Ok… Problem resolved. It was the QNAP firewall. I’ll have to figure out what needs to be added for passthrough… (e.g. the things mentioned by @Simon_Arnold3, above)
Anyone here running QNAP with Roon? And running the QNAP Firewall? Perhaps there’s a configuration file?
Thanks,
- s.west
[edit] After having turned off the firewall, and subsequently discovering all the missing devices, I turned the firewall back on… and the devices remained… I suppose that this suggests the ‘multicast’ failure cited above. This might mean that if I add new devices in the future, I would have to temporarily disable the QNAP’s firewall in order to discover them. However, I would still welcome some guidance on what to do with the QNAP firewall to fix this for all time.
Thanks.