How to Secure Nginx with Let’s Encrypt SSL on Ubuntu (with Auto-renewal)

ByAkensai

Learning how to secure Nginx with Let’s Encrypt SSL on Ubuntu (with auto-renewal) is one of the most important things you can do for your web server. Without HTTPS, browsers flag your site as “Not Secure.” Visitors leave. Search rankings drop. Free SSL certificates from Let’s Encrypt solve this problem completely. They’re trusted by all major browsers, take only minutes to set up, and renew automatically. In this tutorial, you’ll install Certbot, configure SSL for Nginx, and set up a cron job so your certificate never expires. By the end, your site will serve traffic over HTTPS with zero manual maintenance required.

Prerequisites for How to Secure Nginx with Let’s Encrypt SSL on Ubuntu

Before you start, make sure you have the following in place:

– Ubuntu 20.04 or 22.04 , This guide works on both versions.
– Nginx installed and running , Your web server must already be active.
– A domain name , You need a real domain pointed at your server’s IP address. DNS must be fully propagated before certificates will issue.
– Root or sudo access , All commands require elevated privileges.
– Port 80 and 443 open , Let’s Encrypt validates your domain over HTTP. Check your firewall settings first.
– Estimated time: 15–20 minutes.

If you haven’t installed Nginx yet, run:

sudo apt update
sudo apt install nginx -y
sudo systemctl enable nginx
sudo systemctl start nginx

You can verify Nginx is running with sudo systemctl status nginx. Once everything above is confirmed, you’re ready to proceed.

Step-by-Step Guide to Secure Nginx with Let’s Encrypt SSL on Ubuntu

This event shares similarities with: How to Set Up Automated Mysql Database Backups with Cron Jobs

Follow these steps carefully. Each one builds on the last.

Step 1: Update Your Package List

Always start with a fresh package index. This ensures you install the latest version of Certbot.

sudo apt update && sudo apt upgrade -y

Step 2: Install Certbot and the Nginx Plugin

Certbot is the official client for Let’s Encrypt. The Nginx plugin handles all the configuration changes automatically.

sudo apt install certbot python3-certbot-nginx -y

Step 3: Confirm Your Nginx Server Block

Certbot needs to find your domain in your Nginx configuration. Open your server block file:

sudo nano /etc/nginx/sites-available/yourdomain.com

Make sure the server_name directive includes your domain:

server {
    listen 80;
    server_name yourdomain.com www.yourdomain.com;
    root /var/www/yourdomain.com/html;
    index index.html index.htm;
}

Save the file and test your Nginx config:

sudo nginx -t
sudo systemctl reload nginx

Step 4: Open the Firewall for HTTPS

If you’re using UFW, allow HTTPS traffic:

sudo ufw allow 'Nginx Full'
sudo ufw delete allow 'Nginx HTTP'

The Nginx Full profile allows both port 80 and 443. Removing the HTTP-only rule keeps things clean.

Step 5: Obtain Your SSL Certificate

Run Certbot with the Nginx plugin. Replace yourdomain.com with your actual domain:

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

Certbot will ask for your email address and prompt you to agree to the terms of service. It will then verify your domain and install the certificate. When asked about HTTP-to-HTTPS redirects, choose option 2 to redirect all traffic automatically. This is the recommended setting.

Step 6: Verify the SSL Certificate

Once Certbot finishes, open your browser and visit https://yourdomain.com. You should see a padlock icon in the address bar. You can also verify from the terminal:

sudo certbot certificates

This lists all installed certificates, their domains, and expiry dates.

Step 7: Set Up Automatic Certificate Renewal

Let’s Encrypt certificates expire every 90 days. Certbot installs a systemd timer by default on Ubuntu 20.04 and later. Check if it’s active:

sudo systemctl status certbot.timer

You should see it listed as active (waiting). This timer runs twice daily and renews any certificate expiring within 30 days. To test the renewal process without actually renewing:

sudo certbot renew --dry-run

If you see “Congratulations, all renewals succeeded,” auto-renewal is working correctly. If the timer isn’t present, add a cron job manually:

sudo crontab -e

Add this line at the bottom:

0 3    /usr/bin/certbot renew --quiet

This runs the renewal check every day at 3:00 AM.

Troubleshooting Common Issues When You Secure Nginx with Let’s Encrypt SSL

Things don’t always go smoothly. Here are the most common problems and how to fix them.

Error: “Could not bind to IPv4 or IPv6”
This means something is already using port 80. Stop Apache if it’s running: sudo systemctl stop apache2. Then retry Certbot.

Error: “DNS problem: NXDOMAIN”
Your domain’s DNS records aren’t pointing to your server yet. Use dig yourdomain.com to check. Wait for DNS propagation and try again.

Error: “The client lacks sufficient authorization”
Your firewall is blocking port 80. Run sudo ufw allow 80 temporarily, get your certificate, then restrict it again.

Certificate not renewing automatically
Check the Certbot timer: sudo systemctl list-timers | grep certbot. If it’s missing, use the cron job method from Step 7.

Nginx config errors after Certbot runs
Always test with sudo nginx -t after any SSL changes. If something breaks, Certbot backs up your original config. Check /etc/nginx/sites-available/ for backup files.

For detailed Nginx configuration options, refer to the official Nginx documentation.

Conclusion

You now know exactly how to secure Nginx with Let’s Encrypt SSL on Ubuntu (with auto-renewal). Your site serves traffic over HTTPS, browsers show the padlock, and your certificate renews itself without any manual work. That’s a production-ready SSL setup done in under 20 minutes.

From here, you might want to strengthen your SSL configuration further. Consider adding HTTP Strict Transport Security (HSTS) headers to your Nginx config. You could also run your SSL setup through SSL Labs’ Server Test to check your security rating. Aim for an A or A+ grade. These extra steps take your server security from good to excellent.

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