Our problem appears to be DHCP issuing duplicate IP addresses on our W2K network. We have a mixture of PC’s and Wyse Winterms using DHCP to control IP addresses. The Winterms sporadically lockup and refuse to connect to the network. We remove them from the network, let them sit for a few days and they connect fine until the next time they lock up.
When we implemented port security on our Cisco 55xx switches, the mystery deepened. Somehow another MAC address is getting into the switch andshutting down the port. It appeared that someone was connecting unauthorized equipment to out network. Not so. The offending MAC address is from other Winterms on different switches and even in different buildings.
I believe somehow the DHCP server is issuing duplicate IP addresses. These addresses are then somehow picked up by the switch that recognizes them as illegal and the port gets shut down.
Am I on the right track? Can anyone shed any light on this? Wyse won’t respond to my e-mails and Cisco is no help. Their solution is to turn off port security, which has no effect on the problem.