Understanding DNS Records
A clear guide to DNS and its record types — A, AAAA, MX, TXT, NS, CNAME — and how domain names get resolved to IP addresses.
By the ToolsHub team · Updated May 1, 2026
The Domain Name System (DNS) is the internet's phone book. When you type example.com, DNS translates that human-friendly name into the IP address a browser needs to connect. The lookup travels from your resolver to the domain's authoritative name servers, which return the answer.
Common DNS record types
- A — maps a domain to an IPv4 address.
- AAAA — maps a domain to an IPv6 address.
- MX — mail exchange; tells senders which servers accept email for the domain (with priorities).
- TXT — arbitrary text, widely used for SPF, DKIM, and domain verification.
- NS — the authoritative name servers for the domain.
- CNAME — an alias pointing one name to another.
Why DNS changes take time
Each record has a TTL (time to live) that tells resolvers how long to cache it. After you change a record, older cached values can persist until the TTL expires — this is why DNS updates can take minutes to hours to "propagate."
Checking and troubleshooting DNS
When a site or email isn't working, DNS is often the first place to look. Use our DNS Lookup tool to read a domain's A, AAAA, MX, TXT, NS and CNAME records and confirm they point where you expect. If you've just changed a record, the DNS Propagation Checker shows how it looks from resolvers around the world, since caching means not everyone sees the update at once.
- Website down after a move? Check the A/AAAA record points to the new server's IP.
- Email bouncing? Verify the MX records and their priorities.
- SPF/DKIM failing? Those live in TXT records — confirm they exist and are exact.
Setting up a brand-new domain? First check whether the domain name is available to register, and use the WHOIS Lookup to see who owns one that's already taken — then point its DNS records where you need.
Frequently asked questions
- What is a DNS record?
- A DNS record is an instruction in a domain's zone that tells the internet how to handle it — which server hosts the website (A/AAAA), which servers receive its email (MX), and much more.
- What is the difference between an A record and a CNAME?
- An A record points a name directly to an IP address, while a CNAME points one name to another name as an alias. Use a CNAME to point, say, www to your root domain.
- What is TTL in DNS?
- TTL (time to live) is how long, in seconds, resolvers may cache a record before checking again. A low TTL means changes propagate quickly; a high TTL cuts lookups but slows updates.
- How long do DNS changes take to update?
- Usually from a few minutes to a few hours, depending on the record's TTL and caching along the way. You can track progress across global resolvers with our DNS Propagation Checker.