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Overview

The LoginServer handles player authentication, account management, and maintains the list of available game servers. Players connect to the LoginServer first, authenticate, then are redirected to the selected GameServer.

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Architecture

Player Client
     |
     v
LoginServer (port 2106)
     |
     +-- Authenticates player
     +-- Shows server list
     +-- Redirects to GameServer
     |
     v
GameServer (port 7777)

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Network Configuration

Edit login/config/Server.ini to configure LoginServer networking: 
# ---------------------------------------------------------------------------
# Login Server Networking
# ---------------------------------------------------------------------------

# Client connection settings
# Bind address for player client connections
LoginserverHostname = 0.0.0.0
LoginserverPort = 2106

# GameServer connection settings
# Where GameServers connect to register
LoginHostname = 127.0.0.1
LoginPort = 9014
From login/config/Server.ini:19-32, these settings control both client and GameServer connections.

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Port Configuration

PortProtocolPurposeConfigurable
2106TCPPlayer client authenticationYes (LoginserverPort)
9014TCPGameServer registrationYes (LoginPort)
Ensure port 2106 is open in your firewall for incoming client connections.
# Linux firewall example
sudo ufw allow 2106/tcp
sudo ufw allow 9014/tcp

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Security Configuration

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Failed Login Protection

Protect against brute-force attacks: 
# ---------------------------------------------------------------------------
# Security Settings
# ---------------------------------------------------------------------------

# Maximum failed login attempts before IP ban
LoginTryBeforeBan = 5

# Ban duration in seconds (900 = 15 minutes)
LoginBlockAfterBan = 900

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Flood Protection

Defend against connection flooding: 
# Enable flood protection
EnableFloodProtection = True

# Fast connection limit (connections in FastConnectionTime)
FastConnectionLimit = 15

# Normal connection interval (milliseconds)
NormalConnectionTime = 700

# Fast connection interval (milliseconds)
FastConnectionTime = 350

# Maximum connections per IP address
MaxConnectionPerIP = 50
From login/config/Server.ini:52-78, these settings prevent connection exhaustion attacks.

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Account Management

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Auto Account Creation

Allow automatic account creation on first login: 
# ---------------------------------------------------------------------------
# Account Settings
# ---------------------------------------------------------------------------

# Automatically create accounts when logging in
# True = players can create accounts from client
# False = accounts must be created manually
AutoCreateAccounts = True

# Display EULA/license after login
ShowLicence = True
For public servers, consider setting AutoCreateAccounts = False and manually manage accounts for better security.

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Manual Account Creation

If AutoCreateAccounts = False, create accounts manually: 
-- Connect to database
mysql -u l2jmobius -p l2jmobiusc4

-- Create account
INSERT INTO accounts (login, password, access_level, lastServer)
VALUES ('username', SHA1('password'), 0, 1);

-- Create GM account (access_level = 100)
INSERT INTO accounts (login, password, access_level, lastServer)
VALUES ('gmaccount', SHA1('gmpassword'), 100, 1);
Or use the AccountManager tool: 
cd login
./AccountManager.sh

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Game Server Registration

GameServers must be registered with the LoginServer before they can accept players.
1

Enable GameServer Registration

In login/config/Server.ini:
# Allow new GameServers to register
# True = any server can register on free slots
# False = only pre-registered servers allowed
AcceptNewGameServer = True
2

Register GameServer

If AcceptNewGameServer = True, start the GameServer and it will automatically register.
cd game
./GameServer.sh
The GameServer will:
  1. Connect to LoginServer on port 9014
  2. Request server ID (from game/config/Server.ini:42)
  3. Receive hexid authentication key
  4. Save to game/config/hexid.txt
3

Verify Registration

Check the database:
USE l2jmobiusc4;
SELECT * FROM gameservers;
You should see your registered GameServer with:
  • server_id: Your server ID
  • hexid: Authentication key
  • host: GameServer IP binding
4

Configure GameServer

Ensure game/config/Server.ini matches the registered server:
# Must match registered server ID
RequestServerID = 1

# LoginServer connection (must match login/config/Server.ini)
LoginHost = 127.0.0.1
LoginPort = 9014

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Thread Configuration

Optimize LoginServer thread pools in login/config/Threads.ini: 
# ---------------------------------------------------------------------------
# Thread Configuration
# ---------------------------------------------------------------------------

# Scheduled thread pool size
# -1 = auto-configure based on CPU cores / 2
ScheduledThreadPoolSize = 2

# Instant thread pool size
# -1 = auto-configure based on CPU cores / 2
InstantThreadPoolSize = 2
LoginServer requires fewer threads than GameServer since it only handles authentication, not game logic.

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Startup Configuration

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Starting the LoginServer

cd login

# Make scripts executable (first time only)
chmod +x LoginServer.sh LoginServerTask.sh

# Start server
./LoginServer.sh

# Or run in background
nohup ./LoginServer.sh &

# View logs
tail -f log/stdout.log
The LoginServerTask.sh at login/LoginServerTask.sh:8 handles:
  • Automatic restart on crash
  • Log rotation
  • JVM configuration from java.cfg

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JVM Configuration

Edit login/java.cfg to adjust memory settings: 
-server 
-Dfile.encoding=UTF-8 
-Dorg.slf4j.simpleLogger.log.com.zaxxer.hikari=warn 
-XX:+UseZGC 
-Xms128m     # Initial heap: 128MB
-Xmx256m     # Maximum heap: 256MB
LoginServer requires minimal memory compared to GameServer. Default settings (128-256MB) are sufficient for most servers.

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Scheduled Restart

Configure automatic LoginServer restarts: 
# ---------------------------------------------------------------------------
# Scheduled Login Restart
# ---------------------------------------------------------------------------

# Enable scheduled restart
LoginRestartSchedule = False

# Restart interval in hours
LoginRestartTime = 24
LoginServer restarts are typically coordinated with GameServer maintenance windows.

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Health Checks

Verify LoginServer is running correctly:

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Check Server Process

# Linux - check if LoginServer is running
ps aux | grep LoginServer

# Check if ports are listening
netstat -tlnp | grep 2106  # Client port
netstat -tlnp | grep 9014  # GameServer port

# Alternative using ss
ss -tlnp | grep -E '(2106|9014)'

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Monitor Logs

# Real-time log monitoring
tail -f login/log/stdout.log

# Check for errors
grep -i error login/log/*.log
grep -i exception login/log/*.log

# Check authentication attempts
grep -i "login" login/log/stdout.log

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Test Connectivity

# Test client port
telnet localhost 2106

# Test GameServer registration port
telnet localhost 9014

# Using netcat
nc -zv localhost 2106
nc -zv localhost 9014

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Verify GameServer Connection

Check if GameServer is connected: 
# Check LoginServer logs for GameServer registration
grep -i "gameserver" login/log/stdout.log

# Verify in database
mysql -u l2jmobius -p l2jmobiusc4 -e "SELECT server_id, host FROM gameservers;"

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Server List Configuration

The LoginServer presents a list of available GameServers to authenticated players. Configuration is split between LoginServer and GameServer.

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LoginServer Side

In login/config/Server.ini: 
# Accept new game servers on free slots
AcceptNewGameServer = True

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GameServer Side

In game/config/Server.ini: 
# Server display settings
ServerListType = Free        # Server type badge
ServerListAge = 0            # Age restriction (0, 15, 18)
ServerListBrackets = False   # Show [] before name
ServerListClock = False      # Show clock icon

# Server capacity
MaximumOnlineUsers = 3500

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Configuration Files Summary

Key configuration files in login/config/:
FilePurpose
Server.iniCore server settings, ports, security
Database.iniDatabase connection configuration
Threads.iniThread pool settings
Interface.iniInterface configuration

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Troubleshooting

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LoginServer Won’t Start

  1. Check Java version: 
    java -version
# Must be Java 25
  2. Verify database connection: 
    # Test connection
mysql -u l2jmobius -p l2jmobiusc4

# Check tables exist
SHOW TABLES LIKE 'accounts';
SHOW TABLES LIKE 'gameservers';
  3. Check port availability: 
    # Ensure ports are not in use
netstat -tlnp | grep -E '(2106|9014)'
  4. Review logs: 
    cat login/log/stdout.log

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GameServer Can’t Register

Error: “Connection refused” to LoginServer
  1. Verify LoginServer is running: 
    ps aux | grep LoginServer
  2. Check LoginServer port is listening: 
    netstat -tlnp | grep 9014
  3. Verify game/config/Server.ini has correct LoginServer address: 
    LoginHost = 127.0.0.1  # Use actual IP if not on same machine
LoginPort = 9014
  4. Check login/config/Server.ini allows registration: 
    AcceptNewGameServer = True

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Clients Can’t Connect

Error: “Cannot connect to LoginServer”
  1. Check LoginServer is running: 
    netstat -tlnp | grep 2106
  2. Verify firewall allows port 2106: 
    sudo ufw status
sudo ufw allow 2106/tcp
  3. Check client configuration:
    • Ensure client is pointed to correct LoginServer IP
    • Verify protocol version matches (AllowedProtocolRevisions in GameServer)

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Failed Login Attempts

Error: “Account is banned” or “Invalid password”
  1. Check account in database: 
    SELECT login, access_level, lastactive FROM accounts WHERE login = 'username';
  2. Check IP ban: 
    -- Check for IP-based restrictions
SELECT * FROM accounts_ipauth;
  3. Reset ban counter:
    • Wait for LoginBlockAfterBan duration (default 15 minutes)
    • Or restart LoginServer to clear temporary bans

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Production Checklist

Before going live:
  • Set AutoCreateAccounts = False for security
  • Configure proper LoginTryBeforeBan and flood protection
  • Enable ShowLicence = True with your server terms
  • Set AcceptNewGameServer = False after registration
  • Configure database backups
  • Set up monitoring for ports 2106 and 9014
  • Test authentication from external network
  • Verify GameServer registration and connectivity
  • Configure firewall rules
  • Set up log rotation

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Next Steps

With the LoginServer configured:
  1. Configure the GameServer
  2. Review all configuration files
  3. Test the complete authentication flow

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