DNS-based authentication, also known as DNS-01 challenge, is a method used by Let's Encrypt and Certbot to verify domain ownership when issuing SSL/TLS certificates. Instead of modifying files on your web server or responding to HTTP challenges, DNS-based authentication involves adding specific DNS records to your domain's DNS configuration.
Here's how to use DNS-based authentication with Certbot:
Step 1: Install Certbot DNS plugins
First, you need to install Certbot DNS plugins that support DNS-based authentication for your DNS provider. Certbot provides plugins for various DNS providers, allowing you to automate the process of adding and removing DNS records.
For example, if you're using Cloudflare as your DNS provider, you can install the Certbot Cloudflare plugin:
sudo apt update
sudo apt install certbot python3-certbot-dns-cloudflare
Replace cloudflare with the appropriate DNS provider if you're using a different provider.
Step 2: Obtain SSL/TLS certificates
Once you have installed the Certbot DNS plugin for your DNS provider, you can use it to obtain SSL/TLS certificates with DNS-based authentication. Run the following command:
sudo certbot certonly --dns <dns-provider> \
--dns-<dns-provider>-credentials /path/to/credentials.ini \
-d example.com -d www.example.com
Replace <dns-provider> with the name of your DNS provider (e.g., cloudflare) and /path/to/credentials.ini with the path to a file containing your DNS provider API credentials. Make sure to replace example.com and www.example.com with your actual domain(s).
Step 3: Add DNS records
Certbot will prompt you to add specific DNS records to your domain's DNS configuration. These records are used by Let's Encrypt to verify domain ownership. Follow the instructions provided by Certbot to add the required DNS records to your DNS provider's control panel or configuration.
Step 4: Verify SSL/TLS configuration
After adding the DNS records, Certbot will attempt to verify domain ownership by querying the DNS records. Once verification is successful, Certbot will issue the SSL/TLS certificates and store them on your server.
Step 5: Configure Web Server
After obtaining the certificates, you'll need to configure your web server to use them. Certbot may automate this step for you if you used the appropriate options during certificate issuance.
Step 6: Set Up Renewal (Optional)
Finally, you can set up automatic renewal of your SSL/TLS certificates using Certbot's renewal mechanism and a cron job, as described in the previous responses.
By adhering to these procedures, you can employ Certbot's DNS-based authentication method to acquire and oversee SSL/TLS certificates for your domains, guaranteeing secure HTTPS connections for those visiting your website.