Letsencrypt: Tutorial & Best Practices

Tool to create SSL certificates

Let's Encrypt is a free, automated, and open certificate authority (CA). It provides digital certificates that are used to enable HTTPS (Hypertext Transfer Protocol Secure) on websites, which allows secure communication over the Internet.

Let's Encrypt was founded in 2014 with the goal of making it easy for website owners to secure their sites with HTTPS, regardless of their technical expertise or resources. Prior to the creation of Let's Encrypt, obtaining a digital certificate from a trusted CA could be a complex and expensive process, which made it difficult for many smaller websites to implement HTTPS.

Let's Encrypt simplifies the process of obtaining and installing a digital certificate by providing a fully automated system for issuing and renewing certificates. Website owners can use Let's Encrypt to obtain a certificate for their domain by installing the Let's Encrypt software on their web server and following a series of prompts. The process is typically completed in a matter of minutes, and the certificate is issued at no cost.

In addition to making it easier for website owners to secure their sites with HTTPS, Let's Encrypt has also helped to drive the wider adoption of HTTPS on the web. By providing a convenient and free way for website owners to obtain certificates, Let's Encrypt has helped to make HTTPS more widely available and has contributed to the creation of a more secure and trustworthy Internet.

To use Let's Encrypt to create SSL certificates for your website, you will need to follow these steps:

  • Install the Let's Encrypt software on your web server. This will typically involve downloading the software and running an installation script.

  • Run the Let's Encrypt software and follow the prompts to request a certificate for your domain. You will need to specify the domain name or names that you want the certificate to cover, and you may also need to provide additional information such as your email address.

  • Let's Encrypt will verify that you control the domain for which you are requesting a certificate. This is typically done by placing a special file on your web server that Let's Encrypt can access to confirm your ownership of the domain.

  • Once your ownership of the domain has been confirmed, Let's Encrypt will issue a certificate for your domain. The certificate will be valid for a limited period of time, typically 90 days, after which it will need to be renewed.

  • Install the certificate on your web server. This will typically involve copying the certificate files to the appropriate location on your server and configuring your web server software to use the certificate.

  • Enable HTTPS on your website by redirecting all HTTP traffic to HTTPS. This will typically involve updating your server configuration to redirect all traffic to the HTTPS version of your website.

Once you have completed these steps, your website should be secure and accessible over HTTPS. You will need to renew your certificate periodically to keep it up-to-date, but the process of requesting and installing a new certificate should be similar to the process described above.

To get a certificate from Let's Encrypt on a Linux system, you will need to use the certbot command-line tool. certbot is the official command-line tool for interacting with the Let's Encrypt CA, and it can be used to request, install, and manage SSL/TLS certificates for your domains.

To request a certificate for a single domain, you can use the following command:

sudo certbot certonly --standalone -d example.com

This command will request a certificate for the domain example.com using the standalone plugin, which runs its own temporary webserver to handle the validation process.

To request a certificate for multiple domains, you can use the -d flag multiple times, like this:

sudo certbot certonly --standalone -d example.com -d www.example.com

This will request a single certificate that covers both example.com and www.example.com.

Once you have requested a certificate, certbot will guide you through the process of verifying your ownership of the domain and installing the certificate on your web server. The exact steps you will need to follow will depend on your web server software and the specific plugin you are using.

Here's another example of how to use a DNS challenge to create a wildcard certificate:

sudo certbot certonly --manual --preferred-challenges=dns -d "*.example.com"

You can find more detailed instructions and a list of available options in the certbot documentation, which you can access by running the certbot --help command.