How to work around tailscale breaking IPv6 on the host
Yesterday I ran into an incredibly weird issue. I installed the Tailscale client on two of my virtual servers hosted in the Hetzner Cloud (running Ubuntu) and suddenly the websites they offered stopped working. I suspected Tailscale and indeed, tailscale down immediately restored functionality. The websites in question are actually on GitHub Pages and my servers are just acting as reverse proxy to resolve domain and TLS, and a look into the web server’s error.log showed that the issue in serving was that the server could no longer reach its upstream at github.io when Tailscale was active. It wasn’t a general loss of external connectivity though - IPv4 addresses still worked great, the webserver however was trying to connect to the upstream via IPv6 and this is where things failed. ...