Tailscale is a commercial, yet widely open-sourced VPN provider, based on the Wireguard protocol.
The service enables to connect devices to each other, without having to open anything up to the broader internet.

It can be used extensively for free, up to 3 users.

Basic commands

Advanced stuff

In your Tailscale network, DNS configurations can be made

Alternatives

• Headscale is an open-source Tailscale control server: https://headscale.net/stable/
• Netbird is also an alternative for self-hosting: https://github.com/netbirdio/netbird
• Newt Pangolin https://docs.pangolin.net/ can also be self-hosted

Coupling Tailscale with...

For Nginx, there are configurations available.

See more in

Docker with Tailscale

Tailscale can be combined with Docker to build applications that are only accessible via the tailscale network.
See: https://www.youtube.com/watch?v=YTjYXii4WzI

A Docker Compose setup

Requirements: Create a TS_AUTHKEY in: https://login.tailscale.com/admin/settings/keys

Furthermore, you might consider activating

version: "3.7"
services:
  tailscale:
    image: tailscale/tailscale:latest
    hostname: webserver
    container_name: tailscale-webserver
    environment:
      - TS_AUTHKEY=${TS_AUTHKEY}
      - TS_STATE_DIR=/var/lib/tailscale
      - TS_USERSPACE=false
    volumes:
      - tailscale-data:/var/lib/tailscale
    devices:
      - /dev/net/tun:/dev/net/tun
    cap_add:
      - net_admin
      - sys_module
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "tailscale", "status"]
      interval: 30s
      timeout: 10s
      retries: 3

  webserver:
    image: nginx:latest
    container_name: nginx-webserver
    depends_on:
      tailscale:
        condition: service_healthy
    network_mode: service:tailscale
    volumes:
      - ./index.html:/usr/share/nginx/html/index.html:ro
    restart: unless-stopped

volumes:
  tailscale-data:
    driver: local

How Tailscale works

Briefly

Tailscale

In more depth