Problem: We have a lab router (2620) on the outside of our local LAN. The router is set up do give public IP's. It is connected to the local LAN by a VLAN (island). A few days ago we had a hand full of user on a completely separate internal VLAN pull IP's from this "external" router. We shut down the port while we looked in to it. We found nothing that would elude to this being able to happen. We re-enabled the port and haven't had any more issues. So I was hoping someone could enlighten me on what might have taken place.
I have this problem too.