networking – Android devices not finding some devices on my network

Some devices that I know to be on my network and working correctly I cannot find using my Android devices. My desktop PC and laptop have no issues and if I navigate to my router interface everything is showing as fine.

Devices in question are mainly Raspberry Pis and ESP8266 boards, but my Sonos devices are now not showing either.

I use the Android app Network Analyser to scan the LAN and this is failing to show several devices, though sometimes some of them will appear. If I use the app 3C all-in-one toolbox to ping the devices that I know to be on the network (as confirmed by my router interface), but not being shown by the network analyser on my phone, I get “Destination Host Unreachable”.

Having just tried the Network Analyser app on a different Android phone I get a couple of the missing devices showing on that one and they ping fine on that phone.

Can anyone help me understand what is going on here, as, in the first instance one of the Pis is transmitting video that I would like to view on my phone, and I would also like to get my Sonos app reconnecting.

At the end of the day I would really like my phone to be showing me all of the IPs connected to my network.

Thank you.

In response to the request by Robert:

In my mind I was thinking that I may get answer along the lines of such and such a table needs clearing on your phone and all will be fine. It sounds like this may be getting very complicated and I might be out of my depth soon, but here goes.

The ‘router’ is a standard BT Home Hub. There is only one ethernet device connected to it and that is a controller for my central heating. Everything else is connected via WiFi. I have a BT Disk WiFi extender which my phone is currently hooked up to and all the devices reported as connecting through this disk are showing up in my LAN scan app and are pingable.

All the other devices on my network are showing on the BT Hub interface as connecting via 2.4Ghz or 5Ghz. There are devices on each of these frequencies missing from the LAN scan and not pingable by my phone. There are no Static addresses and all IPs are requested from the BT Hub (DHCP).

I think that is my networking knowledge exhausted now.