Domain Name System (DNS) Management Guide

This article will explain about Domain Name Systems and what they do.

In this Domain Name System (DNS) Management article, you will find all the information you need to understand and set up A records, CNAME, MX records and more. Simply click on a title below to skip to the most appropriate FAQ. You can also click the Top button to return and make another selection:

What is the Domain Name System (DNS)?

DNS stands for Domain Name System. The main function of DNS is to translate domain names into IP addresses, which computers can understand. It also provides a list of mail servers which accept emails for each domain name.

The DNS consists of 3 important elements: nameservers, zone files and records. Each one plays an equally important role as nameservers store your zone files, which in turn store your records.

What are nameservers?

A nameserver is a computer server that helps browsers connect a URL to a website. That way, you don’t have to enter an intricate IP address every time you want to visit a website. It’s also where the zone file and DNS records for your domain are stored and organised.

Typically, each website uses 2 nameservers, with one of them acting as a backup to prevent the domain name from going offline. Since every hosting provider uses its own nameservers, they can also be used as an indicator for where your webspace and email can be managed.

One of the advantages of registering your domain name with 123 Reg is that you are free to change your nameserver to point to a third-party provider whenever you like. You’ll still be able to use our web and email systems as well, provided the correct DNS configuration is added at your new nameserver provider.

Please note: if you change your nameservers to point to a third-party provider, you will no longer be able to configure your DNS settings for that domain within your 123 Reg Control Panel. Instead, your DNS records will need to be configured by using the third-party provider that owns those nameservers.

What are zone files?

Zone files are a small set of instructions that tell the nameserver to perform specific tasks or point a domain name to the correct server or IP address, based on the DNS records stored within it.

What are records?

Records are the individual components of your Domain Name System. Here is a quick outline of some of the different types of records used:

  • A records, also known as Address records, are used to point a domain name or subdomain name to an IP address
  • CNAME records, also known as Canonical Name records, are an alias to another domain name. For example, the CNAME for could be This means that when you visit , it will check the DNS records for and point you there
  • TXT records, also known as Text records, are used to hold text information. You can put virtually any text you want into a TXT record, which can be assigned to a particular hostname/zone. The most common use for TXT records is to store SPF (sender policy framework) records and to prevent emails being faked to appear to have been sent from you.
  • SPF records, also known as Sender Policy Framework records, are used for identifying which mail servers are allowed to send email on behalf of your domain. The main purpose is to prevent spammers from sending emails with forged sender’s addresses (‘From:’ addresses) at your domain
  • MX records, also known as Mail Exchanger records, specifies which mail servers are responsible for a specific domain name.

What are cached DNS records?

To speed up DNS, most nameservers on the internet will ‘cache’ (or remember) DNS records themselves so that they don’t have to look up records each time they’re required.

When you visit a website, it’s likely that your ISP’s nameservers will remember the IP address, so that the next time you request that website, the IP address can be retrieved more quickly. In this instance, your ISP’s nameserver is using a cached DNS record. It will use this cached record for a period of time, after which it will retrieve the record again. It will again cache the record and the cycle will repeat.

This is why, when you make changes to your DNS, some people will not immediately see the change as they may well be seeing a cached record.

What does the record with the name @ mean?

The record named @ refers to your domain name in its purest form with no subdomain like www – for example,

It is common practice to set up both an @ record and a www record for your domain name. By doing this, you will ensure that any visitors who omit the ‘www’ prefix of your domain name will still be directed to your website, instead of an error page.

What are subdomains?

A subdomain is a subdivision of a domain name, allowing you to put content in your URL before your namespace. For example, or would be subdomains of the domain name

This is an excellent way of dividing your website if you have different regions, products or even languages.

How do I check my nameservers?

The simplest way to check the nameservers of your domain is to go to a public DNS lookup tool (i.e. and enter your domain name into the provided box.

From there, you’ll be given a detailed list of information that will include your nameservers.

How do I change nameservers?

You can change the nameservers of your domain name from your 123 Reg Control Panel.

Check out the following guide for step-by-step instructions on how to complete this: How do I change the nameservers for my domain name?

How do I set up an A record?

To set up an A record for your domain name, you will need an IP address from your provider.

For further details on how to do this, simply follow the instructions outlined in the following guide: How do I point my domain name to an IP address?

How do I set up a CNAME record?

To set up an CNAME record for your domain name, simply follow the instructions outlined in the following guide: How do I set up a CNAME record on my domain name?

How do I set up a TXT record?

To set up a TXT record for your domain name, simply follow the instructions outlined in the following guide: How do I set up a TXT record on my domain name?

How do I set up an SPF record?

To set up an SPF record for your domain name, simply follow the instructions outlined in the following guide: How do I add an SPF record to my domain name?

How do I set up an MX record?

To set up an MX record for your domain name, simply follow the instructions outlined in the following guide: How do I set up an MX record on my domain name?

What is domain propagation?

DNS (Domain Name System) propagation is a term used to describe the updating of information across the Internet. It takes two forms: changes to your DNS Zone and changes to your WHOIS nameserver information. A change to your DNS Zone information typically affects only a handful of servers and completes much more quickly.

However, the WHOIS is the master record which tells every DNS server in the world the nameserver for your domain.

Your changes may not be visible for up to 48 hours, mainly because millions of DNS servers need to be updated with the new information.

What is TTL and what is it used for?

TTL stands for Time To Live and is used to measure the lifespan of data in a computer or network – for example, when you create an SRV record for your domain name. This dictates the length of time it takes for the cache of the server to update, so if you make a change, this is the length of time it will take the propagate. TTL is measured in seconds, so, for example, a TTL of one hour would equate to a TTL to 3600 seconds.

Please note: When you create records for your domain names through 123 Reg, the TTL is automatically set at 3600 seconds and cannot be changed manually.


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