How to Install Let’s Encrypt SSL in Nginx on Debian 11

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Let’s Encrypt is a certificate authority that provides free SSL certificates for websites. However, it not only offers SSL certificates; it also automates certificate creation, validation, signing, implementation, and renewal of certificates.

Let’s Encrypt is the world’s largest certificate authority, used by more than 250 million websites. It was launched in November 2014 with the goal of all websites being secure and using HTTPS.

Currently, Let’s Encrypt supports auto installation of certificates on Apache, Nginx, Plex, and Haproxy.

Here, we will see how to install Let’s Encrypt SSL Certificate for Nginx on Debian 11.

Prerequisites

I recommend you set up the install Nginx web server on your system before you proceed further.

READ: How to Install LEMP Stack on Debian 11

Create Virtualhost

First, we will need to create an Nginx virtual host to serve the HTTP version of your website.

sudo nano /etc/nginx/conf.d/www.itzgeek.net.conf

Use the below configuration for your website. Do remember to change the values based on your requirement.

You can remove the PHP Fast CGI section if you do not use CMSs like WordPress, Joomla, etc., or PHP-based applications.

server {
   server_name itzgeek.net www.itzgeek.net;
   root /usr/share/nginx/www.itzgeek.net/;

   location / {
       index index.html index.htm index.php;
   }

   access_log /var/log/nginx/www.itzgeek.net.access.log;
   error_log /var/log/nginx/www.itzgeek.net.error.log;

   location ~ \.php$ {
      include fastcgi_params;
      fastcgi_intercept_errors on;
      fastcgi_pass unix:/run/php/php7.4-fpm.sock;
      fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
   }
}

Once you have created the virtual host configuration file, create a root directory to hold your website’s files.

sudo mkdir -p /usr/share/nginx/www.itzgeek.net/

Then, change the ownership and group of the directory.

sudo chown -R www-data:www-data /usr/share/nginx/www.itzgeek.net/

Finally, place the test HTML file on the document root of your domain.

echo "This is a test site @ www.itzgeek.net" | sudo tee /usr/share/nginx/www.itzgeek.net/index.html

Now, you will need to restart the Nginx service to re-read the configurations.

sudo systemctl restart nginx

Create / Update DNS Record

To generate the Let’s Encrypt SSL certificate for your domain, you will need to point your domain to your server IP. So, go to your domain registrar and create an A/CNAME record for your domain. For example, the below image shows the A/CNAME record for the domain www.itzgeek.net.

DNS records changes will take time to propagate. So, wait for a few minutes to hours, depending on the TTL you set for the DNS record.

DNS Records
DNS Records

Install Let’s Encrypt SSL Certificate For Nginx

Install Certbot

In addition to pointing a domain to your server IP, you will also need to install the Certbot ACME client on your system. The Certbot client handles certificate issuance and installation with no downtime.

Certbot is now available as a snap package for Debian operating system. So, first, install the Snapd package.

sudo apt update

sudo apt install -y snapd

Then, update the snapd to the latest version.

sudo snap install core; sudo snap refresh core

Finally, install the Certbot client using the snap command.

sudo snap install --classic certbot

sudo ln -s /snap/bin/certbot /usr/bin/certbot

Install Let’s Encrypt Certificate

Use the certbot command to create a Let’s Encrypt certificate and configure Nginx to use the certificate.

sudo certbot --nginx

Follow the interactive prompt and install the certificate.

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Enter email address (used for urgent renewal and security notices)
 (Enter 'c' to cancel): admin@itzgeek.local << Enter Email ID

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Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf. You must
agree in order to register with the ACME server. Do you agree?
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(Y)es/(N)o: Y  << Agree to Terms and Conditions

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Would you be willing, once your first certificate is successfully issued, to
share your email address with the Electronic Frontier Foundation, a founding
partner of the Let's Encrypt project and the non-profit organization that
develops Certbot? We'd like to send you email about our work encrypting the web,
EFF news, campaigns, and ways to support digital freedom.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(Y)es/(N)o: N << Subscriber to Newsletter
Account registered.

Which names would you like to activate HTTPS for?
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1: itzgeek.net
2. www.itzgeek.net
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Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter 'c' to cancel): 1,2 << Choose Site to Install Let's Encrypt SSL Certificate
Requesting a certificate for www.itzgeek.net

Successfully received certificate.
Certificate is saved at: /etc/letsencrypt/live/www.itzgeek.net/fullchain.pem
Key is saved at:         /etc/letsencrypt/live/www.itzgeek.net/privkey.pem
This certificate expires on 2022-01-17.
These files will be updated when the certificate renews.
Certbot has set up a scheduled task to automatically renew this certificate in the background.

Deploying certificate
Successfully deployed certificate for www.itzgeek.net to /etc/nginx/conf.d/www.itzgeek.net.conf
Congratulations! You have successfully enabled HTTPS on https://www.itzgeek.net

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If you like Certbot, please consider supporting our work by:
 * Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
 * Donating to EFF:                    https://eff.org/donate-le
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Once you activate HTTPS for your domain, the Certbot client will place necessary rewrite rules to redirect traffic from HTTP to the HTTPS site.

In my case, it has placed two rules for below redirections.

  1. http://itzgeek.net >> https://itzgeek.net
  2. http://www.itzgeek.net >> https://www.itzgeek.net

As you can see, the first redirection is not reached to the www HTTPS version of the website. So, you may need to follow the below section to set it up.

Redirect non-www HTTP requests to www HTTPS with Nginx (optional)

You may like to configure the Nginx server to redirect the traffic from the non-www HTTP site to the WWW HTTPS site, I.e., http://itzgeek.net >> https://www.itzgeek.net.

sudo nano /etc/nginx/conf.d/www.itzgeek.net.conf

Add the highlighted redirection in the SSL section.

    listen 443 ssl; # managed by Certbot
 .    .    .
 .    .    .
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

    if ($host = itzgeek.net) {
        return 301 https://www.itzgeek.net$request_uri;
    }

Then, restart the Nginx service.

sudo systemctl restart nginx

Verify Let’s Encrypt Certificate

You can verify the Let’s Encrypt certificate by visiting your website.

http://your-http-web-site

OR

https://your-https-web-site

You should get the HTTPS version of your site now.

Let’s Encrypt SSL Certificate with Nginx on Debian 11
Let’s Encrypt SSL Certificate with Nginx on Debian 11

Test SSL Certificate

Test your Let’s Encrypt SSL certificate for any issues and its security ratings by going to the below URL.

https://www.ssllabs.com/ssltest/analyze.html?d=www.itzgeek.net

Renew Let’s Encrypt Certificate

Let’s Encrypt certificates have a validity of 90 days, and it is highly advisable to renew the certificates before they expire. Thanks to the systemd service, which runs twice a day and automatically renews certificates that are about to expire.

But, I recommend you run the below command to simulate the automatic renewal of your certificate.

sudo certbot renew --dry-run

Output:

Saving debug log to /var/log/letsencrypt/letsencrypt.log

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Processing /etc/letsencrypt/renewal/www.itzgeek.net.conf
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Account registered.
Simulating renewal of an existing certificate for www.itzgeek.net

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Congratulations, all simulated renewals succeeded: 
  /etc/letsencrypt/live/www.itzgeek.net/fullchain.pem (success)
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If the output confirms that the renewal is working correctly, the automatic renewal will happen as expected.

Conclusion

That’s All. I hope you learned how to Install Let’s Encrypt SSL Certificate for Nginx on Debian 11. Share your feedback in the comments section.

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