3com 5500-ei pwr Installation Instruction

 

3-4 

If a switch belongs to an XRN fabric, you need to enable the UDP Helper function on it before 

configuring it as a DHCP relay agent. 

 

Complete the following tasks to configure the DHCP relay agent: 

Required 

Correlating a DHCP Server Group with a Relay Agent Interface 

Required 

Configuring DHCP Relay Agent Security Functions 

Optional 

Configuring the DHCP Relay Agent to Support Option 82 

Optional 

 

Make sure to enable DHCP before you perform other DHCP relay-related configurations, since other 

DHCP-related configurations cannot take effect with DHCP disabled. 

Follow these steps to enable DHCP: 

Enter system view 

— 

Enable DHCP 

Required 

Enabled by default. 

 

To enhance reliability, you can set multiple DHCP servers on the same network. These DHCP servers 

form a DHCP server group. When an interface of the relay agent establishes a correlation with the 

DHCP server group, the interface will forward received DHCP packets to all servers in the server group.  

Follow these steps to correlate a DHCP server group with a relay agent interface: 

Enter system view 

— 

Configure the DHCP server IP 
address(es) in a specified 
DHCP server group 

dhcp-server groupNo ip 
ip-address&<1-8> 

Required 

By default, no DHCP server IP 
address is configured in a 
DHCP server group. 

interface interface-type 
interface-number 

Map an interface to a DHCP 
server group 

dhcp-server groupNo 

Required 

By default, a VLAN interface is 
not mapped to any DHCP 
server group.