User Guide     486
Configuring DHCP Service Configuration Examples
Figure 5-28 Network Topology for Option82 in DHCP Relay
Gi1/0/2Gi1/0/1
DHCP Server
192.168.0.59/24
Switch A
DHCP Relay
00:00:FF:FF:27:12
VLAN 2
192.168.2.1/24
Group 1
PCPC
192.168.2.50-192.168.2.100
VLAN 2
192.168.2.1/24
Group 2
PCPC
192.168.2.150-192.168.2.200
5.4.2  Configuration Scheme
To meet the requirements,  you can configure Option82  in  DHCP Relay on Switch A. 
With DHCP Relay enabled, the switch can forward DHCP requests and replies between 
clients and the server. With Option82 enabled, SwitchA informs the DHCP server of the 
group information of each computer, so that the DHCP server can assign IP addresses of 
different address pools to the computers in different groups.
The overview of the configurations are as follows: 
1)  Configuring Switch A
a.  Configure 802.1Q VLAN. Add all computers to VLAN 2. For details, refer to 
Configuring 802.1Q VLAN.
b.  Configure the interface address of VLAN 2. For details, refer to Configuring Layer 3 
Interfaces.
c.  Configure DHCP relay and enable Option82 in DHCP Relay. In this example, both  
DHCP Interface Relay and DHCP VLAN Relay can implement the requirements. 
Demonstrated with T1600G-28TS, 5.4.3 Configuring the DHCP Relay Switch 
provides configuration procedures to configure DHCP Interface Relay in two ways: 
using the GUI and using the CLI. 
2)  Configuring the DHCP Server
The detailed configurations on the DHCP server may be different among different 
devices. You can refer to the related document that is for the DHCP server you use.  
Demonstrated with a Linux ISC DHCP Server, 5.4.4 Configuring the DHCP Server 
provides information about how to set its DHCP configuration file.