I’ve set up my custom domain. Everything works. I’m able to access my app via the custom domain. The issue is I’m also able to access the app from the default hostname (example.fly.dev).
For obvious reasons, I don’t want my app to be accessible from multiple domains.
How can I disable the default hostname? There doesn’t appear to be a button to do so.
Just in case it’s relevant, I set up my domain with an A record pointing to my v4 address, and an AAAA record pointing to my v6 address.
Unfortunately you can’t disable the default domain. You would have to find some way to prevent that working yourself, perhaps with a redirect.
Take a look at this thread for some additional thoughts:
Most application frameworks have a way to redirect to the canonical hostname.
Note that you can’t really prevent people from hitting your IP address with a different hostname. The hostname a client sends is mostly just a hint.