18.5 DHCP Snooping

1.SW1配置DHCP

[SW1]dhcp enable 
[SW1]vlan batch 10
[SW1]interface Vlanif 10 
[SW1-Vlanif10]IP address 192.168.1.254 24
[SW1-Vlanif10]dhcp select interface 
[SW1]interface GigabitEthernet 0/0/1
[SW1-GigabitEthernet0/0/1]port link-type access 
[SW1-GigabitEthernet0/0/1]port default vlan 10
[SW1]interface GigabitEthernet 0/0/2
[SW1-GigabitEthernet0/0/2]port link-type access 
[SW1-GigabitEthernet0/0/2]port default vlan 10

2.PC1自动获取IP地址

PC>ipconfig

Link local IPv6 address...........: fe80::5689:98ff:fefd:3065
IPv6 address......................: :: / 128
IPv6 gateway......................: ::
IPv4 address......................: 192.168.1.253
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.1.254
Physical address..................: 54-89-98-FD-30-65

3.R2配置DHCP，SW2端口加入VLAN 10

[R2]dhcp enable
[R2]interface GigabitEthernet 0/0/0
[R2-GigabitEthernet0/0/0]ip address 192.168.2.254 24
[R2-GigabitEthernet0/0/0]dhcp select interface 
[SW1]interface GigabitEthernet 0/0/24
[SW1-GigabitEthernet0/0/24]port link-type access 
[SW1-GigabitEthernet0/0/24]port default vlan 10

4.PC2自动获取IP地址

PC2>ipconfig
Link local IPv6 address...........: fe80::5689:98ff:fe23:524e
IPv6 address......................: :: / 128
IPv6 gateway......................: ::
IPv4 address......................: 192.168.2.253
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.2.254
Physical address..................: 54-89-98-23-52-4E

5.SW1配置DHCP Snooping

[SW1]dhcp snooping enable 
[SW1]vlan 10
[SW1-vlan10]dhcp snooping enable

6.PC1、PC2重新自动获取IP地址

PC1>ipconfig /renew
IPv4 address......................: 192.168.1.252
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.1.254
Physical address..................: 54-89-98-FD-30-65
PC2>ipconfig /renew
Link local IPv6 address...........: fe80::5689:98ff:fe23:524e
IPv4 address......................: 192.168.1.251
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.1.254
Physical address..................: 54-89-98-23-52-4E