Netopia 3346N-ENT User Guide (en)

7-28  Firmware User Guide
DHCP Relay Agent
The Netopia Firmware Version 8.6.1 offers DHCP Relay Agent functionality, as defined in RFC1542. A DHCP 
relay agent is a computer system or a gateway that is configured to for ward DHCP requests from clients on the 
LAN to a remote DHCP ser ver, and to pass the replies back to the requesting client systems. 
When a DHCP client star ts up, it has no IP address, nor does it know the IP address of a DHCP ser ver. 
Therefore, it uses an IP broadcast to communicate with one or more DHCP ser vers. These broadcasts are 
normally limited to the network segment on which the client is located, and do not pass through gateways such 
as the Netopia Router. If the Netopia Router is configured to act as a DHCP ser ver, it will assign the client an 
address from an address pool configured locally in the Netopia Router and respond to the client's request 
However, if the Netopia Router is configured to act as a DHCP relay agent, it does not satisfy the DHCP request 
itself, but instead for wards the request to one or more remote DHCP ser vers. These ser vers process the 
request, assign an address from an address pool configured on the remote ser ver, and for ward the response 
back to the Netopia Router for deliver y back to the client. The agent then sends the response to the client on 
behalf of the DHCP ser ver. This process is transparent to the client, which doesn't know that it is 
communicating through an intermediar y rather than directly to a local ser ver. Using DHCP relay, it is possible to 
centralize the configuration information for the host computers at many remote sites at a single location, easing 
the burden of administering configuration management for remote sites.
To configure the Netopia Router to act as a DHCP relay agent, from the Main Menu navigate to the System 
Configuration menu.
                              Served IP Addresses
 -IP Address------Type----Expires--Host Name/Client Identifier-----------------
 ----------------------------------SCROLL UP-----------------------------------      Excluded for the gateway's IP address      Excluded      DHCP    00:24    Barr's XPi 120
 ---------------------------------SCROLL DOWN----------------------------------
 Lease Management...
Hit RETURN/ENTER for available operations.