Today I installed CentOS 7 on a PC. At that time, I chose the minimal installation mode. Immediately after the installation was completed, I used ifconfig to check the ip address of the machine (the local area network already has DHCP), and found that an error was reported, indicating that the ifconfig command was not found.
[root@centos1 ~]# ifconfig
-bash: ifconfig: command not found
First, habitually enter echo $PATH (check the current PATH environment variable, the same function as the DOS path command, note that the commands in the Linux system are size-sensitive written), the display result is as follows:
[root@centos1 ~]# echo $PATH
/usr/local/sbin:/usr/local/bin: /usr/sbin :/usr/bin:/root/bin
Display the result from above Look, the path /usr/sbin where the system management program is placed already exists, which is the path where the external command is placed. Check the /usr/sbin/ directory directly with ls , but I don't see ifconfig , what's going on? [root@centos1 ~]# ls /usr/sbin/ I still don't give up, and I can't find ifconfig with the find command ? [root@centos1 ~]# find / -name "ifconfig" At this time, I have a bottom line, it should be Replace ifconfig with a command
. I checked on Baidu, and sure enough, the ip command has been used instead of the ifconfig command. The common parameters of the ip command are listed below .
ip [options] Operation object {link|addr|route...}
# ip link show # Display network interface information
# ip link set eth0 upi # Turn on the network card
# ip link set eth0 down # Turn off the network card
# ip link set eth0 promisc on # Enable the mixed mode of the network card
# ip link set eth0 promisc offi # Turn off the mixed mode of the network card
# ip link set eth0 txqueuelen 1200 # Set the queue length of the network card
# ip link set eth0 mtu 1400 # Set the maximum transmission unit of the network card
# ip addr show # Display network card IP information
# ip addr add 192.168.0.1/24 dev eth0 # Set the eth0 network card IP address 192.168.0.1
# ip addr del 192.168.0.1/24 dev eth0 # Delete the eth0 network card IP address
# ip route list # View routing information
# ip route add 192.168.4.0/24 via 192.168.0.254 dev eth0 # Set the gateway of the 192.168.4.0 network segment to 192.168.0.254, and the data goes through the eth0 interface
# ip route add default via 192.168.0.254 dev eth0 # Set the default gateway to 192.168.0.254
# ip route del 192.168.4.0/24 # Delete the gateway of the 192.168.4.0 network segment
# ip route del default # Delete the default route |
输入ip addr命令后，发现enp2s0网卡（这个enp2s0是我这里的网卡）没有ip地址。
[root@centos1 ~]# ip addr
既然没有ip地址，那直接去/etc/sysconfig/network-scripts目录中看一下的网卡ip信息的配置文件名吧。
[root@centos1 ~]# ls /etc/sysconfig/network-scripts/
ifcfg-enp2s0 ifdown-eth ifdown-post ifdown-Team ifup-aliases ifup-ipv6 ifup-post ifup-Team init.ipv6-global
ifcfg-lo ifdown-ippp ifdown-ppp ifdown-TeamPort ifup-bnep ifup-isdn ifup-ppp ifup-TeamPort network-functions
ifdown ifdown-ipv6 ifdown-routes ifdown-tunnel ifup-eth ifup-plip ifup-routes ifup-tunnel network-functions-ipv6
ifdown-bnep ifdown-isdn ifdown-sit ifup ifup-ippp ifup-plusb ifup-sit ifup-wireless
从结果看，之前保存网卡ip信息的配置文件名也由以前的ifcfg-eth0变成了ifcfg-enp2s0，好吧，既然你给他命这么个名，那我就先用着。先cat一下ifcfg-enp2s0
[root@centos1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-enp2s0
HWADDR=00:E0:69:01:6A:96
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME=enp2s0
UUID=5b0a7d76-1602-4e19-aee6-29f57618ca01
ONBOOT=no
从上面的配置中有看到虽然BOOTPROTO=dhcp，但是ONBOOT=no，这里用vi将ONBOOT=no改成ONBOOT=yes，然后重启CentOS。
[root@centos1 ~]# shutdown -r
重启完成后输入帐号和密码进入命令提示操作符继续用ip addr查看网卡信息。结果如下：
[root@centos1 ~]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:e0:69:01:6a:96 brd ff:ff:ff:ff:ff:ff
inet 172.8.1.200/24 brd 172.8.1.255 scope global enp2s0
valid_lft forever preferred_lft forever
inet6 fe80::2e0:69ff:fe01:6a96/64 scope link
valid_lft forever preferred_lft forever
从上面结果看到，通过DHCP分配到的ip地址是172.8.1.200，虽然是测试机，但为了便于今后的远程连接，我们还是给这台机配置一个固定ip吧。
用vi打开ifcfg-enp2s0，输入以下参数，再用#将BOOTPROTO=dhcp注释。
IPADDR0=172.8.1.211
PREFIX0=24
GATEWAY0=172.8.1.1
DNS1=172.8.1.1
完整参数如下，好了，网络配通了。明天继续其它功能测试。
[root@centos1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-enp2s0
HWADDR=00:E0:69:01:6A:96
TYPE=Ethernet
#BOOTPROTO=dhcp
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME=enp2s0
UUID=5b0a7d76-1602-4e19-aee6-29f57618ca01
ONBOOT=yes
IPADDR0=172.8.1.211
PREFIX0=24
GATEWAY0=172.8.1.1
DNS1=172.8.1.1
当联上互联网后，我们可以用yum install net-tools安装net-tools组件，将ifconfig命令找回来。有了互联网一切都好办了。
[root@centos1 ~]#yum install net-tools