Glossary
DNS
Domain Name System
What is DNS?
DNS (Domain Name System) is the internet's address book. It translates human-friendly domain names like example.com into the numeric IP addresses that computers use to find each other. Every time you visit a website or send an email, a DNS lookup happens behind the scenes.
DNS is more than just website addresses. A domain's DNS zone holds many record types that control where email is delivered, which servers are allowed to send mail on your behalf, and how security policies are published. Getting these records right is essential for both website uptime and email deliverability.
Common DNS Record Types
- A / AAAA - Point a domain name to an IPv4 or IPv6 address
- CNAME - Alias one name to another, often used for subdomains and CDNs
- MX - Tell the world which servers receive email for your domain
- TXT - Hold text data, including SPF, DKIM, and DMARC email authentication records
- NS - Define which name servers are authoritative for the domain
- TTL - Each record has a time-to-live that controls how long it is cached
DNS in Practice
- Website launch - Pointing A and CNAME records at your hosting or CDN brings a site live
- Email authentication - SPF, DKIM, and DMARC all live in DNS as TXT records; DMARCsimple monitors these records and reports on whether your email passes authentication
- Troubleshooting - Many "site down" or "email missing" issues trace back to a wrong or missing DNS record
- CCMS managed hosting - DNS configuration and review is part of every CCMS hosting and email deliverability engagement