duplicate IP

[rmillikensau29]

What is the best practice to prevent someone from making a device the same IP as your Gateway switch ?

I am at a High school and a student or students from time to time make a phone or other device the same IP as my core switch. Is there a tool or software out there that  I can use to prevent that ? 

[Tinashe Ndhlovu]

IP Source Guard.. but its not as simple as three words... read up on IP Source Guard and the myriad of other features you will learn while doing so. Should give you a good idea of where to start. But to answer your question yes IP Source Guard may help in your situation.