OK, like many others, I could not get ARC to stream other than using WiFi. After many attempts, I was successful in configuring my ATT router (BGW210-700) using the following steps. Inspect the router stickers to find the “access code” and write it down for later. The IP address is usually 192.168.1.254
You will need to find the IP and MAC address of your Roon Core, in my case a Nucleus+
I am running Win 10, so after launching Roon, I used the command prompt (CMD) to verify that my core was on the network. There are several ways to get the MAC address from the IP address, I won’t go into that here, Google is your friend.
Then on my network connected laptop, I used the browser to type in the router IP address (192.168.1.254) which opens my AT+T
router configuration screen.
You likely will be prompted to enter your router “access code” at some point.
First thing I did was go to the “Firewall” tab, then the sub-tab “Firewall advanced” and turn ALL of the buttons you see to OFF.
Then I went to the “IP Passthrough” tab, changed the “Allocation mode” to “Passthrough”, and the “Passthrough mode” to “DHCPS-fixed”
Then on the “Passthrough Fixed MAC Address” click on the “device list-choose from list” where you will see a LOT of choices. If you see your core listed, select it and it will auto-fill in the Mac address. In my case there was an entry named “ROCK” that had the same MAC address of my core that I had already discovered. If your core is NOT listed, you can enter the MAC address manually in the indicated “manual entry” box. Hit the save button.
At that point I thought everything was setup correctly, but when I logged onto Roon and went to the ARC page, it was still not showing an ARC connection to my core. I then rebooted everything… router, core, laptop and iphone that had ARC installed on it. After I did that, ARC worked on my phone even with wifi disabled.
Hope this helps others.