Dhcp Relay Agent Configuration Example - 3Com Switch 4800G 24-Port Configuration Manual

820 C 58: DHCP R
HAPTER
DHCP Relay Agent
Configuration
Example
A C
ELAY GENT ONFIGURATION
Network requirements
VLAN-interface 1 on the DHCP relay agent (Switch A) connects to the network
where DHCP clients reside. The IP address of VLAN-interface 1 is 10.10.1.1/24 and
IP address of VLAN-interface 2 is 10.1.1.2/24 that communicates with the DHCP
server 10.1.1.1/24. As shown in the figure below, Switch A forwards messages
between DHCP clients and the DHCP server.
Network diagram
Figure 249 Network diagram for DHCP relay agent
DHCP client DHCP client
DHCP client
Configuration procedure
# Enable DHCP.
<SwitchA> system-view
[SwitchA] dhcp enable
# Enable the DHCP relay agent on VLAN-interface 1.
[SwitchA] interface vlan-interface 1
[SwitchA-Vlan-interface1] dhcp select relay
[SwitchA-Vlan-interface1] quit
# Configure DHCP server group 1 with the DHCP server 10.1.1.1, and correlate
the DHCP server group 1 with VLAN-interface 1.
[SwitchA] dhcp relay server-group 1 ip 10.1.1.1
[SwitchA] interface vlan-interface 1
[SwitchA-Vlan-interface1] dhcp relay server-select 1
n
Performing the configuration on the DHCP server is also required to guarantee
■
the client-server communication via the relay agent. Refer to "DHCP Server
Configuration Examples" on page 809 for DHCP server configuration
information.
If the DHCP relay agent and server are on different subnets, routes in between
■
must be reachable.
Vlan-int1 Vlan-int2
10 .10 .1 .1/24 10.1.1 .2/24
10.1.1 .1/24
Switch A
DHCP relay agent
DHCP client
Vlan-int2
Switch B
DHCP server