The **DNS Deliverability Checker** queries public DNS servers for essential records related to email sending. It looks specifically for four critical records:
- **MX (Mail Exchanger):** Shows where your incoming email should be delivered.
- **A (Address):** Maps your domain name to an IP address.
- **SPF (Sender Policy Framework):** Authorizes mail servers allowed to send email on behalf of your domain.
- **DKIM (DomainKeys Identified Mail):** Provides an encryption key used to sign outgoing emails, proving they haven't been tampered with.
- **DMARC (Domain-based Message Authentication, Reporting & Conformance):** Sets the policy for how receiving servers should handle emails that fail SPF or DKIM checks (e.g., quarantine or reject).