Displaying A Binding Table - Cisco Catalyst 4500 Series Configuration Manual

Chapter 50 Configuring DHCP Snooping, IP Source Guard, and IPSG for Static Hosts

Displaying a Binding Table

The DHCP snooping binding table for each switch contains binding entries that correspond to untrusted
ports. The table does not contain information about hosts interconnected with a trusted port because each
interconnected switch has its own DHCP snooping binding table.
This example shows how to display the DHCP snooping binding information for a switch:
Switch# show ip dhcp snooping binding
MacAddress
------------------
00:02:B3:3F:3B:99
Switch#
Table 50-2
Table 50-2
Field
MAC Address
IP Address
Lease (seconds)
Type
VLAN
Interface
Displaying the DHCP Snooping Configuration
This example shows how to display the DHCP snooping configuration for a switch:
Switch# show ip dhcp snooping
Switch DHCP snooping is enabled.
DHCP Snooping is configured on the following VLANs:
Insertion of option 82 is enabled
Option82 on untrusted port is not allowed
Verification of hwaddr field is enabled
Interface
---------
FastEthernet2/1
FastEthernet3/1
GigabitEthernet1/1
Switch#
About IP Source Guard
The IP source guard feature is enabled on a DHCP snooping untrusted Layer 2 port. Initially, all IP traffic
on the port is blocked except for DHCP packets that are captured by the DHCP snooping process. When
a client receives a valid IP address from the DHCP server, or when you configure a static IP source
binding, a per-port and VLAN access control list (VACL) is installed on the port. This process restricts
OL-25340-01
IpAddress
---------------
55.5.5.2
describes the fields in the show ip dhcp snooping binding command output.
show ip dhcp snooping binding Command Output
Description
Client hardware MAC address
Client IP address assigned from the DHCP server
IP address lease time
Binding type; dynamic binding learned by DHCP snooping or
statically-configured binding.
VLAN number of the client interface
Interface that connects to the DHCP client host
10 30-40 100 200-220
Trusted
-------
yes
yes
no
Lease(sec) Type
---------- -------------
6943 dhcp-snooping
Rate limit (pps)
----------------
10
none
20
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
About IP Source Guard
VLAN Interface
---- --------------------
10 FastEthernet6/10
50-19