Cisco Catalyst 2960-XR User Manual

PurposeCommand or Action
Example:
Switch(config)# ip dhcp snooping
•
String of up to 63 ASCII characters (no spaces)
•
Configured hostname for the switch
If the hostname is longer than 63 characters, it is truncated
to 63 characters in the remote-ID configuration.
Note
information option format remote-id
string acsiistring2
The default remote ID is the switch MAC address.
(Optional) If the switch is an aggregation switch connected to an edge
switch, this command enables the switch to accept incoming DHCP
snooping packets with option-82 information from the edge switch.
ip dhcp snooping information option
allow-untrusted
Example:
Switch(config)# ip dhcp snooping
information option allow-untrusted
Step 6
The default setting is disabled.
Enter this command only on aggregation switches that are
connected to trusted devices.
Note
Specifies the interface to be configured, and enter interface configuration
mode.
interface interface-id
Example:
Switch(config)# interface
gigabitethernet2/0/1
Step 7
(Optional) Configures the circuit-ID suboption for the specified interface.
ip dhcp snooping vlan vlan information
option format-type circuit-id [override]
string ASCII-string
Step 8
Specify the VLAN and port identifier, using a VLAN ID in the range
of 1 to 4094. The default circuit ID is the port identifier, in the format
vlan-mod-port.
Example:
Switch(config-if)# ip dhcp snooping vlan
You can configure the circuit ID to be a string of 3 to 63 ASCII
characters (no spaces).
1 information option format-type
curcuit-id override string ovrride2
(Optional) Use the override keyword when you do not want the
circuit-ID suboption inserted in TLV format to define subscriber
information.
(Optional) Configures the interface as trusted or untrusted. Use the no
keyword to configure an interface to receive messages from an untrusted
client. The default setting is untrusted.
ip dhcp snooping trust
Example:
Switch(config-if)# ip dhcp snooping
trust
Step 9
(Optional) Configures the number of DHCP packets per second that an
interface can receive. The range is 1 to 2048. By default, no rate limit
is configured.
ip dhcp snooping limit rate rate
Example:
Switch(config-if)# ip dhcp snooping
limit rate 100
Step 10
We recommend an untrusted rate limit of not more than 100
packets per second. If you configure rate limiting for trusted
interfaces, you might need to increase the rate limit if the port
is a trunk port assigned to more than one VLAN with DHCP
snooping.
Note
Catalyst 2960-XR Switch Security Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29434-01 179
Configuring DHCP
Enabling DHCP Snooping and Option 82

Cisco Catalyst 2960-XR Specifications

General

Stacking Bandwidth	80 Gbps
Layer Support	Layer 2 and Layer 3
Jumbo Frame Support	9198 bytes
RAM	512 MB
Input Voltage	100-240V AC
Model	Catalyst 2960-XR
Uplink Interfaces	4 x 1G SFP or 2 x 10G SFP+
Downlink Interfaces	24 or 48 x Gigabit Ethernet ports
Power Supply	Internal
MAC Address Table Size	16, 000 entries
PoE	Available on PoE models
Weight	4.5 kg
Features	energy efficiency
Stacking	Up to 8 switches
Operating Temperature	0 to 45°C