A DNS zone file is the set of DNS records that tells the internet how a domain should work. It contains records such as A, AAAA, MX, CNAME, TXT and NS records, which control where a website points, how email is delivered and how third-party services verify domain ownership.

For Apexhost customers, understanding zone files is useful when reviewing DNS settings, preparing a migration, troubleshooting website or email issues, or making changes supplied by a hosting, email or software provider. You do not always need to edit a raw zone file directly, but the term zone file is commonly used to describe the full DNS record set for a domain.

A DNS zone is the authoritative collection of DNS records for a domain. A zone file is the data that defines that zone. In practical terms, it is the complete list of records and values that tell DNS resolvers how to answer queries for the domain.

For example, a zone file may include:

* An A record that points example.com.au to a website server

* A CNAME record that points www.example.com.au to another host name

* MX records that direct email to the correct mail platform

* TXT records used for SPF, DKIM, DMARC or domain verification

* NS records that identify the authoritative nameservers for the zone

Some DNS platforms show these records in a visual DNS editor rather than as a plain-text file, but the underlying purpose is the same.

The zone file controls whether key services for your domain work correctly. If records are missing, incorrect or saved in the wrong DNS host, your website, email or connected applications may fail.

Zone files are important because they:

* Control website routing for the root domain and subdomains

* Define email delivery through MX and related TXT records

* Support Microsoft 365, Google Workspace and other external services

* Help verify domain ownership for SSL certificates, cloud platforms and third-party tools

* Provide the DNS settings that may need to be copied during a migration

A small change in a zone file can have a wide effect. This is why DNS changes should only be made when you understand the required outcome or have confirmed values from the relevant provider.

Most zone files contain a combination of standard DNS record types. The exact records depend on how the domain is used.

A record

This points a host name to an IPv4 address. It is commonly used for website hosting.

AAAA record

This points a host name to an IPv6 address.

CNAME record

This creates an alias from one host name to another host name. It is commonly used for subdomains such as www.

MX record

This tells other mail servers where to deliver email for the domain.

TXT record

This stores text-based values used for email authentication, verification and service configuration.

NS record

This identifies which nameservers are authoritative for the domain or subdomain.

SOA record

This stands for Start of Authority. It contains administrative information about the zone, such as the primary authoritative server and timing values used by DNS systems.

Before updating DNS records in a zone file, make sure you have:

* Access to the control panel that hosts the active DNS zone

* Permission to make DNS changes for the domain

* The exact record values provided by your hosting, email or software provider

* A copy of the current DNS records in case you need to revert changes

* An understanding of whether the change affects the root domain, a subdomain, email routing or a third-party service

If you are unsure where the active DNS zone is hosted, first check the domain’s nameservers. Updating records in the wrong portal will not affect live DNS.

The exact steps depend on where your DNS is hosted, but the general process is similar across most platforms.

1. Log in to the control panel or DNS portal that manages the active DNS zone for your domain.

2. Open the DNS management area for the relevant domain. This may be labelled DNS, Zone Editor, DNS Zone Records or similar.

3. Review the existing records carefully before making changes. Confirm which record type, host name and value need to be updated.

4. If you are changing an existing service, record the current values before you edit them.

5. Add, edit or remove the required DNS record exactly as instructed by your provider.

6. Save the change.

7. Allow time for DNS propagation and caching before testing from all networks.

[Screenshot: DNS zone editor showing a domain’s active records]

If your provider has supplied multiple records, enter each one exactly as provided. Missing even one required record can affect the service being configured.

You may need to review or update a zone file when:

* Moving a website to a new hosting server

* Changing email delivery to Microsoft 365, Google Workspace or another mail provider

* Adding SPF, DKIM or DMARC records

* Verifying a domain for an SSL certificate or third-party platform

* Creating a subdomain such as shop.example.com.au or app.example.com.au

* Migrating DNS from one provider to another

In many of these cases, the safest approach is to copy the existing zone first, then add or change only the records required for the new service.

* Updating DNS in a control panel that is not authoritative for the domain

* Replacing the wrong record

* Forgetting to preserve MX, SPF, DKIM or DMARC records during a website migration

* Creating duplicate records for the same host name without intending to do so

* Confusing an A record with a CNAME record or an MX record

* Expecting the change to work instantly everywhere

* Deleting records before recording the old values

Because DNS affects both website access and email flow, it is good practice to make changes carefully and during a time when you can monitor the result.

The website or email stopped working after a DNS change

This often means a required record was changed, removed or not copied into the active zone. Review the current zone file and compare it with the previous configuration or the provider’s required settings.

The DNS update does not seem to work

Confirm that the domain is using the expected nameservers and that the record was updated in the active DNS host. If the settings are correct, allow more time for caching and propagation.

A third-party service cannot verify the domain

Check that the required TXT, CNAME or other verification record was entered exactly as provided. Also confirm that it was added to the correct host name.

Only some users can see the change

This is commonly caused by DNS caching. Different networks and resolvers may refresh at different times.

Is a zone file the same as DNS records?

A zone file is the complete collection of DNS records for a domain. People often use the terms interchangeably when referring to the domain’s DNS configuration.

Do I always edit a raw text zone file?

No. Many hosting providers present the zone through a DNS editor or control panel interface instead of showing the raw file directly.

Can changing one record affect email?

Yes. Some DNS changes can affect website access only, while others can affect email delivery, verification or spam protection. Always review related records before saving changes.

How long do zone file changes take?

The change is usually saved immediately at the DNS host, but cached DNS results may take time to refresh across different networks. This delay is commonly called DNS propagation.

• What is DNS? (DNS)

• Nameservers (DNS)

• DNS Propagation (DNS)

• TTL (DNS)

• A Records (DNS Records)

• AAAA Records (DNS Records)

• CNAME Records (DNS Records)

• NS Records (DNS Records)

• Change DNS records

Need More Help?

If you require further assistance, please contact Apexhost Support at support@apexhost.com.au.