We recently had a problem show up where some broadcast traffic (DHCP, ARP, and IGMP) is being sent from our router's MAC address to the ethernet broadcast address, but not from our router, and only on one single VLAN. I used switch logs and MAC tables to track the traffic to one of our wireless controllers, but am struggling to track it further than that. We have a cluster of two 7220 controllers. The controllers don't seem to have any comprehensive MAC address table, and the router's MAC isn't showing up as a client. How can I figure out what the actual source of this unwanted traffic is?