· Recently, more often than not when I open the Roon app on either my Android phone or Android tablet, I'm sat there waiting for it find the Roon server. Sometimes, it eventually finds the core and hit connect and other times it sits there looping for ages, never able to find it. The core is on the network ok and the admin UI can be reached from the phone. I don't have this issue with a Windows PC (Win 10) running the app.
Tell us about your home network
·Router: Deciso DEC850 running OPNSense. There is a CAT5e cable running to an unmanaged Netgear switch which serves a few wired devices and a cable running to a TPLink TL-WPA8631P Powerline adapter (running Open WRT) which doubles as a wireless access point. The signal goes upstairs to another Powerline adapter (TPLink TL-PA8010P) which then goes into a TPLink unmanaged switch, to which the Roon Core (Intel NUC 8i5) is connected.
Thanks for the clear description. Since the Roon Remote on Windows works and the Android devices can reach the Roon Server admin UI, this looks like a discovery issue specific to the Android side of the network path.
A few things would help us narrow it down:
Is the Android phone or tablet on the same WiFi network as the Roon Server, or are they ever on a guest network, VPN, or mobile data when this happens?
Does the issue improve if you fully close and reopen the Android app, or if you switch the phone or tablet to the other access point in your setup?
Have there been any recent changes to the network, such as router settings, DHCP reservations, multicast or IGMP settings, or firmware updates on the router or access point?
Given the mix of OPNSense, powerline, and a separate wireless access point, I’d also take a look at [url=https://help.roonlabs.com/portal/en/kb/articles/networking-best-practices]Networking Best Practices[/url], since the discovery layer Roon uses can be sensitive to segmented or partially isolated networks.
If you can share which WiFi the Android devices are using when the problem occurs, and whether they’re on the same subnet as the Roon Server, we can take the next step from there.
I currently only have a single “flat” network, so no vlans and no guest WiFi right now (and only one WiFi access point) so the phone and tablet are always on the same WiFi network and therefore same subnet as the core and never on mobile data when in the house.
I try fully closing and reopening the app but it seems to be mixed bag. Sometimes it will open up and find the server within 10 seconds, other times it sits there chugging away for a long time before it finds it.
As far as the network is concerned, no firmware updates for the WiFi access point but the usual incremental updates to the router (it is OPNSense, after all ). I’ve not made any changes to DHCP reservations or done anything with IGMP.
I’ve made a few changes though, such as adding a failover WAN and am now using the home.arpa domain in conjunction with Unbound DNS although I’ve been using that for a good while now and way before these issues starting occurring.
Thank you for providing such a detailed breakdown of your network topology. That helps immensely.
Since your Windows PC connects flawlessly and the Android devices can easily open the Server’s Web Admin UI via TCP, we can rule out a general connectivity issue. This is almost certainly a Multicast/UDP Discovery issue occurring specifically between the Wi-Fi segment and the wired network.
Roon relies heavily on Multicast (IGMP) and UDP broadcasts for the Remote app to “find” the Server.
Android is notoriously strict about handling multicast traffic due to aggressive OS-level power-saving features, making it way more sensitive to network anomalies than Windows.
Looking at your setup, there are three main “suspects” where these discovery packets might be getting dropped or delayed:
1. The Powerline Adapters (TP-Link)
Powerline modules are infamous for how they handle multicast traffic. To prevent flooding the electrical wiring, many Powerline adapters either aggressively throttle or outright drop multicast packets. Since your NUC is sitting behind a Powerline link, the UDP requests from your Android devices (“Where is the Roon Server?”) might simply be lost in the wiring.
2. OpenWRT Wireless Settings
Since your AP is running OpenWRT, it might be actively filtering or modifying multicast traffic. We highly recommend checking the following settings in your OpenWRT wireless configuration:
IGMP Snooping: Try toggling this setting. If it's on, ensure it's configured correctly, or try disabling it to see if behavior improves.
Multicast to Unicast (mcast_to_unicast): This setting converts multicast packets into unicast to save Wi-Fi bandwidth, but it frequently breaks Roon discovery on Android. Try setting this to Disabled for your Wi-Fi interface.
3. OPNSense & Unbound DNS
Since you recently configured a Failover WAN and the home.arpa domain:
Ensure that your OPNSense firewall rules for the local interface have the "Allow Options" checkbox enabled (this allows IP options such as multicast packets to pass through).
Double-check if Unbound DNS isn't triggering a DNS Rebinding protection event when Roon tries to resolve local hostnames.
A Quick Workaround to Test Immediately
Next time your Android device gets stuck on the "Looking for Roon Server" screen:
Tap "Help" or "Configure Roon OS / Advanced" (depending on the screen you get).
Look for the option to enter the IP address manually.
Type in the static/DHCP-reserved IP of your Intel NUC.
This forces the Android app to connect directly via TCP, bypassing the multicast discovery layer entirely. If this connects instantly every time, it confirms that Multicast filtering in your Powerline/OpenWRT setup is the root cause.
Thanks for such a detailed reply. I’ve been here before i.e. had this issue and it just seemed to resolve itself and it’s happened again: the Roon app has been opening up as it should for the past few days. It’s baffling because I’ve not made any further changes to my network config!
I’ll see how things go over the next few days and if all ok I’ll report back and if need be, close this ticket.
). I’ve not made any changes to DHCP reservations or done anything with IGMP.