I plan to selfhost nextcloud, for now just for bookmark sync. is there a point to installing a vpn on the computer running the instance? it shouldnt matter as long as i have https right? what about if i dont have a domain? i cant have https without a domain (ill buy one later just want everything to work first). or maybe use one of those free domain providers for now to get https? what do you guys think?
When you do something like Reverse Proxy or Tailscale, your devices make an outbound connection to the Reverse proxy (or with Tailscale it goes to their auth/directory service) using UPnP.
UPnP is standard protocol these days, and how pretty much any communication or gaming app works. The port opening is performed dynamically by the router, the port number is different every time an outbound connection is made, and it’s ephemeral (both in the range and that the port closes after the session is complete). This isn’t something that’s typically blocked or disabled, as it would break all sorts of things.
https://en.m.wikipedia.org/wiki/Universal_Plug_and_Play
I may have misstated exactly how it works - I studied it when it was released, it became ubiquitous and always works, so I haven’t stayed current or reread anything for a while. It just works (and man has it saved me a ton of manual port config).
The fact, that I have to enable it on a device by device basis on my router speaks to the opposite. You shouldn’t let some app open random ports on your router and you didn’t need to do so for years