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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 22 Configuring DHCP Features and IP Source Guard
Configuring DHCP Server Port-Based Address Allocation
•
Only one IP address can be assigned per port.
•
Reserved addresses (preassigned) cannot be cleared by using the
clear ip dhcp binding
global
configuration command.
•
Preassigned addresses are automatically excluded from normal dynamic IP address assignment.
Preassigned addresses cannot be used in host pools, but there can be multiple preassigned addresses
per DHCP address pool.
•
To restrict assignments from the DHCP pool to preconfigured reservations (unreserved addresses are
not offered to the client and other clients are not served by the pool), you can enter the
reserved-only
DHCP pool configuration command.
Enabling DHCP Server Port-Based Address Allocation
Beginning in privileged EXEC mode, follow these steps to globally enable port-based address allocation
and to automatically generate a subscriber identifier on an interface.
After enabling DHCP port-based address allocation on the switch, use the
ip dhcp pool
global
configuration command to preassign IP addresses and to associate them to clients. To restrict
assignments from the DHCP pool to preconfigured reservations, you can enter the
reserved-only
DHCP
pool configuration command. Unreserved addresses that are part of the network or on pool ranges are
not offered to the client, and other clients are not served by the pool. By entering this command, users
can configure a group of switches with DHCP pools that share a common IP subnet and that ignore
requests from clients of other switches.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
ip dhcp use subscriber-id client-id
Configure the DHCP server to globally use the
subscriber identifier as the client identifier on all
incoming DHCP messages.
Step 3
ip dhcp subscriber-id interface-name
Automatically generate a subscriber identifier based
on the short name of the interface.
A subscriber identifier configured on a specific
interface takes precedence over this command.
Step 4
interface
interface-id
Specify the interface to be configured, and enter
interface configuration mode.
Step 5
ip dhcp server use subscriber-id client-id
Configure the DHCP server to use the subscriber
identifier as the client identifier on all incoming
DHCP messages on the interface.
Step 6
end
Return to privileged EXEC mode.
Step 7
show running config
Verify your entries.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.