Configuring L2 and L3 Relay Features 89933Configuring L2 and L3 RelayFeaturesThis chapter describes how to configure the L2 DHCP Relay, L3 DHCPRelay, and IP Helper features on PowerConnect 8024 and 8024F switches.The topics covered in this chapter include:• L2 and L3 Relay Overview• Default L2/L3 Relay Values• Configuring L2 and L3 Relay Features (Web)• Configuring L2 and L3 Relay Features (CLI)• Relay Agent Configuration ExampleL2 and L3 Relay OverviewWhen a DHCP client and server are in the same IP subnet, they can directlyconnect to exchange IP address requests and replies. However, buying andmaintaining a DHCP server on each subnet can be expensive and is oftenimpractical. The relay features on the PowerConnect 8024 and 8024Fswitches can help enable communication between DHCP clients and DHCPservers that reside in different subnets. Configuring L3 DHCP relay alsoenables the bootstrap protocol (BOOTP) relay.What Is L3 DHCP Relay?Network infrastructure devices can be used to relay packets between a DHCPclient and server on different subnets. Such a device, an Layer 3 Relay agent,is often a router or L3 switch. The L3 relay agent must have an IP interface onthe client subnets and, if it does not have an IP interface on the server’ssubnet, it should be able to route traffic toward the server’s subnet.The PowerConnect DHCP Relay Agent enables DHCP clients and servers toexchange DHCP messages across different subnets. The relay agent receivesthe requests from the clients, and checks the valid hops andgiaddr fields in
