Fixed / static IP addresses are always a good idea for fixed / static devices, like smart home devices…
Rule of thumb: if you permanently install a WiFi device, it should get a fixed IP.
(And no, not every Matter device speaks IPv6… and yes, there are ARP caches, theoretically everything should get the message if an IP address changes, but we don’t even know what the firmware of our ST hub looks like from the inside - despite using tons of FOSS software that is kept closed for whatever reason…).
Yes, I don’t switch off my router either. The problem is that DHCP (dynamically assigned IP) devices on your router have a lease time, maybe an hour, maybe a day, depends on your router/gateway configuration. If your matter device isn’t on or active at the time the lease expires, the router/gateway may give that IP address to another device on your network. This reservation prevents the router from reassigning that address to other end-point devices. Your matter device will keep the same IP address even if the lease expires and the device is not on/active at the time. The next time the router sees your matter device (or any device you create a reservation for) on the network, it will give that device the “reserved” IP address, so essentially it never changes, similar to a static IP address.
Should I just click on ‘use the following ip address’ and type the address in something like 192.168.1.xxx? If yes, should I leave the subnet mask and default gateway blank? I am still thinking this is not going to solve the problem as this is going to affect all the devices?
When you say assign ip address to that device, should I do that in the router configuration?
This is a windows PC IP configuration. You need to make the change in your gateway/router. You don’t want to make a change here, this will not affect your matter device.
Ok, this looks like the correct place. You’ll have to find the device listed by mac address and click the “ON” box next to the device. You don’t have to change the last 3 digits unless you want to. I have a schema that I use for IP’s but just clicking on the ON box should create the reservation for your device.
I cannot see any way to set the reservation for IPv6. Are you sure this is in the router config? Also, the current matter devices for me has ipv4 address only which contradicts what you said so can explain a bit more on what I should do?
IPv6 addresses are generated by the devices automatically, there’s no need for reservations or DHCP servers like in IPv4. Also, most routers user interface won’t display the IPv6 addresses, that’s why you can only see IPv4.
If the problem is that “twice in few months” it goes offline it can be everything and it’s almost impossible to replicate or know if the action taken is a fix. It may as well be the WiFi router being low-end or the AC having a bug in the software.
Have you checked if, when it’s not accessible with Matter, it works with the vendor’s app or cloud integrations or if the WiFi router marks it as offline? That would help narrowing down the issue and confirm if it’s Matter related or not.
It could also be associated to firmware updates of the SmartThings hub, when the Matter controller restarts, devices might not reconnect (and that would be a bug in their firmware).
