Been *slowly* making my way through the slides and audio of #fosdem2023 (I speed scanned the automated transcripts a couple of weeks ago).
I finally hit @pgl's “Bizarre DNS” talk:
https://fosdem.org/2023/schedule/event/dns_bizarre_and_unusual_uses_of_dns/
I thought I kept good track of odd DNS usage, but I didn't know about the Google and OpenDNS/Umbrella “my external IP” DNS hack.
Threw together a super tiny #golang project that uses both hacks: https://github.com/hrbrmstr/extip
@hrbrmstr @pgl have you seen Akamai's? Gives the unicast IP (v4 or v6) of the recursive nameserver, any ECS in the request and a representative IP from the ECS subnet - https://www.akamai.com/blog/developers/introducing-new-whoami-tool-dns-resolver-information (if you query directly against the auth servers the NS result will be your external IP of course) - it replaced whoami.akamai.net which was a quick operationalization of a stupid perl script I put together in the very early 2000s
@pgl @john Aaaand, now anyone can wield these dark magics:
https://github.com/hrbrmstr/extip-svr
```
$ dig +short myip.is TXT @ip.rudis.net -4
"73.16.132.205"
```
It has not been tested heavily.
I guess we'll also see how long the server I stood up works for.
@hrbrmstr Noice. That's going on the list.