DNS stands for Domain Name System. It is the system that helps computers find websites, email services and other internet services by translating human-readable names such as domainname.com.au into the IP addresses that computers use to connect to each other.
DNS is important because people remember names more easily than numbers. Without DNS, you would need to know the IP address of every website or service you wanted to use. DNS also makes it possible to direct different services for the same domain, such as a website, email and third-party verification records, to the correct destination.
If you own a domain name, manage website hosting, use business email or connect services such as Microsoft 365 or Google Workspace, you will regularly rely on DNS even if you do not change DNS records yourself.
How DNS works
When someone enters a domain name into a web browser, a DNS lookup takes place behind the scenes to find out where that domain should point.
The DNS lookup process usually works like this:
1. Your browser or device checks whether it already has a recent DNS answer stored in its cache.
2. If it does not, the request is sent to a DNS resolver, usually operated by your internet provider or another DNS service.
3. The resolver checks the wider DNS system to find the authoritative DNS records for the domain.
4. The correct record is returned, such as the IP address for a website or the mail server for email.
5. Your device uses that answer to connect to the correct service.
This process normally happens in seconds and is repeated constantly across the internet for websites, email delivery, app connections and many other services.
Why DNS matters
DNS affects whether your website, email and connected services work properly. If DNS records are missing, incorrect or pointing to the wrong provider, visitors may not be able to reach your website and email may stop being delivered correctly.
DNS is commonly used for:
* Directing your website to your hosting server
* Routing email to the correct mail service
* Verifying domain ownership for external services
* Supporting security features such as SPF, DKIM, DMARC and DNSSEC
* Connecting subdomains such as www, mail or shop to the correct service
Because DNS is so central to internet services, even a small change can have a wide effect. For this reason, DNS records should only be updated when you understand the change being made or have been given confirmed values by your provider.
Common DNS terms
Understanding a few common DNS terms makes it much easier to manage domains and troubleshoot problems.
Domain name
A human-readable internet address such as domainname.com.au.
IP address
A numerical address used by computers and servers to identify each other on a network.
DNS zone
The collection of DNS records for a domain.
Name servers
The servers that host the DNS zone for a domain and answer DNS queries about it.
DNS resolver
A service that looks up DNS answers on behalf of your device.
TTL
Short for Time To Live. This controls how long a DNS answer may be cached before it must be checked again.
Propagation
The time it takes for DNS changes to be seen across different networks and resolvers.
Common DNS record types
DNS uses different record types for different purposes. The most common ones include the following.
A record
Points a domain or subdomain to an IPv4 address. This is commonly used to direct a website to a hosting server.
AAAA record
Points a domain or subdomain to an IPv6 address.
CNAME record
Points one hostname to another hostname instead of directly to an IP address.
MX record
Tells the internet which mail servers receive email for the domain.
TXT record
Stores text-based information, often used for SPF, DKIM, DMARC and domain verification.
NS record
Identifies the authoritative name servers for the domain.
SRV record
Used by some applications and services to identify service locations.
PTR record
Used for reverse DNS, mapping an IP address back to a hostname.
DNS and website hosting
DNS and website hosting are related, but they are not the same thing. Website hosting is the server space where your website files and databases are stored. DNS is the system that tells visitors where that hosting server is.
This means a domain can be registered with one provider, hosted with another provider and use DNS hosted somewhere else entirely. What matters is that the domain’s active name servers hold the correct DNS records for the services you use.
If you change hosting providers, DNS often needs to be updated so that the domain points to the new server. If you change name servers, you must make sure all required website and email records exist at the new DNS provider before making the switch.
DNS and email
DNS is also essential for email. Your domain’s MX records tell other mail servers where to deliver messages for your domain. Additional TXT records such as SPF, DKIM and DMARC help verify that email is legitimate and improve deliverability.
If email DNS records are missing or incorrect, you may experience problems such as:
* Email not being delivered to your mailbox
* Outgoing mail being marked as spam
* Failures when setting up Microsoft 365 or Google Workspace
* Problems verifying domain ownership for email services
When changing DNS, always check whether the domain has email records that need to be preserved. Website-related changes can accidentally affect email if the DNS zone is incomplete.
DNS propagation and caching
After you make a DNS change, the new record may not appear everywhere immediately. This is because DNS answers are cached for a period of time based on the record’s TTL and the behaviour of different resolvers.
Some DNS changes appear within minutes, while others may take longer to be reflected across different networks. During this period, some visitors may reach the new destination while others still reach the old one.
This delay is commonly called DNS propagation, although the change itself is usually made as soon as it is saved on the authoritative DNS server. The waiting period mainly comes from cached answers expiring across the internet.
Common DNS issues
DNS problems can affect websites, email and connected services in different ways. Common issues include:
* The domain points to old or incorrect name servers
* A records or CNAME records point to the wrong server
* MX records are missing or incorrect
* SPF, DKIM or DMARC records were not copied during a DNS migration
* Changes are being checked before cached records have expired
* DNS is being updated in the wrong provider portal
If a website or email service stops working after a DNS change, first confirm which provider currently hosts the DNS for the domain and then check whether all required records are present there.
Before you change DNS
Before making DNS changes, it is good practice to have the following information ready:
* The full domain name
* Access to the portal where the active DNS zone is managed
* The exact DNS records or values supplied by your provider
* A record of the current DNS settings in case you need to restore them
* An understanding of whether the change may affect website, email or third-party services
If you are unsure where your DNS is hosted, check the domain’s active name servers first. This helps avoid making changes in the wrong control panel.
Frequently asked questions
Does DNS host my website?
No. DNS does not host the website itself. It tells visitors where the website is hosted.
Can I change DNS without moving my website?
Yes. You can update DNS records or even move DNS hosting without moving the website itself, provided the records continue to point to the correct server.
How long do DNS changes take?
Some changes appear quickly, while others may take longer depending on caching and TTL settings. It is normal for results to vary between networks during this period.
Will changing name servers affect email?
It can. If the new DNS zone does not include the correct MX, SPF, DKIM or DMARC records, email delivery may be disrupted.
Do I need to understand every DNS record?
No, but it helps to understand the purpose of the records you are changing. Incorrect DNS updates can affect live services.
Related Articles
Domain Names Explained (Domains)
DNSSEC (Domains)
WHOIS (Domains)
Domain Transfers (Domains)
Choosing the Right Hosting (Getting Started)
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