Short answer
DNS records are structured answers in the domain name servers. They control IP addresses, mail servers and verifications.
Common record types
A and AAAA point domain names to IPv4 and IPv6. MX points to mail servers. TXT is often used for verification and email security.
DNS and troubleshooting
When a website, email or verification does not work, DNS records are often the first place to check. TTL controls how long answers may be cached.
Security-related records
SPF, DKIM and DMARC are normally stored in TXT records. CAA can control which certificate authorities may issue TLS certificates for the domain.
Common questions
Are DNS records public?
Yes, most DNS records are intended to be publicly resolvable.
How fast do DNS changes apply?
It depends on TTL and resolver caches. Changes can apply quickly or take hours.