Users Guide

Table Of Contents
Layer-2 and Layer-3 Relay Features 1225
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Layer-2 and Layer-3 Relay Features
Dell EMC Networking N-Series Switches
This chapter describes how to configure the Layer-2 (L2) DHCP relay, Layer-
3 (L3) DHCP relay, and IP Helper features on Dell EMC Networking
N-Series 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 Example
L2 and L3 Relay Overview
When a DHCP client and server are in the same IP subnet, they can directly
connect to exchange IP address requests and replies. However, buying and
maintaining a DHCP server on each subnet can be expensive and is often
impractical. The IP Helper/DHCP Relay features on the Dell EMC
Networking N-Series switches can help enable communication between
DHCP clients and DHCP servers that reside in different subnets.
Configuring L3 DHCP relay also enables the bootstrap protocol (BOOTP)
relay.
What Is L2 DHCP Relay?
In Layer-2 switched networks, hosts (DHCP clients) may be connected
directly to a switch which is connected to a router configured as a DHCP relay
agent, or they may be connected directly to a DHCP server (unusual). In this
instance, some of the client device information required by the DHCP server
may not be included in the DHCP packets sent by the DHCP client. An L2
NOTE: Dell EMC Networking N1100-ON Series switches do not support the L3
relay. feature.