private MAC address

[jef212]

Hi All,

I'm not new to home networking and i've been running dd-wrt routers for years... I'm a software developer, so, "technologically" curious by nature but admittedly have never really researched in-depth low level technical details of networking.

I'm probably being paranoid and plan on doing further research and learning on my own but I've been seeing strange things on my home network lately. The one I wanted to ask here about was about private MAC Addresses...

Google knows all but I can't really find anything in plain English about typical use, or, scenarios where they would be used. I have a private mac address showing up on my lan [dhcp] that I haven't been able to identify.

I've used NMap but it can't identify anything about it either. I'm looking for any information that may be useful in helping me understand where and what this device may be.

Thanks in advance.

 

[getochkn]

Does it get assigned an IP? Can always try the old discconect everything and reboot the router, then start connecting stuff one by one till you figure out what it is.

 

[jef212]

Yes it does get assigned an IP. I've tried disconnecting/reconnecting everything before... the issue I run into is the sheer quantity of network/internet connected devices we own and services found. I suspect this may have something to do with one of these media devices that we use e.g., chromecast, roku, or perhaps even some VM that runs somewhere for some reason that I have yet to identify. There are so many apps and games [apple, android, minecraft] on these devices it's hard to sort them out.

I was hoping to learn more about why one of these devices/services/apps might have a need for a private MAC, which I don't seem to find much information about on Google, or, forums such as this.

 

[getochkn]

You can try a tool called advanced ip scanner, scan your network, then sometimes it gives you info about the device, even a manufactuer which can help.

Easy things to try too. Change the wifi password and reboot. This will stop all wifi devices and cut the # of devices down and then see if it still comes back up. If not, it's a wifi device and you've narrowed it down. if not then it's a plugged in device.

 

[Alabalcho]

First, some terminology. MAC addresses are not "private" - they are unique around the world. You are probably thinking about private IP addresses, like 192.168.xxx.yyy.

You know what that MAC address is. You can lookup who this MAC address was assigned to from many web sites (Google/Bing for "MAC address lookup"). On my Android phone/tablet, I have a nice app Fing which lists these names along the IP addresses.

 

[jef212]

First, some terminology. MAC addresses are not "private" - they are unique around the world. You are probably thinking about private IP addresses, like 192.168.xxx.yyy.

You know what that MAC address is. You can lookup who this MAC address was assigned to from many web sites (Google/Bing for "MAC address lookup"). On my Android phone/tablet, I have a nice app Fing which lists these names along the IP addresses.

This designation comes from those/any MAC Address lookup service... there are MAC Address ranges that are used for internal network uses and what I'm trying to figure out is the what/why/where, etc. I haven't been able to find a clear description of their purpose/use.

 

[jef212]

You can try a tool called advanced ip scanner, scan your network, then sometimes it gives you info about the device, even a manufactuer which can help.

Easy things to try too. Change the wifi password and reboot. This will stop all wifi devices and cut the # of devices down and then see if it still comes back up. If not, it's a wifi device and you've narrowed it down. if not then it's a plugged in device.

This "private" mac address only showed up after I recently changed password to 14+ characters using WPA2, so, unlikely hacked. I am assuming it's something internal but no idea what yet... Also, Those scanners cannot determine the vendor/manufacturer, O/S, or basically anything about this and it's probably due to the internal/private nature of it but still have yet to find an explanation.