DHCP大家应该不陌生吧！想必也很清楚，不过我还是想在这写有关DHCP配置需要注意的地方。

先看一个示例图：

 

 

网络环境：

路由器作为DHCP servers ，交换机提供VLAN接口，三台电脑模拟三个不同网段VLAN1：192.168.1.0/24、VLAN2：192.168.2.0/24、VLAN3：192.168.3.0/24。

路由器配置：

第一种解决方法：使用路由口与接入交换机相连。

ip dhcp pool vlan1

 network 192.168.1.0 255.255.255.0  dns-server 1.1.1.1 ip dhcp pool vlan2  network 192.168.2.0 255.255.255.0  dns-server 2.2.2.2 ip dhcp pool vlan3  network 192.168.3.0 255.255.255.0  dns-server 3.3.3.3

interface FastEthernet0/1

 no ip address  duplex auto  speed auto ! interface FastEthernet0/1.1  encapsulation dot1Q 1 native  ip address 192.168.1.2 255.255.255.0 ! interface FastEthernet0/1.2  encapsulation dot1Q 2  ip address 192.168.2.2 255.255.255.0 ! interface FastEthernet0/1.3  encapsulation dot1Q 3  ip address 192.168.3.2 255.255.255.0

交换机配置：

interface FastEthernet0/1

 switchport mode trunk ! interface FastEthernet0/2 ! interface FastEthernet0/3 ! interface FastEthernet0/4 ! interface FastEthernet0/5 ! interface FastEthernet0/6 ! interface FastEthernet0/7 ! interface FastEthernet0/8 ! interface FastEthernet0/9 ! interface FastEthernet0/10  switchport access vlan 2 ! interface FastEthernet0/11  switchport access vlan 2 ! interface FastEthernet0/12  switchport access vlan 2 ! interface FastEthernet0/13  switchport access vlan 2 ! interface FastEthernet0/14  switchport access vlan 2 ! interface FastEthernet0/15  switchport access vlan 2 ! interface FastEthernet0/16  switchport access vlan 3 ! interface FastEthernet0/17  switchport access vlan 3 ! interface FastEthernet0/18  switchport access vlan 3 ! interface FastEthernet0/19  switchport access vlan 3 ! interface FastEthernet0/20  switchport access vlan 3 ! interface FastEthernet0/21  switchport access vlan 3 ! interface FastEthernet0/22  switchport access vlan 3 ! interface FastEthernet0/23  switchport access vlan 3 ! interface FastEthernet0/24  switchport mode trunk ! interface GigabitEthernet1/1 ! interface GigabitEthernet1/2 ! interface Vlan1  no ip address ! interface Vlan2  no ip address ! interface Vlan3  no ip address

==================================================================

第二种解决方法：使用交换口与接入交换机相连。

interface FastEthernet0/0/0

 switchport mode trunk ! interface FastEthernet0/0/1  switchport access vlan 2  switchport mode access  shutdown ! interface FastEthernet0/0/2  switchport access vlan 3  switchport mode access  shutdown ! interface Vlan1  ip address 192.168.1.1 255.255.255.0 ! interface Vlan2  ip address 192.168.2.1 255.255.255.0 ! interface Vlan3  ip address 192.168.3.1 255.255.255.0