How to Setup Alien Swarm Dedicated Server

Alien Swarm is free shoot em up adaptation to the classic Alien Swarm mode for Unreal Tournament 2004 by Black Cat Games. Game supports dedicated server, and was released for free by Valve on Steam. You can download the game and start your own dedicated server by following the guide below.

There are basically two ways you can setup Alien Swarm dedicated server, one via steam, and other via hldsupdatetool.

How to Setup Alien Swarm Dedicated Server From Steam
1. Go to tools tab in Steam and double click ‘Alien Swarm Dedicated Server’.
2. A window will pop up with several server settings, fill in these.

  • Server Name
  • RCON Password

and start server.

Once your server is up and running, you can configure it to run under whatever settings you want by tweaking the settings under ‘Configure‘.
You can change the default campaign, what campaign should server run when no players are in server.

How to Assign Your Dedicated Server to a Steam Group
You can enter “sv_steamgroup <n>” in the ‘Console‘ tab, where ‘n’ is the ID of your chosen Steam Group, members of this group will be able to see your dedicated server from main menu. You can find the ID number by your Steam Group admin page.


How to Setup Alien Swarm Dedicated Server with HLDSUpdatetool
1. Download and Install the tool from here.
2. Open a command prompt in the directory where you installed the tool.
3. Run hldsupdatetool to ensure you the latest files and for a list of commands.
4. Create a directory of your server files i.e ‘C:/AlienSwarmServer‘.
5. Update the game files by running this command.

hldsupdatetool -command update -game alienswarm -dir “C:\AlienSwarmServer”

5. Create ‘C:\AlienSwarmServer\swarm\cfg\server.cfg‘ for configuring server settings.
6. Open command prompt in your server directory and run this command to start the server.
Note: You must start in the lobby map in order to properly start the server.

srcds.exe -console -game swarm +map lobby -maxplayers 4 -autoupdate

Alien Swarm only supports Windows dedicated server, Linux is not supported as of right now. Even if you download the files with hldsupdatetool in Linux, it will only give you Windows files.

Alien Swarm Port Forwarding Guide
You need to port forward these ports, 27015, 27005, and all connection issues will be resolved.

Alien Swarm Example Server CFG

hostname YourServerName
rcon_password “YourRCONpassword”
sv_password “” // only needed to make your server private.
sv_contact “”

hostport 27016
sv_lan 0 // enable LAN = 1; disable LAN = 0
sv_region 255
sv_allow_lobby_connect_only 0 //enable/disable Lobby connections 1/0

mp_disable_autokick 1 //disables autokick=1
sv_allow_wait_command 0
sv_alltalk 1
sv_alternateticks 0
sv_clearhinthistory 0
sv_consistency 1
sv_pausable 0
sv_voiceenable 1
sv_cheats 0
sv_forcepreload 1
sv_pure_kick_clients 0

exec banned_user.cfg
exec banned_ip.cfg

sv_log_onefile 0
sv_logbans 1
sv_logecho 0
sv_logfile 1
sv_logflush 0
sv_logsdir logs

sv_minrate 30000
sv_maxrate 60000
sv_minupdaterate 66
sv_maxupdaterate 101
sv_mincmdrate 66
sv_maxcmdrate 101

Edit to add your own server name, rcon password and contact info, this is an example Alien Swarm server cfg, should only be used as a guide.

Alien Swarm Public and Private Servers
Regular source command line works in Alien Swarm as it is based around Source engine, something of a mix though.
1. Anyway, in order to setup a private server, you can use this command, by opening up the command prompt in your server directory.

srcds.exe -game swarm -ip -port 27015 -maxplayers 4 +exec server.cfg +map lobby -lan 1

Put your internal IP in place of “”, and you will be good to go.

2. Now in order to setup Alien Swarm public server, go to server directory, open command prompt and use this command.

srcds.exe -game swarm -ip -port 27015 -maxplayers 4 +exec server.cfg +map lobby -lan 0 -console

Here, put your public internet IP in place of “”. You can follow the our Static IP Tutorial, if you are on a dynamic IP and want to host an Alien Swarm Dedicated Public Server.

How to Fix Alien Swarm Steam Library Errors
There are couple of files that are missing from the Steam which cause this error.

Unable to load Steam support library.
This server will operate in LAN mode only.

There is no permanent fix yet, meanwhile a temporary workaround is to copy these files from game server root “vstdlib_s.dll, tier0_s.dll, steamclient.dll, and Steam.dll”. Alternatively you can download these files from here.

Zawad Iftikhar is the founder of, an FPS enthusiast and a Call of Duty veteran, having participated multiple eSports competition.