How to Make a Vanilla Terraria Server: World, Config and Port

First launch

1. On Windows, find TerrariaServer.exe in the game's installation folder. Official server files are available separately; on Linux, choose files matching your game version.
2. Launch without a config file to use the wizard: select or create a world, then choose a port, player limit and optional password.
3. For repeatable launches, create serverconfig.txt and start the server with -config serverconfig.txt. The official wiki documents world, maxplayers, port, password and motd.
4. Allow the default TCP port 7777 through the firewall and forward it on a home router for friends outside your network. Ask one to try Multiplayer > Join via IP with your public address and port.

Do not confuse the server PC's private address with its public address. If only the owner can connect, check the firewall, forwarding and entered port first.

Back up and choose hosting

Use the server's save and exit commands before copying the .wld world file; closing the window abruptly can lose recent changes. Keep a copy off the server, especially before updating.

With a host, check world import, automatic backups and serverconfig.txt access. See Terraria hosting offers to compare vanilla needs separately from a large modpack.