inSSIDer just missed a network - the one that I’m trying to locate the source. I saw it start on my iPhone using AirPort Utility, but it was not listed in the inSSIDer network display just now using MetaGeek Plus, while being listed on my phone.
Previously I had seen it multiple times using the free version. The last time was this morning, before activating my trial for the Plus version.
I had wanted to do a packet capture on that network, but obviously inSSIDer won’t give me any info on a network that it does not detect. Bummer.
The device that I’m searching for is the source of a wireless network that has an SSID of ESP_7E4539 and is in the 2.4 GHz band. It is off most of the time, and when it comes on, typically is only on for about a minute. That behavior itself is suspicious. Is it sending data to someone? Amplitude checks suggested it is in my living room. It still shows up when all electrical power is off in that room. I’ve eliminated most battery powered devices in that room (others I know of supposedly have no Wi-Fi capability).
There are a surprising amount of devices out there that can create “networks” in your home. I recommend reading this article I wrote about this very thing here which will maybe help you. I discovered that both my Chromecast and Xbox were deploying networks for various reasons.
Is there a way to set up a capture on a known SSID that is not currently active?
Eye P.A. is probably a better tool for capturing on a specific channel, but inSSIDer can also do this job. To perform a capture across all channels, simply open inSSIDer and go to File > Start a Packet Capture. If you want to capture on a specific channel, you will need to dive into a network on the specific channel (using the binoculars icon) and then start a packet capture from there.
Mystery solved! …thanks to a clue provided by inSSIDer and WireShark.
If anyone else reports an unknown device in their house in the 2.4 GHz band with occasional brief spurts with an SSID begining with ESP, ask them if they have a Simplisafe alarm system that has been disconnected from Wi-Fi.