How To Look For Mac Information

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.

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. Download os x yosemite for macbook pro 2017. 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. Download the latest version of itunes. 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. Comcast assigns a system wide (dynamic) IP. There is no static IP.

On initial setup, a WiFi connection is first established between the thermostat and the router. The thermostat's MAC and CRC and a username and password are entered into the Total Connect software setup. It is then possible to read or set thermostat values using Total Connect Web pages. I know how to do this with a static IP or a DNS service that automatically tracks changes in dynamic IP addresses.

Does anyone understand how this works with Total Connect? This post was extremely helpful, thanks itdownsouth:) I used show interface to find MAC addresses on our switches (reason for this is poor network documentation and mis-labeled switchports and wall jacks.).