Chapter 20
Configuring DHCP Features
Figure 20-2 Suboption Packet Formats
Circuit ID Suboption Frame Format
Suboption
type
1 byte
Remote ID Suboption Frame Format
Suboption
type
1 byte
Configuring DHCP Features
These sections describe how to configure DHCP snooping and option 82 on your switch:
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Default DHCP Configuration
Table 20-1
Table 20-1 Default DHCP Configuration
Feature
DHCP server
DHCP relay agent
DHCP packet forwarding address
Checking the relay agent information
DHCP relay agent forwarding policy
DHCP snooping enabled globally
DHCP snooping information option
DHCP snooping limit rate
78-11380-10
Circuit
ID type
Length
Length
1
6
0
4
1 byte 1 byte 1 byte
Remote
ID type
Length
Length
2
8
0
6
1 byte 1 byte 1 byte
Default DHCP Configuration, page 20-5
DHCP Snooping Configuration Guidelines, page 20-6
Configuring the DHCP Server, page 20-6
Enabling DHCP Snooping and Option 82, page 20-7
shows the default DHCP configuration.
VLAN
Module Port
2 bytes
1 byte 1 byte
MAC address
6 bytes
Default Setting
Enabled
Enabled
None configured
Enabled (invalid messages are dropped)
Replace the existing relay agent information
Disabled
Enabled
None configured
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Configuring DHCP Features
1
2
2
2
20-5