Joining a Game

Overview

This guide explains how to join multiplayer servers in Nitrox Unlocked, whether you’re connecting to a friend’s server, a LAN server, or a dedicated public server.

Prerequisites

Required

Nitrox Unlocked installed
Subnautica (base game)
Same Nitrox version as server
Same Subnautica version as server

Network Info Needed

Server IP address (for direct connect)
Server port (default: 11000)
Server password (if required)

Connection Methods

There are three ways to connect to a server:

1. LAN Discovery (Local Network)

For servers on your local network:

Launch Nitrox

Start the Nitrox Launcher and launch Subnautica with multiplayer enabled.

Open Join Server Menu

In the main menu, navigate to the multiplayer/join server section.

Select from LAN Servers

Available LAN servers should appear automatically in the server list.Source: LANBroadcastClient.cs:38-50 - LAN discovery searches for servers via UDP broadcast

Click to Connect

Select the server and click “Join” or “Connect”.

LAN discovery requires the server to have LANDiscoveryEnabled=true in its configuration.

How LAN Discovery Works: The client broadcasts discovery requests on predefined ports. Servers with LAN discovery enabled respond with their connection information. Source: LANBroadcastClient.cs:52-143

// Client searches for servers every 5 seconds
while (!cancellationToken.IsCancellationRequested)
{
    NetDataWriter writer = new();
    writer.Put(LANDiscoveryConstants.BROADCAST_REQUEST_STRING);
    foreach (int port in LANDiscoveryConstants.BROADCAST_PORTS)
    {
        client.SendBroadcast(writer, port);
    }
    await Task.Delay(5000, cancellationToken);
}

2. Direct IP Connection

For internet servers or manual connection:

Launch Nitrox

Start the Nitrox Launcher and launch Subnautica with multiplayer.

Select Direct Connect

Choose “Direct Connect” or “Add Server” option.

Enter Server Details

Input the server information:

Server Name: Friendly name (your choice)
IP Address: Server’s IP
Port: Server port (default: 11000)

Name: My Local Server
IP: 127.0.0.1
Port: 11000

Save and Connect

Save the server entry and click connect.

Source: ServerList.cs:92-156 - Server entries are stored in format: Name|Address|Port

3. Saved Server List

Once you’ve connected to a server, it’s saved for easy reconnection:

Open Server List

In the multiplayer menu, view your saved servers.

Select Server

Choose from your previously connected servers.

Connect

Click connect to join.

Server List Location:

%AppData%\Nitrox\servers

Source: ServerList.cs:11,27 - Default port is 11000

public const int DEFAULT_PORT = 11000;
public static string DefaultFile => Path.Combine(NitroxUser.AppDataPath, SERVERS_FILE_NAME);

Connection Process

Understanding what happens when you connect:

Client Starts Connection

The client attempts to connect to the server IP and port via UDP.Source: Disconnected.cs:52-63

Version Check

Server and client verify they’re running compatible Nitrox versions.Source: MultiplayerSessionManager.cs:59-84

switch (nitroxVersion.CompareTo(SessionPolicy.NitroxVersionAllowed))
{
case -1:
    Log.Error($"Client is out of date. Server: {ServerVersion}, Client: {localVersion}");
    CurrentState.Disconnect(this);
    return;
case 1:
    Log.Error($"Server is out of date...");
    CurrentState.Disconnect(this);
    return;
}

Session Policy Exchange

Server sends session policy including:

Console disable settings
Server rules
Authentication requirements

Source: MultiplayerSessionManager.cs:59-84

Player Authentication

You provide:

Player name
Server password (if required)
Color preferences

Source: MultiplayerSessionManager.cs:86-91

Session Reservation

Server reserves a slot for you and sends reservation confirmation.Source: MultiplayerSessionManager.cs:93-97

Initial World Sync

The server sends world data:

World state
Other players’ positions
Built structures
Game time

This can take time depending on world size and connection speed.

Join Complete

You spawn into the multiplayer world!Source: MultiplayerSessionManager.cs:99-102

Authentication & Permissions

Player Name Selection

When connecting, you’ll choose your player name:

Used for identification in-game
Shown in server logs
Persists across sessions

Server Password

If the server has a password:

# Server configuration
ServerPassword=MyPassword123

You must enter the correct password to join.

Permission Levels

Servers can have different permission levels: Source: Perms.cs:5-27

public enum Perms : byte
{
    NONE,        // No permissions
    PLAYER,      // Default - basic commands, no cheats
    MODERATOR,   // Manage players, use vanilla cheats
    ADMIN,       // Full server administration
    CONSOLE      // All permissions (console only)
}

Default Permission:

New players get PLAYER permission by default
Can be changed in server config: DefaultPlayerPerm=PLAYER

Localhost Exception:

Players connecting from 127.0.0.1 get admin by default
Controlled by: LocalhostIsAdmin=true

Source: SubnauticaServerConfig.cs:104-105

Getting Admin Access

To get admin permissions on a server:

In-Game Console
Server-Side Grant
Localhost Auto-Admin

If you have the admin password:

# Open console (usually F3 or ~)
admin <password>

Server admin can promote you:

# In server console
op <playername>
# or
promote <playername> <PLAYER|MODERATOR|ADMIN>

If running client on same machine as server:

Connect using 127.0.0.1
Automatically granted admin (if LocalhostIsAdmin=true)

Troubleshooting Connection Issues

Version mismatch error

Error: “Client is out of date” or “Server is out of date”Solution:

Ensure you and the server are using the same Nitrox version
Update Nitrox client or ask server admin to update
Verify Subnautica game version also matches

Connection timeout

Symptoms: “Connecting…” then timeout or failure.Solutions:

Verify server is online
- Ask server admin to confirm server is running
Check IP and port
- Ensure you have the correct IP address
- Verify port number (default: 11000)
- Try pinging the server: ping <server_ip>
Network issues
- Server may have port forwarding misconfigured
- Your firewall may be blocking outbound connections
- ISP may be blocking UDP traffic

Wrong password

Error: Authentication failed or access denied.Solution:

Double-check the password (case-sensitive)
Ensure you’re using the server password, not admin password
Ask server admin to verify current password

Stuck on 'Loading world' screen

Symptoms: Connection succeeds but world never finishes loading.Possible Causes:

Large world with many entities
Slow internet connection
Server’s InitialSyncTimeout too short

Solutions:

Wait longer (can take 2-5 minutes for large worlds)
Ask server admin to increase InitialSyncTimeout:
```
InitialSyncTimeout=300000  # 5 minutes
```
Check your network connection quality

Server not appearing in LAN list

Solutions:

Verify LAN discovery is enabled on server:
```
LANDiscoveryEnabled=true
```
Use direct IP connection instead
- Even on LAN, you can manually enter the server IP
Check network
- Ensure you’re on the same subnet
- Check firewall isn’t blocking broadcast packets

Disconnected during gameplay

Possible Causes:

Network instability
Server crash
Server kicked/banned you
Excessive lag/timeout

Solutions:

Check your internet connection
Verify server is still running
Check server logs for kick/ban messages
Reduce network load (close downloads, streaming, etc.)

Finding Servers

Public Server Lists

Nitrox doesn’t have an official public server browser. Servers are typically found through community channels.

Where to find servers:

Nitrox Discord community
Subnautica multiplayer forums
Reddit communities
Steam discussions
Friend invites

Hosting Your Own

Want to create your own server for friends?

Host a Server

Learn how to set up and run your own Nitrox server

Connection Best Practices

Before Connecting

Verify Nitrox version matches server
Check you have server IP and port
Prepare password if needed
Close bandwidth-heavy apps

During Connection

Wait patiently during world sync
Don’t spam reconnect if it fails
Monitor your network connection
Check game logs if issues occur

Performance Tips

Use wired connection over WiFi
Close unnecessary background apps
Update graphics drivers
Lower in-game settings if needed

Etiquette

Respect server rules
Don’t grief other players’ builds
Communicate with teammates
Report bugs to server admin

Understanding Connection States

The client goes through several connection states: Source: MultiplayerSessionConnectionStage.cs and MultiplayerSessionManager.cs:122-139

DISCONNECTED - Not connected
ESTABLISHING_SESSION_POLICY - Negotiating rules
AWAITING_SESSION_RESERVATION - Requesting slot
SESSION_RESERVED - Slot confirmed
JOINING_SESSION - Loading world
JOINED - In game!

public void UpdateConnectionState(IMultiplayerSessionConnectionState sessionConnectionState)
{
    Log.Debug($"Updating session stage from '{fromStage}' to '{sessionConnectionState.CurrentStage}'");
    CurrentState = sessionConnectionState;
    ConnectionStateChanged?.Invoke(CurrentState);
}

Client Log Files

If you encounter issues, check client logs:

%AppData%\Nitrox\logs\game-[PlayerName]-[Date].log

Source: Log.cs:91,162-171 Logs include:

Connection attempts
Version checks
Authentication status
Error messages
Network events

Quick Connection Reference

Connection Type	IP Format	Port	Discovery
Localhost	`127.0.0.1`	11000	Manual
LAN	`192.168.x.x`	11000	Auto/Manual
Internet	Public IP	11000	Manual
Custom Port	Any valid IP	Custom	Manual

When in doubt, use direct IP connection. It’s the most reliable method and works for all server types.

Get Started

Features

Guides

Development

Overview

Prerequisites

Required

Network Info Needed

Connection Methods

1. LAN Discovery (Local Network)

2. Direct IP Connection

3. Saved Server List

Connection Process

Authentication & Permissions

Player Name Selection

Server Password

Permission Levels

Getting Admin Access

Troubleshooting Connection Issues

Finding Servers

Public Server Lists

Hosting Your Own

Host a Server

Connection Best Practices

Before Connecting

During Connection

Performance Tips

Etiquette

Understanding Connection States

Client Log Files

Quick Connection Reference

Next Steps

Troubleshooting

Host Your Own Server

Build docs developers (and LLMs) love

Get Started

Features

Guides

Development

​Overview

​Prerequisites

Required

Network Info Needed

​Connection Methods

​1. LAN Discovery (Local Network)

​2. Direct IP Connection

​3. Saved Server List

​Connection Process

​Authentication & Permissions

​Player Name Selection

​Server Password

​Permission Levels

​Getting Admin Access

​Troubleshooting Connection Issues

​Finding Servers

​Public Server Lists

​Hosting Your Own

Host a Server

​Connection Best Practices

Before Connecting

During Connection

Performance Tips

Etiquette

​Understanding Connection States

​Client Log Files

​Quick Connection Reference

​Next Steps

Troubleshooting

Host Your Own Server

Build docs developers (and LLMs) love

Overview

Prerequisites

Connection Methods

1. LAN Discovery (Local Network)

2. Direct IP Connection

3. Saved Server List

Connection Process

Authentication & Permissions

Player Name Selection

Server Password

Permission Levels

Getting Admin Access

Troubleshooting Connection Issues

Finding Servers

Public Server Lists

Hosting Your Own

Connection Best Practices

Understanding Connection States

Client Log Files

Quick Connection Reference

Next Steps