Hi all, I'm struggling to identify the cause of a really strange issue that has started to plague our network of Mac devices. We use Cisco switches and have port security turned on which means any device that registers more than one MAC address triggers a port violation which then shuts down the port for a short period of time (5 mins I believe). A few months ago we suddenly started get lots of violations from Mac devices the were all registering additional MAC addresses (2 usually) that all had the same 6 character prefix (00:00:40). So far we've not been able to determine the cause and now getting pretty desperate and exploring all possible avenues. All we know id that prefix is registered to a company called Applicon from back in the day but is now shut down. Has anyone come across this issue or know of any possible reason why this may be happening? Thanks