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by baby_souffle 936 days ago
> I dig that idea, I'll have to think of the best way to pull that data while keeping the app stateless and fast.

Reverse DNS lookups are usually pretty quick:

```shell

  > time dig +short -x 2600:dead::beef
  customer.my-isp.net.
  dig +short -x 2600:dead::beef  0.00s user 0.01s system 1% cpu 0.882 total
```
2 comments

This might be useful to review:

https://news.ycombinator.com/formatdoc

"Text after a blank line that is indented by two or more spaces is reproduced verbatim. (This is intended for code.)"

Thanks.

I spend all day writing markdown and fenced blocks with type-hint is muscle memory at this point

Reverse DNS does not give you all the hostnames that can point to a particular IP address though.
Other than brute forcing, I don't think anything does — that's the beauty and the curse of a proper federated system :)
In fact, it might not even give you any names that point to an IP address, since it might be out of sync with the forward system, especially if the records are built by hand.