The letsencrypt.md file provides instructions for enabling HTTPS on your website using Let's Encrypt.

1. References

   • LetsEncrypt.org
   • Documentation

2. Setup for Debian 11

   apt install certbot python3-certbot-apache -y
   git clone https://github.com/letsencrypt/letsencrypt
   cd letsencrypt
   ./letsencrypt-auto --help   # Suite Command List

   Usage Examples

   ./letsencrypt-auto --apache -d yourdomain.com

   Certonly Example

   ./letsencrypt-auto certonly --standalone --email infouniversalbits@gmail.com -d universalbit.it 

3. Setup for Debian 12

   • LetsEncrypt Debian 12 Setup

Let's Encrypt has made updates regarding how certificates are granted, particularly affecting domain and IP validation methods.
As of January 2026:

• Domain validation: You must prove ownership/control of the domain via HTTP/HTTPS challenge, DNS challenge (TXT record), or use the Certbot with supported options.
• IP certificate support: Let’s Encrypt does not issue certificates directly to IP addresses unless proper reverse DNS and proof is provided. Make sure your domain resolves correctly and you pass validation steps.
• Firewall/Network Controls: Ensure Let's Encrypt servers can reach your public server via the validation method you select.

More info and current updates on validation requirements are available here:

• Let’s Encrypt Validation Methods
• Let’s Encrypt Community Announcements

apt install certbot python3-certbot-apache -y
git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt
./letsencrypt-auto --help   # List commands

Obtain and Install (Apache):

./letsencrypt-auto --apache -d yourdomain.com

Obtain Only (Standalone mode):

./letsencrypt-auto certonly --standalone --email -d 

See LetsEncrypt Debian Guide