These tutorials use Unity v2021.1, and Netcode for GameObjects 1.0.0 prerelease.
This Unity Multiplayer tutorial will teach you how to implement connection approval so that clients have to send the correct password to be able to connect to the server.
Video published 14th Nov 2021
For project files access, check out the repository here: https://github.com/dilmerv/UnityMultiplayerPlayground
Thank you to Dilmer Valecillos and his Youtube channel for the video tutorials! These contributions are a fantastic help to the community.