In short the answer will be you can't. It is usually not possible for a person to get the MAC address of a computer from its IP address alone. These two addresses originate from different sources.

Simply stated, a computer's own hardware configuration determines its MAC address while the configuration of the network it is connected to determines its IP address. However, computers connected to the same TCP/IP local network can determine each other's MAC addresses.

Mar 26, 2016 - If it is on your local network then the best you can do is find its IP, which still wont give you the physical location. Type command in the search box (Start->Run for Windows XP) and press Enter. At the Command Prompt, type *ipconfig /all Note: Be sure to put a space between ipconfig and /all. When you're troubleshooting internet and networking problems over the phone, one key piece of information is your IP address. Creative code for qt creator. This is easy to find on both a Mac and Windows computer.

The technology called ARP - Address Resolution Protocol included with TCP/IP makes it possible. Using ARP, each computer maintains a list of both IP and MAC addresses for each device it has recently communicated with.

I thought the aim of this exercise was to FIND an IP address. Doesn't using PING imply you already know the IP (or hostname) which makes ARP redundant?

How do you PING a MAC? Assuming no IP or hostname info, I have used a portscanner (like LanSpy or Zenmap) to get MAC > IP info. Currently my preferred method if the device isn't listed in Spiceworks:-) There was a time when I was a baby admin and I didn't want to raise alarms by installing a scanner that I wrote a batch file (yes, that long ago) that PINGed every IP on a subnet, then immediately ran ARP redirecting output to a text file. But that depends on the device in question being set to respond to PING requests. I realize this is an old topic, but someone like myself may be looking for an answer. I became admin of a network with little over 200 devices, which none of the cabling was mapped.

I was told I was responsible for the cabling, so I began looking for a way other than toning out all the cables. I was fortunate to have Cisco switches and Windows Server 2008. I was able to use the Cisco Network Assistant to grab MAC addresses and the port number, then in DHCP on the Server 2008 I could find the MAC and corresponding IP. Furthermore I could also get the computer name from DHCP and correlate that to which user was on the machine using PDQ inventory to see who was logged in to the machine. Most of this of course depends on the devices being in use.

I've been able to create an accurate map of about 90% of my network without touching the cables. Great for finding an IP if you have the MAC address. My instance where I found this useful was after updating the firmware on a switch remotely via TFTP, the IP of the switch would change (making pinging redundant, obviously).

Trying a network scan over Spiceworks or rescanning the single device would not update the IP and I needed an alternate way to find it. This method worked perfectly.

Hopefully this helps those trying to understand the purpose of this practice and how it was in-fact useful. I understand the issues in attempting to use a MAC address to locate a device from outside of its local network. What puzzles me is how Honeywell Total Connect does this with their WiFi connected thermostats.

The hardware configuration is: a Honeywell WiFi thermostat that is WiFi connected to a Netgear N600 router which uses DHCP to assign an IP adddress. The router is connected to Comcast with a Motorola SB6120 modem.