RethinkDNS Resolver That Deploys to CF Workers, Deno Deploy, Fastly, Fly.io

I doubt their choice of implementing something so performance-critical as a DNS server in JavaScript. It seems like a slow language for that purpose.

When I was looking for ad-block solutions on Android, Rethink DNS was actually on the top of my list. However, when I found out that their server was written in JavaScript, I did some benchmarking.

Rethink's server processed DNS requests in 400-500ms, which could potentially make a new webpage render up to half a second slower the first time:

  ~ > curl -w "DNS Time: %{time_namelookup}s\nConnect: %{time_connect}s\nTotal: %{time_total}s\n" -H "accept: application/dns-message" -H "content-type: application/dns-message" --data "<binary-data>" -o nul -s https://sky.rethinkdns.com/1:6AcDACIBLIDAAFQwIAAACA==
  DNS Time: 0.004995s
  Connect: 0.142332s
  Total: 0.462496s

  ~ > curl -w "DNS Time: %{time_namelookup}s\nConnect: %{time_connect}s\nTotal: %{time_total}s\n" -H "accept: application/dns-message" -H "content-type: application/dns-message" --data "<binary-data>" -o nul -s 1.1.1.1
  DNS Time: 0.000026s
  Connect: 0.006273s
  Total: 0.008822s

Just fyi (not talking down this project, more providing alternatives) - dnsdist (part of OpenDNS "suite") which is mostly "sold" as a DNS load balancer - is also a perfect stub resolver, that can do DoH/DoT on both ends, that can block certain websites, and is very easy on resources.

Not that many people talk about its usage as a stub resolver, and I don't know why!

Cool! "Pi-hole -esque" is a nice descriptor.

Tangent: Bunny.net is my new favorite CDN / cloud service provider. They have scriptable DNS too.

The Rethink DNS mobile app hasn't seen a release in years. Is the project still alive?

https://github.com/celzero/rethink-app