Enabling DHCP Support for Multiple Subnets Using DHCP Relay Agent in Win Server 2003

If you have multiple subnets in your network, and do not have a DHCP server on every subnet, determine whether your current routers relay DHCP/BOOTP messages.

If your routers cannot be used for DHCP/BOOTP relay, set up a DHCP/BOOTP relay agent on at least one computer running Windows Server 2003 on each subnet. The DHCP/BOOTP relay agent relays DHCP and BOOTP message trafficbetween the DHCP-enabled clients on the local network and a remote DHCP server located on another physical network by using the IP address of the remote DHCP server.

If your routers cannot be used for DHCP/BOOTP relay and you choose not to configure DHCP/BOOTP relay agents, you must configure your network so that a DHCP server has a network adapter on each subnet it serves. You can accomplish this by either placing a DHCP server on each subnet, or by multihoming DHCP servers. This distributed configuration does not provide fault tolerance. If a DHCP server becomes unavailable, DHCP clients on the subnet cannot receive IP addresses and options.

Add the DHCP Relay Agent

To add the DHCP Relay Agent follow this procedure

Go to Start—>Administrative Tools—> Open Routing and Remote Access.

From Routing and Remote Access/server name/IP Routing/General – click general

Right-click General, and then click New Routing Protocol.

In the Select Routing Protocol dialog box, click DHCP Relay Agent, and then click OK.

Configure global DHCP Relay Agent properties

To configure global DHCP Relay Agent properties

Go to Start—>Administrative Tools—> Open Routing and Remote Access.

From Routing and Remote Access/server name/IP Routing/DHCP Relay Agent click DHCP Relay Agent.

Right-click DHCP Relay Agent, and then click Properties.

On the General tab, in Server address, type the IP address of your DHCP server, and then click Add.

Repeat the above step for each DHCP server you need to add, and then click OK.

Enable the DHCP Relay Agent on a router interface

To enable the DHCP Relay Agent on a router interface

Go to Start—>Administrative Tools—> Open Routing and Remote Access.

From Routing and Remote Access/server name/IP Routing/DHCP Relay Agent, click DHCP Relay Agent.

Right-click DHCP Relay Agent, and then click New Interface.

Click the interface you want to add, and then click OK.

In the DHCP Relay Properties dialog box, on the General tab, verify that the Relay DHCP packets check box is selected.

If needed, in Hop-count threshold and Boot threshold (seconds), click the arrows to modify the thresholds.