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Multiplayer FAQ

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If you ask for help in this section, please provide as much info as possible.

Here are some simple guideline-questions that you should answer:

  • What are the specs of the server?
  • What OS is the server running on?
  • What is your connection speed? speedtest.net
  • Did you try to fix your problem and how?
  • What's the issue, exactly and what did you try to fix it?
  • Is the server being run on a VPS or home computer?
Answering these questions in your thread helps us help you. Threads like "I can't connect, please help" is a waste of your time, as you will have to provide the information anyways.

Table of content













Common Errors">common







Administrating a server">admin





Q: How do I get to play Multiplayer?

A: Multiplayer is part of the normal game since build 26. If you are still playing some outdated beta, update your game through Steam or Desura.

If you opted into a beta/tst branch on Steam, go back to the normal build. Right click PZ in your library, click "Properties" and navigate to the "Betas" tab. Now, select "NONE" from the dropdown.

Q: How do I set up a server in Windows/Mac/Linux?

A: For Windows you can use this tutorial: http://theindiestone.com/forums/index.php/topic/5795-how-to-run-a-server/

People running a Linux server can follow the instructions posted by Connall here: http://theindiestone.com/forums/index.php/topic/5841-buying-running-a-linux-project-zomboid-server/


To host a server, navigate to your game installation folder (for Steam users, the default location is Steam\SteamApps\common\ProjectZomboid) and find the batch-file called ProjectZomboidServer.bat.

Start it by double clicking it.

A command prompt window will pop up. Upon first startup, it will create a userdatabase and create an admin account while asking you to set up a password for it.

After setting up the password, it will finish creating and starting up the server and say "*** SERVER STARTED****".

If you are getting an error, saying "The system cannot find the path specified" while trying to create the spawnregions or user database, let it go through and once the server started without those, close the cmd window and start up the server again by executing the ProjectZomboidServer.bat.

If you want to host a server with lots of people, you should make sure your internet connection is fast and you have enough RAM in your rig.

See “How do I use more/less RAM”">RAM for how to allocate more memory to your server.

To allow people to connect to your server you will need to forward the necessary ports.

The necessary standard ports to forward are 16261 (UDP) which serves as a handshake port for communicating with the server.

For each possible player slot on your server, you need to forward additional TCP ports, which are used to stream the world to the player clients.

If you want a server with 10 slots, you would have to forward

16261 UDP

16262 - 16272 TCP

A quick and easy way to test if your ports are forwarded properly are http://www.canyouseeme.org/ and http://www.yougetsignal.com/tools/open-ports/.

Good guides on how to forward ports are found all over the internet. Portforward.com has good guides on hand and covers a lot of routers. Port Forwarding sounds harder in theory that it actually is. It mostly just involves getting into the menu of your router.

If you have no access to your router, please consult whoever is in charge of your network (parents, room mates, admins, etc).


With this we’re making the assumption you understand your way around linux. For a more in depth guide, go visit: http://theindiestone.com/forums/index.php/topic/5841-buying-running-a-linux-project-zomboid-server/

You’ll want to install default-jdk and screen onto the server if you don’t have these already.

Now we need to grab the Steam CMD so we can download the actual Project Zomboid software. It’s recommended that you run SteamCMD on a seperate user.

You should add a new user by doing:


adduser steam
Once that’s sorted we need to switch over to the new user. It should be noted anytime I refer to “steam” in the file directory context, then it means the user folder. If you decide to name the user something else the directories change also. Something to keep note of. “Steam” is not the same as “steam” in the directory context as well.


su - steam
this will switch the user from root, to steam.

Now we need to actually get the SteamCMD. To do this we run this command:


wget http://media.steampowered.com/installer/steamcmd_linux.tar.gz
It should eventually download and once it does we need to actually get the contents out of the folder. To do this we run


tar -xvzf steamcmd_linux.tar.gz
Now we got to run SteamCMD

To do this we can do:


cd /home/steam/steamcmd


./steamcmd.sh +login steamusername steampassword +force_install_dir directory/you/want/to/install/to +app_update 108600 validate +exit
Steamusername being your steam username and password being the steam password.

You should have a projectzomboid-dedi-server.sh file in your ProjectZomboid folder, if not you will need to rerun the command up above.

You will also need to create a Zomboid folder in the users home folder. You will need to create a folder of “db” in that folder as well and dowload this db file and place it in the “db” folder: https://dl.dropboxus...553835/world.db

Whether or not you will whitelist the server it’s best to put the file in. You’ll now need to edit the projectzomboid-dedi-server.sh and set your RAM values. This is dependant on how much RAM your server has, I personally didn’t set them to use my complete server capacity, I did about half but the choice is up to you. (Kirrus: Don't set more than 80% of your VM's capacity.) Use Filezilla and double click on the file and it should open it up in an editor, find these two lines:

-Xms1024m \

-Xmx1024m \

And edit the values to your choosing.

Now we need a certain script:


wget http://kirrus.co.uk/stuff/pz/wheezy-glibc-sid.shbash wheezy-glibc-sid.sh
This is only required for those who are running a Debian OS, Ubuntu (I am told) should be fine.

We’re almost there. So here’s what we got to do now.


cd /home/steam/Steam/SteamApps/common/ProjectZomboid


It will start the server. You need to run the server in screen, or when you close the terminal program you’re using, the server will shutdown as well.


You'll need to find your info.plist file (in Project Zomboid.app/Contents) and edit a line in there:


Change the MainClassName from something like zombie/gameStates/mainscreenstate to this. Note that you'll need to change it back if you actually want to play PZ, so make sure you make a copy of the old info.plist.

From there, you need to run the game from the JavaAppLauncher (Project Zomboid.app/Contents/MacOS) to make sure you get console output and can see what's going on with your server. Right now the only way to host and join your own server on OS X is to have two full copies of the game downloaded.

Q: How do I use more/less RAM?

A: You’ll need to edit the projectzomboid-dedi-server.sh file or the ProjectZomboidServer.bat file and find lines that look like:

-Xms1024m \ -Xmx1024m \

These are your RAM values. It is advised that you don’t use more than 80% of your available RAM. If you’re running the server from a home computer, then the RAM values should be tonned down significantly more.

Q: How do I reset/start a new world?

A: To reset the servers world you will need to navigate to your server’s /Zomboid/Sandbox folder. In there should be a folder called “servertest” deleting this will folder will reset the world. Make sure to do this when the server is off (or the server program is not running) and restart the server.

Q: Are LAN servers possible/how?

A: Yes. LAN servers are completely possible, the usual installation instructions need to be carried out with regards to setting up a server. This info can be found at: http://theindiestone.com/forums/index.php/topic/5795-how-to-run-a-server/

You should then be able to connect the server.

Q: Can I use mods and/or custom maps on my mp server?

Yes! You can.


In order to have mods running on the server, first you need to download some mods that are supported by the version of the game you are playing, you then have to put those mods in your Zomboid -> Mods directory. You will then need to change your servertest.ini file to include the mods




Different mods are separated by a ; between each name of the mod. In order for this to completely work, both the server and the clients need to have the mods installed and running in order for players to be able to connect to the server. Maps are much the same, you can find more info here: http://theindiestone.com/forums/index.php/topic/7897-build-26-custom-maps-spawn-locations/?p=103784

Q: Can I change the length of days or the ammount of Zombies/loot? / How do I change the sandbox settings of my server?

A: Sandbox settings of the server are set up via the SandboxVars.lua which should be saved in Zomboid\Server\*servername*_SandboxVars.lua

If necessary, download this updated PZServerSettings.exe and place it in your PZ installation folder to set it up easily:


Q: Is there a way to respawn loot? / How do I perform a Soft Reset?

A: Respawning loot is currently only possible through either resetting the server completely or performing a soft reset.

A soft reset will completely redistribute loot containers and wipe dead bodies and blood splatters off the server.

To perform a Soft Reset, quit the server. Edit the ProjectZomboidServer.bat with a text editor and add -Dsoftreset to it


".\jre64\bin\java.exe" -Xms2048m -Xmx2048m -Djava.library.path=./ -cp lwjgl.jar;lwjgl_util.jar;sqlitejdbc-v056.jar;trove-3.0.3.jar;./ -Dsoftreset zombie.network.GameServerPAUSE
Now run the batch file and let it finish. Once done, close the CMD and delete the -Dsoftreset entry from the batch file.

Restart the server by running the batch again.

Q: How do zombies spawn?

A: Much like items they seem to spawn once then begin to wittle down as they don’t actually seem to respawn. There’s no settings for zombies right now, nothing to alter their spawning or how they act like in Singleplayer Sandbox.

Q: Why can't people connect to my server?

A: There can be a number of factors surrounding why people can’t access your server. For the most part this sort of stuff applies to people who are hosting servers from their homes, if you’re using a VPS or dedicated gameserver provider to host the server you shouldn’t encounter these problems. If you do, first refer to any avaialable guides that may help resolve the issue, then contact your server provider to see if they would be willing to help.

For home computers here’s what you can check:

1. Check your ports. Chances are your ports aren’t accepting connections, and for good reasons as this is generally a security feature for the routers. Routers are so vaired, that we can’t actually give a lot of specifics for you. However visiting a site like: portforward.com and finding your router model should give you an idea on how to set up your port forwarding.

The following ports that should be forwarded is the 16261 as UDP as it’s considered a handshake port for the server. All further ports are configured as TCP and are used to configure map data to each user. So one port should be forwarded for every player you wish to have on the server. So for example 16262 - 16272 would allow ten players.

If you want to test if the port is forwarding then you can use a port checker such as http://www.yougetsignal.com/tools/open-ports/ to test and see if the port is open. Make sure that your server is running before testing the port as some routers, won’t open the port until there’s a connection running.

2. Firewalls and antivirus. The oldest trick in the book, these could be causing problems for the server and may wish to turn these off or add PZ/Java to the exception list.

3. Correct IP. There are two types of IP, an internal IP and an external IP. Internal IPs are used for connecting within the computer or network while externals are for people connecting from outside the network. Make sure you are giving people an external IP and not an internal one. To check your IP, you can just google “What’s my IP” or visit http://www.whatismyip.com/

If you’re absoloutely certain it’s none of these problems post to multiplayer help board.

Common Errors

Q: I’m trapped in a server! The map won’t load anymore, what’s going on? It looks like a black border.

A:You have either lost connection to the server, or the server has crashed. You’ll need to check your internet connection, or the server owner will need to restart the server. If you’re certain this is not the case, then the server may not have the ports configured correctly to allow map streaming to each player. If you’re the server owner here’s some info on the matter.

The following ports that should be forwarded is the 16261 as UDP as it’s considered a handshake port for the server. All further ports are configured as TCP and are used to configure map data to each user. So one port should be forwarded for every player you wish to have on the server. So for example 16262 - 16272

Q: I’m getting some console messages about… “Delay Packets”

A: This seems to be a common problem affecting a lot of users. There’s no known concrete fixes, just a couple of hot fixes.

One such fix is to try and disable firewalls or anti-virus which might be causing the issue. If you have been able to connect to the server but has now changed and you’re getting these messages you can try removing the save folder associated with the server. If it’s still not working you might be unfortunately stuck. It is possible that it’s a server specific issue, try connecting to a different server and see what happens.

Making sure the username is using a proper file name characters (as the username is saved to a folder, so if you’re using improper characters (like “/” “!” etc) it won’t work. It’s also entirely possible that the server is full, or all the ports opened by the server operator are in use. This means that you won’t be able to connect to the server and will instead, need to connect to a different server.

Q: My server keeps crashing with people on it!

A: Odds are you don’t have enough RAM or you haven’t allocated enough of your RAM to the server. If you’re running a public server on a home computer, this will be more of an issue. If running off a VPS it’s still a possibility. Generally 2GB gets around 10-15 players and 4GB can cover 20-30 possibly.

Q: I get this message of… Client version (956) doesn't match server (958) when I try to connect to a server. What’s going on?

A: This is indicating that there is a Project Zomboid build mismatch between the client and server. Say the message was like this “Client version (x) doesn’t match server (y)”

If Client (x) number is less than server (y) then that means that the server is running a newer build and the client is running an older build. So best way to check is to make sure that steam has updated your game to the newest version possible.

If server (y) number is less than (x) then that means that the server is outdated from the client and the server still needs to be updated.

Q: I was on a friends server, it was working fine but then we restarted and we started having problems. What do I do?

A: There are a couple of possible solutions to this. The first is try deleting the save associated with the server, in the event that’s causing a conflict. If that doesn’t work, it might mean the server hoster has not quite configured the ports correctly and isn’t allowing map streaming.

Administrating a server

Server Settings

There are various options for servers. The server options are set up via the ServerOptions.ini file in your Zomboid folder

(Windows: C:\Users\<username>\Zomboidserver)

(LinuxL /home/<user>/Zomboid/Server)

Just open it with a text editor and change them as you see fit.

When done with the changes, save the file and reboot the server.

You can also change these settings ingame (when logged in as an admin) via /changeoption optionName=*value* and then /reloadoptions.

Possible options:

PVP = true //Enable PVP.

PauseEmpty = false //If true the server won't update if no players are on it (farming won't progress, etc.)

GlobalChat = true //Enable the Global Chat (/all command in chat).

Open = true //Open to all (no whitelist)

ServerWelcomeMessage = <RGB:1,0,0> Welcome to Project Zomboid MP test ! to chat locally press \"t\", to global chat press \"y\" or add \"/all\" before chatting <LINE> Press /help to have a list of server commands <LINE> <RGB:1,1,1> //Displayed message in the global chat when a client connect.

LogLocalChat = false //Log the local chat in the chat window (client side).

AutoCreateUserInWhiteList = false //If you server is open, this option will allow the server to create the user in whitelist if they entered the server with a password, so his username will be protected.

DisplayUserName = true //False = you won't see another players username on top of their head + their name won't be logged inside the local chat

SpawnPoint = 0,0,0 //Use this to define a custom spawn point instead of the random one from character creation.

SafetySystem = true //Allow the user to change their safety (if false and if PVP=true, then the safety will always be off).

ShowSafety = true //Allow the players to see if someone have his safety off with the skull icon.

SafetyToggleTimer = 100 //When the player disable safety it take some times before HE enable it (tho the other players see it instantly), define it here

SafetyCooldownTimer = 120 //Every time you hit someone in safety off, add this timer to the cool down before you can actually toggle safety off

SpawnItems = //Add spawning items to new player, ex : Base.Axe,Base.WaterBottleFull... (every item need to be separated by a ",")

DefaultPort = 16261 //Default port used by the server

Mods=BedfordFalls;AnotherMod... //Used to add mods to your server, like maps or other things, player will NEED to have this mods installed.

DoLuaChecksum = true //Do the lua checksum

Public = false //If true send the info of the server to pz.com to be visible in the public server list

PublicName = //Required for public server

PublicDescription = //Optionnal, for public server

MaxPlayers = 64 //Max players who can connect on the server (admin can by pass this)

PingFrequency = 10 //Time between each client ping, in second

PingLimit = 400 //Ping limit before being kicked, need to be 5 time over, in millisecond, 0 disbaled it.

HoursForLootRespawn = 0 //Enable loot respawn if > 0, then the zone need to be unseen for X (this parameter) hours before respawn loot in it.

MaxItemsForLootRespawn = 4 //For the loot respawn, if a container have more items than this number, it won't respawn loot (use it to limit respawn in safe house for example..)

HoursForZombiesRespawn = 0 //Enable zombies respawn if > 0, then the zone need to be unseen for X (this parameter) hours before respawn zombies on it, only on road.

IncreaseZombieRespawnBy=0 //Ammount of additional zombies you want to have spawned if HoursForZombiesRespawn > 0. Example, an area spawns a default of 10 Zombies. You have IncreaseZombieRespawnBy=20 -> The area will spawn 30 Zombies (10 naturally and 20 additional zombies).

Administrative commands

There are various commands for admins. There will be more in the future. This list will be updated as it goes:

adduser = Use this command to add a new user in a whitelisted server, use : /adduser username=pwd

save = Save the current world

quit = Quit the server (but save it before)

chopper = Start the choppers (do noise)

gunshot = Start a gunshot (do noise)

startrain = Start rain on the server

stoptrain = Stop rain on the server

grantadmin = Grant the admin rights to a user, use : /grantadmin username

removeadmin = Remove the admin rights to a user, use: /removeadmin “username”

reloadoptions = Reload the options on the server (ServerOptions.ini) and send them to the clients

banuser = Ban a user, reason is not mandatory, use : /banuser username=reason ip=true/false, ex /banuser rj=pvp ip=true

unbanuser = Unban a player, use : /unbanuser username

kickuser = Kick a user, reason is not mandatory, use : /kickuser username=reason

addalltowhitelist = Add all the current users connected with a password in the whitelist, so their account is protected.

addusertowhitelist = Add the user connected with a password in the whitelist, so his account is protected, use : /addusertowhitelist username

removeuserfromwhitelist = Remove the user from the whitelist, use: /removeuserfromwhitelist username

showoptions = Show the list of current Server options with their values.

changeoption = Use this to change a server option, use : /changeOption optionName=newValue

godmod = Set a player invincible, use : /godmod username=true/false, ex /godmod rj=true

invisible = Set a player invisible, use : /invisible username=true/false, ex /invisible rj=true

additem = Add an item to a player, the username isn't mandatory, if you don't specify it the item will be added to you, use /additem username module.item, ex : /additem rj Base.Axe.

createhorde = Use this to spawn a horde near you, user : /create horde count, ex /createhorde 150

changepwd = Use this command to change your password, use : /changepwd previouspwd newpwd.

You can type “/help” to get a full list or “/help *command*” to get the help tooltip for this command.


Thanks to nasKo for being the original author of the thread and helping to write the FAQ.

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