[c-nsp] SNMP OIDs to monitor DHCP pool conflicts

[Justin Shore]

Does anyone happen to know if there are any SNMP OIDs for monitoring the 
conflicts in a DHCP pool on an Cisco router?  We're having severe 
problems caused by a combination of new OSs using gratutious ARPs and a 
particular model of DSL modem/router that responds to their g-arps, 
causing the client to assume that the IP sent out in the DHCP OFFER is 
already in use which prompts a DHCP DECLINE to be sent a conflict to be 
logged, and the IP in question to be removed from the pool.  The end 
result is that the DHCP pool runs out of IPs and all the users suffer 
for it.

Windows Vista, OS X, and the D-Link WBR/EBR x310 models all generate 
gratuitous ARPs (and I know that the D-Link's are malformed, though I 
can't say that about the other 2).

I could stay ahead of this problem if could monitor the DHCP pools via 
SNMP.  I can trigger an alert based off of this info.  I've enabled DHCP 
server packet debugging to log all offer OFFERs and DECLINEs but that is 
an after-the-fact tool.  I could also use kron to flush the conflicts 
but that won't actually help fix the cause of the problem.

Thanks
  Justin