Optimizing Email Deliverability: SPF, DKIM, and PTR Explained
The Email Deliverability function in cPanel helps you identify and resolve DNS issues. Correct DNS records signal to other mail servers (such as Gmail, Outlook, or Bluewin) that your messages come from a trustworthy sender and are not spam.
The Three Pillars of Deliverability
To ensure your emails are delivered successfully, cPanel uses three central mechanisms:
1. DKIM
Verifies the sender and ensures that the message has not been tampered with during transit.
2. SPF
Defines which servers (IPs) are authorized to send emails on behalf of your domain.
3. PTR (Reverse DNS)
Checks whether the sender's IP address can be associated with a valid domain name.
Checking Status and Resolving Issues
In the deliverability table, you can see immediately if action is required:
- Repair: The system automatically corrects invalid entries (only possible if your nameservers are hosted with us).
- Manage: Here you can manually view, copy, or adjust the records.
Adjusting SPF Records (e.g., for Mailchimp)
Do you use external services like newsletter tools (Mailchimp) or CRM systems? Then you must extend the SPF record so that these services are allowed to send on your behalf:
- Click "Manage" next to your domain.
- Scroll to SPF and click "Customize".
- Under "Additional Settings", add the corresponding domain to the Include List.
- Click "Install a Customized SPF Record".
CURIAWEB Tip:
Make sure the PTR record (Reverse DNS) is set correctly. If an error is displayed here, please contact our support, as PTR records can often only be adjusted by the data center operator.
Important Note for External Nameservers:
Are you using external nameservers (e.g., Cloudflare or from another registrar)? Then you must copy the DKIM and SPF values displayed in cPanel and manually store them with your DNS provider.Are you having problems with rejected emails? The CURIAWEB team will be happy to analyze your header data and help with the configuration.
