What A, AAAA, MX, TXT and CNAME records actually do, in plain language, with the tools to check any domain's records in seconds.

Every time a browser loads a website, sends an email, or verifies a domain, it is reading DNS records behind the scenes. Most people only run into DNS when something breaks: an email is not arriving, a website will not resolve, or a hosting migration needs new records pointed at the right server. This guide covers the record types you will actually run into, what each one is for, and how to check them yourself.

What DNS records are, in one sentence

A DNS record is a line in a domain's configuration that tells the internet where to send traffic, mail, or verification requests for that domain. A domain usually has several records of different types, each handling a different job.

A record

The A record points a domain to an IPv4 address, such as 203.0.113.10. This is the record that makes example.com load a specific server. If a website is not loading after a hosting change, the A record is usually the first thing to check, since it may still be pointing at the old server.

AAAA record

Same job as an A record, but for IPv6 addresses instead of IPv4. Most domains now have both an A and an AAAA record so the site works over either protocol, depending on the visitor's network.

MX record

The MX (Mail Exchange) record tells other mail servers where to deliver email for a domain. It points to a mail server hostname rather than an IP address directly, and usually comes with a priority number, where a lower number is tried first. Getting the MX record wrong, or leaving a stale one after switching email providers, is one of the most common reasons email suddenly stops arriving.

TXT record

A TXT record holds arbitrary text tied to a domain. In practice it is almost always used for verification and email authentication: proving domain ownership to Google Search Console or another service, or publishing SPF, DKIM and DMARC policies that tell receiving mail servers which servers are allowed to send email on the domain's behalf. A domain can, and usually does, have several TXT records at once.

CNAME record

A CNAME (Canonical Name) record points one hostname to another hostname instead of to an IP address directly, for example pointing www.example.com to example.com. It is commonly used for subdomains handled by a third-party service, such as a help desk or a CDN, so that provider can change its own IP addresses without anyone needing to update the customer's DNS. One rule to remember: a domain cannot have a CNAME record at its root alongside other records of the same name, which is why root domains typically use an A record instead.

How to check a domain's records yourself

You do not need to install anything to see this information. SEOpeck's DNS Lookup tool returns the A, AAAA, MX, TXT and CNAME records for any domain in one request. If you only care about mail delivery, the MX Lookup tool shows just the mail servers and their priority. And if you already know the IP address and want to go the other direction, the IP to Hostname tool and Hostname to IP tool handle reverse and forward lookups.

A quick troubleshooting checklist

• Website not loading after a host change: check the A (and AAAA) record points to the new server's IP.
• Email not arriving: check the MX record points to the current provider's mail servers, with the correct priority.
• A service says the domain is not verified: check the TXT record it asked you to add is present and exactly matches, with no extra spaces.
• A subdomain will not resolve: check whether it should be a CNAME pointing at the provider's hostname, and confirm there is no conflicting record at the same name.

DNS changes can take time to spread across the internet because of caching, so if a record looks correct but is not working yet, it is often worth waiting for the record's TTL (time to live) to expire before assuming something is misconfigured.