I was given the mac address of a computer that was on my wifi . It was not my computer. There were 2 computers, mine plugged to the modem and a 2nd computer with different mac address than mine. So I have the mac address. If someone registered that computer is there any way I can find out who it is registered to? BY the computer mac address?
Nope. MAC addresses are extremely easy to modify, and there is no centralized registry of them anyways. There's really nothing you can do beyond setting a secure wifi password (that means using WPA2) to prevent them from connecting in the future.
Like others said, you can't find exactly who, but you can find the network he is usualy connected if he is one of your neighbor, and that may reveal some information about him. For this, we need to assume a few things:
- You are close to him to be able to capture his traffic, or proble signal;
- He was not using some powerful antenna to strong his signal;
- He didn't change his MAC Address to a fake one;
- He has a wireless network nearby (again, lets pretend he is one of your neighbor);
Then, you use airodump-ng to capture all clients connected to nearby networks, if you are lucky enough it will show his mac address and the wireless network he is connected.
I found his network, so what?
Well, in the past with the network bssid you could find the exactly lagitude and longitude, today there are some database's that still have this information.
Recommendations: Protect your Wireless conection with WPA2 and use a strong password (>32), even if you use WPA2 and put a stupid password, people will break the password by capturing a WPA2 handshake from your network and brute force it.
If the MAC has not been spoofed you can use queries like http://www.coffer.com/mac_find/ to identify the hardware vendor. Sometimes this will identify the device manufacturer sometimes only the NIC manufacturer but provided it wasn't spoofed it will give you more information than you would have by just knowing a hex string. You can then use this information to inform further investigations.