This article gives you a quick overview of Domain Name System (DNS) and how it influences your website, email address etc.

What is DNS?

DNS stands for Domain Name System. It's how your computer finds the resources it needs on the Internet.

The Internet is made up of millions of computers, talking to each other across high-speed data connections. Each is identified by a unique number. DNS tells your computer where it can find the computer handling a particular service.

Websites, instant messages - these are all handled by server computers, and DNS is how you find the right server for the right Internet service. One of the most important details your computer receives when it connects to the Internet is where to look for DNS information.

Who is DNS important for?

Most people won't need to worry about DNS, because it's handled automatically by their Internet connection. Understanding DNS is important for people who have their own domain names. If you have email or a website based on your domain name, your DNS records will make it possible to send email to you, receive email from you, and view your webpages.

Domain owners who have their domain hosted with Paradise have the option of allowing Paradise to handle their email and website, in which case our help desk will be able to take care of DNS records.

I have a domain name. How do my DNS records work?

If you have a domain, you also have a domain host The host is the company that maintains the domain and its DNS information. The host has the 'authoritative DNS' server, where all other DNS servers on the Internet get their information about your domain.

The host's records will show where the servers handling email and webpages for your domain are located. So if your domain host is not handling your email and web page, the DNS records for your domain will need to be altered to point towards the hosts handling those services.

What records will I need?

For any service you have, you will need an 'A record'. An A record points towards a specific server. For example,
www.paradise.net.nz directs your browser to look at the server on
203.96.152.127. This is a web server, so the
Paradise website can be found there.

If you have email based on your domain, you will need an MX record

MX is short for Mail Exchange. It points towards the server that handles email for a particular domain.

If you have your own private email server, you will need a PTR record. (This isn't strictly true, but in order to fight spam, many email servers will refuse to accept email from a mail server that doesn't have a PTR record.) The PTR record works in reverse, and allows an email server to find out who owns the mail server trying to deliver messages to it at the moment, when all it knows is the numeric address.

What is a C name?

A C name shows that the DNS information for a domain is the same as another domain.

As an example, a company Dave's Plumbing has several different domains: davesplumbing.co.nz, davetheplumber.co.nz and davefixesdrains.co.nz. davesplumbing.co.nz has an A record and an MX record.

Dave shifts his hosting around from time to time, so each time he moves the website and email, he updates the davesplumbing.co.nz DNS records to point towards the new servers.

davetheplumber.co.nz and davefixesdrains.co.nz< both have C names pointing towards davesplumbing.co.nz. When someone tries to use them to look at Dave's website or send him email, they tell the visitor's computer to 'look at that domain over there for our DNS info'. They don't need to be updated separately, because they always point to where the correct information can be found.

How can I change my records?

You can have our webmaster update your records by emailing us the details. Please let us know the records and IP addresses to be changed, and send the request from your main contact email address.

Please note: a change made to your DNS records will usually update and become available on the our DNS servers within the day. It may take up to 48 hours for other DNS servers in New Zealand to update their own records from our server, and it could take a week or longer before the majority of DNS servers on the Internet will have the new information. Unfortunately, each DNS server has its own schedule for updating, so it is not possible to shorten the time it takes.

Where can I find my DNS information?

The current records can be found using a DNS search tool, like the ones found at http://www.dnsstuff.com/ . Please keep in mind that this will show you the information that has been added to the DNS records by someone with authority over the domain. If the records have been written incorrectly, the information shown will not be useful.

Finding the correct information to enter into your records can often be tricky. Many of our customers spread their Internet services around different hosts to cover special requirements. In these cases, we ask our customers to keep written records of IP addresses, server names and the contact details for each of these hosts, because it may not be possible for us to locate these details on your behalf.

We often receive calls from customers who have had their services set up by someone who has since left the company, or IT staff on a short term contract, and are now having great difficulty contacting the different hosts who are providing their Internet services. While we can sometimes help to identify the different providers, there is no guarantee that this will be possible.

Where can I learn more about DNS?

There is a great deal of information about DNS available, including history and specialised DNS features not covered in this document. A good place to start is http://en.wikipedia.org/wiki/Dns .

How to find your IP address

To find which IP address you are connected to, go to www.whatismyip.com and it will automatically tell you what address you're using.