How to Protect Your Game Server from DDoS Attacks

Why Game Servers Are Targeted

Game servers are common targets for DDoS attacks because they run on known ports, require low-latency connections, and disruption is immediately noticeable to players. Competitors, disgruntled players, or trolls may target your server.

Basic Protection

Firewall Rules

# Only allow necessary ports
sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow 22/tcp          # SSH
sudo ufw allow GAME_PORT/udp   # Your game port
sudo ufw enable

Rate Limiting with iptables

# Limit connections per IP to game port
sudo iptables -A INPUT -p udp --dport GAME_PORT -m connlimit --connlimit-above 5 -j DROP

# Rate limit new connections
sudo iptables -A INPUT -p udp --dport GAME_PORT -m recent --set --name GAME
sudo iptables -A INPUT -p udp --dport GAME_PORT -m recent --update --seconds 10 --hitcount 20 --name GAME -j DROP

Fail2Ban for Game Servers

While Fail2Ban is typically used for SSH, you can create custom jails for game server abuse:

sudo tee /etc/fail2ban/jail.d/gameserver.conf <<EOF
[gameserver]
enabled = true
port = GAME_PORT
protocol = udp
filter = gameserver
logpath = /path/to/game/logs
maxretry = 50
findtime = 60
bantime = 3600
EOF

Keep Your IP Private

• Use a separate IP for SSH management vs game traffic if possible
• Do not share your server IP on public forums without protection
• Consider using a proxy service for game traffic

If You Are Under Attack

1. Identify the attack type (volumetric, protocol, application)
2. Check your server logs and ss -tunp
3. Temporarily restrict traffic to known player IPs
4. Contact your hosting provider for upstream mitigation