2960X DHCP Snooping - bindings ignored log message

[Warren Sullivan - Corp]

Hi Guys,

We are in the process of rolling out DHCP Snooping across our access network, we have a pilot site running with no issues, but i'm wondering what this log message means? i can't seem to find anything;

Jan  9 21:50:35.969 AEST: %DHCP_SNOOPING-6-AGENT_OPERATION_SUCCEEDED: DHCP snooping database Read succeeded.
Jan  9 21:50:35.969 AEST: %DHCP_SNOOPING-6-BINDING_COLLISION: Binding collision.  67 bindings ignored

This popped up after a scheduled reload.

It's on a 2960X stack

Thanks!

[paul driver · Accepted solution]

Hello

My understanding it occurs when the Snoop D/B is being read and the switch sees binding already associated with dhcp client so it report a collision and ignores it.

res

Paul

[Warren Sullivan - Corp]

Perfect, thanks very much!

[Francesco Molino]

Hi

As Paul mentioned, this is due to a collision of entry versus what requested.

DHCP snooping binding is keyed on the combination of MAC and VLAN.
This message occurs when the switch is checking the database for that switch and it sees already an entry matching same MAC and VLAN, in that case, in read mode, the entry from the file db is ignored and you get the message you pasted in your post.