Has anyone recently tried putting Roon Server on a dual-homed Linux box so that devices on two subnets can see the server?
I tried and it mostly worked but searches would occasionally hang. This was back when searches were buggy anyway, so I could never tell what the root problem was.
How does Roon access streaming on a dual homed system? Does it use both subnets or just one?
Thanks.
Edit: by streaming, I mean Qobuz or Tidal, not RAAT streaming to endpoints.
Was not really working for me but this might be because I also have multi-homed clients (Roon Remote) – so the Remote sees two servers and and thus wants two licenses or forces you to de-authorize a Core. This didn’t work well because it’s actually only one Core instance. You might also get into similar troubles should you have clients that roam between the two subnets. I never tested this scenario as the whole thing was a setup error in my case and not something I wanted to do.
The standard route (the 0.0.0.0 entry in the routing table) is used to access the internet or more precisely anything outside of the known networks (the other entries in the routing table).
I use a Roon ROCK with two subnets, but one is normal (the one with the router), and in the second I have a direct cable connection with the DAC (without other network peripherals in the respective subnet).
The above configuration is very easy to do in Roon ROCK or Roon Core on Windows.
In contrast, I was unable to do it in AudioLinux, even though I tried many times (including with the support of the manufacturer).
I don’t even want to think about what it means to configure a Linux linked to two normal subnets… 
So the “other” subnet has no router in your setup? It’s just an unrouted subnet between the Linux server and the endpoints?
Yes, no router. Just one direct cable from Roon ROCK to DAC.
I have this working nicely on a Synology NAS. I set up a VLAN, plugged the Synology into both networks, and Roon just worked.