3com S7906E 설치 설명서

 

3-4 

Enable the DHCP relay agent 
on the current interface 

dhcp select relay 

Required 

With DHCP enabled, interfaces 
work in the DHCP server mode.

 

If the DHCP client obtains an IP address via the DHCP relay agent, the address pool of the subnet to 

which the IP address of the DHCP relay agent belongs must be configured on the DHCP server. 

Otherwise, the DHCP client cannot obtain a correct IP address. 

 

To improve reliability, you can specify several DHCP servers as a group on the DHCP relay agent and 

correlate a relay agent interface with the server group. When the interface receives requesting 

messages from clients, the relay agent will forward them to all the DHCP servers of the group. 

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

Enter system view 

— 

Create a DHCP server group 
and add a server into the group 

dhcp relay server-group group-id 
ip ip-address 

Required 

Not created by default. 

Enter interface view 

interface interface-type 
interface-number 

— 

Correlate the DHCP server 
group with the current interface 

dhcp relay server-select group-id 

Required 

By default, no interface is 
correlated with any DHCP 
server group. 

 

z 

You can specify up to twenty DHCP server groups on the relay agent and up to eight DHCP server 

addresses for each DHCP server group. 

z 

The IP addresses of DHCP servers and those of relay agent’s interfaces cannot be on the same 

subnet. Otherwise, the client cannot obtain an IP address. 

z 

A DHCP server group can correlate with one or multiple DHCP relay agent interfaces, while a relay 

agent interface can only correlate with one DHCP server group. Using the dhcp relay 

server-select command repeatedly overwrites the previous configuration. However, if the 

specified DHCP server group does not exist, the interface still uses the previous correlation. 

z 

The group-id argument in the dhcp relay server-select command is configure by using the dhcp 

relay server-group command.