How to Use No-Steam Mode

By default, Project Zomboid servers use the Steam Workshop and Steam Networking (P2P) for connectivity. Working in No-Steam Mode (using the -nosteam flag) allows players from other platforms like GOG to join your server and allows for a completely DRM-free experience.

Note: Enabling this mode changes how networking and mods work significantly. The server will no longer automatically download Workshop items.

Why use No-Steam Mode?

• GOG Crossplay: Allow friends who own the game on GOG to join.
• Offline Play: Run a server on a local network without an internet connection.
• Version Control: Prevent mods from updating automatically and breaking your save file.
• Privacy: Your server will not appear on the Steam global server list.

Server-Side Setup

1. Enable the Flag

On your hosting platform or local server, you need to add -nosteam to the startup command.

1. Stop your server.
2. Open the File Manager.
3. Edit your startup script (e.g., StartServer64.sh or server_start.sh).
4. Find the execution line and add the flag at the end:

./ProjectZomboid64 "$@" -nosteam

2. Port Forwarding

In Steam mode, Steam handles the connection. In No-Steam mode, you must have your ports open correctly on your router/firewall:

• 16261 (UDP): Main game port.
• 16262+ (UDP): Direct connection ports for individual players (one per player slot is recommended in some versions).

Managing Mods Manually

This is the most difficult part of No-Steam mode. Since the server cannot "talk" to the Steam Workshop, you must provide the mod files yourself.

1. Download the mods from the Workshop on your local PC.
2. Navigate to your local Steam Workshop folder: SteamLibrary\steamapps\workshop\content\108600\
3. Upload the folders (named by their Workshop ID) to the server's Zomboid/mods/ directory.
4. In your servertest.ini, you must still list the Mod ID in the Mods= line, but the WorkshopItems= line will be ignored.

Client-Side Setup (Joining)

Players on Steam must also launch their game in No-Steam mode to connect to a No-Steam server.

1. Right-click Project Zomboid in your Steam Library.
2. Select Properties -> General.
3. In Launch Options, type: -nosteam
4. Launch the game.

Troubleshooting