Tailscale killed my DNS

I am working on a remote location today, on a shared venue network.

After rebooting my Mac I could no longer connect to any website domain, which led me to believe that DNs was not resolving. And indeed, pinging www.google.com gave no results. Even when tethered to my iPhone, I could not connect to any website. Connecting to VPN by IP did work though, and pinging 8.8.8.8 worked fine as well.

Luckily, I could search for clues on my phone, and ran into this command that I have not used before:

scutil --dns which gives you a nice list of DNS resolvers as they are used by the system, and, on top of that list this entry:

resolver #1
  search domain[0] : tailf67a92.ts.net
  nameserver[0] : 100.100.100.100
  if_index : 24 (utun4)
  flags    : Supplemental, Request A records, Request AAAA records
  reach    : 0x00000003 (Reachable,Transient Connection)
  order    : 102000

I restarted Tailscale, and we are online again 🎉.