What are DNS records used for in sending and receiving mail?

Different DNS records serve different email functions:

MX records: Direct incoming mail to the correct server. Required for receiving email.

• SPF records: List which servers can send mail for your domain.
• DKIM records: Publish public keys to verify message signatures.
• DMARC records: Define policies for handling authentication failures.
• PTR records: Enable reverse DNS lookups to verify sending server identity.
• A/AAAA records: Map hostnames to IP addresses for server connections.
• CNAME records: Create aliases, often used for tracking domains.

Each record type is a different document in your maritime credentials. Missing any one can block your passage.