Default Dhcp Configuration; Dhcp Snooping Configuration Guidelines - Cisco Catalyst 2950 Software Configuration Manual

Configuring DHCP Features

Default DHCP Configuration

Table 19-1
Table 19-1
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 option to accept packets on
untrusted ingress interfaces
DHCP snooping limit rate
DHCP snooping trust
DHCP snooping VLAN
DHCP snooping MAC address verification
1. The switch responds to DHCP requests only if it is configured as a DHCP server.
2. The switch relays DHCP packets only if the IP address of the DHCP server is configured on the SVI of the DHCP client.
3. Use this feature when the switch is an aggregation switch that receives packets with option-82 information from an edge

DHCP Snooping Configuration Guidelines

These are the configuration guidelines for DHCP snooping.
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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
19-6
shows the default DHCP configuration.
Default DHCP Configuration
3
switch.
You must globally enable DHCP snooping on the switch.
DHCP snooping is not active until DHCP snooping is enabled on a VLAN.
Before globally enabling DHCP snooping on the switch, make sure that the devices acting as the
DHCP server and the DHCP relay agent are configured and enabled.
Before configuring the DHCP snooping information option on your switch, be sure to configure the
device that is acting as the DHCP server. For example, you must specify the IP addresses that the
DHCP server can assign or exclude, or you must configure DHCP options for these devices.
If the DHCP relay agent is enabled but DHCP snooping is disabled, the DHCP option-82 data
insertion feature is not supported.
If a switch port is connected to a DHCP server, configure a port as trusted by entering the ip dhcp
snooping trust interface configuration command.
Chapter 19
Default Setting
Enabled in IOS software, requires configuration
2
Enabled
None configured
Enabled (invalid messages are dropped)
Replace the existing relay agent information
Disabled
Enabled
Disabled
None configured
Untrusted
Disabled
Enabled
Configuring DHCP Features
1
2
2
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