Arma 3: Server Config File

Arma 3 Server Configuration Overview
Setup	Arma 3: Dedicated Server ● Arma 3: Dedicated Server (Chinese Simplified) ● Arma 3: Dedicated Server (Chinese Traditional)
Files	Arma 3: Server Config File ● Arma 3: Basic Server Config File ● Arma 3: Server Profile
Other	Multiplayer Server Commands ● Arma 3: Mission voting ● Arma 3: Headless Client ● BattlEye

This page is about Arma 3 server configuration. For previous titles, see Arma 2: Server Config File.

This article deals with the server.cfg, a configuration file which one can use to configure various game server settings such as the difficulty level, how many votes are needed, and welcome messages. The name server.cfg means nothing, and this file can be called anything. The real name is determined by the -config command line option when launching the dedicated server. There is no default name: when no filename is specified, no server configuration file is loaded.

Server Options

Parameter	Default	Description	Since
passwordAdmin = "xyzxyz";	""	Password to protect admin access.	N/A
password = "xyz";	""	Password required to connect to server.	N/A
serverCommandPassword = "xyzxyz";	""	Password required by alternate syntax of serverCommand server-side scripting (Case-Sensitive).	N/A
hostname="My Server";	UNKNOWN	Servername visible in the game browser.	N/A
maxPlayers = 10;	64 (DS)	The maximum number of players that can connect to server. The final number will be lesser between number given here and number of mission slots.	N/A
motd[]= {"Welcome to my server.", "Hosted in the net."};	{}	Two lines welcome message. Comma is the 'new line' separator.	N/A
admins[] = {"<UID>"};	{}	Whitelisted clients can use #login without password. See Logged In Admin.	1.70
headlessClients[] = {"<IP>"};	{}	Headless Client IPs. Multiple connections and addresses are allowed in case of multiple Headless Clients. See Arma 3: Headless Client.	N/A
localClient[] = {"<IP>"};	{}	Indicates clients with unlimited bandwidth and nearly no latency. See Arma 3: Headless Client.	N/A
filePatchingExceptions[] = {"<UID>"};	{}	Whitelisted clients ignore the rules defined by allowedFilePatching and verifySignatures, allowing them to join the server with any mods of their choice. Signature errors are still logged by the server upon connection. ⚠ Signature errors may still kick the user if the error happens before the server knows the clients SteamID, for example when trying to join with completely unsigned pbo's.	This entry has existed since 2016, but only became fully operational in 2.10
Server Behaviour
voteThreshold = 0.33;	UNKNOWN	Percentage of votes needed to confirm a vote. 33% in this example.	N/A
voteMissionPlayers = 3;	UNKNOWN	Start mission-voting when X numberOfPlayers connect.	N/A
allowedVoteCmds[] = { {"kick", false, false, 0.75} };	{}	See Arma 3: Mission voting.	N/A
allowedVotedAdminCmds[] = { { "mission", true, true } };	{}	See Arma 3: Mission voting.	N/A
kickduplicate = 1;	UNKNOWN	Do not allow duplicate game IDs. Second player with an existing ID will be kicked automatically. 1 means active, 0 disabled.	N/A
loopback = true;	false	Adding this option will force server into LAN mode. This will allow multiple local instances of the game to connect to the server for testing purposes. At the same time it will prevent all non-local instances from connecting.	N/A
upnp = true;	false	Automatically creates port mapping on UPNP/IGD enabled router. This option allows to create a server behind NAT (the router must have public IP and support UPNP/IGD protocol). Read more Internet Gateway Device (IGD) Standardized Device Control Protocol. ⚠ When enabled then this setting may delay server start-up by 600s (standard UDP timeout of 10 minutes) if blocked on firewall or bad routing etc. Thus in such case is recommended to disable it.	N/A
allowedFilePatching = 0;	0	Prevent or allow file patching for the clients (including the HC) 0 is no clients 1 is Headless Clients only 2 is all clients	1.50
allowedLoadFileExtensions[] = {"sqf","txt"};	UNKNOWN	Only allow files with listed extensions to be loaded via loadFile command. Not listing any extension means everything is allowed. Defining the setting as empty arrays means nothing is allowed.	1.20
allowedPreprocessFileExtensions[] = {"sqf","sqs"};	UNKNOWN	Only allow files with listed extensions to be loaded via preprocessFile / preprocessFileLineNumbers commands. Not listing any extension means everything is allowed. Defining the setting as empty arrays means nothing is allowed.	1.20
allowedHTMLLoadExtensions[] = {"htm","html"};	UNKNOWN	Only allow files and URLs with listed extensions to be loaded via htmlLoad command. Not listing any extension means everything is allowed. Defining the setting as empty arrays means nothing is allowed.	1.28
allowedHTMLLoadURIs[] = {"http://arma3.com"};	UNKNOWN	Only allow files from listed URIs and URLs to be loaded via htmlLoad command. Comment out if not used. Can use += to add to the existing list. Not listing any extension means everything is allowed. Defining the setting as empty arrays means nothing is allowed.	N/A
disconnectTimeout = 5;	90	Server wait time before disconnecting client after loss of active traffic connection, range 5 to 90 seconds.	1.56
maxdesync = 150;	UNKNOWN	Max desync value until server kick the user	1.56
maxping= 200;	UNKNOWN	Max ping value until server kick the user	1.56
maxpacketloss= 50;	UNKNOWN	Max packetloss value until server kick the user	1.56
kickClientsOnSlowNetwork[] = { 0, 0, 0, 0 };	UNKNOWN	Defines if {<MaxPing>, <MaxPacketLoss>, <MaxDesync>, <DisconnectTimeout>} will be logged (0) or kicked (1)	1.56
enablePlayerDiag = 1	0	Logs players' bandwidth and desync info every 60 seconds, as well as "network message is pending" owner identity.	N/A
callExtReportLimit = 1000;	1000	If server initiated callExtension takes longer than specified limit in milliseconds, the warning will be logged into server .rpt file as well as reflected in the extension return result.	N/A
kickTimeout[] = { {0, -1},{1, 180},{2, 180},{3, 180} };	UNKNOWN	kickTimeout[] = { {kickID, timeout}, ... }; kickID (type to determine from where the kick originated e.g. admin or votekick etc.) 0 - manual kick (vote kick, admin kick, bruteforce detection etc.) 1 - connectivity kick (ping, timeout, packetloss, desync) 2 - BattlEye kick 3 - harmless kick (wrong addons, steam timeout or checks, signatures, content etc.) timeout = in seconds how long until kicked player can return >0 seconds -1 until missionEnd -2 until serverRestart	1.90
votingTimeOut = 60;	60	Voting timeout	N/A
votingTimeOut[] = {60, 90};	{60, 90}	Voteing timeout {ready, notReady}	1.90
roleTimeOut = 90;	90	Role seleciton timout	N/A
roleTimeOut[] = {90, 120};	{90, 120}	Role selection timeout {ready, notReady}	1.90
briefingTimeOut = 60;	60	Briefing timeout	N/A
briefingTimeOut[] = {60, 90};	{90, 120}	Briefing timeout {ready, notReady}	1.90
debriefingTimeOut = 45;	45	Briefing timeout	N/A
debriefingTimeOut[] = {60, 60};	{90, 120}	Debriefing timeout {ready, notReady}	1.90
lobbyIdleTimeout = 300;	300	Lobby idle timeout Independent of set lobbyIdleTimeout in the config file, it will be at least MAX(votingTimeout, lobbyTimeout, briefingTimeout, debriefingTimeout) + 5 seconds by default, this makes it 300 seconds of time for people in lobby and 95 in roleTimeout or briefing screen	1.90
missionsToServerRestart = 8;	UNKNOWN	Number of times missionEnd happens before server initiate process restart (uses actual session startup command-line parameters, not possible to combine with `missionsToShutdown` )	N/A
missionsToShutdown = 8;	UNKNOWN	Number of times missionEnd happens before server initiate process shutdown (has same behavior as setting named `missionsToHardRestart`)	N/A
autoSelectMission = true;	false	When enabled, the server auto-starts next mission in mission cycle and waits for players in the role selection. This allows full mission information in server browser and then results in proper filtering of the servers. This is lesser-variant (trimmed) of server startup command-line parameter -autoInit. Might collide with campaign linked missions / need mission cycle etc.	N/A
randomMissionOrder = true;	UNKNOWN	When enabled, the server random start / next selection with one of missions from mission rotation list. ( setting goes outside(before) Mission class {}; )	N/A
disableChannels[] = { {0,false,true} };	{}	disableChannels[] = { {channelID, text, voice}, ... }>; ChannelID : Number - use single digit of (0 to 6) to define channelID. Default: No restriction to any channels, with text/von chat set to false. text : Boolean - use true to disable usage of text-chat for defined channelID. Default: false voice : Boolean - use true to disable usage of voice-chat (VON) for defined channelID. Default: false List of channels ID: 0 = Global 1 = Side 2 = Command 3 = Group 4 = Vehicle 5 = Direct 6 = System ⓘ Missions which use Description.ext#disableChannels will override any setting of disableChannels[] in the server.cfg.	-
Other Options
verifySignatures = 2;	0	Enables or disables the signature verification for addons. Verification disabled = 0. 1 Will default back to 2	-
drawingInMap = false;	true	Enables or disables the ability to place markers and draw lines in map.	1.64
disableVoN = 1;	0	Enables or disables the Voice over Net.	N/A
vonCodecQuality = 10;	3	Defines VoN codec quality. Value range is from 1 to 20. Since 1.62 supports range 1-20 Since 1.64 will support range 1-30 8kHz is 0-10, 16kHz is 11-20, for 21-30 it is 32kHz for SPEEX codec and 48kHz for OPUS codec.	-
vonCodec = 1;	0	Defines VoN codec type. Value range is from 0 to 1. Since Arma 3 update 1.58 supports value 1 Value 0 uses older SPEEX codec, while 1 switches to new IETF standard OPUS codec.	-
skipLobby = false;	false	If true, joining player will skip role selection. This is only used if no Mission, Campaign or Config setting skipLobby is defined (See Description.ext#skipLobby).	N/A
allowProfileGlasses = false;	true	If false, glasses set in player profile will be ignored. This is only used if no Mission, Campaign or Config setting allowProfileGlasses is defined (See Description.ext - allowProfileGlasses)	2.06
zeusCompositionScriptLevel = 0;	1	0: all scripts are forbidden 1: only attributes are allowed (including custom attributes added by mods) 2: all scripts are allowed including init scripts This is only used if no Mission, Campaign or Config setting zeusCompositionScriptLevel is defined (See Description.ext - zeusCompositionScriptLevel).	2.06
logFile = "server_console.log";	UNKNOWN	Enables output of dedicated server console into textfile. Default location of log is same as crash dumps and other logs. (Local settings) Note that this does not change the location of the "net.log" file, which is enabled with the -netlog command line option.	N/A
doubleIdDetected = "command";	""	See Server Side Scripting
onUserConnected = "command";	""		N/A
onUserDisconnected = "command";	""		N/A
onHackedData = "command";	""		N/A
onDifferentData = "command";	""		N/A
onUnsignedData = "command";	""		N/A
onUserKicked = "command";	""		N/A
regularCheck = "command";	""		N/A
BattlEye = 1;	1	Enables or disables the BattlEye anti-cheat engine. Requires installed BattlEye on server and clients joining the server	N/A
timeStampFormat = "none";	""	Set the timestamp format used on each report line in server-side RPT file. Possible values are "none", "short", "full".	N/A
forceRotorLibSimulation = 0;	0	Enforces the Advanced Flight Model on the server. 0 (up to the player). 1 - forced AFM, 2 - forced SFM.	1.34
persistent = 1;	0	Mission keeps running when all clients disconnect. Enabling the persistence option will make missions that have either base or instant respawn keep on running after all players have disconnected. The other respawn types will not make a mission persistent. The kind of respawn a certain mission uses is set in its Description.ext.	N/A
requiredBuild = xxxxx;	UNKNOWN	Minimum required client version. Clients with version lower than requiredBuild will not be able to connect. If requiredBuild is set to a large number, like requiredBuild = 999999999; for example, it will automatically be lowered to the current server version.	N/A
statisticsEnabled = 1;	1	Allows to opt-out of Arma 3 analytics for the server by using 0	1.56
forcedDifficulty = "regular";	""	Enforces the selected difficulty on the server. forcedDifficulty = "<difficultyClass>"; If Recruit, Regular or Veteran is passed as the parameter, the particular difficulty options will be taken from data config, from the class CfgDifficultyPresets. If Custom will be passed as the parameter, the particular flags will be taken from CustomDifficulty class from server's profile (only Custom is saved to the profile). If mission cycle is defined in the server.cfg, the difficulty set in the mission cycle overrides the difficulty set by forcedDifficulty parameter.	1.56
missionWhitelist[] = {"intro.altis"};	{}	Limit the available missions for the admin for the mission change. See Arma 3: MP Mission Names for a full list.	1.56
steamProtocolMaxDataSize = 1024;	1024	Limit for maximum Steam Query packet length. Increasing this value is dangerous as it can cause Arma 3 server to send UDP packets of a size larger than the MTU. This will cause UDP packets to be fragmented which is not supported by some older routers. But increasing this will fix the modlist length limit in Arma 3: Launcher.	2.00
class AdvancedOptions { LogObjectNotFound = true; // logging enabled SkipDescriptionParsing = false; // parse description.ext ignoreMissionLoadErrors = false; // do not ingore errors queueSizeLogG = 1000000; // if a specific players message queue // is larger than 1MB and #monitor is running, // dump his messages to a logfile for analysis };	N/A	2.02 LogObjectNotFound - false to skip logging "Server: Object not found" messages SkipDescriptionParsing - true to skip parsing of description.ext/mission.sqm. Will show pbo filename instead of configured missionName. OverviewText and such won't work, but loading the mission list is a lot faster when there are many missions 2.04 ignoreMissionLoadErrors - when set to true, the mission will load no matter the amount of loading errors. If set to false, the server will abort mission's loading and return to mission selection 2.08 queueSizeLogG - if #monitor is running and a player's Guaranteed Message Queue size (Listed as G: in #monitor) goes above the threshold, all that player's message types and sizes are dumped to a logfile in the RPT directory (see Crash Files); the dumping itself is logged server-side.	2.022.042.08
armaUnitsTimeout = 30;	30	Defines how long the player will be stuck connecting and wait for armaUnits data. Player will be notified if timeout elapsed and no units data was received	2.06

Server Administration

If BattlEye RCon is not in use, there can only be 1 server admin at any given time. There are two ways of becoming admin, through a vote or through login with authenticated credentials.

Voted In Admin

It is possible to become a server administrator through player voting process. Such admin has less abilities than logged in admin.
For example, voted in admin would be able to kick a player, but only logged in admin would be able to ban a player.
For more information on voting and voting configuration see page Server Voting.

Logged In Admin

To log in as admin, one is required to type in#login command followed by server password, which matches password defined in passwordAdmin param.
Since Arma2OA it is possible to add one or several user ids UIDs into admins[] server config parameter, which would allow listed users to log in as admin by simply typing #login without a password.
This presents several advantages for managing the servers. The server owner can have multiple admins selected from the community and doesn't have to provide each one with server admin password.
The adding and removing of UIDs is done on the server side which makes it easy to add and to remove admins if necessary. On the server, admins are handled on first come first served basis.
Here are the rules:

• If there is already a logged in admin on the server, the new admin will not be able to log in until previously logged in admin logs out
• If there is a voted in admin on the server, the logged in admin will override voted in admin and take admin role
• There is no difference between logged in admin that used admin password or logged in admin that was whitelisted with admins[] param

The logged in and voted in admins have different set of Multiplayer Server Commands available to them. See serverCommandAvailable for more information.

Server Security

Several of these settings directly contribute to the security of the server and have been highlighted as important, particularly for running public - no password - servers.

The most updated ones that give a good protection (and are, de facto, the standard for public servers) are

battlEye = 1;
verifySignatures = 2;
allowedFilePatching = 0;
allowedLoadFileExtensions[] = { "hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi" };
allowedPreprocessFileExtensions[] = { "hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi" };
allowedHTMLLoadExtensions[] = { "htm","html","xml","txt" };
// allowedHTMLLoadURIs[] = {};
passwordAdmin = "xyzxyz123";
serverCommandPassword = "xyzxyz456";

Notes

The properties allowedLoad*/allowedPreprocess*/allowedHTML* are server.cfg settings with array list of extensions for server-side use only. The above listed examples are for basic game multiplayer modes. Server admins may attempt to make it stricter for their servers. However, if too strict then server's log file will contain warning entries about unable read.

With the exception of allowedHTMLLoadURIs those arrays covers both files inside and outside PBOs so don't change the above defaults w/o testing first as there is a chance it will break the game.

• To read loadFile , preprocessFile , preprocessFileLineNumbers and to remember, those works on files only-within Arma 3 server directory and its sub-directories!
• Refer to ArmA: Addon Signatures for current best practices in server mod signing and the use of key signature files.
• To further increase servers security, remember that BattlEye has the ability to use server-side (including preventing remote execution) and client-side script check filters.
  • These BattlEye filters needs to be written specifically for each mission and mod as the scripting differs in each of them.

Safe Folder Structure

Engine supports absolute outside Arma 3 server folder for command-line parameters -servermod=, -mod= and same for profile directories and config locations. This puts those out of reach by various load script command features which are limited only within Arma 3 folder and it is sub-directories for security reason. thus e.g. safe folder-structure looks like:

• \arma3server\
• \arma3server\@publicmods\
• \arma3server_servermods_secrethash\
• \arma3server_profiles_and_configs_secrethash\

Note that callExtensions are loaded only from Arma 3 server root / sub-folders

Example Configuration File

Show text

// server.cfg

// GLOBAL SETTINGS
hostname = "Fun and Test Server";		// The name of the server that shall be displayed in the public server list
password = "";							// Password for joining, eg connecting to the server
passwordAdmin = "xyz";					// Password to become server admin. When in Arma MP and connected to the server, type '#login xyz'
serverCommandPassword = "xyzxyz";		// Password required by alternate syntax of [[serverCommand]] server-side scripting.

logFile = "server_console.log";			// Where the logfile should go and what it should be called

// WELCOME MESSAGE ("message of the day")
// It can be several lines, separated by comma
// Empty messages "" will not be displayed at all but are only for increasing the interval
motd[] = {
	"", "",
	"Two empty lines above for increasing interval",
	"Welcome to our server",
	"", "",
	"We are looking for fun - Join us Now !",
	"http://www.example.com",
	"One more empty line below for increasing interval",
	""
};
motdInterval = 5;					// Time interval (in seconds) between each message


// JOINING RULES
maxPlayers = 64;					// Maximum amount of players. Civilians and watchers, beholder, bystanders and so on also count as player.
kickDuplicate = 1;					// Each ArmA version has its own ID. If kickDuplicate is set to 1, a player will be kicked when he joins a server where another player with the same ID is playing.
verifySignatures = 2;				// Verifies .pbos against .bisign files. Valid values 0 (disabled), 1 (prefer v2 sigs but accept v1 too) and 2 (only v2 sigs are allowed).
equalModRequired = 0;				// Outdated. If set to 1, player has to use exactly the same -mod= startup parameter as the server.
allowedFilePatching = 0;			// Allow or prevent client using -filePatching to join the server. 0, is disallow, 1 is allow HC, 2 is allow all clients (since Arma 3 v1.50)
filePatchingExceptions[] = {"123456789","987654321"}; // Whitelisted Steam IDs allowed to join with -filePatching enabled
//requiredBuild = 12345;			// Require clients joining to have at least build 12345 of game, preventing obsolete clients to connect


// VOTING
voteMissionPlayers = 1;				// Tells the server how many people must connect so that it displays the mission selection screen.
voteThreshold = 0.33;				// 33% or more players need to vote for something, for example an admin or a new map, to become effective


// INGAME SETTINGS
disableVoN = 0;					// If set to 1, Voice over Net will not be available
vonCodec = 1; 					// If set to 1 then it uses IETF standard OPUS codec, if to 0 then it uses SPEEX codec (since Arma 3 update 1.58+)
vonCodecQuality = 30;			// since 1.62.95417 supports range 1-20 //since 1.63.x will supports range 1-30 //8kHz is 0-10, 16kHz is 11-20, 32kHz(48kHz) is 21-30
persistent = 1;					// If 1, missions still run on even after the last player disconnected.
timeStampFormat = "short";		// Set the timestamp format used on each report line in server-side RPT file. Possible values are "none" (default),"short","full".
BattlEye = 1;					// Server to use BattlEye system
allowedLoadFileExtensions[] = {"hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi"}; //only allow files with those extensions to be loaded via loadFile command (since Arma 3 build 1.19.124216)
allowedPreprocessFileExtensions[] = {"hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi"}; //only allow files with those extensions to be loaded via preprocessFile/preprocessFileLineNumber commands (since Arma 3 build 1.19.124323)
allowedHTMLLoadExtensions[] = {"htm","html","xml","txt"}; //only allow files with those extensions to be loaded via HTMLLoad command (since Arma 3 build 1.27.126715)
//allowedHTMLLoadURIs[] = {}; // Leave commented to let missions/campaigns/addons decide what URIs are supported. Uncomment to define server-level restrictions for URIs

// TIMEOUTS
disconnectTimeout = 5;			// Time to wait before disconnecting a user which temporarly lost connection. Range is 5 to 90 seconds.
maxDesync = 150;				// Max desync value until server kick the user
maxPing= 200;					// Max ping value until server kick the user
maxPacketLoss= 50;				// Max packetloss value until server kick the user
kickClientsOnSlowNetwork[] = { 0, 0, 0, 0 }; // Defines if {<MaxPing>, <MaxPacketLoss>, <MaxDesync>, <DisconnectTimeout>} will be logged (0) or kicked (1)
kickTimeout[] = { {0, -1}, {1, 180}, {2, 180}, {3, 180} };
votingTimeOut[] = {60, 90};		// Kicks users from server if they spend too much time in mission voting
roleTimeOut[] = {90, 120};		// Kicks users from server if they spend too much time in role selection
briefingTimeOut[] = {60, 90};	// Kicks users from server if they spend too much time in briefing (map) screen
debriefingTimeOut[] = {45, 60};	// Kicks users from server if they spend too much time in debriefing screen
lobbyIdleTimeout = 300;			// The amount of time the server will wait before force-starting a mission without a logged-in Admin.


// SCRIPTING ISSUES
onUserConnected = "";
onUserDisconnected = "";
doubleIdDetected = "";

// SIGNATURE VERIFICATION
onUnsignedData = "kick (_this select 0)";	// unsigned data detected
onHackedData = "kick (_this select 0)";		// tampering of the signature detected
onDifferentData = "";				// data with a valid signature, but different version than the one present on server detected


// MISSIONS CYCLE (see below)
randomMissionOrder = true;	// Randomly iterate through Missions list
autoSelectMission = true;	// Server auto selects next mission in cycle

class Missions {};			// An empty Missions class means there will be no mission rotation

missionWhitelist[] = {};	// An empty whitelist means there is no restriction on what missions' available

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Mission rotation

One can set an automatic mission rotation. Without an admin, the server will automatically select a mission when at least one player is connected. Once the mission is done and if there are still players on the server, it will automatically switch to the next in the cycle.

Example:

ⓘ

When difficulty is set to difficulty = "Custom"; the server will look into USERNAME.Arma3Profile file for the definition of custom difficulty, which should look like this: click to see example

class Missions
{
	class TestMission01
	{
		template = MP_Marksmen_01.Altis;
		difficulty = "veteran";
		class Params {};
	};

	class TestMission02
	{
		template = MP_End_Game_01.Altis;
		difficulty = "veteran";
		class Params {};
	};

	class TestMission03
	{
		template = MP_End_Game_02.Altis;
		difficulty = "veteran";
		class Params {};
	};

	class TestMission04
	{
		template = MP_End_Game_03.Altis;
		difficulty = "veteran";
		class Params {};
	};
};

Arma 3 Apex - Mission collection

Mainly intended for MP campaigns. If the progress is defined in the MPMissions class, server administrator can simply add the whole campaign by adding campaign class into the server.cfg. See the example below.

config.cpp:

class MPMissions
{
	class Apex
	{
		briefingName = $STR_A3_CoopCampaignName;

		class EXP_m01
		{
			briefingName = $STR_A3_exp_m01_missionname;
			directory = "a3\missions_f_exp\campaign\missions\exp_m01.tanoa";
		};

		class EXP_m02
		{
			briefingName = $STR_A3_exp_m02_missionname;
			directory = "a3\missions_f_exp\campaign\missions\exp_m02.tanoa";
		};

		class EXP_m03
		{
			briefingName = $STR_A3_exp_m03_missionname;
			directory = "a3\missions_f_exp\campaign\missions\exp_m03.tanoa";
		};
	};
};

server.cfg:

// MISSIONS CYCLE
class Missions
{
	class Apex{};
};

Also the difficulty of the each mission can be overridden

class Missions
{
	class Apex
	{
		class EXP_m01
		{
			difficulty = "veteran";
		};
	};
};

Additional details

For hosting server behind NAT or firewall, please ensure gameport and STEAMports are forwarded and open!
Set the ICMP "echo reply" as allowed so the server is able return ping delay properly.
It's recommended to enable the NAT traversal (so called "Edge traversal" in Windows Firewall) for arma3server.exe, arma3.exe to better support clients/servers behind NAT.

Overriding Mission Parameters

On dedicated server, only an admin can set mission options provided by mission maker via class Params. However as a server owner it is possible to override default setting with your own. See Mission Parameters for more info.