Secure HTTP Traffic with Certbot

What is Certbot?

Certbot is a tool that automates the process of getting a signed certificate via Let’s Encrypt to use with TLS.

For most operating system and web server configurations, Certbot creates signed certificates, manages the web server to accept secure connections, and can automatically renew certificates it has created. In most cases, Certbot can seamlessly enable HTTPS without causing server downtime.

Before You Begin

Make sure you have registered a Fully Qualified Domain Name (FQDN) and set up A and AAAA DNS records that point to your Linode’s public IPv4 and IPv6 addresses. Consult our DNS Records: An Introduction and DNS Manager guides for help with setting up a domain.

Use Certbot on Debian

1. Install the Certbot and web server-specific packages, then run Certbot:

   sudo apt install certbot python-certbot-nginx
   sudo certbot --nginx
   

2. Certbot will ask for information about the site. The responses will be saved as part of the certificate:

   # sudo certbot --nginx
   Saving debug log to /var/log/letsencrypt/letsencrypt.log
   Plugins selected: Authenticator nginx, Installer nginx
   
   Which names would you like to activate HTTPS for?
   -------------------------------------------------------------------------------
   1: example.com
   2: www.example.com
   -------------------------------------------------------------------------------
   Select the appropriate numbers separated by commas and/or spaces, or leave input
   blank to select all options shown (Enter 'c' to cancel):

3. Certbot will also ask if you would like to automatically redirect HTTP traffic to HTTPS traffic. It is recommended that you select this option.

4. When the tool completes, Certbot will store all generated keys and issued certificates in the /etc/letsencrypt/live/$domain directory, where $domain is the name of the domain entered during the Certbot certificate generation step.

   Note

   Certbot recommends pointing your web server configuration to the default certificates directory or creating symlinks. Keys and certificates should not be moved to a different directory.

   Finally, Certbot will update your web server configuration so that it uses the new certificate, and also redirects HTTP traffic to HTTPS if you chose that option.

5. If you have a firewall configured on your Linode, you can add a firewall rule to allow incoming and outgoing connections to the HTTPS service. On Debian, UFW is a commonly used and simple tool for managing firewall rules. Install and configure UFW for HTTP and HTTPS traffic:

   sudo apt install ufw
   sudo systemctl start ufw && sudo systemctl enable ufw
   sudo ufw allow http
   sudo ufw allow https
   sudo ufw enable
   

Use Certbot on Ubuntu

1. Install the Certbot and web server-specific packages, then run Certbot:

    sudo apt update
    sudo apt install certbot python3-certbot-nginx
    sudo certbot --nginx
   

2. Certbot will ask for information about the site. The responses will be saved as part of the certificate:

   # sudo certbot --nginx
   Saving debug log to /var/log/letsencrypt/letsencrypt.log
   Plugins selected: Authenticator nginx, Installer nginx
   
   Which names would you like to activate HTTPS for?
   -------------------------------------------------------------------------------
   1: example.com
   2: www.example.com
   -------------------------------------------------------------------------------
   Select the appropriate numbers separated by commas and/or spaces, or leave input
   blank to select all options shown (Enter 'c' to cancel):

3. Certbot will also ask if you would like to automatically redirect HTTP traffic to HTTPS traffic. It is recommended that you select this option.

4. When the tool completes, Certbot will store all generated keys and issued certificates in the /etc/letsencrypt/live/$domain directory, where $domain is the name of the domain entered during the Certbot certificate generation step.

   Note

   Certbot recommends pointing your web server configuration to the default certificates directory or creating symlinks. Keys and certificates should not be moved to a different directory.

   Finally, Certbot will update your web server configuration so that it uses the new certificate, and also redirects HTTP traffic to HTTPS if you chose that option.

5. If you have a firewall configured on your Linode, you can add a firewall rule to allow incoming and outgoing connections to the HTTPS service. On Ubuntu, UFW is a commonly used and simple tool for managing firewall rules. Install and configure UFW for HTTP and HTTPS traffic:

    sudo apt install ufw
    sudo systemctl start ufw && sudo systemctl enable ufw
    sudo ufw allow http
    sudo ufw allow https
    sudo ufw enable
   

Use Certbot on CentOS 7

1. Enable the EPEL repository:

   sudo yum install epel-release
   sudo yum update
   

2. Install the Certbot and web server-specific packages, then run Certbot:

   sudo yum install python2-certbot-nginx nginx
   sudo certbot --nginx
   

3. Certbot will ask for information about the site. The responses will be saved as part of the certificate:

   # sudo certbot --nginx
   Saving debug log to /var/log/letsencrypt/letsencrypt.log
   Plugins selected: Authenticator apache, Installer apache
   
   Which names would you like to activate HTTPS for?
   -------------------------------------------------------------------------------
   1: example.com
   2: www.example.com
   -------------------------------------------------------------------------------
   Select the appropriate numbers separated by commas and/or spaces, or leave input
   blank to select all options shown (Enter 'c' to cancel):

4. Certbot will also ask if you would like to automatically redirect HTTP traffic to HTTPS traffic. It is recommended that you select this option.

5. When the tool completes, Certbot will store all generated keys and issued certificates in the /etc/letsencrypt/live/$domain directory, where $domain is the name of the domain entered during the Certbot certificate generation step.

   Note

   Certbot recommends pointing your web server configuration to the default certificates directory or creating symlinks. Keys and certificates should not be moved to a different directory.

   Finally, Certbot will update your web server configuration so that it uses the new certificate, and also redirects HTTP traffic to HTTPS if you chose that option.

6. If you have a firewall configured on your Linode, you may need to add Firewall Rules to allow incoming and outgoing connections to the HTTPS service. On CentOS, firewalld is the default tool for managing firewall rules. Configure firewalld for HTTP and HTTPS traffic:

    sudo firewall-cmd --zone=public --permanent --add-service=http
    sudo firewall-cmd --zone=public --permanent --add-service=https
    sudo firewall-cmd --reload
   

Use Certbot to Renew All Certificates

You can renew all existing certificates that will expire in under 30 days with the following command:

certbot renew

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• Certbot Official Documentation