Users Guide

Remove static DHCP snooping entry from the binding table
• Remove a static DHCP snooping entry from the binding table in CONFIGURATION mode.
no ip dhcp snooping binding mac mac-address vlan vlan-id
Example for removing static DHCP snooping entry in the binding table
OS10(config)# no ip dhcp snooping binding mac 00:04:96:70:8a:12 vlan 100
Clear dynamically-learned entries from DHCP snooping binding table
• Use the following command in EXEC mode:
clear ip dhcp snooping binding [mac mac-address] [vlan vlan-id] [interface {ethernet slot/
port/sub-port | port-channel port-channel-id}]
CAUTION: Clearing the DHCP snooping binding table using the clear ip dhcp snooping binding command also clears the
SAV and DAI entries on the system. This aects the trac from clients that are connected to the DHCP snooping-
enabled VLANs.
Example for clearing dynamically-learned entries from DHCP snooping binding table
The following example clears all dynamic DHCP snooping binding entries that are associated to the MAC address 04:56:79:86:73:fe
OS10# clear ip dhcp snooping binding mac 04:56:79:86:73:fe
The following example clears all dynamic DHCP snooping binding entries that are associated to VLAN 100:
OS10# clear ip dhcp snooping binding vlan 100
The following example clears all the dynamic DHCP snooping binding entries that are associated to VLAN 100 with MAC address
04:56:79:86:73:fe on port-channel 10:
OS10# clear ip dhcp snooping binding mac 04:56:79:86:73:fe vlan 100 port-channel 10
View contents of DHCP binding table
• Use the following command in EXEC mode:
show ip dhcp snooping binding [vlan vlan-name]
Example for viewing contents of DHCP binding table
OS10# show ip dhcp snooping binding
Codes : S - Static D – Dynamic
IPv4 Address MAC Address Expires(Sec) Type VLAN Interface
=========================================================================
10.1.1.22 11:22:11:22:11:22 120331 S 100 ethernet1/1/4
33.1.1.44 11:22:11:22:11:23 120331 S 200 port-channel100
103.1.1.5 11:22:11:22:11:24 120331 D 300 ethernet1/1/5:4
DHCP snooping examples
DHCP snooping in a simple layer 2 network
This example uses a simple topology with a DHCP snooping switch and a DHCP server. A DHCP client is connected to the snooping switch
and a rouge DHCP server attempts to pose as a legitimate DHCP server. With a conguration similar to the following, the DHCP snooping
switch drops packets from the rouge DHCP server which is connected to an untrusted port.
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System management