· Car WiFi can't connect Carplay to iPhone with Tailscale Running. This makes sense as it's not on the Tailscale network. For reference: It connects to the phone successfully without Tailscale running. I've tried disabling wifi on the iPhone and then starting Tailscale to try to get Tailscale to communicate using a cellular connection and then enable wifi to get the car connected, but that does not work. Is there a workaround other than reenabling upnp on my router and drop the use of Tailscale (which worked well, by the way)?
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· Carplay running on 2024 car; iPhone 12 running Arc and Tailscale; Mac Mini Roon Server running Tailscale
Thank you for reaching out! You have hit on a very common and frustrating quirk with how iOS handles networking.
Because Wireless CarPlay creates a direct, internet-less Wi-Fi connection between your iPhone and your car, iOS often gets confused when a VPN like Tailscale is running. The system tries to route the Tailscale tunnel traffic over the car’s local Wi-Fi instead of your cellular connection, effectively breaking both the internet and the CarPlay handshake.
Since you mentioned that you could simply re-enable UPnP, that tells us your home network has a public IP address and you do not actually need Tailscale to bypass ISP-level restrictions (like CGNAT).
The Best Solution: Manual Port Forwarding
If you disabled UPnP for security reasons (which is a smart move!), you do not have to rely on Tailscale. Instead, you can set up a Manual Port Forwarding rule on your router.
Manual port forwarding is secure because it strictly opens the single specific port required for Roon ARC, whereas UPnP dynamically opens ports for any device that asks. By setting up a manual rule, you can disable Tailscale entirely, Roon ARC will connect flawlessly, and Wireless CarPlay will work without any VPN interference.
Find the port number listed in Roon under Settings > Roon ARC.
Log into your router and create a TCP port forwarding rule pointing to your Mac Mini's local IP address and that specific ARC port.
The Tailscale Workaround: iOS Shortcuts
If you prefer to keep Tailscale in your setup, the most reliable community workaround involves using Apple's built-in Shortcuts app to automate the VPN connection so it does not block the initial CarPlay handshake:
Open the Shortcuts app on your iPhone and go to the Automation tab.
Create a new Personal Automation for When CarPlay Connects.
Add an action to Start Tailscale.
Create a second automation for When CarPlay Disconnects with an action to Stop Tailscale.
This allows your iPhone to establish the local Wi-Fi connection to the car before Tailscale activates and takes over the network routing.
We hope this helps get you back on the road with your music!
Thank you for the timely and thorough response to my issue. I’ve tried the shortcut approach without success, but will relook at it. The port forwarding is something I’ve not done, but sounds like a viable solution. Thanks again !