IOT / ESP8266 stuff and multiple access points

I have multiple access points for my wifi network - Cambium E400s in my case with an EdgeRouter Lite. I have had all sorts of issues in getting various IOT stuff onto my wifi. This has included bulbs (LIFX), controllers (Broadlink) and actual ESP8266 boards (Wemos). I have usually managed to get there in the end, but recently everything got kicked off and I could not get them back on.

There seem to be hints on the internet that others have had similar problems, but not necessarily definitive solutions.

After much cussing, I may finally have cracked it and sharing here to maybe help others avoid my pain. I'm not sure if this is unique to Cambium APs (or perhaps even the ERL), but the internet seems to hint that it is possibly more to do with invariably cheap wifi chips (perhaps even ESP8266s) that find their way into IOT stuff. Someone that knows more about wireless networking than me (i.e. something that knows anything about wireless networking) might be able to chime in with whys, wherefores and whether it is unique to my set up or not.

For my set up, I have managed to get reliable results with:

Client isolation OFF (yes, I know that now)

Proxy ARP / respond to ARP requests on behalf of clients OFF (thanks @rphenix)

Using different SSIDs for each AP

That last one is the latest development and took me by surprise when it actually worked. I could see in the logs that the IOT device would attempt to connect, then shortly after get booted off for "disconnect-info code=8". I couldn't find that code on anything Cambium related, but Ruckus suggests that "Reason Code 8 is due to client leaving the BSS by means of AP moving the client to another access point using non-aggressive load balancing".

I'm not really sure what that means, and I didn't want to muck around with the roaming settings in my APs. The entire point of them is that we get wifi around the house seamlessly. However for me, I was able to set up another WLAN just for IOT stuff and then set a different name for that WLAN SSID on each access point (Cambium's cloud management solution lets you do this easily enough once you find the setting). None of the IOT stuff is intended to move around the house, so tying them to a single AP shouldn't matter.

Only 24 hours in so far, but managed to get everything to connect first try (compared to dozens of failed efforts previously) and everything seems solid so far.