Reference Guide
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 contents of the binding table.
EXEC Privilege mode
show ip dhcp snooping
View the DHCP snooping statistics with the show ip dhcp snooping command.
Example of the show ip dhcp snooping Command
FTOS#show ip dhcp snooping
IP DHCP Snooping : Enabled.
IP DHCP Snooping Mac Verification : Disabled.
IP DHCP Relay Information-option : Disabled.
IP DHCP Relay Trust Downstream : Disabled.
Database write-delay (In minutes) : 0
DHCP packets information
Relay Information-option packets : 0
Relay Trust downstream packets : 0
Snooping packets : 0
Packets received on snooping disabled L3 Ports : 0
Snooping packets processed on L2 vlans : 142
DHCP Binding File Details
Invalid File : 0
Invalid Binding Entry : 0
Binding Entry lease expired : 0
List of Trust Ports :Te 0/49
List of DHCP Snooping Enabled Vlans :Vl 10
List of DAI Trust ports :Te 0/49
Drop DHCP Packets on Snooped VLANs Only
Binding table entries are deleted when a lease expires or the relay agent encounters a DHCPRELEASE.
Starting with FTOS version 8.2.1.1, 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.
To view the number of entries in the table, use the show ip dhcp snooping binding command. This output
displays the snooping binding table created using the ACK packets from the trusted port.
FTOS#show ip dhcp snooping binding
Codes : S - Static D - Dynamic
IP Address MAC Address Expires(Sec) Type VLAN Interface
================================================================
10.1.1.251 00:00:4d:57:f2:50 172800 D Vl 10 Gi 0/2
10.1.1.252 00:00:4d:57:e6:f6 172800 D Vl 10 Gi 0/1
10.1.1.253 00:00:4d:57:f8:e8 172740 D Vl 10 Gi 0/3
10.1.1.254 00:00:4d:69:e8:f2 172740 D Vl 10 Te 0/50
288