SOLVED: Honeywell T9 Smart Thermostat
Posted: Thu Nov 17, 2022 5:25 am
I know there are similar posts here about this issue, but I have not seen any that were able to get this working. Here's a little background on my setup. I currently have a ZBT-WE826T with a Quectel EP06 modem connected to AT&T with an Unlimited Tablet Plan SIM. I have the WiFi disabled on the WE826 because it is awful anyway. Only LAN connection on my WE826 is to the WAN port of my TP-Link Archer A7 which is in AP mode. Archer handles all of the Wifi and the WE826 does all of the DHCP, Routing, Firewall, etc. The WE826 is currently running GoldenOrb_2022-11-06. All devices on my LAN have NO issues connecting and working as expected (Roku, Firestick, Apple TV, Ring alarm, etc.) I purchased the T9 thermostat and have had no success in getting it to work.
I know from the many posts about this issue that all of the cellular providers use CGNAT and that is what is causing the issue. I have done a lot of troubleshooting with Honeywell support and the ONLY time we were able to get it to work was when they suggested that I connect the thermostat to my iPhone hotspot. That worked flawlessly, but obviously it is not practical. My iPhone is ALSO on AT&T and I would assume that it would also be affected by CGNAT when acting as a hot spot, no? So, my theory is that the only thing causing this issue would have to be the firewall on the WE826, but as I have read numerous times, it is useless to try and setup port forwarding in this environment.
Honeywell has given me the pertinent information on the ports that the thermostat communicates on, but I guess that is pointless if the firewall in this environment is basically just a decoration. I have seen some users mention the use of a VPN in order to obtain a public facing IP address, but not real clear on how to use that to setup port forwarding.
The solution that most people have had is to just buy a different thermostat, but I really want to conquer this challenge without throwing in the towel. If anyone can shed some light as to WHY it would work when connected to the AT&T network through the hot spot on my iPhone, but doesn't work when connected to my LAN, I would greatly appreciate it. (I think you're going to tell me the issue is double NAT)
I know from the many posts about this issue that all of the cellular providers use CGNAT and that is what is causing the issue. I have done a lot of troubleshooting with Honeywell support and the ONLY time we were able to get it to work was when they suggested that I connect the thermostat to my iPhone hotspot. That worked flawlessly, but obviously it is not practical. My iPhone is ALSO on AT&T and I would assume that it would also be affected by CGNAT when acting as a hot spot, no? So, my theory is that the only thing causing this issue would have to be the firewall on the WE826, but as I have read numerous times, it is useless to try and setup port forwarding in this environment.
Honeywell has given me the pertinent information on the ports that the thermostat communicates on, but I guess that is pointless if the firewall in this environment is basically just a decoration. I have seen some users mention the use of a VPN in order to obtain a public facing IP address, but not real clear on how to use that to setup port forwarding.
The solution that most people have had is to just buy a different thermostat, but I really want to conquer this challenge without throwing in the towel. If anyone can shed some light as to WHY it would work when connected to the AT&T network through the hot spot on my iPhone, but doesn't work when connected to my LAN, I would greatly appreciate it. (I think you're going to tell me the issue is double NAT)