拓扑图如上：pc1、 pc2 为DHCP Client ;Router2为DHCP Server;
在Ruter0的F0/0接口上使用ip helper-address address命令来作DHCP服务器Router2的代理。
配置如下：
1路由器R0上的配置：.
R0#sh run
Building configuration...
Current configuration:
!
!
interface FastEthernet0/0
ip address 172.16.1.254 255.255.255.0
ip helper-address 172.16.3.2
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 172.16.2.1 255.255.255.0
duplex auto
speed auto
!
router rip
version 2
network 172.16.0.0
no auto-summary
!
2.路由器R1上的配置：
R1#sh run
Building configuration...
Current configuration:
!
hostname R1
!
interface FastEthernet0/0
ip address 172.16.2.2 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 172.16.3.1 255.255.255.0
duplex auto
speed auto
!
router rip
version 2
network 172.16.0.0
no auto-summary
!
3.路由器R2上的配置：
R2#sh run
Building configuration...
Current configuration:
!
hostname R2
!
memory-size iomem 15 //15%的内存大小用于iomem
ip subnet-zero //可以使用全0网段IP
!
ip dhcp pool tiger506 //配置DHCP地址池
network 172.16.1.0 255.255.255.0
default-router 172.16.1.254
dns-server 200.1.1.1
!
interface FastEthernet0/0
ip address 172.16.3.2 255.255.255.0
duplex auto
speed auto
!
router rip
version 2
network 172.16.0.0
no auto-summary
!
路由器上已经配置好了，在主机网卡上我们选择“自动获取IP地址”。
出处：互联网