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CHAPTER
22-1
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02
22
Configuring DHCP Features and IP Source Guard
This chapter describes how to configure DHCP snooping and the option-82 data insertion features on
the Catalyst 3750-E or 3560-E switch. It also describes how to configure the IP source guard feature.
Unless otherwise noted, the term switch refers to a Catalyst 3750-E or 3560-E standalone switch and to
a Catalyst 3750-E switch stack.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release, and see the “DHCP Commands” section in the Cisco IOS IP Command
Reference, Volume 1 of 3: Addressing and Services, Release 12.2.
This chapter consists of these sections:
• Understanding DHCP Features, page 22-1
• Configuring DHCP Features, page 22-8
• Displaying DHCP Snooping Information, page 22-15
• Understanding IP Source Guard, page 22-16
• Configuring IP Source Guard, page 22-17
• Displaying IP Source Guard Information, page 22-19
Understanding DHCP Features
DHCP is widely used in LAN environments to dynamically assign host IP addresses from a centralized
server, which significantly reduces the overhead of administration of IP addresses. DHCP also helps
conserve the limited IP address space because IP addresses no longer need to be permanently assigned
to hosts; only those hosts that are connected to the network consume IP addresses.
These sections contain this information:
• DHCP Server, page 22-2
• DHCP Relay Agent, page 22-2
• DHCP Snooping, page 22-2
• Option-82 Data Insertion, page 22-3
• DHCP Snooping and Switch Stacks, page 22-8
• Cisco IOS DHCP Server Database, page 22-6
• DHCP Snooping Binding Database, page 22-6