Table of contents

Records

Records power the Internet. Here’s some important ones to know.

DNS records

• A record - The record that holds the IPv4 address

www A   nonlinearity.io    10.10.10.1

This maps www.nonlinearity.io. For the base domain, the @ symbol is used.

@ A   nonlinearity.io    10.10.10.1

• AAAA record - The record that holds the IPv6 address

www A   nonlinearity.io    fe80::1

Email records

• A DMARC policy tells a receiving email server what to do after checking a domain’s Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) records. The DMARC record stores a domain’s DMARC policy.

_dmarc.example.com 	TXT 	v=DMARC1; p=quarantine; adkim=r; aspf=r; rua=mailto:[email protected];

It’s setup by you to help receiving email servers protect against spammers using your custom domain.

• DKIM has two parts. The DKIM record is in the DNS records for the domain. The DKIM header is in the email. The email provider generates a public and private key. the public key is added to the public DKIM DNS record. The DKIM in the email header is signed with the private key.