a friend of mine in another company told me that they had a problem with a client
he is not the switching admin there and the admin had told them there are more than mac addresses going from client to switch, so it causes port security violation and error disable and ...
the NIC was changed and problem was solved
now this is my question,
can a bad NIC cause this ? I have seen bad NIC's causing Flap and so the port has been error disabled but have you ever experienced a defective NIC with generates multiple mac addresses ? (making the switch shut it down if port security violation is configured)