这里介绍H3C设备DHCP中继配置，华为交换机也是类似。 如图，SWA是核心交换机，只做DHCP中继，为了方便更好理解dhcp中继原理，这里测试RTA给交换机vlan10分配地址，RTB给交换机vlan20分配地址。

首先配置SWA,RTA,RTB的基础配置保证各个网段互通。 SWA配置： [SWA]vlan 10 [SWA-vlan10]quit [SWA]vlan 20 [SWA-vlan20]quit [SWA]interface Vlan-interface 10 [SWA-Vlan-interface10]ip address 192.168.10.254 24 [SWA-Vlan-interface10]quit [SWA]interface Vlan-interface 20 [SWA-Vlan-interface20]ip address 192.168.20.254 24 [SWA-Vlan-interface20]quit [SWA]interface GigabitEthernet 1/0/2 [SWA-GigabitEthernet1/0/2]port link-type access [SWA-GigabitEthernet1/0/2]port access vlan 10 [SWA-GigabitEthernet1/0/2]quit [SWA]interface GigabitEthernet 1/0/3 [SWA-GigabitEthernet1/0/3]port link-type a ccess [SWA-GigabitEthernet1/0/3]port access vlan 20 [SWA-GigabitEthernet1/0/3]quit [SWA]ip route-static 0.0.0.0 0.0.0.0 192.168.1.1 RTA配置： [RTA]interface GigabitEthernet 0/0 [RTA-GigabitEthernet0/0]ip address 192.168.1.1 24 [RTA-GigabitEthernet0/0]quit [RTA]interface GigabitEthernet 0/1 [RTA-GigabitEthernet0/1]ip address 192.168.2.1 24 [RTA-GigabitEthernet0/1]quit [RTA]ip route-static 192.168.10.0 24 192.168.1.2 [RTA]ip route-static 192.168.20.0 24 192.168.1.2 RTB配置： [RTB]interface GigabitEthernet 0/0 [RTB-GigabitEthernet0/0]ip address 192.168.2.2 24 [RTB-GigabitEthernet0/0]quit [RTB]ip route-static 192.168.1.0 24 192.168.2.1 [RTB]ip route-static 192.168.10.0 24 192.168.2.1 [RTB]ip route-static 192.168.20.0 24 192.168.2.1 ————————————-三台设备的基础配置完毕 SWA配置dhcp中继: [SWA]dhcp enable [SWA]interface Vlan-interface 10 [SWA-Vlan-interface10]dhcp select relay //配置dhcp类型为中继 [SWA-Vlan-interface10]dhcp relay server-address 192.168.1.1 //指定中继的最终dhcp地址 [SWA-Vlan-interface10]quit 配置RTA地址池和dhcp服务： [RTA]dhcp enable [RTA]dhcp server ip-pool vlan10 //配置一个地址池 [RTA-dhcp-pool-vlan10]network 192.168.10.0 24 [RTA-dhcp-pool-vlan10]gateway-list 192.168.10.254 [RTA-dhcp-pool-vlan10]dns-list 202.96.134.133 114.114.114.114 [RTA-dhcp-pool-vlan10]expired day 0 hour 4 [RTA-dhcp-pool-vlan10]quit [RTA-GigabitEthernet0/0]dhcp select server //最好添加这一步 其实SWA的vlan10去找dhcp分配地址是使用vlan10的192.168.10.254这个地址代理获取地址，所以交换机会根192.168.10.254这个地址来分配192.168.10.0/24段的地址给设备。由此，可以理解路由器根据地址池配置的网关信息来准确分配地址。 配置vlan20的中继最终dhcp服务器是RTB [SWA]interface Vlan-interface 20 [SWA-Vlan-interface20]dhcp select relay [SWA-Vlan-interface20]dhcp relay server-address 192.168.2.2 [SWA-Vlan-interface20]quit 配置RTB: [RTB]dhcp enable [RTB]dhcp server ip-pool vlan20 [RTB-dhcp-pool-vlan20]network 192.168.20.0 24 [RTB-dhcp-pool-vlan20]gateway-list 192.168.20.254 [RTB-dhcp-pool-vlan20]dns-list 8.8.8.8 [RTB-dhcp-pool-vlan20]expired day 0 hour 4 [RTB-dhcp-pool-vlan20]quit [RTB]interface GigabitEthernet 0/0 [RTB-GigabitEthernet0/0]dhcp select server //最好添加这一步 [RTB-GigabitEthernet0/0]quit

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