Questions about free-tier tunnels and streaming audiobooks.
My Goal:
I want my wife’s phone to use a single server URL in her app (e.g., audiobooks.mydomain.com) at all times. I don't want her to have to switch servers in the app manually.
- Away from home: It should route through the Cloudflare Tunnel so she can stream her books.
- At home: It should route entirely over our local Wi-Fi so she can bulk-download large audiobooks at gigabit speeds without piping gigabytes of raw media files through the free tier tunnel, keeping me completely safe from getting banned by Cloudflare for high media bandwidth.
The Plan (and the IPv4 / IPv6 Hurdle):
To achieve this, I am planning to implement Split-Brain DNS using my local AdGuard Home instance to intercept audiobooks.mydomain.com internally and point it straight to my server's local IPv4 address (e.g., 192.168.1.50).
However, my server is strictly IPv4-only (IPv6 is enabled on my local LAN however), but our cellular carriers use native IPv6.
I'm worried about a specific caching/fallback scenario: When my wife walks back into the house and her phone reconnects to the local Wi-Fi, it will query AdGuard Home and get the local IPv4 address. But because smartphones aggressively prefer IPv6, I am concerned the phone might try to reuse a cached public IPv6 address it received while on cellular data or bypass the local IPv4 override entirely to hit Cloudflare's public edge network anyway.
My Questions for the Community:
- Is my concern about the phone bypassing the local IPv4 DNS override via a cached public IPv6 AAAA record valid?
- If I add a custom filtering rule in AdGuard Home to completely block/nullify IPv6 queries for that specific domain (e.g.,
||audiobooks.mydomain.com^$v6), will that successfully force her phone to drop back to the local IPv4 address while at home? - For those running Audiobookshelf or similar low-bandwidth audio services through Tunnels, is the trickle-bandwidth from streaming a single book small enough that Cloudflare doesn't care, or is the Split-Brain DNS approach strictly necessary to protect my account during bulk-sync downloads?
Appreciate any insight, configurations, or advice you guys have!
Sorry for having to use AI to write this but if I wrote it, you probably wouldn't have any idea what I was asking as I tend to ramble, but this is the gist of what I'm trying to figure out.