配置设备作为DHCP中继示例（中继与服务器处于同一网络）

操作步骤

1. 在SwitchA上配置DHCP中继。

   # 配置接口加入VLAN。

   <HUAWEI> system-view
   [HUAWEI] sysname SwitchA
   [SwitchA] vlan batch 100 200
   [SwitchA] interface gigabitethernet 0/0/2
   [SwitchA-GigabitEthernet0/0/2] port link-type hybrid
   [SwitchA-GigabitEthernet0/0/2] port hybrid pvid vlan 100
   [SwitchA-GigabitEthernet0/0/2] port hybrid untagged vlan 100
   [SwitchA-GigabitEthernet0/0/2] quit
   [SwitchA] interface gigabitethernet 0/0/1
   [SwitchA-GigabitEthernet0/0/1] port link-type hybrid
   [SwitchA-GigabitEthernet0/0/1] port hybrid pvid vlan 200
   [SwitchA-GigabitEthernet0/0/1] port hybrid untagged vlan 200
   [SwitchA-GigabitEthernet0/0/1] quit
   [SwitchA] interface vlanif 200 
   [SwitchA-Vlanif200] ip address 10.10.20.1 24
   [SwitchA-Vlanif200] quit
   

   # 在接口下使能DHCP中继功能。

   [SwitchA] dhcp enable
   [SwitchA] interface vlanif 100
   [SwitchA-Vlanif100] ip address 10.20.20.1 24
   [SwitchA-Vlanif100] dhcp select relay 
   [SwitchA-Vlanif100] dhcp relay server-ip 10.10.20.2
   [SwitchA-Vlanif100] quit

2. 在SwitchA上配置缺省路由。

   [SwitchA] ip route-static 0.0.0.0 0.0.0.0 10.10.20.2
   

3. 在SwitchB上配置基于全局地址池的DHCP服务器功能。

   # 使能DHCP服务。

   <HUAWEI> system-view
   [HUAWEI] sysname SwitchB
   [SwitchB] dhcp enable

   # 配置接口VLANIF200工作在全局地址池模式。

   [SwitchB] vlan 200 
   [SwitchB-vlan200] quit
   [SwitchB] interface gigabitethernet 0/0/1
   [SwitchB-GigabitEthernet0/0/1] port link-type hybrid
   [SwitchB-GigabitEthernet0/0/1] port hybrid pvid vlan 200
   [SwitchB-GigabitEthernet0/0/1] port hybrid untagged vlan 200
   [SwitchB-GigabitEthernet0/0/1] quit
   [SwitchB] interface vlanif 200 
   [SwitchB-Vlanif200] ip address 10.10.20.2 24
   [SwitchB-Vlanif200] dhcp select global
   [SwitchB-Vlanif200] quit

   # 创建地址池并配置相关属性。

   [SwitchB] ip pool pool1
   [SwitchB-ip-pool-pool1] network 10.20.20.0 mask 24
   [SwitchB-ip-pool-pool1] gateway-list 10.20.20.1
   [SwitchB-ip-pool-pool1] option121 ip-address 10.10.20.0 24 10.20.20.1
   [SwitchB-ip-pool-pool1] quit

4. 在SwitchB上配置静态路由。

   [SwitchB] ip route-static 10.20.20.0 255.255.255.0 10.10.20.1
   

5. 验证配置结果。

   # 在SwitchA上执行命令display dhcp relay interface vlanif 100命令用来查看DHCP中继的配置信息。

   [SwitchA] display dhcp relay interface vlanif 100
    DHCP relay agent running information of interface Vlanif100 :
    Server IP address [00] : 10.10.20.2
    Gateway address in use : 10.20.20.1
   

   # 在SwitchB上使用display ip pool name pool1命令用来查看IP地址池的分配情况，“Used”字段表示已经分配出去的IP地址数量。

   [SwitchB] display ip pool name pool1
     Pool-name        : pool1
     Pool-No          : 0
     Lease            : 1 Days 0 Hours 0 Minutes
     Domain-name      : -
     Option-code      : 121
     Option-subcode : --
     Option-type    : hex
     Option-value   : 18640A1414141401
     DNS-server0      : -
     NBNS-server0     : -
     Netbios-type     : -
     Position         : Local
     Status           : Unlocked
     Gateway-0        : 10.20.20.1
     Network          : 10.20.20.0
     Mask             : 255.255.255.0
     VPN instance     : --
     Logging          : Disable
     Conflicted address recycle interval: -
     Address Statistic: Total       :253       Used        :2
                        Idle        :251       Expired     :0
                        Conflict    :0         Disabled     :0
                                                                                   
    -------------------------------------------------------------------------------
     Network section
            Start           End       Total    Used Idle(Expired) Conflict Disabled
    -------------------------------------------------------------------------------
         10.20.20.1    10.20.20.254     253       2        251(0)       0     0
    -------------------------------------------------------------------------------