Netgear XSM4324FS Software Administration Manual Software Version 12.x - Page 625

M4300 Series and M4300-96X Fully Managed Switches DHCP L2 Relay DHCP relay agents eliminate the need to have a DHCP server on each physical network. Relay agents populate the giaddr field and also append the Relay Agent Information option to the DHCP messages. DHCP servers use this option for IP addresses and other parameter assignment policies. These DHCP relay agents are typically IP routing-aware devices and are referred to as Layer 3 relay agents. In some network configurations, Layer 2 devices can append the relay agent Information option as they are closer to the end hosts. Host #1 1/0/5 1/0/6 1/0/4 Layer 2 Switch #1 DHCP Server #1 Host #2 Figure 61. DHCP L2 relay These Layer 2 devices typically operate only as bridges for the network and might not have an IPv4 address on the network. Lacking a valid IPv4 source address, they cannot relay packets directly to a DHCP server on another network. These Layer 2 devices append the Relay agent information option and broadcast the DHCP message. This section provides information about where a Layer 2 relay agent fits in and how it is used. CLI: Enable DHCP L2 Relay 1. Enter the following commands: (Netgear Switch)#vlan database (Netgear Switch)(Vlan)#vlan 200 (Netgear Switch)(Vlan)#exit DHCP L2 Relay and L3 Relay 625 Software Administration Manual