We have been receiving reports from users connected to a specific switch that they have been being dropped off of the network for anywhere from one minute to 5 minutes. I have checked the Cisco switch that they are connected to and have found a couple of errors.
entry number 22 : C4K_L2MAN-6-INVALIDSOURCEADDRESSPACKET (Suppressed 11 times)Packet received with invalid source MAC address (00:00:00:00:00:00) on port Gi1/1 in vlan 173 timestamp: 149635257
The port that is reporting the error, Gi1/1, is the connection between this switch and our core switch. The other issue that I have seen is in the DHCP tables for these users. I have noticed that some of the clients connected to the switch have multiple entries in the DHCP table for their computers. Some are only a day apart, but they are using the same MAC address.