Setting static IP addresses

Thanks - it’s not possible to “unassign” a statically set IP address from within the router, because the router has no control over that address. It appears in the router’s Device table only because it sees traffic to and from the device, and not because it has any control over the address.

But, having said that, you jogged my memory that I had changed that device from being wi-fi connected to being Ethernet connected and had not rebooted the router since - so although everything was working OK, the router’s internal device table seemed to be corrupted.

Having rebooted the router, I now have 11 devices in my router’s DHCP table, which means I can finish the task of adding all of their addresses as “reserved” - by adding the last one of the eleven. Hopefully that will contribute to the network’s long-term stability (which to date has not been great).

Thanks again - a solution without needing to factory reset the router!

It is usually best to set the Sonos IPs outside the DHCP address window as if set inside it some other device could beat Sonos to the desired IP address and then the Sonos would get a random address.

That may be possible on some routers, but not mine! The only way you can “reserve” an IP address for a given Sonos MAC address is via an option in the DHCP table. Obviously it can only get into the DHCP table if it’s using DHCP, and then it must have an IP address within the DHCP range!

But once it’s in the DHCP table it (in effect) gets an infinitely long lease for its IP address, so nothing else can beat the device to its allocated address.

Typical of a poorly designed router.

You are wrong on the “nothing can beat it” statement. Maybe nothing will usually beat it as long as there are no IPs assigned (directly not DHCP) in other devices that conflict and that the Sonos device is always active often enough to keep the lease renewed.

The lease is not infinitely long, the router sets that, it can be 135 years if the router supports that so your point is close enough there.

From my router’s manual:

https://docs.netgate.com/pfsense/en/latest/services/dhcp/ipv4.html

This IP address is a preference, not a reservation. Assigning an IP address here will not prevent another host from using the same IP address. If the IP address is in use when this client requests a lease, the server will instead assign the client an address from the general pool. For this reason, the GUI does not allow assigning static IP mappings inside of the DHCP pool.

I suspect it’s typical of a router where they design the UI to reduce the chances of the owner doing something stupid. And, given that they are meant to be used by anyone in the general population, that’s probably a wise choice.  It would be nice if they had both an “advanced” settings page and a “properly advanced” settings page, but that would cost more, so they are not likely to do that.

As far as I can see, my router’s documentation does not describe in detail how “reserved” IP addresses are assigned, so it may keep a list of “reserved” IP addresses forever, or it might do something else!

And there is, I think, in a nutshell, the very problem. Each router handles this issue slightly differently, which makes it somewhat challenging to write a definitive ‘do it this way’ article.

I’ve recently been struggling with both a StarLink device, and a T-Mobile 5G device, neither of which even provide the opportunity for access to the DHCP table in order to allow reserved IP addresses. I suspect they think they know better than the average consumer. And they may, but it’s frustrating for those of us who are (slightly) non average. 

I have recently and finally moved from my Apple router of 2011 vintage to one supplied by the broadband service provider consequent to moving from copper wire to fibre for the last mile to the home. All my Sonos units are wired back to the core network so this change was glitch free as far as Sonos is concerned. As of now none of the Sonos units have a reserved IP address as they did in the Apple router and all seems to be fine for a couple of weeks now, so I will hold off dabbling with reservations till/if Sonos units run into trouble. 

I remember @Corry P recently questioning the need for such reservations for Sonos….

I’d question the need too but there are enough posts here to convince me it is a viable first step to network troubleshooting. Takes a few minutes to do on your own and no playing phone tag with support.

With my old all-in-one router I was not seeing issues, updated to a much better router and dedicated WiFi APs and was seeing issues until I set them.

It may certainly be that there are newer devices that are less susceptible to this. I’ve not seen any issue on either the StarLink nor the T-Mobile routers…but I have an objection to them thinking they need to keep this practice away from me. But I’ve certainly seen it as an issue in the past, on other devices, or at the least, issues seemed to be resolved when I did the effort.