Perhaps you have put in your WiFi credentials in the Sonos controller, and the router is ignoring the Ethernet cable that connects the BOOST to the router? 

I’m not sure what you mean, Bruce.

Boost does show up on the router as a non-connected Ethernet device, my speakers and Boost all show up on the Sonos controller as on the subnet (WM0), and the speakers work OK.

So, I’m guessing the router just isn’t correctly showing Boost as an active device.

That’s certainly a possibility, I’m not familiar with your router and how it works, but if all devices show up as WM:0, then your BOOST is definitely in action. Perhaps your question would be better posed to the CS folks at the manufacturer of your router. 

Thinking about a new router anyway.  I’m on Spectrum and have the Sagemcom fast5260.

Which router are you using?

I happen to use a Netgear of some type, but have never done any investigation into the quality of routers, so don’t take that as a recommendation. It works for me, and I reserve IP addresses for all network devices. I check for firmware updates, reboot it, and change the password monthly. 

Admirably Anal Retentive :)

  bet you wash your hands for 20 seconds as well!

that said, thanks, I appreciate the feedback.