Terraria has many options to make servers more secure/private, such as adding a password or setting up a whitelist. Whitelists are only possible with the popular TShock mod, which allows more control over servers. In addition to adding whitelists, TShock will enable users to add admins or use admin commands on Terraria servers.
1. Log in to the BisectHosting Starbase panel.
2. Stop the server.
3. Select the Settings tab and choose T-Shock Config.
4. On the EnableWhitelist line, set the value to true.
5. Press the Save button.
6. Start the server.
7. Go to the Console tab.
8. Run the following command to whitelist a player: whitelist <Player IP>
9. The console will confirm that the player IP has been whitelisted.