Deployment Guide

If multiple IP addresses are expected for the same MAC address, repeat this step for all IP addresses.
Clearing the Binding Table
To clear the binding table, use the following command.
● Delete all of the entries in the binding table.
EXEC Privilege mode
clear ip dhcp snooping binding
Displaying the Contents of the Binding Table
To display the contents of the binding table, use the following command.
● Display the DHCP snooping information.
EXEC Privilege mode
show ip dhcp snooping
● Display the contents of the binding table.
EXEC Privilege mode
show ip dhcp snooping binding
View the DHCP snooping statistics with the show ip dhcp snooping command.
View the DHCP snooping binding table using the show ip dhcp snooping binding command.
The following example output of the show ip dhcp snooping binding command displays that different IP addresses are
mapped to the same MAC address:
The following example shows a sample output of the show ip dhcp snooping binding command for a device connected
to both the VLT peers. The Po 10 interface is the VLT port channel connected to a ToR switch or an end device.
DellEMC#show ip dhcp snooping binding
Codes : S - Static D - Dynamic
IP Address MAC Address Expires(Sec) Type VLAN Interface
=========================================================================
10.1.1.10 00:00:a0:00:00:00 39735 S Vl 200 Po 10
10.1.1.11 00:00:a0:00:00:00 39736 S Vl 200 Po 10
10.1.1.25 00:00:a0:00:00:00 162 D Vl 200 Po 10
The following example shows a sample output of the show ip dhcp snooping binding command for a device connected
to one of the VLT peers only (orphaned). The physical interface is the one that is directly connected to the VLT peer.
The following example shows a sample output of the show ip dhcp snooping binding command for a device connected
to the peer VLT node, but not to itself. The Po 10 interface is the VLTi link between the VLT peers.
DellEMC#show ip dhcp snooping binding
Codes : S - Static D - Dynamic
IP Address MAC Address Expires(Sec) Type VLAN Interface
=========================================================================
10.1.1.10 00:00:a0:00:00:00 39735 S Vl 200 Po 10
10.1.1.11 00:00:a0:00:00:00 39736 S Vl 200 Po 10
10.1.1.25 00:00:a0:00:00:00 162 D Vl 200 Po 10
Drop DHCP Packets on Snooped VLANs Only
Binding table entries are deleted when a lease expires or the relay agent encounters a DHCPRELEASE.
Line cards maintain a list of snooped VLANs. When the binding table fills, DHCP packets are dropped only on snooped
VLANs, while such packets are forwarded across non-snooped VLANs. Because DHCP packets are dropped, no new IP address
assignments are made. However, DHCP release and decline packets are allowed so that the DHCP snooping table can decrease
in size. After the table usage falls below the maximum limit of 4000 entries, new IP address assignments are allowed.
Dynamic Host Configuration Protocol (DHCP)
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