To host Garry's Mod for friends, click Start New Game and pick a map. Set the player count above Single Player, tick Peer-To-Peer and click Start Game. Your friends then join you from their Steam friends list, with no server files and no router settings.
What a Listen Server Is
A game you start from the main menu is a listen server. Your copy of Garry's Mod runs the server and your game at the same time. Nobody else can stay on it after you quit, and your PC does all the work.
The host of a listen server is a superadmin automatically. You get every admin tool in Sandbox without installing anything.
A listen server is right for a few friends on one evening. For a server that stays online when you're not playing, make a dedicated server.
Start a Multiplayer Game
Open Start New Game
From the main menu, click Start New Game. The map list opens.
Pick a Gamemode and Map
Use the gamemode selector on the main menu to switch gamemode, for example from Sandbox to another one you've installed. Click a map in the list to select it.
Set the Player Count
Open the player count menu beside the map list. It offers Single Player, then 2, 4, 8, 16, 32, 64 and 128 Players. Any choice above Single Player makes it a multiplayer game.
Choose How Friends Connect
Tick Peer-To-Peer for friends on the internet, or Local Server for people on your home network. Type a Server Name so friends can spot it.
Start the Game
Click Start Game. Your friends can join once the map has loaded.
The server options only appear once you pick more than one player. Single Player has no server settings at all.
Peer-To-Peer, Local Server or Neither
The menu won't let you tick Local Server and Peer-To-Peer together. Ticking one unticks the other.
| Option | Who can join | How they join |
|---|---|---|
| Peer-To-Peer | Anyone on the internet you let in | Through Steam: they join you from their friends list |
| Peer-To-Peer: Friends Only | Only your Steam friends | Same as above |
| Local Server | People on the same home network | Find Multiplayer Game, then the Local Network tab |
| Neither ticked | Anyone who can reach your public IP | The connect command, after you forward a port |
Peer-To-Peer: Friends Only only works with Peer-To-Peer ticked. The menu greys it out otherwise.
Peer-To-Peer uses Steam's networking. Steam connects your friends to you directly where it can, and relays the traffic through Steam's servers where it can't. That's why you don't need to touch your router.
Local Server sets sv_lan 1. The server then skips Steam authentication and only accepts players from local network addresses. Anyone outside your house can't join, however they try.
How Friends Join You
Your friend opens their Steam friends list, right-clicks your name and picks Join Game. Their game connects to yours.
You can also invite them. Open the Steam overlay with Shift+Tab, find them in your friends list and send an invite.
Add a Password
Friends Only is the simplest way to keep strangers out. If you want a password as well, open the console before you click Start Game and set it:
sv_password "pickles"Anyone who joins is asked for it. Clear it with sv_password "" when you're done.
Addons and Content
Your friends need the same models and materials as you. If they don't have them, they see big red ERROR signs and purple and black checkerboard textures.
Lua files are different. Garry's Mod sends your addons' Lua to every player when they join, with no setup.
The easiest fix for content is a Workshop collection. Put every addon you use into one collection and ask your friends to subscribe to all of it before they join. The Workshop guide explains collections in full.
Your PC Is the Server
Your PC runs the whole game for everyone, so a heavy map or a big addon list slows your friends down too. Your internet upload speed matters more than your download speed. Valve warns that a home connection may not have the upload capacity for a large game.
Keep the player count to what your PC and connection can handle. For more than a handful of players, a dedicated server on a separate machine works better.
Common Problems
Check that you picked more than Single Player and ticked Peer-To-Peer. If you ticked Friends Only, the person must be on your Steam friends list. Restart the game with the right settings if any of these was wrong.
The Local Network tab only shows servers on your own network. If your friend is at another house, untick Local Server and tick Peer-To-Peer instead.
They're missing content that your addons or map use. Send them your Workshop collection and ask them to subscribe to all of it, then rejoin.
Your PC is running the server and your game at once. Lower your graphics settings, close other programs and use fewer addons. A wired connection helps more than Wi-Fi.
You and your friends must be on compatible versions. If one of you is on the dev branch, switch back in Steam: right-click Garry's Mod, open Properties, then Betas. Restart Steam if the update doesn't download.
That's how a listen server works. It stops when the host quits. For a server that stays online, make a dedicated server.
Next Steps
When you're ready for a server that runs all the time, read How to Make a Garry's Mod Dedicated Server. To run DarkRP with friends, see Install DarkRP and an Admin Mod.
Want to see a big DarkRP server running? Join Justified: justified.gg
