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Nginx HTTPS Setup

Introduction​

Securing your web applications with HTTPS is essential in today's internet landscape. HTTPS encrypts the data exchanged between your users and your server, protecting sensitive information from potential eavesdroppers and attackers. This tutorial will guide you through setting up HTTPS on your Nginx web server, a crucial step in securing your web applications.

HTTPS works by implementing SSL/TLS (Secure Sockets Layer/Transport Layer Security) protocols. These protocols create an encrypted connection between your users' browsers and your server, ensuring that all data transmitted remains private and unaltered during transfer.

Prerequisites​

Before starting with this tutorial, make sure you have:

  • A server with Nginx installed
  • A registered domain name pointing to your server
  • Root or sudo access to your server
  • Basic familiarity with terminal commands

Understanding SSL/TLS Certificates​

SSL/TLS certificates are digital files that:

  • Verify the identity of your website
  • Enable encrypted connections
  • Create trust between your users and your website

There are several types of certificates:

  1. Domain Validated (DV) - Basic verification of domain ownership
  2. Organization Validated (OV) - Includes organization verification
  3. Extended Validation (EV) - Highest level of validation

For a beginner setup, we'll focus on Domain Validated certificates, which are often free and sufficient for basic security needs.

Getting an SSL/TLS Certificate​

Let's Encrypt provides free, automated SSL/TLS certificates. We'll use Certbot to obtain and install a Let's Encrypt certificate.

Installing Certbot​

First, let's install Certbot and the Nginx plugin:

bash
# For Ubuntu/Debian systems
sudo apt update
sudo apt install certbot python3-certbot-nginx

# For CentOS/RHEL systems
sudo yum install certbot python3-certbot-nginx

Obtaining a Certificate​

Now, let's obtain a certificate for your domain:

bash
sudo certbot --nginx -d yourdomain.com -d www.yourdomain.com

Replace yourdomain.com with your actual domain name. If successful, Certbot will:

  1. Verify your domain ownership
  2. Obtain certificates
  3. Automatically configure Nginx
  4. Set up certificate renewal

The output should look something like:

Congratulations! You have successfully enabled HTTPS on
https://yourdomain.com and https://www.yourdomain.com

You should test your configuration at:
https://www.ssllabs.com/ssltest/analyze.html?d=yourdomain.com

Manual Nginx HTTPS Configuration​

While Certbot can automatically configure Nginx, understanding how to manually set up HTTPS is valuable knowledge. Here's how to configure Nginx for HTTPS:

Step 1: Create an Nginx Server Block​

Create or modify your Nginx server block configuration:

nginx
server {
    listen 80;
    server_name yourdomain.com www.yourdomain.com;
    
    # Redirect all HTTP traffic to HTTPS
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl;
    server_name yourdomain.com www.yourdomain.com;
    
    # SSL/TLS certificate paths
    ssl_certificate /etc/letsencrypt/live/yourdomain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/yourdomain.com/privkey.pem;
    
    # Document root directory
    root /var/www/yourdomain.com/html;
    index index.html index.htm;
    
    # Additional server configuration...
}

Step 2: Configure SSL Parameters​

For better security, add these SSL parameters to your HTTPS server block or in a separate file (e.g., /etc/nginx/snippets/ssl-params.conf) that you can include:

nginx
# Optimized SSL settings
ssl_protocols TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 1d;
ssl_session_tickets off;

# OCSP Stapling
ssl_stapling on;
ssl_stapling_verify on;
resolver 8.8.8.8 8.8.4.4 valid=300s;
resolver_timeout 5s;

# Security headers
add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload";
add_header X-Content-Type-Options nosniff;
add_header X-Frame-Options DENY;
add_header X-XSS-Protection "1; mode=block";

If using a separate file, include it in your server block:

nginx
server {
    listen 443 ssl;
    # Other server settings...
    
    include snippets/ssl-params.conf;
    
    # Rest of configuration...
}

Step 3: Test and Restart Nginx​

Before applying changes, test your Nginx configuration:

bash
sudo nginx -t

If the test is successful, restart Nginx:

bash
sudo systemctl restart nginx

Understanding the HTTPS Flow​

Here's a simplified diagram of how HTTPS works with Nginx:

Best Practices for Nginx HTTPS Configuration​

1. Redirect HTTP to HTTPS​

Always redirect HTTP traffic to HTTPS to ensure users are always on a secure connection:

nginx
server {
    listen 80;
    server_name yourdomain.com www.yourdomain.com;
    return 301 https://$host$request_uri;
}

2. Implement Strong Security Headers​

Security headers protect against various attacks:

nginx
add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload";
add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://www.google-analytics.com";
add_header X-Content-Type-Options nosniff;
add_header X-Frame-Options DENY;
add_header X-XSS-Protection "1; mode=block";
add_header Referrer-Policy strict-origin-when-cross-origin;

3. Use Strong Ciphers and TLS Versions​

Disable outdated protocols and ciphers:

nginx
ssl_protocols TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;

4. Configure Diffie-Hellman Parameters​

Generate and use strong DH parameters:

bash
sudo openssl dhparam -out /etc/nginx/dhparam.pem 2048

Then add to your Nginx configuration:

nginx
ssl_dhparam /etc/nginx/dhparam.pem;

5. Set Up Automated Certificate Renewal​

Let's Encrypt certificates expire after 90 days. Certbot sets up an automatic renewal process, but verify it's working correctly:

bash
sudo certbot renew --dry-run

Troubleshooting Common Issues​

Certificate Not Found​

If Nginx can't find your certificate files:

  1. Verify the paths in your configuration match the actual certificate location
  2. Check file permissions (Nginx needs read access)
  3. Ensure certificates were successfully generated

Mixed Content Warnings​

If your site shows mixed content warnings:

  1. Use a tool like Why No Padlock to identify insecure content
  2. Update resources to use HTTPS URLs
  3. Add this header to force HTTPS for all content:
nginx
add_header Content-Security-Policy "upgrade-insecure-requests";

Certificate Validation Errors​

If visitors see certificate validation errors:

  1. Verify your certificate chain is complete
  2. Ensure your domain name matches the certificate's common name or subject alternative names
  3. Check if your certificate has expired

Testing Your HTTPS Setup​

After setting up HTTPS, test your configuration:

  1. Visit your site with HTTPS (https://yourdomain.com)
  2. Check for the padlock icon in your browser
  3. Test your site with SSL Labs
  4. Verify automatic HTTP to HTTPS redirection works

Summary​

Setting up HTTPS with Nginx is a critical security measure for any website. In this tutorial, you've learned:

  • The importance of HTTPS for web security
  • How to obtain free SSL/TLS certificates with Let's Encrypt
  • How to configure Nginx for HTTPS
  • Best practices for SSL/TLS configuration
  • Troubleshooting common HTTPS issues

By implementing these steps, you've significantly improved your website's security, protected your users' data, and improved your site's reputation with both users and search engines.

Additional Resources​

Exercises​

  1. Set up HTTPS on a test domain and aim for an A+ rating on SSL Labs.
  2. Configure HTTP/2 with your HTTPS setup for improved performance.
  3. Implement HSTS preloading for your domain.
  4. Set up multiple subdomains with a wildcard certificate.
  5. Create a bash script to check certificate expiration and send alerts.

If you spot any mistakes on this website, please let me know at [email protected]. I’d greatly appreciate your feedback! :)