Certbot

Certbot is a free and open-source software tool, sponsored by the Electronic Frontier Foundation (EFF). Its primary purpose is to automate the process of obtaining and managing SSL/TLS certificates from Certificate Authorities (CAs), most notably Let's Encrypt. Certbot significantly simplifies the task of enabling HTTPS on web servers, making secure websites more accessible for everyone.

Certbot automates several steps that were traditionally manual and error-prone, including verifying domain ownership, obtaining the certificate, installing it on a web server, and configuring automatic renewal.

Overview

Before tools like Certbot and services like Let's Encrypt, obtaining and installing SSL/TLS certificates was often a complex, manual, and sometimes expensive process. Certbot aims to streamline this by providing an easy-to-use command-line interface (CLI) that handles much of the heavy lifting.

It communicates with Certificate Authorities using the ACME protocol (Automatic Certificate Management Environment), an open standard for automating certificate management.

Purpose

The main purpose of Certbot is to promote the widespread adoption of HTTPS by:

• Providing free SSL/TLS certificates via Let's Encrypt.
• Automating the process of obtaining certificates, which previously often required manual steps.
• Automating the installation of certificates on popular web servers like Apache and Nginx.
• Automating the renewal of certificates before they expire.

This automation reduces the technical barriers and cost associated with implementing HTTPS, making it easier for website administrators to secure their sites.

Key Features

Certbot offers several features that automate certificate management:

• Automated Issuance: Interacts with CAs using the ACME protocol to prove domain control and get certificates.
• Automated Installation: Includes plugins for popular web servers (like Apache and Nginx) that can automatically edit configuration files to install the certificate and enable HTTPS.
• Automated Renewal: Sets up systems (like Cron jobs or systemd timers) to automatically check for certificate expiry and renew them well in advance.
• Multiple Web Server Support: Offers plugins for seamless integration with various web server software.
• Command-Line Interface (CLI): Primarily controlled via a powerful and flexible command-line interface.
• Wildcard Certificate Support: Can obtain wildcard certificates (securing all subdomains under a domain) using DNS-based domain validation.

Installation on Debian Linux (CLI Tutorial)

Installing Certbot on a Debian-based Linux server (like Ubuntu) using its official repository is the recommended method to ensure you get the latest version and receive timely updates.

Prerequisites:

• A Linux server running a Debian-based distribution (e.g., Debian 10+, Ubuntu 18.04+).
• Command-line access (SSH).
• sudo privileges.
• An internet connection on the server.
• A registered Domain name pointing to your server's IP address.
• A web server (Apache or Nginx recommended for automatic configuration plugins) already installed and configured to serve your domain.

Steps:

1. Add the Certbot Repository:

The official repository provides up-to-date Certbot packages.

     sudo apt update  
     sudo apt install -y certbot  # Install certbot base package first
     sudo apt install -y python3-certbot-nginx # Or python3-certbot-apache for Apache  

Note: On newer Debian/Ubuntu versions, Certbot might be directly available in the main repository without needing a separate one, especially for basic `certbot` and web server plugins. The command above is the most common way to install it.

1. Verify the installation:

Check that Certbot is installed and accessible.

     certbot --version  

After installation, you can proceed to obtain and install certificates using Certbot commands.

Updating Certbot on Debian Linux (CLI Tutorial)

Since you installed Certbot using the system's package manager (`apt`), updating Certbot is the same process as updating any other software package on your Debian server.

Prerequisites:

• A Linux server with Certbot installed via `apt`.
• Command-line access (SSH).
• `sudo` privileges.

Steps:

1. Update the system's package list:

Fetch the latest information about available packages from all configured repositories.

     sudo apt update  

1. Upgrade installed packages:

Install the newest versions of all packages currently installed on the system, including Certbot if an update is available in the repositories you configured.

     sudo apt upgrade -y  

This command will automatically update Certbot and any installed plugins if new versions are available in the repositories.

Keeping Certbot updated is important because newer versions may include bug fixes, security improvements, support for new TLS/ACME features, or compatibility updates for web server plugins.

How to Use Certbot (Briefly)

Once installed, the main commands you'll use are:

• Obtain and Install (with plugin):

 sudo certbot --nginx -d your_domain.com    

(or `--apache`) This attempts to automatically configure your web server.

• Obtain only (manual):

 sudo certbot certonly --standalone -d your_domain.com  

(Uses a temporary web server) or

 sudo certbot certonly --manual -d your_domain.com  

(Requires manual DNS or HTTP verification). You'll need to manually install the certificate files produced.

• Renew Certificates:

 sudo certbot renew  

This command checks all installed certificates obtained via Certbot and renews those that are due for renewal. This command is automatically run by a system timer or cron job set up during the initial installation.

Certbot documentation provides detailed instructions for various scenarios and web servers.

See also

• SSL certificate
• TLS/SSL
• HTTPS