Oh yeah, forgot to mention. On a given tailnet, users can only reach their own machines. Each machine that joins the network has an “owner” shown under the machine name in the admin portal. By default users can only reach their own machines, not everyone’s else’s. As the network admin you can manage that through the ACLs tab.
What is the alternative, here? Letting all machines on a tailnet talk sounds like a security issue. Maybe a better onboarding flow that prompts you to set ACLs when inviting a new user?
It seems you're assuming the firewall or my machine configuration was the issue rather than a tailscale "sharing" feature issue.
I am, among other things, a network engineer, and previously I shared my tailnet with my brother's windows machine by logging him into my account directly, and it worked flawlessly.
I want TS to win, but they've got product and engineering work to do if they're serious.
