We gave every user a static local IP address, bound them with their MAC addresses, and provided them access to different resources.
But, a user has spoofed their MAC address to connect using another IP address, causing a conflict. This person is also hogging on the resources allotted to the legitimate user.
I gave the legitimate user a new IP address, but after a few hours its all the same.
How can I retrieve info about the person and identify them?