Tutorial: How to setup a Dedicated Left 4 Dead 2 (L4d2) server on Linux (CentOS 5.6)

Most of the tutorials out there are dated or missing fixes that required time and effort to search and resolve. I am throwing this together as I go through the installation in the hopes it saves someone else some time. As always feel free to comment for help. I’ve run valve based servers on/off for about 10 years (CS, TFC, CS:S, TF2, L4d and L4d2).

In the next tutorial I will outline how to leverage cloud servers for an On-Demand Left4dead2 Server. No need to pay monthly fee’s for a server you use a couple times a month with your buddies. You will be able to start/stop the server within minutes, and only pay for what you use – pennies on the hour for a faster machine than you’d get with a monthly game server provider.

Format a server with centos 5.6 and login as root install screen if its not installed already:

yum install screen

launch new screen session:

screen

change root password

passwd

create user to run l4d2 hlds service

adduser l4d2

Change the password for the new user

passwd l4d2

install 32bit c++ library (needed by HLDS)

yum install libstdc++.i386

Add symlink to gunzip to avoid error durring HLDS installation

ln -s /bin/gunzip /bin/uncompress

Lets open up a couple ports on the default IPTABLES firewall so L4d2 desktops can access our server

nano /etc/sysconfig/iptables

Paste the following rules directly above this line”-A RH-Firewall-1-INPUT -j REJECT –reject-with icmp-host-prohibited”

-A RH-Firewall-1-INPUT -m udp -p udp --dport 27015 -j ACCEPT
-A RH-Firewall-1-INPUT -m udp -p udp --dport 27005 -j ACCEPT
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 27015 -j ACCEPT
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 27005 -j ACCEPT

Restart IPTABLES so this new configuration takes:

service iptables restart

Verify new configuration is in place:

iptables -L

Switch to l4d2 user

su - l4d2

Download HLDS Update tool:

wget http://www.steampowered.com/download/hldsupdatetool.bin

Make the download executable and launch it

chmod +x hldsupdatetool.bin && ./hldsupdatetool.bin

Download L4d2 server

./steam -command update -game left4dead2 -dir “.”

You’ll need a STEAM GROUP ID to associate with your server. Create a new group if necessary:

On your desktop, right click steam taskbar icon > Community
Select "Groups" then "Create new group".
Fill out the details, attach an awesome avatar, hit ok, invite your buddies.
Click on group admin options on the groups profile page > select edit.
Note your Group ID, copy this number for use in the next step.

Create the ever important server.cfg file

nano ~/left4dead2/left4dead2/cfg/server.cfg

Paste this as a starting point:

//Server name
hostname "Your L4D2 Server Name" // Server Name

// RCON password to administer server from ingame, change maps etc.
rcon_password "YOUR_RCON_PASSWORD_HERE"

// Set a search key to help join your server from ingame
// This can be anything, but make it unique
sv_search_key "YOUR_SEARCH_KEY"

// Server Admin Contact
sv_contact "YOUR EMAIL ADDRESS HERE" 

// Disable LAN - Leave this as 0
sv_lan 0

// Host game server port (default 27015)
hostport 27015   

// Region - This sets the lobby in which your server will be part of
// You will want to set this to the closest location to your server
// eastcoast - sv_region 0
// westcoast - sv_region 1
// south america - sv_region 2
// europe - sv_region 3
// asia - sv_region 4
// australia - sv_region 5
// middle east - sv_region 6
// africa - sv_region 7
// world - sv_region 255
sv_region 1 

// Set gametypes (whichever you plan to use the server for, likely only versus)
// options: versus, coop, survival
// to do versus and coop "mp_gametype "versus,coop"
sv_gametypes "versus"

// Allow connections without creating lobby
sv_allow_lobby_connect_only 0

// Steam group # to assign to server
sv_steamgroup "YOUR_STEAM_GROUP_ID_HERE"

// Disable Autokick
mp_disable_autokick 1 

// No Cheating!
sv_cheats 0 		 // Disallow Cheats

// Misc.
sv_clearhinthistory 0    //Clear Server Side Hint History
sv_consistency 1         //Enforce file consistency
sv_pausable 0            //Server not pausable
sv_voiceenable 1         // enable voice communication
sv_alltalk 0             // You can switch this in game using rcon, best to leave it off by default
z_difficulty hard

// LOGGING
log on              //Creates a logfile (on | off)
sv_logecho 0        //default 0; Echo log information to the console.
sv_logfile 1        //default 1; Log server information in the log file.
sv_log_onefile 0    //default 0; Log server information to only one file.
sv_logbans 1        //default 0;Log server bans in the server logs.
sv_logflush 0       //default 0; Flush the log files to disk on each write (slow).
sv_logsdir logs     //Folder in the game directory where server logs will be stored.

//Network Tweaks - Increase network performance
sv_minrate 15000    //default "5000"; Min bandwidth rate allowed on server, 0 = unlimited
sv_maxrate 30000    //default "0";  Max bandwidth rate allowed on server, 0 = unlimited
sv_mincmdrate 20    //default 0; This sets the minimum value for cl_cmdrate. 0 = unlimited [cevo=67]
sv_maxcmdrate 33    //default 40; (If sv_mincmdrate is > 0), [cevo=101]

Be sure to change the following variables in the above configuration: hostname, rcon_password, sv_region, sv_steamgroup, sv_search_key

Determine what IP is attached to the outside interface (eth0):

/sbin/ifconfig
Look for the "inter addr:" line next to eth0, this is your outside accessible IP

Start the Left4Dead server with the above noted IP:

~/left4dead2/./srcds_run -game left4dead2 +maxplayers 8 +ip YOUR_SERVER_IP +map c5m1_waterfront -console

To connect to your server from in game, you need to issue these commands in your desktop console. You need to do this before you start a lobby. This tells steam to use your server when it searching for a server from lobby:

mm_dedicated_force_servers YOUR.SERVER.IP.ADDRESS
sv_search_key "YOUR_SV_SEARCH_KEY_FROM_SERVERCFG"

Developer Console on your local desktop can be enabled from Keyboard options > Advanced

Thanks to James for his original L4d2 server guide which this article is based on, located here: http://jamespo.org.uk/wp/archives/862