29:4d:a3:cc txqueuelen (Ethernet)
RX packets bytes (151.8 MiB)
RX errors dropped overruns frame
TX packets bytes (1.2 MiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (2.6 MiB)
RX errors dropped overruns frame
TX packets bytes (2.6 MiB)
TX errors dropped overruns carrier collisions [root@localhost sunjimeng]# ifconfig eno16777736 hw ether :0c::4d:a3:dd
[root@localhost sunjimeng]# ifconfig
eno16777736: flags=<UP,BROADCAST,RUNNING,NOARP,MULTICAST> mtu
inet 0.0.0.64 netmask 0.0.0.0 broadcast 255.255.255.255
ether 00:0c:29:4d:a3:dd txqueuelen (Ethernet)
RX packets bytes (151.8 MiB)
RX errors dropped overruns frame
TX packets bytes (1.2 MiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
inet6 :: prefixlen scopeid 0x10<host>
loop txqueuelen (Local Loopback)
RX packets bytes (2.7 MiB)
RX errors dropped overruns frame
TX packets bytes (2.7 MiB)
TX errors dropped overruns carrier collisions