Service Manual

Displaying the Contents of the DHCPv6 Binding Table
To display the contents of the DHCP IPv6 binding table, use the following command.
• Display the contents of the binding table.
EXEC Privilege mode
show ipv6 dhcp snooping biniding
Example of the show ipv6 dhcp snooping binding Command
View the DHCP snooping statistics with the show ipv6 dhcp snooping command.
Dell#show ipv6 dhcp snooping binding
Codes : S - Static D – Dynamic
IPv6 Address MAC Address Expires(Sec) Type VLAN Interface
=========================================================================
11:11::22 11:22:11:22:11:22 120331 S Vl 100 Te 1/1
33::22 11:22:11:22:11:23 120331 S Vl 200 Te 1/1
333:22::22 11:22:11:22:11:24 120331 D Vl 300 Te 1/2
Debugging the IPv6 DHCP
To debug the IPv6 DHCP, use the following command.
• Display debug information for IPV6 DHCP.
EXEC Privilege mode
debug ipv6 dhcp
IPv6 DHCP Snooping MAC-Address Verification
Configure to enable verify source mac-address in the DHCP packet against the mac address stored in the
snooping binding table.
• Enable IPV6 DHCP snooping .
CONFIGURATION mode
ipv6 dhcp snooping verify mac-address
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.
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.
Dell#show ip dhcp snooping binding
Codes : S - Static D - Dynamic
IP Address MAC Address Expires(Sec) Type VLAN Interface
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Dynamic Host Configuration Protocol (DHCP)
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