Introduction
In the digital landscape, securing your website with an SSL/TLS certificate is no longer an option, it's a necessity. Not only does it ensure the privacy of your users' data, but it also enhances your website's credibility and improves its ranking in search engines. Let's Encrypt, a free, automated, and open certificate authority (CA), has revolutionized the way websites secure themselves. This article will guide you through the process of acquiring a Let's Encrypt certificate with DNS validation on Ubuntu 18.04, empowering you to secure your website efficiently and reliably.
Understanding DNS Validation
Before delving into the technical details, let's understand why DNS validation is a preferred method for Let's Encrypt certificate issuance.
Imagine you're trying to prove your identity to a friend. You could send them a postcard, but anyone could intercept it. DNS validation is like sending them a secret code, only you and the friend know. Let's Encrypt uses this mechanism to verify that you own the domain before issuing the certificate.
Benefits of DNS Validation
- Security: DNS validation is considered more secure than the HTTP challenge method because it doesn't rely on the website being accessible over HTTP.
- Flexibility: It allows you to obtain a certificate even if your webserver isn't accessible on port 80 or 443.
- Reliability: It's a more robust method, as it doesn't rely on the potential instability of webserver configurations.
Setting Up the Prerequisites
To embark on this journey, let's gather the necessary tools and configurations for a smooth experience.
1. Install Certbot
Certbot is a user-friendly tool developed by the Let's Encrypt team, specifically designed for acquiring and managing Let's Encrypt certificates. Installing it is a breeze:
sudo apt update
sudo apt install certbot
2. Choose Your DNS Provider
Certbot supports a wide range of DNS providers. You'll need to choose one that best suits your needs:
- CloudFlare: A popular DNS provider known for its security and performance.
- DigitalOcean: An excellent choice if you host your website on DigitalOcean.
- AWS Route 53: A powerful DNS service for those using AWS.
- Google Cloud DNS: A reliable option for Google Cloud users.
3. Configure Your DNS Provider
You'll need to set up your DNS provider to interact with Certbot. Each provider has its own specific configuration, so consult their documentation for detailed instructions.
For example, to configure CloudFlare, you'll need to create an API token and enable DNS API access.
Obtaining the Let's Encrypt Certificate
Now that the stage is set, let's dive into the process of acquiring your certificate.
1. Run Certbot with DNS Validation
The command below initiates the certificate acquisition process using the dns-cloudflare plugin for CloudFlare. Replace cloudflare with the plugin corresponding to your DNS provider.
sudo certbot certonly --manual --preferred-challenges dns --manual-auth-hook /path/to/auth.sh --manual-cleanup-hook /path/to/cleanup.sh -d example.com -d www.example.com
certonly: This flag instructs Certbot to only obtain a certificate, not install it automatically.--manual: Specifies that manual validation is required.--preferred-challenges dns: Indicates that DNS validation is the preferred method.--manual-auth-hook: Specifies the script to be run for DNS record creation.--manual-cleanup-hook: Specifies the script to be run for DNS record cleanup.-d example.com: Specifies the domain names for which the certificate is requested.
2. Create the Authentication Script
The auth.sh script is responsible for creating the necessary DNS records.
#!/bin/bash
# This script creates the required DNS record for Let's Encrypt validation
DOMAIN=$1 # Domain name to validate
TXT_VALUE=$2 # The TXT record value
echo "Creating DNS record for $DOMAIN"
# Replace with your DNS provider's API commands
# ... create DNS record with $DOMAIN and $TXT_VALUE ...
3. Create the Cleanup Script
The cleanup.sh script is responsible for deleting the DNS records after the certificate is issued.
#!/bin/bash
# This script deletes the DNS records created for Let's Encrypt validation
DOMAIN=$1 # Domain name to validate
echo "Deleting DNS record for $DOMAIN"
# Replace with your DNS provider's API commands
# ... delete DNS record with $DOMAIN ...
4. Execute Certbot
After creating the scripts, run the Certbot command again. Certbot will prompt you to manually create the DNS records using the provided instructions. Once you've completed the manual step, Certbot will proceed with the validation and certificate issuance.
Installing and Configuring the Certificate
Now that you have your certificate, it's time to install and configure it on your webserver.
1. Install the Certificate
Certbot can automatically install the certificate for you. Use the following command, ensuring to replace --standalone with your webserver configuration:
sudo certbot certonly --standalone -d example.com -d www.example.com
2. Configure Your Webserver
Depending on your webserver software, you'll need to configure it to use the newly obtained certificate.
- Apache:
- Update your Apache configuration file (usually
/etc/apache2/sites-available/your-site.conf) to include the certificate and key. - Reload Apache with the command
sudo systemctl reload apache2.
- Update your Apache configuration file (usually
- Nginx:
- Update your Nginx configuration file (usually
/etc/nginx/sites-available/your-site.conf) to include the certificate and key. - Reload Nginx with the command
sudo systemctl reload nginx.
- Update your Nginx configuration file (usually
Verifying Your Certificate
To ensure that everything is working correctly, you can verify the certificate using tools like:
- SSL Labs: https://www.ssllabs.com/ssltest/
- Qualys SSL Labs: https://qualys.com/ssllabs/ssltest/
These tools will provide detailed information about your certificate, including its validity, encryption strength, and security protocols.
Renewing Your Certificate
Let's Encrypt certificates are valid for 90 days. Fortunately, Certbot has built-in renewal capabilities, making this process seamless.
1. Configure Automatic Renewal
Certbot can be configured to automatically renew your certificate before it expires. Use the following command:
sudo certbot renew --dry-run
This command will run a dry run of the renewal process, ensuring everything is configured correctly.
2. Schedule Automatic Renewals
Certbot can be scheduled to automatically renew certificates on a regular basis. To do so, create a cron job:
sudo crontab -e
Add the following line to the crontab file:
0 0 * * * root /usr/bin/certbot renew --quiet
This will automatically renew your certificates at midnight every day.
Conclusion
Acquiring a Let's Encrypt certificate with DNS validation on Ubuntu 18.04 is a relatively straightforward process. By following the steps outlined in this article, you can secure your website, enhance user trust, and improve its overall performance. Remember to choose the DNS provider that best suits your needs, configure your webserver, and schedule automatic renewals for a worry-free experience.
FAQs
1. What are the different types of Let's Encrypt certificate challenges?
- HTTP challenge: Requires the website to be accessible over HTTP.
- DNS challenge: Requires the control of the domain's DNS records.
- Email challenge: Requires access to an email address associated with the domain.
2. Why is DNS validation more secure than HTTP challenge?
DNS validation is more secure because it doesn't rely on the website being accessible over HTTP, making it less susceptible to attacks.
3. Can I use a different DNS provider?
Yes, Certbot supports numerous DNS providers. You can choose one that best suits your needs.
4. What if I don't have a domain registered?
You'll need to register a domain before you can obtain a Let's Encrypt certificate.
5. What happens if my certificate expires?
If your certificate expires, your website will no longer be secure, and users will receive security warnings. Ensure you schedule automatic renewals to prevent this from happening.
6. How often should I renew my certificate?
Let's Encrypt certificates are valid for 90 days, so you should renew them at least once every 90 days.