每個二層交換機上配置好VLAN ，在三層交換機上配置好VLAN ip ，在三層交換機上打開fa0/1-fa0/3的trunk ，再給三層交換機配置dhcp服務，下面是VLAN10的，每個VLAN配一遍，

sw1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

sw1(config)#ip dhcp ?

excluded-address Prevent DHCP from assigning certain addresses

pool Configure DHCP address pools

relay DHCP relay agent parameters

snooping DHCP Snooping

sw1(config)#ip dhcp pool vlan 10

sw1(config)#ip dhcp pool vlan 10

sw1(config)#ip dhcp pool?

pool

sw1(config)#ip dhcp pool vlan10

sw1(dhcp-config)#network 192.168.10.0 255.255.255.0

sw1(dhcp-config)#def

sw1(dhcp-config)#default-router 192.168.10.254

sw1(dhcp-config)#exit

sw1(config)#ip dhcp ex

sw1(config)#ip dhcp excluded-address 192.168.10.100 192.168.10.254

sw1(config)#

驗證

三層交換機dhcp服務配置命令