Understanding DNS

What is DNS?

DNS is an abbreviation for Domain Name System.



The Domain Name System translates host names such as www.netregistry.com.au into IP addresses (216.3.128.12), which are assigned to servers, that hold data information such as a website or email service.


When you type in a domain name to your web browser or e-mail client, it has to connect with your web hosting or email service. For this to happen, the domain name must be registered and pointed to the correct servers, which occurs through the Domain Name System.


In order for a domain name to find its corresponding website or email service, it must be delegated to a name server.

Every name server contains a zone file, which contains zone records. These are used to translate domain names into IP addresses, which represent the computer servers that host your website or email service.


DNS Issues?

There are several reasons why a domain name isn't connecting to a website or email service. These can include:


The domain name

  • has expired
  • doesn't exist/has been misspelled
  • is delegated to a name server that doesn't hold accurate zone files
  • is pointed to the correct service but something is wrong with the service


For a domain name to open a website, all three parts (the domain, name server/zone records and the website/email service) must be functioning correctly and connected to one another.


Check Your DNS Status?

Perform a Whois lookup against your domain name. This is explain if the domain

  • has expired?
  • who is the Registrar
  • it's delegation


If it's delegated to the wrong name servers, modify your domains name servers.


What does each zone record do?

For an email or website hosting service to function alongside a domain name, the domain name requires a zone file.


Within your domain's zone file, there are several different kinds of zone records and each record serves a specific function. Below is a table describing each type of record that exists within your domains zone file and how you can use them.


The Domain Name System (DNS) offers specific instructions on updating DNS records on your domain name see our support articles for Cloud and cPanel. Or to manage DNS with a different provider see how to modify nameservers.


Record Type Description
A A records are used to direct your domain name (eg: www.mywebsite.com) to to IPv4 IP addresses – which then directs the user to your website. IPv4 IP numbers look something like this: 122.140.201.66
AAAA AAAA records are used to direct your domain name (eg: www.mywebsite.com) to IPv6 IP addresses – which then directs the user to your website. IPv6 IP numbers look something like this: 3ffe:1900:4545:3:200:f8ff:fe21:67cf. They were introduced when the internet ran out of IPv4 combinations.
CAA A Certification Authority Authorization (CAA) record is used to specify which certificate authorities (CAs) are allowed to issue certificates for a domain.
CNAME CNAME records (also called Canonical records) are simply alias records that point to domain names, rather than an IP address (as A records do). They are usually used to point a domain to a service, like Tumblr, Gmail or Wordpress, where user accounts are sub domains or directories of the service. When users change the IP address associated with their A record, all CNAME records that point to that A record update automatically.
DKIM DKIM records are similar to SPF records in that they're used to combat email spoofing. The method they use to combat email spoofing is a bit different from SPF records however. Where as SPF records use IP address checks, DKIM records make use of a private/public key relationship between the sending mail server and the DNS server. DKIM records help prevent email spoofing by adding a digital signature to outgoing message headers using the DKIM standard.
MX MX records are used to direct a domain name to an email exchange server. MX records must always point to domain names which belong to another zone record and not an IP address. The IP address is always resolved by the A Record.
NS The NS records contain the name server information for the zone they exist on.
SOA A Start of Authority record is a special resource record included in every zone file. The SOA record supplies certain basic information about the zone including the zones primary authoritative server.
SPF The Sender Policy Framework (SPF) is an extension to the Simple Mail Transfer Protocol (SMTP). SPF records allow software to identify and reject forged email addresses in the SMTP MAIL FROM (Return-Path), a typical nuisance in e-mail spam. The Sender Policy Framework allows the owner of a domain name to create special TXT records (SPF records are actually just TXT records with specific SPF code inserted into them) that specify which email servers are authorised to send emails on behalf of that domain name.
SRV An SRV record is a specification of data in the DNS, defining the location of a server for specified services. For more information, click here.
TXT TXT (also SPF and DKIM) zone records allow the owner of a domain to specify which IP addresses are allowed to send emails using their domain.
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