IP reverse dns

Is there a way to set an IP reverse dns value ?

Do you mean mapping IPs over the private network back to an app? Or public DNS?

I mean declaring a domain to the public ip4 allocated to an app.


Is there any updates about it?

You can point your DNS A/AAAA records at your Fly app’s IP4 and IP6 addresses or CNAME your sub.domain.tld to your app’s fly.dev name (ref).

For instance, for one of my Fly apps, midway, here’s the DNS records Fly set up (on their fly.dev domain) for me:

➜ dig midway.fly.dev A midway.fly.dev AAAA +short

And here are the A/AAAA records I setup with my DNS provider (AWS for nx and Cloudflare for n):

➜  dig nx.rethinkdns.com A n.rethinkdns.com AAAA +short

With that, I am able to access my Fly app with names: midway.fly.dev or nx.rethinkdns.com or n.rethinkdns.com or any-random-63-chars.nx.rethinkdns.com.

As noted above, in my case, zones are split between AWS and Cloudflare, but you can also use Fly to register and host your DNS which makes dealing with TLS offload on Fly that much easier.

I suspect the original ask was about setting a PTR record for a fly app’s ip. I’m only familiar with them in the context of outbound smtp, which I’d be surprised if fly allowed in the first place.