What a DNS record is
A DNS record is one instruction stored in a domain's zone file. Each record has a name, a type, a value, and a TTL that controls how long it may be cached. Together, the records for a domain define how the internet should treat requests for that name.
Common record types
Different types serve different purposes:
- A maps a name to an IPv4 address.
- AAAA maps a name to an IPv6 address.
- MX points mail to the right server.
- CNAME aliases one name to another.
- TXT holds arbitrary text, often used for verification and email policies like SPF.
- PTR supports reverse lookups from an IP back to a name.
Why it matters
Records are how you control a domain's behavior without touching the underlying servers. Want to move your website? Update the A record. Want to switch email providers? Update the MX records. Because answers are cached based on TTL, planned changes often involve lowering the TTL first so updates propagate quickly. For example, setting an A record to 203.0.113.10 directs all web visitors to that server. You can read a domain's records using the WhatIP dns-lookup tool.