Project Zomboid Dedicated Server: Setup & Settings (Build 42)

1. Install the server

In the Steam client the server sits under Library → Tools as “Project Zomboid Dedicated Server”; PZwiki advises not to start it from Steam. On a machine without Steam, use SteamCMD:

force_install_dir <folder for the server>
login anonymous
app_update 380870 validate
quit

Steps adapted from PZwiki, Dedicated server. PZwiki also advises running the server on Linux as its own user, not as root. Re-running app_update 380870 validate updates it.

2. Ports

Players reach the server on 16261 and 16262, so both must be open in the firewall and forwarded on the router; PZwiki gives both as UDP (PZwiki, Dedicated server). A second server on the same machine needs its own pair, set in its own .ini.

3. Start scripts and memory

On Windows, StartServer64.bat reserves 16 GB up front (-Xms16g) and caps the server at 16 GB. On a machine with less free memory, lower both numbers in that file before the first start — PZwiki notes the server will not start otherwise (PZwiki, Dedicated server). On Linux the limit is -Xmx8g in ProjectZomboid64.json — the script itself says to edit it there: “Edit memory option -Xmx in ProjectZomboid64.json for 64bit servers”.

4. First start and the config files

The first start asks for the admin account's password in the console — “Enter new administrator password:” — then writes the server's files into its Server folder — %USERPROFILE%\Zomboid\server on Windows, ~/Zomboid/Server on Linux (PZwiki, Server settings). Each file is named after the server, servertest by default; the server's code names 5 of them, where PZwiki lists four (it leaves out servertest_zombies.ini):

• servertest.ini
• servertest_SandboxVars.lua
• servertest_spawnpoints.lua
• servertest_spawnregions.lua
• servertest_zombies.ini

servertest.ini holds the server settings listed below; servertest_SandboxVars.lua holds the world's sandbox rules (every option and preset: sandbox settings). Settings can also be changed while the server runs, with /showoptions, /changeoption and /reloadoptions.

5. Start options

Add them after the start script, for example start-server.sh -servername mysurvivors:

• -adminpassword — admin password
• -adminusername — admin account name
• -cachedir= — moves the game's Zomboid folder, where the Server folder lives, to another path
• -nosteam — a non-Steam server, for players on the non-Steam version (GOG)
• -servername — picks the server's name — which config files it reads and which save it uses

16 more options are in the server's code without a description we can source: -anti-cheats, -console_dot_txt_size_kb=, -coop, -debugLogFile=, -debuglog=, -disablelog=, -gui, -ip, -no-attachment, -no-foraging, -no-worldgen, -port, -seed=, -steamvac, -udpport, -useTimeStampedLogFileNames=. The -servername and -nosteam descriptions follow PZwiki, Dedicated server; -cachedir= follows PZwiki, Game files.

6. Join the server

In the game: Join → Favorites, add the server's public IP and port 16261, then an account name and password (PZwiki, Dedicated server). Whether a new name gets in depends on the Open setting, on by default — the game's tooltip: “Clients may join without already having an account in the whitelist. If set to false, administrators must manually create username/password combos.” Players on the non-Steam version need a server started with -nosteam; on a LAN or VPN use the local address.

All 144 server settings (servertest.ini)

Every setting the server reads from its .ini, with its default and allowed range from the code and the tooltip the game shows for it. 23 settings ship without a tooltip. One mismatch inside the game: the BadWordPolicy tooltip lists choices up to 4, but the code accepts 1–3.