How To Secure Nginx with Let's Encrypt on Ubuntu 20.04

An easy way to obtain and install free TLS/SSL certificates
Priyanka Sharma
Priyanka Sharma

Created: 05/21/2020 7:09 AM - Updated: 05/21/2020 7:09 AM

Introduction

Let’s Encrypt is a Certificate Authority (CA) that provides an easy way to obtain and install free TLS/SSL certificates, thereby enabling encrypted HTTPS on web servers. It simplifies the process by providing a software client, Certbot, that attempts to automate most (if not all) of the required steps. Currently, the entire process of obtaining and installing a certificate is fully automated on both Apache and Nginx.

Here we  will use Certbot to obtain a free SSL certificate for Nginx on Ubuntu 20.04 and set up your certificate to renew automatically.

To follow the steps you will require:-


  • One Ubuntu 20.04 server including a sudo-enabled non-root user and a firewall.

  • A registered domain name. 

  • Both of the following DNS records set up for your server. 

    • An A record with Nexahost.com pointing to your server’s public IP address.
    • An A record with www.Nexahost.com pointing to your server’s public IP address.

Step 1 — Installing Certbot

The first step to using Let’s Encrypt to obtain an SSL certificate is to install the Certbot software on your server.

sudo apt install certbot python3-certbot-nginx

Step 2 — Confirming Nginx’s Configuration

Certbot needs to be able to find the correct server block in your Nginx configuration for it to be able to automatically configure SSL. Specifically, it does this by looking for a server_name directive that matches the domain you request a certificate for.

To check, open the configuration file for your domain using nano or any other text editor:

  • sudo nano /etc/nginx/sites-available/Nexahost.com

Find the existing server_name line. It should look like this:

/etc/nginx/sites-available/Nexahost.com
...
server_name Nexhost.com www.Nexahost.com;
...

If it does, exit your editor and move on to the next step.

If it doesn’t, update it to match. Then save the file, quit your editor, and verify the syntax of your configuration edits:

  • sudo nginx -t

If you get an error, reopen the server block file and check for any typos or missing characters. Once your configuration file’s syntax is correct, reload Nginx to load the new configuration:

  • sudo systemctl reload nginx

Certbot can now find the correct server block and update it automatically.

Next, let’s update the firewall to allow HTTPS traffic.

Step 3 — Allowing HTTPS Through the Firewall

If you have the ufw firewall enabled, as recommended by the prerequisite guides, you’ll need to adjust the settings to allow for HTTPS traffic.

Nginx registers a few profiles with ufw upon installation.

You can see the current setting by typing:

  • sudo ufw status

It will probably look like this, meaning that only HTTP traffic is allowed to the web server:

Output
Status: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere Nginx HTTP ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6) Nginx HTTP (v6) ALLOW Anywhere (v6)

To additionally let in HTTPS traffic, allow the Nginx Full profile and delete the redundant Nginx HTTP profile allowance:

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

Your status should now look like this:

  • sudo ufw status
Output
Status: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere Nginx Full ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6) Nginx Full (v6) ALLOW Anywhere (v6)

Next, let’s run Certbot and fetch our certificates.

Step 4 — Obtaining an SSL Certificate

Certbot provides a variety of ways to obtain SSL certificates through plugins. The Nginx plugin will take care of reconfiguring Nginx and reloading the config whenever necessary. To use this plugin, type the following:

  • sudo certbot --nginx -d Nexahost.com -d www.Nexahost.com

This runs certbot with the --nginx plugin, using -d to specify the domain names we’d like the certificate to be valid for.

If this is your first time running certbot, you will be prompted to enter an email address and agree to the terms of service. After doing so, certbot will communicate with the Let’s Encrypt server, then run a challenge to verify that you control the domain you’re requesting a certificate for.

If that’s successful, certbot will ask how you’d like to configure your HTTPS settings.

Output
Please choose whether or not to redirect HTTP traffic to HTTPS, removing HTTP access. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1: No redirect - Make no further changes to the webserver configuration. 2: Redirect - Make all requests redirect to secure HTTPS access. Choose this for new sites, or if you're confident your site works on HTTPS. You can undo this change by editing your web server's configuration. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Select the appropriate number [1-2] then [enter] (press 'c' to cancel):

Select your choice then hit ENTER. The configuration will be updated, and Nginx will reload to pick up the new settings. certbot will wrap up with a message telling you the process was successful and where your certificates are stored:

Output
IMPORTANT NOTES: - Congratulations! Your certificate and chain have been saved at: /etc/letsencrypt/live/Nexahost.com/fullchain.pem Your key file has been saved at: /etc/letsencrypt/live/Nexahost.com/privkey.pem Your cert will expire on 2020-08-18. To obtain a new or tweaked version of this certificate in the future, simply run certbot again with the "certonly" option. To non-interactively renew *all* of your certificates, run "certbot renew" - 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

Your certificates are downloaded, installed, and loaded. 

Conclusion

In this guide, you installed the Let’s Encrypt client certbot, downloaded SSL certificates for your domain, configured Nginx to use these certificate .

Was this article helpful?

0 Out of 0 Marked As Helpfull

Have more questions? Please Contact Us