What is the Domain Name System (DNS)

A rolodex of contact cards

Domains – How do they work?

As a website owner or administrator, you’ve no doubt come across the terms domain or domain name system (DNS). Much like a phone or TV, you don’t need to know how the bit in the middle works to make use of it. But there may be a dreaded day when a project manager – or worse, a web developer or system administrator – gives you an ‘A record’ or nameservers to change before your fancy new website can go live.

What is the Domain Name System (DNS)

The domain name system is really just the phone book of the internet. It allows us to register a domain name and tell others where the website or services connected to that domain name live.

Who runs the Domain Name System

“The Internet Corporation for Assigned Names and Numbers (ICANN) is a nonprofit organisation responsible for coordinating the maintenance and procedures of several databases related to the namespaces and numerical spaces of the Internet, ensuring the network’s stable and secure operation.” – Wikipedia

What is a Domain Name

A domain name is a human-friendly naming system for displaying the unique location of your website, email or internet-based services.
What makes up a domain name?

http:// – This is call the protocol – in this case ‘hypertext transport protocol’ (others include: ftp:// | https://)
rouge-media – This is the domain name
.com – This is the Top Level Domain (TLD) – others could be .org, .gov, etc
www This is a subdomain

Subdomains can be created at a server level and are treated as an independent domain in its own server space. Subdomains are useful if we want to subdivide the domain for other purposes. I.e.

www is by definition a subdomain. It generally tells us that a website lives on this address. The use of www is commonplace but it’s not a necessary requirement and is often omitted as a preference to simplify the URL. For instance, here at Rouge, we use the following (a different domain to

Think of a domain name as a contact name in your phones address book. The name is the bit you see but it’s much easier to remember or search for a name than a phone number. Like your contacts, every domain name has a unique number associated with it called an IP address.

What’s an IP address?

Every machine or device on a network (including the internet) has a unique address called an IP address, currently in this format: IP stands for Internet Protocol address. Think of this an IP address like a street address. Every machine has one. IPs can be permanent, usually for mail servers or websites but can also be dynamically assigned to individual machines or devices on a network or assigned by an ISP. Your home router will have an IP address, but it may change from day to day.

How does a domain name ‘resolve’ to an IP address?

To avoid us having to remember an IP address to find a website or email people, the Domain Name System (DNS) provides a way to match domain names with IP addresses.

I.e. instead of
or [email protected] instead of [email protected]

The simplified lookup process:
1. Key in a domain name into a web browser or send an email
2. Special Domain Name Servers around the world resolve the domain name and return the IP address to you
3. Your device now knows the IP address and can contact the host (server)

DNS Propagation

When a new domain is registered, DNS changes are made or websites are moved to new servers, the domain name servers around the world need to be made aware of the changes. The servers do not update in real-time and some only update once a day or longer. This means that the propagation of the DNS changes can take time to go around the planet. When planning a website launch, its commonplace to expect DNS propagation to take up to 72 hours.

Digging a bit deeper – DNS records and different types of web traffic

There are a number of different DNS records that provide different ways of routing traffic to internet-based places and services. Listed below are the most common that you may need to change. Here is a useful reference to explain record types in more details:


For a domain to be able to route traffic- be that website requests or email, etc, – It has to have a home and be associated with a Name Server (NS). A Name Server is a server with DNS software installed on it. It holds all the information about the records for a particular domain and where to send traffic.

A name server takes this format:


An MX record tells senders how to send an email for your domain. Each MX record points to an email server that’s configured to process mail for that domain. There’s typically one record that points to a primary server, then additional records that point to one or more backup servers. For users to send and receive an email, their domain’s MX records must point to a server that can process their mail.

An MX Record typically looks like this: MX 86400 0 MX 86400 10 MX 86400 20
– One primary and 2 backup servers
86400 – Time to Live (TTL) in seconds. In this case the server checks for changes every day. (86400 seconds = 1 day)
0 (10, 20) – Priority. The lowest number is tried by the server first.

Check your MX records here:


An A or Address record (also known as a host record) links a domain to the physical IP address of a computer hosting that domain’s services. If a website is hosted on a different server, and therefore with a different IP address, then a change to the relevant A record needs to be made.

An A record takes the form of an IP address:

How can Rouge Media help?

Please get in touch with your website brief and we can help turn it into digital reality with minimum fuss and as little jargon as possible!

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