前面讲过了三层交换机如何配置DHCP，现在用路由器配置其实更简单
拓扑图如下:
其中172.16.0.0网段我还是采用/24的配置方式。因为我配置的大环境用不了太多IP地址
Router(config)#service dhcp//开启dhcp服务
Router(config)#ip dhcp pool sub//配置名为sub的地址池
Router(dhcp-config)#network 172.16.4.0 255.255.255.0//设置为/24的网段
Router(dhcp-config)#default-router 172.16.4.1
Router(dhcp-config)#dns-server 172.16.4.2
Router(config)#ip dhcp excluded-address 172.16.4.1 172.16.4.2
Router(config)#interface GigabitEthernet0/1
Router(config-if)#ip address 172.16.4.1 255.255.255.0//端口IP一定要注意为/24配置结果：
顺便再做个NAT使其连接外部网络
自定义的地址池为：201.4.4.10-201.4.4.100
命令如下：
Router>en
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#ip nat pool sub 201.4.4.10 201.4.4.100 netmask 255.255.255.0
Router(config)#ip nat inside source list 1 pool sub
Router(config)#access-list 1 permit 172.16.4.0 255.255.255.0
Router(config)#int g 0/1
Router(config-if)#ip nat inside
Router(config-if)#int g0/0
Router(config-if)#ip nat outside
Router(config-if)#ebd.
Router(config-if)#end
Router#show ip nat statistics//查看nat配置
Total translations: 0 (0 static, 0 dynamic, 0 extended)
Outside Interfaces: GigabitEthernet0/0
Inside Interfaces: GigabitEthernet0/1
Hits: 0 Misses: 1
Expired translations: 0
Dynamic mappings:
-- Inside Source
access-list 1 pool sub refCount 0
pool sub: netmask 255.255.255.0
start 201.4.4.10 end 201.4.4.100
type generic, total addresses 91 , allocated 0 (0%), misses 0
Router#路由协议就选rip了
不要忘记配置静态路由！
测试如下：
