How to protect game servers UDP port traffic using Nginx

You can use Nginx to protect UDP traffic from DDoS attacks its not just for web based traffic what uses TCP ports.

Here is a example of how you can protect game servers that run on UDP ports using Nginx to prevent DDoS attacks it can be Minecraft, Counter Strike, Team fortress PUBG etc.

Nginx.conf

stream {
    # Memory Zone to Limit concurrent connections per IP
    limit_conn_zone $binary_remote_addr zone=udp_addr:100m;

    # Upstream to your internal Steam game server
    upstream game_servers {
        hash $remote_addr:$remote_port consistent; # Ensures consistent routing
        server 127.0.0.1:27020; # Replace with your game server internal IP make sure the port game server uses is private and not public Nginx should be the only public port
    }

    server {
        listen 27015 udp reuseport; # Listen on UDP 27015
        proxy_pass game_servers;
        
        # Optimization for game traffic
        proxy_timeout 60s; 
        proxy_responses 0; # Important: Forward all responses
        
        # Limit connections per IP address to 10 Connections.
        limit_conn udp_addr 10;
        
        # Limit speed to 50k per second
        proxy_download_rate 50k;
        proxy_upload_rate 50k;
    }
}