DNS is one of the parts of the internet that most website owners never have to think about until something breaks. A website suddenly stops loading, email stops arriving, or a new subdomain refuses to work, and the problem often turns out to be a DNS record.

DNS, or the Domain Name System, translates names such as example.com into information that computers can use. DNS does much more than point a domain at a web server. Different record types tell DNS resolvers where websites live, where email should be delivered, which hostnames are aliases, and how other systems should treat a domain.

What Is a DNS Record?

A DNS record is an entry in a DNS zone. Each record has a name, a type, a value, and usually a TTL, or time to live. The exact interface varies between registrars and hosting providers, but the underlying concepts are the same.

Record	Purpose	Typical value
A	Maps a hostname to an IPv4 address	203.0.113.10
AAAA	Maps a hostname to an IPv6 address	2001:db8::10
CNAME	Makes one hostname an alias of another	www.example.com
MX	Specifies mail delivery servers	mail.example.com
TXT	Stores text used by many services	SPF, verification, policy data
NS	Identifies authoritative nameservers	ns1.example.com

A Records

An A record maps a hostname to an IPv4 address. For example, an A record for example.com might point to 203.0.113.10. When a browser needs the IPv4 address for that hostname, a recursive resolver can obtain the answer from the authoritative DNS servers.

A records are commonly used for the root domain and for hostnames such as www, shop, or app. If you move a website to another server and DNS is managed separately from your hosting account, changing its A record is one way to direct traffic to the new server.

AAAA Records

An AAAA record performs the equivalent job for IPv6. If your server has both IPv4 and IPv6 connectivity, you may have both A and AAAA records for the same hostname.

Do not add an AAAA record simply because IPv6 exists. The IPv6 address needs to be correctly configured and reachable. A broken AAAA record can cause some visitors to experience failures even though the IPv4 configuration works.

CNAME Records

A CNAME record makes one hostname an alias of another hostname. For example, www.example.com can point to example.com. The important distinction is that a CNAME points to a name, not directly to an IP address.

CNAME records are also common when using third-party services. A provider may tell you to create something such as verify.example.com CNAME token.provider.example. The exact value must be copied from the provider because the target is usually service-specific.

MX Records and Email

MX records tell sending mail servers where email for a domain should be delivered. An MX record contains a hostname and a priority value. Lower numerical preference values are normally attempted first.

For example, a domain might have:

example.com.    MX    10    mail.example.com.

The MX record does not contain the mail server’s IP address. The mail server hostname must itself resolve through A or AAAA records. That is why a mistake in either the MX record or the address record can break mail delivery.

TXT Records

TXT records are flexible text records used by many systems. They are commonly associated with domain verification and email authentication.

• SPF: identifies servers authorized to send mail for a domain.
• DKIM: publishes a public key used to validate signed messages.
• DMARC: publishes a policy for handling messages that fail authentication checks.
• Service verification: proves domain control to providers and platforms.

TXT records can look complicated because different services use different formats. Do not edit a verification value unless you know which service depends on it.

NS Records and Nameservers

NS records identify the authoritative nameservers for a DNS zone. Your registrar’s nameserver settings determine which DNS servers are authoritative for the domain. Those servers then publish the zone’s A, AAAA, MX, TXT, and other records.

This distinction is important. Changing a record inside a DNS zone is not the same thing as changing the domain’s authoritative nameservers. If you change nameservers, you can effectively move the entire DNS zone to another provider.

TTL and DNS Caching

TTL controls how long a resolver may cache a DNS answer. A lower TTL can make planned changes easier to roll out, while a higher TTL can reduce repeated DNS queries. TTL does not mean every device on the internet will refresh at exactly the same time.

Before a planned migration, administrators often lower relevant TTL values ahead of the change. After the new configuration is stable, TTL can be increased again if appropriate.

Common DNS Mistakes

• Creating an A record pointing to the old server.
• Adding an AAAA record for an IPv6 address that does not work.
• Deleting an MX record while trying to change website DNS.
• Creating duplicate or conflicting records for the same hostname.
• Putting a hostname in a field that expects an IP address.
• Forgetting that example.com and www.example.com are different hostnames.
• Changing nameservers without recreating required email and verification records.

How to Troubleshoot DNS

Start by deciding exactly what is failing. Website resolution, email delivery, and a third-party verification problem can involve completely different records.

On a Linux or macOS system, commands such as these can help:

dig example.com A
dig example.com AAAA
dig example.com MX
dig example.com TXT
dig www.example.com CNAME

Compare the answers against the authoritative configuration. If a recursive resolver still has an older answer cached, the result may differ temporarily from the authoritative server.

DNS Change Checklist

1. Document the existing DNS records before making changes.
2. Identify whether DNS is managed by your registrar, host, or another provider.
3. Change only the records required for the task.
4. Check A and AAAA records when moving a website.
5. Protect MX, SPF, DKIM, and DMARC records when changing web hosting.
6. Use dig or another DNS lookup tool to verify the result.
7. Allow for caching and TTL before assuming a change failed.

Final Thoughts

DNS becomes much less intimidating once each record type has a specific job. A records handle IPv4 addresses, AAAA handles IPv6, CNAME creates aliases, MX directs email, TXT carries service and policy information, and NS identifies authoritative DNS servers.

If you are moving a site or setting up a new domain, understanding these records can prevent a surprisingly large number of avoidable outages. For hosting, domains, DNS management, and the infrastructure behind your website, visit GaugeHosting.

Authoritative vs. Recursive DNS

It helps to distinguish between a recursive resolver and an authoritative DNS server. Your laptop or phone usually asks a recursive resolver for an answer. That resolver may already have the answer cached, or it may query the authoritative servers responsible for the domain. The authoritative server is the source of truth for the zone.

This distinction explains why two networks can temporarily return different DNS answers after a change. One resolver may have refreshed while another still has a cached response within its TTL.

Record Names and the Root Domain

DNS interfaces often represent the root of a zone with an @ symbol. That means a record such as @ A 203.0.113.10 applies to the bare domain. A record for www applies to www.example.com.

This is a common source of confusion when following instructions from a hosting provider. If the interface already knows which domain you are editing, entering the full domain name where it expects only a hostname can create an unintended record.

DNS Is Not the Same as Web Hosting

DNS only tells clients where a service can be found. It does not install a website, configure Apache or Nginx, create a database, or make an application respond correctly. A correct A record can point traffic to a server that has no website configured for that hostname.

Related Reading

• Domain Names vs Web Hosting: What's the Difference?

For web hosting, domains, DNS, and website infrastructure, visit GaugeHosting.