This is a follow on from https://community.tp-link.com/en/home/forum/topic/548906 where there was no resolution.

The TP-Link Archer MR600 Router is being used for wireless connections to a Home Assistant installation to keep these (sometimes unkown pedigree) internet connected devices isolated from our in home devices and computers ( I have a second wireless network for that) and as a backup internet connection should thee ADSL connection fail - which for my house is quite often if only for 5/10 minutes.

The default IP subnet on the TP-Link router is 192.168.1.0. WAN connection under normal  circumstanes is to my local network with a 192.168.10.0 subnet. BUT when the device losses the local connection it (as intended) connects to Vodafone 4G BUT the subnect then changes to 192.168.0.0. This causes me a lot of pain with my Home assistant installation, basically everything wireless that was connected to the TP-link losses its connection especially the TP-Link Tapo devices! A typical message is:  xxxxx P110 Failed setup, will retry: ('Unable to query the device, timed out: 192.168.0.75: ', TimeoutError()) (obviosly because it is not on that network now), It seems to take them a single minute to get new IPs on the 192.168.0.0 subnet. but when after correcting the TP-Link subnet back to 192.168.1.0 they do not get a new IP! Fortunatley half of them are connected to a second access point and these survive the TP-Link's shenanegans. As another little note the Spotlilights(L630) reconnect after a few minutes.

It must be noted that the Vodafone provided external IP is a NAT address on usually a 10.x.x.0 subnet but I have noticed that the external DNS server is on a 192.168.x.x subnet so they are using both ranges.

The problem does not occur every time but I wonder if Vodafone issue a 192.168.1.0 NAT address and the TP-Link (rightly) considers this a clash so defaults to 192.168.0.0

Now my question is: If I go through the pain of changing the subnet on the TP-Link router to say something in the 172.16.0.0 range would this stop the problem re-occurring?

Otherwise I'm going to have to use it as a 4g Modem only and buy a different wireless router for the Home Assistant installation which would be a shame as I usually expect same brand devices to work well together...

TIA Tim.