Proper authentication prevents unauthorized access to player accounts and protects your server from impersonation attacks and account takeovers.

Enable Online Mode

Configure proper authentication in server.properties:

server.properties Configuration:

# Enable Mojang authentication (ALWAYS true for public servers)
online-mode=true

# Prevent proxy connections
prevent-proxy-connections=false

# Enable player verification
enforce-whitelist=false

Online Mode Benefits:

Verifies players own their Minecraft accounts
Prevents name spoofing and impersonation
Maintains player UUID consistency
Required for secure plugin authentication
Enables proper whitelist/ban enforcement

Never disable online-mode on public servers. This opens your server to account theft and impersonation attacks.

Install AuthMe Plugin

Add advanced authentication features with AuthMe:

AuthMe Features:

Additional password protection
Two-factor authentication (2FA)
Session management
Login attempt monitoring
Email verification
Country-based restrictions

AuthMe Installation:

Download AuthMe from SpigotMC
Place in plugins folder and restart
Configure database connection
Set up email settings for verification
Configure security settings

Basic AuthMe commands:

/register password email  # Register account
/login password           # Login to account
/changepassword old new   # Change password
/email add email         # Add email address
/2fa add                 # Enable 2FA

Configure Two-Factor Authentication

Set up 2FA for enhanced account security:

2FA Setup in AuthMe:

# config.yml settings
Security:
  twoFactorAuthentication:
    enabled: true
    length: 6
    issuer: 'MyMinecraftServer'
    windowSize: 3

Email:
  mailSMTP: 'smtp.gmail.com'
  mailPort: 587
  mailAccount: 'server@yourdomain.com'
  mailPassword: 'your-app-password'

Player 2FA Setup:

Player uses /2fa add command
Server generates QR code link
Player scans QR with authenticator app
Player confirms with /2fa confirm CODE
2FA is now required for future logins

Set Up Login Protection

Configure advanced login security measures:

AuthMe Security Configuration:

settings:
  sessions:
    enabled: true
    timeout: 10

security:
  minPasswordLength: 8
  passwordMaxLength: 30
  preventOtherCase: true
  
restrictions:
  maxLoginPerIp: 3
  maxJoinPerIp: 4
  kickPlayersBeforeLogin: true
  allowedNicknameCharacters: '[a-zA-Z0-9_]*'
  
protection:
  enableAntiBot: true
  antiBotSensibility: 5
  antiBotDuration: 10

Login Attempt Monitoring:

Track failed login attempts per IP
Temporary IP bans after multiple failures
Alert administrators to brute force attempts
Log all authentication events

Implement Session Management

Control player sessions for better security:

Session Security Features:

Session timeout: Auto-logout after inactivity
IP binding: Sessions tied to specific IPs
Device tracking: Recognize trusted devices
Concurrent limits: One session per account

Session Commands:

# Admin session management
/authme sessions  # View active sessions
/authme logout PlayerName  # Force logout
/authme purgebannedplayers  # Clean old data

# Player session commands
/logout  # Manual logout
/session  # Check session status

Configure Country Restrictions

Block connections from specific countries if needed:

GeoIP Protection Setup:

protection:
  countries:
    enabled: true
    whitelist: 
      - 'US'
      - 'CA'
      - 'GB'
    blacklist:
      - 'CN'
      - 'RU'
  
  countryProtection:
    enableProtection: true
    isWhitelist: true
    message: 'Your country is not allowed on this server'

Alternative IP Protection:

Use VPN detection services
Block known proxy/VPN IP ranges
Implement CAPTCHA for suspicious IPs
Require email verification for new countries

Country restrictions should be used carefully as they can block legitimate players. Consider your server's target audience.

Email Verification System

Require email verification for account registration:

Email Configuration:

EmailSettings:
  mailSMTP: 'smtp.gmail.com'
  mailPort: 587
  mailAccount: 'noreply@yourdomain.com'
  mailPassword: 'your-app-password'
  mailSenderName: 'MyServer'
  
registration:
  enableEmailConfirmationSystem: true
  doubleEmailCheck: true
  emailRegistration: true
  
VerificationEmail:
  subject: 'Verify your account'
  htmlMessage: 'Click to verify: <VERIFICATION_CODE>'

Email Verification Commands:

# Player commands
/email add your@email.com  # Add email address
/email confirm CODE        # Confirm email with code
/email recover            # Request password recovery

# Admin commands
/authme email PlayerName  # Check player email
/authme verify PlayerName # Manually verify player

Monitor Authentication Events

Track and analyze authentication patterns:

Logging Configuration:

# Enable detailed logging
settings:
  logConsoleCommands: true
  logPlayerCommands: true

# Database logging
DataSource:
  backend: 'MYSQL'
  logDb: true
  
# Security event logging
Security:
  logFailedAttempts: true
  logSuccessfulLogins: true

Key Metrics to Monitor:

Failed login attempts per IP
Multiple account registrations from same IP
Rapid login/logout patterns
Unusual login times/locations
2FA bypass attempts

Best Practices

Maintain strong authentication security:

Regular updates: Keep AuthMe and related plugins current
Strong passwords: Enforce minimum complexity requirements
Backup authentication data: Secure database backups
Staff training: Train moderators on authentication systems
Regular audits: Review authentication logs weekly
Emergency procedures: Plan for compromised accounts
Clear instructions: Help players understand security features

Strong authentication is your first line of defense. Combine multiple security layers and educate your community about account security best practices.

Player Authentication Security Setup