Install NGINX with security modules

First, install NGINX and ensure it has the necessary modules for rate limiting and security headers.

sudo apt update
sudo apt install -y nginx nginx-module-http-limit-req
sudo systemctl enable nginx

sudo dnf update -y
sudo dnf install -y nginx
sudo systemctl enable nginx

Configure rate limiting zones

Create multiple rate limiting zones to handle different types of traffic patterns and attack vectors.

http {
    # Basic rate limiting zone - 10 requests per second per IP
    limit_req_zone $binary_remote_addr zone=basic:10m rate=10r/s;
    
    # Strict rate limiting for login/admin pages - 2 requests per minute
    limit_req_zone $binary_remote_addr zone=login:10m rate=2r/m;
    
    # API rate limiting - 100 requests per minute per IP
    limit_req_zone $binary_remote_addr zone=api:10m rate=100r/m;
    
    # Connection limiting - max 20 connections per IP
    limit_conn_zone $binary_remote_addr zone=conn_limit_per_ip:10m;
    
    # Request body size limiting to prevent large payload attacks
    client_max_body_size 10M;
    
    # Connection timeout settings
    client_body_timeout 12;
    client_header_timeout 12;
    send_timeout 10;
    
    # Buffer size limits
    client_body_buffer_size 16K;
    client_header_buffer_size 1k;
    large_client_header_buffers 2 1k;
    
    include /etc/nginx/sites-enabled/*;
}

Configure security headers

Add comprehensive security headers to protect against XSS, clickjacking, and other web-based attacks.

# Security headers configuration
add_header X-Frame-Options "SAMEORIGIN" always;
add_header X-XSS-Protection "1; mode=block" always;
add_header X-Content-Type-Options "nosniff" always;
add_header Referrer-Policy "no-referrer-when-downgrade" always;
add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

Hide NGINX version
server_tokens off;

Rate limiting status codes
limit_req_status 429;
limit_conn_status 429;

Create DDoS protection configuration

Configure specific protection rules for common DDoS attack patterns and slow HTTP attacks.

# DDoS Protection Configuration

Block common attack patterns
map $http_user_agent $limit_bots {
    ~*(google|bing|yandex|msnbot) "";
    ~*(AhrefsBot|MJ12bot|DotBot) $binary_remote_addr;
    ~*(SemrushBot|BLEXBot|DomainStatsBot) $binary_remote_addr;
    default "";
}

Rate limit suspicious bots
limit_req_zone $limit_bots zone=bots:10m rate=1r/m;

Slow HTTP attack protection
client_body_timeout 5s;
client_header_timeout 5s;

Connection flood protection
limit_conn_zone $server_name zone=perserver:10m;

Geographic blocking (example)
map $geoip_country_code $allowed_country {
    default yes;
    CN no;  # Block China
    RU no;  # Block Russia
    # Add more countries as needed
}

Configure virtual host with protection

Apply the rate limiting and security measures to your specific virtual hosts.

server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;
    
    # Include security headers
    include /etc/nginx/conf.d/security-headers.conf;
    include /etc/nginx/conf.d/ddos-protection.conf;
    
    # Apply connection limits
    limit_conn conn_limit_per_ip 20;
    limit_conn perserver 200;
    
    # Basic rate limiting for all requests
    limit_req zone=basic burst=20 nodelay;
    
    # Block based on geographic location
    if ($allowed_country = no) {
        return 403;
    }
    
    # Block suspicious bots
    limit_req zone=bots burst=2 nodelay;
    
    # Special protection for admin/login pages
    location ~ ^/(admin|login|wp-admin) {
        limit_req zone=login burst=5 nodelay;
        
        # Additional security for admin areas
        deny 192.168.1.0/24;  # Block internal networks if needed
        allow 203.0.113.0/24; # Allow specific IP ranges
        deny all;
        
        try_files $uri $uri/ =404;
    }
    
    # API endpoint protection
    location /api/ {
        limit_req zone=api burst=50 nodelay;
        
        # CORS headers for API
        add_header 'Access-Control-Allow-Origin' '$http_origin';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization';
        
        try_files $uri $uri/ =404;
    }
    
    # Static file caching and protection
    location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff|woff2|ttf|svg)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        limit_req zone=basic burst=50 nodelay;
    }
    
    # Block access to sensitive files
    location ~ /\. {
        deny all;
    }
    
    location ~ ~$ {
        deny all;
    }
    
    # Main location block
    location / {
        try_files $uri $uri/ =404;
    }
    
    # Error page customization to hide server info
    error_page 403 /403.html;
    error_page 404 /404.html;
    error_page 429 /429.html;
    error_page 500 502 503 504 /50x.html;
    
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}

Create custom error pages

Configure custom error pages to avoid revealing server information during attacks.

sudo mkdir -p /var/www/html/error-pages

    
    


    
Too Many Requests
    
Please slow down and try again later.

Configure logging for monitoring

Set up detailed logging to monitor attack attempts and rate limiting effectiveness.

# Custom log format for security monitoring
log_format security_log '$remote_addr - $remote_user [$time_local] '
                       '"$request" $status $body_bytes_sent '
                       '"$http_referer" "$http_user_agent" '
                       'rt=$request_time uct="$upstream_connect_time" '
                       'uht="$upstream_header_time" urt="$upstream_response_time" '
                       'limit_req_status=$limit_req_status';

Security access log
access_log /var/log/nginx/security.log security_log;

Enable and test configuration

Activate the site configuration and test all protection mechanisms.

sudo ln -s /etc/nginx/sites-available/protected-site /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

Set up fail2ban integration

Configure fail2ban to automatically ban IPs that trigger rate limits repeatedly.

sudo apt install -y fail2ban

sudo dnf install -y fail2ban

[nginx-rate-limit]
enabled = true
port = http,https
logpath = /var/log/nginx/security.log
failregex = limiting requests, excess:. by zone . client: 
findtime = 300
bantime = 600
maxretry = 5

sudo systemctl enable --now fail2ban
sudo systemctl status fail2ban

Load testing verification

Use a simple load testing tool to verify rate limiting works correctly.

# Install Apache Bench for testing
sudo apt install -y apache2-utils  # Ubuntu/Debian
sudo dnf install -y httpd-tools  # AlmaLinux/Rocky

Test rate limiting - should show 429 errors
ab -n 100 -c 10 http://example.com/

Check the results in logs
sudo grep "429" /var/log/nginx/access.log

Create monitoring script

Set up automated monitoring to track attack attempts and system performance.

#!/bin/bash

NGINX Security Monitoring Script
LOG_FILE="/var/log/nginx/security.log"
REPORT_FILE="/var/log/nginx/security-report.txt"

echo "NGINX Security Report - $(date)" > $REPORT_FILE
echo "=====================================" >> $REPORT_FILE

Count rate limit violations in last hour
RATE_LIMITS=$(grep "$(date '+%d/%b/%Y:%H')" $LOG_FILE | grep -c "429")
echo "Rate limit violations in last hour: $RATE_LIMITS" >> $REPORT_FILE

Top attacking IPs
echo "\nTop attacking IPs:" >> $REPORT_FILE
grep "429" $LOG_FILE | awk '{print $1}' | sort | uniq -c | sort -nr | head -10 >> $REPORT_FILE

fail2ban status
echo "\nfail2ban banned IPs:" >> $REPORT_FILE
fail2ban-client status nginx-rate-limit >> $REPORT_FILE

echo "Report saved to: $REPORT_FILE"

sudo chmod +x /usr/local/bin/nginx-security-monitor.sh

Run monitoring script
sudo /usr/local/bin/nginx-security-monitor.sh

Set up automated reporting

Configure cron to run security monitoring and send reports.

# Add to cron for hourly monitoring
echo "0     root /usr/local/bin/nginx-security-monitor.sh" | sudo tee -a /etc/crontab

Implement request fingerprinting

Use advanced detection based on request patterns and user behavior.

# Advanced request fingerprinting
map $http_user_agent $suspicious_ua {
    default 0;
    ~*python 1;
    ~*curl 1;
    ~*wget 1;
    "" 1;  # Empty user agent
}

Combine multiple factors for scoring
map "$suspicious_ua:$request_method" $risk_score {
    default 0;
    ~1:POST 2;
    ~1:GET 1;
}

Rate limit based on risk score
limit_req_zone $binary_remote_addr zone=high_risk:10m rate=1r/s;
limit_req_zone $binary_remote_addr zone=medium_risk:10m rate=5r/s;

Configure SSL-specific protection

Add protection for HTTPS traffic and SSL-specific attacks.

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name example.com;
    
    # SSL Configuration
    ssl_certificate /path/to/certificate.pem;
    ssl_certificate_key /path/to/private-key.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-RSA-AES256-GCM-SHA512:DHE-RSA-AES256-GCM-SHA512:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;
    
    # SSL-specific rate limiting
    limit_req zone=basic burst=10 nodelay;
    
    # Include all security configurations
    include /etc/nginx/conf.d/security-headers.conf;
    include /etc/nginx/conf.d/ddos-protection.conf;
    include /etc/nginx/conf.d/advanced-protection.conf;
    
    location / {
        # Apply risk-based rate limiting
        if ($risk_score = 2) {
            limit_req zone=high_risk burst=2 nodelay;
        }
        if ($risk_score = 1) {
            limit_req zone=medium_risk burst=5 nodelay;
        }
        
        try_files $uri $uri/ =404;
    }
}