What are the most important DNS records?

For most domains the essential records are A (or AAAA) records that point your domain to a server, MX records that route email, and TXT records that hold verification and email-authentication data like SPF and DMARC. NS records are also required because they delegate your domain to its nameservers.

How many DNS records can a domain have?

There is no fixed limit set by the DNS protocol. A domain can have many records of different types and multiple records of the same type, for example several A records for load balancing or several MX records for mail redundancy. Practical limits come from your DNS provider, not the protocol.

Do DNS changes take effect immediately?

No. Resolvers cache records for the duration of their TTL (time to live), so a change can take anywhere from a few minutes to 48 hours to be seen everywhere. This delay is called DNS propagation.

DNS Records Explained: A Complete Guide to Every Record Type

DNS (the Domain Name System) is the phone book of the internet: it translates human-friendly names like example.com into the machine addresses and routing instructions computers actually use. A DNS record is a single instruction in that phone book. It tells the internet where to send web traffic, where to deliver email, who is allowed to issue your SSL certificates, and more. The whole system is defined by RFC 1034 and RFC 1035, the original 1987 specifications that still govern how names resolve today.

Remember one thing and the rest follows. Each record has a type (A, MX, TXT, and so on), a name (which hostname it applies to), a value (what it points to), and a TTL (how long resolvers may cache it). Everything below is a variation on that idea.

Want to see every record for a domain right now? Our DNS analyzer resolves all the types covered here in a single pass.

The record types you actually need to know

Dozens of record types exist, all of them catalogued in the IANA DNS parameters registry. In day-to-day work, seven of them cover almost everything.

Record	Purpose	Points to	Common use
A	Maps a name to an IPv4 address	`93.184.216.34`	Your website's server
AAAA	Maps a name to an IPv6 address	`2606:2800:220:1::`	IPv6-capable servers
CNAME	Aliases one name to another name	`target.example.com`	Subdomains, CDNs
MX	Routes email for the domain	`mail.example.com` (priority)	Email delivery
TXT	Holds arbitrary text	`"v=spf1 ..."`	Verification, SPF, DKIM, DMARC
NS	Delegates the domain to nameservers	`ns1.provider.com`	Which servers answer for you
CAA	Restricts who can issue SSL certs	`0 issue "letsencrypt.org"`	Certificate security

A and AAAA: where your site lives

An A record points a hostname to an IPv4 address; an AAAA record does the same for IPv6. When someone visits your site, their browser looks up the A/AAAA record to find the server's IP. The two are not interchangeable. They serve different IP versions, and you often run both. See A vs AAAA records for when each matters.

CNAME: aliases

A CNAME says "this name is really an alias for that name." It's how www.example.com often points at example.com, and how you point a subdomain at a CDN or SaaS host. One rule matters above the rest: a CNAME can't coexist with other records on the same name, per RFC 1034 (section 3.6.2), which is exactly why you can't put one on a root domain. The full story is in CNAME vs A records.

MX: email routing

MX (Mail Exchange) records tell the world which servers accept email for your domain, each with a priority number (lower wins). Without correct MX records, mail to your domain bounces. Details and worked examples are in MX records explained.

TXT: verification and email authentication

TXT records hold free-form text, which has made them the home for some of the most important modern records: SPF, DKIM and DMARC (email authentication), plus domain-ownership verification for services like Google and Microsoft. Start with TXT records explained.

NS: delegation

NS records declare which nameservers are authoritative for your domain. They're set at your registrar and copied into your DNS zone. Get them wrong and nothing else resolves. See NS records explained.

CAA: certificate authority authorization

CAA records are a security control that lists which certificate authorities are allowed to issue SSL/TLS certificates for your domain. They're optional, but worth setting. See CAA records explained.

TTL and propagation

Every record carries a TTL (time to live) in seconds, telling resolvers how long they may cache the answer. A low TTL (300s) means changes appear quickly but generates more lookups; a high TTL (86400s) is efficient but slow to update. Caching is the reason edits aren't instant. See DNS propagation explained for realistic timelines and how to speed up a migration.

How to inspect your records

You don't need command-line tools to audit a domain. Our DNS analyzer resolves A, AAAA, MX, TXT, NS, CNAME and CAA records in one pass and flags common misconfigurations. If you prefer the terminal, how to check DNS records walks through dig and nslookup.

Once these seven record types make sense, almost every DNS task becomes the same job: reading and editing the right line in the phone book. Pointing a domain at a host, setting up email, verifying ownership, debugging an outage. They all come down to that.