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Installing Certbot and renewing certificates

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.

In this tutorial, you will use Certbot to obtain a free SSL certificate for Apache on Ubuntu 18.04 and set up your certificate to renew automatically.

This tutorial will use a separate Apache virtual host file instead of the default configuration file. We recommend creating new Apache virtual host files for each domain because it helps to avoid common mistakes and maintains the default files as a fallback configuration.

Prerequisites

To follow this tutorial, you will need:

A fully registered domain name. This tutorial will use your_domain as an example throughout.

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

An A record with your_domain pointing to your server’s public IP address.

An A record with www.your_domain pointing to your server’s public IP address.

Apache installed. Be sure that you have a virtual host file for your domain. This tutorial will use /etc/apache2/sites-available/your_domain.conf as an example.

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.

Certbot is in very active development, so the Certbot packages provided by Ubuntu tend to be outdated. However, the Certbot developers maintain a Ubuntu software repository with up-to-date versions, so we’ll use that repository instead.

Install Certbot’s Apache package with apt:

sudo apt -y install certbot python3-certbot-apache

Certbot is now ready to use, but in order for it to configure SSL for Apache, we need to verify some of Apache’s configuration.

Step 2 — Set Up the SSL Certificate

Certbot needs to be able to find the correct virtual host in your Apache configuration for it to automatically configure SSL. Specifically, it does this by looking for a ServerName directive that matches the domain you request a certificate for.

You should have a VirtualHost block for your domain at /etc/apache2/sites-available/your_domain.com.conf with the ServerName directive already set appropriately.

To check, open the virtual host file for your domain using nano or your favorite text editor:

sudo nano /etc/apache2/sites-available/your_domain.conf

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

/etc/apache2/sites-available/your_domain.conf

...

ServerName your_domain;

...

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 apache2ctl configtest

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

sudo systemctl reload apache2

Certbot can now find the correct VirtualHost block and update it.

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. Luckily, Apache 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

Apache ALLOW Anywhere

OpenSSH (v6) ALLOW Anywhere (v6)

Apache (v6) ALLOW Anywhere (v6)

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

sudo ufw allow 'Apache Full'

sudo ufw delete allow 'Apache'

sudo ufw status

Your status should now look like this:

Output

Status: active

To Action From

-- ------ ----

OpenSSH ALLOW Anywhere

Apache Full ALLOW Anywhere

OpenSSH (v6) ALLOW Anywhere (v6)

Apache 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 Apache plugin will take care of reconfiguring Apache and reloading the config whenever necessary. To use this plugin, type the following:

sudo certbot --apache -d your_domain -d www.your_domain

This runs certbot with the --apache plugin, using -d to specify the names you’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 Apache 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/your_domain/fullchain.pem

Your key file has been saved at:

/etc/letsencrypt/live/your_domain/privkey.pem

Your cert will expire on 2018-07-23. 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"

- Your account credentials have been saved in your Certbot

configuration directory at /etc/letsencrypt. You should make a

secure backup of this folder now. This configuration directory will

also contain certificates and private keys obtained by Certbot so

making regular backups of this folder is ideal.

- 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. Try reloading your website using https:// and notice your browser’s security indicator. It should indicate that the site is properly secured, usually with a green lock icon. If you test your server using the

SSL Labs Server Test⁠

, it will get an A grade.

Let’s finish by testing the renewal process.

Step 5 — Verifying Certbot Auto-Renewal

The certbot package we installed takes care of renewals by including a renew script to /etc/cron.d, which is managed by a systemctl service called certbot.timer. This script runs twice a day and will automatically renew any certificate that’s within thirty days of expiration.

To check the status of this service and make sure it’s active and running, you can use:

sudo systemctl status certbot.timer

You’ll get output similar to this:

Output

● certbot.timer - Run certbot twice daily

Loaded: loaded (/lib/systemd/system/certbot.timer; enabled; vendor preset: enabled)

Active: active (waiting) since Tue 2020-04-28 17:57:48 UTC; 17h ago

Trigger: Wed 2020-04-29 23:50:31 UTC; 12h left

Triggers: ● certbot.service

Apr 28 17:57:48 fine-turtle systemd[1]: Started Run certbot twice daily.

To test the renewal process, you can do a dry run with certbot:

sudo certbot renew --dry-run

If you see no errors, you’re all set. When necessary, Certbot will renew your certificates and reload Apache to pick up the changes. If the automated renewal process ever fails, Let’s Encrypt will send a message to the email you specified, warning you when your certificate is about to expire.

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