dhcp服务的配置：
在一台虚拟机（客户端）发送数据包，将IP范围内的地址随机分给另外一台虚拟机，接收后可使用ifconfig命令查看是否在范围之内。本次实验使用两台虚拟机：我们通过真机连接Desktop虚拟机进行发送：
[kiosk@foundation21 Desktop]$ ssh [email protected] 切换到超级用户
[email protected]'s password:
Last login: Fri Apr 20 21:53:19 2018 from foundation22.ilt.example.com
[root@localhost ~]# yum search dhcp
Loaded plugins: langpacks
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
============================== N/S matched: dhcp ===============================
dhcp-common.x86_64 : Common files used by ISC dhcp client and server
dhcp-libs.i686 : Shared libraries used by ISC dhcp client and server
dhcp-libs.x86_64 : Shared libraries used by ISC dhcp client and server
dhclient.x86_64 : Provides the ISC DHCP client daemon and dhclient-script
dhcp.x86_64 : Dynamic host configuration protocol software
dnsmasq.x86_64 : A lightweight DHCP/caching DNS server
Name and summary matches only, use "search all" for everything.
***记住安装dhcp时候需要进行yum源的搭建与共享，不然都无法安装dhcp更加没办法进行配置。点击打开链接，这个链接里面为我自己写的yum源的搭建与共享，一步步按照来即可。
[root@localhost ~]# yum install dhcp.x86_64 -y 在Desktop安装dhcp安装包
[root@localhost ~]# cd /etc/dhcp/
[root@localhost dhcp]# ls
dhclient.d dhcpd6.conf dhcpd.conf
[root@localhost dhcp]# vim dhcpd.conf 编辑文件，将文件内容复制
Try 'cp --help' for more information.
[root@localhost dhcp]# cp /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcpd.conf 复制
cp: overwrite ‘/etc/dhcp/dhcpd.conf’? y 出现overwrite代表命令好了
[root@localhost dhcp]# ls
dhclient.d dhcpd6.conf dhcpd.conf
[root@localhost dhcp]# vim dhcpd.conf
文件内容如下：34行以后删除，27,28行删除，其它内容按照图片修改即可。
[root@localhost dhcp]# systemctl start dhcpd 打开dhcpd
[root@localhost dhcp]# systemctl enable dhcpd
ln -s '/usr/lib/systemd/system/dhcpd.service' '/etc/systemd/system/multi-user.target.wants/dhcpd.service'
[root@localhost dhcp]# cat /var/lib/dhcpd/dhcpd.leases 查看与另外一台机子里面查看的ifconfig对比看是否相同
# The format of this file is documented in the dhcpd.leases(5) manual page.
# This lease file was written by isc-dhcp-4.2.5
server-duid "\000\001\000\001\"mYvRT\000\000\025\012";
lease 172.25.254.207 {
starts 6 2018/04/21 02:09:07;
ends 6 2018/04/21 02:19:07;
cltt 6 2018/04/21 02:09:07;
binding state active;
next binding state free;
rewind binding state free;
hardware ethernet 00:21:cc:5e:3f:1e; 对照文件
uid "\001\000!\314^?\036";
client-hostname "L3-A17229";
}
[root@localhost dhcp]# systemctl stop dhcpd
然后重置server拔网线进去查看ifconfig,对照相应的MAC值，相同的话DHCP即配置成功。
