Introduction To Dhcp Relay Agent; Application Environment; Fundamentals - 3Com MSR 50 Series Configuration Manual

34
Introduction to DHCP
Relay Agent
Application
Environment

Fundamentals

DHCP R
When configuring the DHCP relay agent, go to these sections for information you
are interested in:
"Introduction to DHCP Relay Agent" on page 589
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"DHCP Relay Agent Configuration Task List" on page 591
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"Configuring the DHCP Relay Agent" on page 591
■
"Displaying and Maintaining the DHCP Relay Agent Configuration" on page
■
596
"DHCP Relay Agent Configuration Example" on page 596
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"Troubleshooting DHCP Relay Agent Configuration" on page 597
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n
The DHCP relay agent configuration is supported only on Layer 3 Ethernet
■
interfaces (or subinterfaces), virtual Ethernet interfaces, VLAN interfaces, and
serial interfaces.
DHCP Snooping must be disabled on the DHCP relay agent.
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Since DHCP clients request IP addresses via broadcast messages, the DHCP server
and clients must be on the same subnet. Therefore, a DHCP server must be
available on each subnet. It is not practical.
DHCP relay agent solves the problem. Via a relay agent, DHCP clients
communicate with a DHCP server on another subnet to obtain configuration
parameters. Thus, DHCP clients on different subnets can contact the same DHCP
server for ease of centralized management and cost reduction.
Figure 172 shows a typical application of the DHCP relay agent.
A
ELAY GENT
C
ONFIGURATION