Apples new IOS has caused an increase in these reported issues of the device “filling up.”

If you go to settings - WiFi - press the little i next to the WiFi and untick private address it seems to help some users. The box seems to be seeing the address change in some cases as an extra / new device joining every single day. So after a few weeks it’s overwhelmed.

You need to factory reset also.

If that doesn’t help - a new hub might.

This issue doesn’t seem to be impacting all, just noticed a few posts where they have the same devices listing a bunch since ios14.

Edited by ukhardy07 (Sat 28-Nov-20 22:00:19)

Thank you for posting that. It's pretty much exactly what I had written in the first draft of my previous post but because I wasn't 100% sure I removed it. I hadn't had enough time to research it and find supporting information but I had my suspicions. All I came across last night was Apple's post on the matter which really doesn't say very much about how it works. It implies that the private MAC address stays the same for a particular wi-fi network but this isn't actually the case at all.

What Apple means is that it stays the same when associated with a particular BSSID - until it doesn't stay the same. If you have one router with dual band, it has two BSSIDs; one for 2.4GHz and 5GHz. If you add just one dual-band extender to the setup, that's another two BSSIDs so you already have four separate device identities which the iPhone/iPad creates to cope with these four BSSIDs.

Even with four separate identities created, the Apple device may drop these and generate new ones at an unspecified time in the future. That may be as often as several times a day according to Fing which posts an interesting table comparing Apple's MAC anonymizing to that in Android 10 and beyond.

Once the BT router's device list gets beyond a certain size, it starts behaving unpredictably. It doesn't fail to give an IP address every time, only some of the time. This happens with wired devices that have a fixed MAC address as well as wi-fi clients, Apple or not. Disabling private wi-fi addresses within iOS/iPadOS settings will help to slow the rate at which the router's device list gets too large.

Thanks for all the info, really useful.

We have no iOS devices so it can't be that, but the DHCP issue sounds like a definite possibility.
I do have another switch (router with the bb disabled) hard wired to the BT box, and it's DHCP is currently switched off.
Maybe I could try using the DHCP on that box instead.

It's definitely worth trying the old router as a DHCP server. Putting a new DHCP server in certainly fixed all the connection problems for my client. Don't forget to disable DHCP on the BT Smart hub and let us know how you get on. Good luck!

Thank you Sarah!

Now it is all beginning to make sense. I had this issue with previous Home Hubs and also with the Smart hub 2 until the latest firmware update, which seems to be stable (40+ days running!). I have quite a few Apple devices and I was always getting connection problems with Apple devices.

But you are absolutely right, the Smart Hub 2 device connection list still shows devices that are no longer connected taking up an IP address space with no way to clear this list unless I carry out a factory reset. Would have thought a company as large as BT would have noticed and resolve this issue.

On a side note, does anyone know what the maximum device connection limit on the Smart Hub 2 is? I think it may be around 30 but I could be wrong.

In reply to a post by PS123:

the Smart Hub 2 device connection list still shows devices that are no longer connected taking up an IP address space with no way to clear this list unless I carry out a factory reset.

Have you tried this?
In the Smart Hub 2 Manager:
1. Click on Advance settings.
2. Click on My network (and enter admin password)
3. In the list of devices, you should see clickable blue "Remove" buttons against each non-connected device.

In reply to a post by Zebsy:

It's a BT Smart Hub - it's 4 years old

Before I had FTTP enabled two weeks ago my 6 year old router Home Hub 4 went on the blink and they sent me a new router out without charge no problem at all.

I have since sent it back as it is the property of BT.

They do send you a return pre postage bag for it to go in.