Linux中利用DHCP服务为特定设备分配固定IP

实质：实现设备与IP的绑定。

服务模式：服务器/客户端

PC1为服务器，PC2为客户端。PC1和PC2均为RHEL7系统

1、查看服务器PC1系统版本，ip信息

[root@PC1 ~]# cat /etc/redhat-release  ## 查看系统版本
Red Hat Enterprise Linux Server release 7.0 (Maipo)
[root@PC1 ~]# ifconfig | head -n 3  ## 查看IP
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.10  netmask 255.255.255.255  broadcast 192.168.10.10
        inet6 fe80::20c:29ff:fe66:37f7  prefixlen 64  scopeid 0x20<link>

2、安装DHCP服务 （提前配置好yum仓库）

[root@PC1 ~]# yum install dhcp
Loaded plugins: langpacks, product-id, subscription-manager
This system is not registered to Red Hat Subscription 
Installed size: 1.4 M
Is this ok [y/d/N]: y
………………
Installed:
  dhcp.x86_64 12:4.2.5-27.el7                                                   

Complete!

3、DHCP服务配置文件所在位置

[root@PC1 dhcp]# pwd
/etc/dhcp
[root@PC1 dhcp]# ls
dhclient.d  dhcpd6.conf  dhcpd.conf

4、在服务器PC1中修改DHCP服务配置文件

[root@PC1 dhcp]# vim /etc/dhcp/dhcpd.conf   ## ip地址范围为50-150
ddns-update-style none;
ignore client-updates;
subnet 192.168.10.0 netmask 255.255.255.0 {
range 192.168.10.50 192.168.10.150;
option subnet-mask 255.255.255.0;
option routers 192.168.10.1;
option domain-name "linuxprobe.com";
option domain-name-servers 192.168.10.1;
default-lease-time 21600;
max-lease-time 43200;
}

各参数意义：

5、在服务器PC1中重启DHCP服务，并设动为开机自动启动

[root@PC1 dhcp]# systemctl restart dhcpd
[root@PC1 dhcp]# systemctl enable dhcpd
ln -s '/usr/lib/systemd/system/dhcpd.service' '/etc/systemd/system/multi-user.target.wants/dhcpd.service'

6、 在客户机PC2中验证自动分配IP效果

[root@PC2 Desktop]# ifconfig | head -n 3  ## 查看当前ip，未分配
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 00:0c:29:25:bb:3e  txqueuelen 1000  (Ethernet)
        RX packets 445  bytes 27249 (26.6 KiB)
[root@PC2 Desktop]# vim /etc/sysconfig/network-scripts/ifcfg-eno16777728  ## 修改网卡配置文件，设为开机启动
HWADDR=00:0C:29:25:BB:3E
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=eno16777728
UUID=a0c2aa6b-48e1-4822-a67c-151155cc14bd
ONBOOT=yes
[root@PC2 Desktop]# systemctl restart network  ## 重启网卡
[root@PC2 Desktop]# ifconfig | head -n 3  ## 查看此时ip
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.50  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe25:bb3e  prefixlen 64  scopeid 0x20<link>

7、查看客户机PC2网卡MAC地址、PC2主机名称（绑定ip时需要使用MAC地址，MAC地址具有唯一性）

[root@PC2 Desktop]# ifconfig | head -n 6  ## 查看PC2的MAC地址
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.50  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe25:bb3e  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:25:bb:3e  txqueuelen 1000  (Ethernet)
        RX packets 498  bytes 31249 (30.5 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
[root@PC2 Desktop]# hostname  ## 查看主机名称
PC2

8、在服务器PC1中修改配置文件，将特定IP和客户机PC2绑定

[root@PC1 dhcp]# vim /etc/dhcp/dhcpd.conf
ddns-update-style none;
ignore client-updates;
subnet 192.168.10.0 netmask 255.255.255.0 {
range 192.168.10.50 192.168.10.150;
option subnet-mask 255.255.255.0;
option routers 192.168.10.1;
option domain-name "linuxprobe.com";
option domain-name-servers 192.168.10.1;
default-lease-time 21600;
max-lease-time 43200;
host PC2 {
hardware ethernet 00:0c:29:25:bb:3e;
fixed-address 192.168.10.100;
}
}

9、在服务器PC1中重启DHCP服务

[root@PC1 dhcp]# systemctl restart dhcpd

10、在客户机PC2中进行验证

[root@PC2 Desktop]# ifconfig | head -n 3  ## 查看此时ip，仍然是50
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.50  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe25:bb3e  prefixlen 64  scopeid 0x20<link>
[root@PC2 Desktop]# systemctl restart network  ## 重启网卡服务
[root@PC2 Desktop]# ifconfig | head -n 3 ## 查看此时ip，可见已经实现了绑定
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.100  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe25:bb3e  prefixlen 64  scopeid 0x20<link>

总结：

• 实现特定IP与特定设备的绑定仅需要修改服务器端配置文件，然后在客户端重启网卡
• 服务器端修改配置文件需要的关键信息为客户端网卡MAC地址、主机名称