How to play Terraria multiplayer with Steam friends
To play Terraria with friends using Steam you need to run and setup Terraria Server, which is a console app that is located at Terraria root folder. For example c:\SteamLibrary\steamapps\common\Terraria\start-server-steam-friends.bat
Just run it via Steam or shortcut, don't do anything further. If you will run the server first you may get an error Steam - Error: An error occurred while updating Terraria (app running). In that case open task manager and end all processes with Terraria name.
Find Terraria's root folder
First, go to the Terraria's root folder. The location depends on where your Steam library folder is. To find it out:
Run Steam client;
Go to Steam → Settings in the main menu;
Go to Downloads;
Click on Steam Libraries Folder;
Find your library folder.
All games are installed under d:\SteamLibrary\. That is the primary Steam library folder. Next, go to the steamapps/common/Terraria:
Run the server
In the root folder, you will find some useful files. I assume that you are using the Windows operation system:
TerrariaServer.exe — the main server file. Can be run stand-alone;
serverconfig.txt — the config file with all server parameters;
start-server.bat — a Windows batch file which starts the server using the serverconfig.txt file. Also contains a loopback to restart the server if it should crash;
start-server-steam-friends.bat — a batch file to start the server and play with friends on Steam — exactly what we need;
start-server-steam-private.bat — run the server, but all players will be invited manually.
Execute the start-server-steam-friends.bat file and set up the server by answering questions in the console application.
Setup the server
The Terraria Server console application window will appear. You will be asked to choose the existing world or create a new one. Type n to create a new world or press number to select an existing one. Then press Enter to confirm;
Now you can select the max players limit. Press Enter to set for 8 and continue;
Press Enter again to set server port to 7777 which is the default;
Press y and Enter to set auto port forwarding which is needed;
Now set password or press Enter to allow any friend to connect;
Wait few seconds until the server is initialized. Now we are ready to play with friends;
Connect to the game
Go back to Terraria and select Multiplayer → Join via IP;
Double click to select your character;
Now you will be prompted to enter IP-address of the server you want to connect to. But we also see our created world. In my case it is Soma2. Click on it to join.
Time to join friends
We are ready to play. Let's assume that you are a friend who wants to connect.
Find the Terraria game page in your library;
Under the play button you will find links to profiles of your friends who are playing the game right now;
Find the friend who created the Terraria server;
Go to his profile;
Click on the Join button;
Terraria will be executed. After that you will be able to select your character;
Profit! You are playing Terraria with your friend.
Terraria Server features
As friends are connecting to your server you will see conforming messages in the terminal. Please note that you can type in a command and press Enter to execute it. You may want to ban someone for example. Here is the full list of commands: