Tracking Down Unknown Network Devices

This is going to be a short and sweet post, but it touches on something I had to deal with just the other day.

I was going through my router, which I do on a regular basis, to check what unknown network devices were showing up in the network list. In my case I usually do this for two reasons. The first is to name all my devices in the router itself and typically assign it a static IP. The second is for pure security. I want to know what devices are on my network, and who the device belongs to.

The particular unknown network device that I noticed, and could not identify was named “GainSpand48cb6“. I usually take pride in naming my devices, so GainSpan was not something that I had setup. I made the assumption that the d48cb6 was the last 6 digits in the mac address, which I confirmed by looking at the device info more deeply.

unknown network device gainspand


Now, the second issue was that the device was offline, so I could not ping it, or do any traffic sniffing on it to see what it was doing. The next step was to just start searching. I started with a reverse mac address look-up, which tells me the mac is registered to a company called GainSpan Corp. Sometimes a simple mac look up will tell you everything you need to know, but when I follow the trail further GainSpan is just the company that makes the wifi radio in the device, darn… had to dig deeper.

As I kept digging, I eventually found something that caught my eye… a post containing Fitbit in the title.



The culprit turned out to be my Fitbit Aria scale, which DOES connect over wifi, but for some reason it did not occur to me.

Oh well, at least I know for next time and can share with everyone else who might have one of these scales, that the hostname shows up as GainSpan in your network device list.

12 thoughts on “Tracking Down Unknown Network Devices”

  1. I also came across a MAC address starting with the same leading 00-1D-C9, but in my case it turned out to be my Ring video doorbell. So there’s another device to consider…

    1. Indeed, ring uses a GreenSpan wifi module which is set so it is not Pingable. ln this case you don’t want to block this from your network. I would rename it on your router for something more recognizable.

  2. This information was extremely helpful. I was having the same issue with the name GainSpan appearing on my router then disappearing before I could identify the device. Great detective work.

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