Domain Names and DNS Explained

Are you confused by the difference between "Domain Management" and "DNS Management"? Do you want to understand who has control over your domains? This article aims to answer these and other related questions in simple terms.

This article builds on the previous article Internet Terminology for Beginners.

Domain Names and Domain Name Management

Your domain name is used to point people and systems and certain resources. For example, your domain name may be mycompany.co.uk. This single domain name could be used for a variety of purposes - for example:

• www.mycompany.co.uk can point to your corporate website
• ...@mycompany.co.uk will then be used for your email
• remote.mycompany.co.uk is the address used to remotely access your office systems from home
• blog.mycompany.co.uk might be a subsidiary website

As can be seen, domain names may be used for a lot more than just being the address of your website.

Who Manages Your Domain?

Each top-level domain (.co.uk, .com, .org. etc.) will have a separate organisation known as an Internet Registry, responsible for maintaining a register of who owns each domain name.

In the UK, for example, .co.uk domains are managed by Nominet. You can find out more about Nominet by visiting their website.

Nominet and other Internet Registries do not, however, deal directly with those people and organisations who wish to register a domain name for themselves - instead, they deal through 3rd parties known as Registrars. These are typically ISPs and other Internet-based businesses based around offering the service of registering domain names.

The Registrar will manage your domain.

What Does Managing The Domain Mean?

Domain Name registrations are for a fixed period of time (typically two years) and so Domain Management means dealing with the ownership of that domain, dealing with the renewal process of that domain and controlling who provides the DNS Management (see below) without actually providing the DNS Management itself.

Domain Management does not cover any aspects of what the domain is used for - it does not, for example, provide management of the information about where your website is hosted or which server deals with the email sent to that domain. That is covered by DNS Management.

How Do I Find Out Who Is Managing My Domain?

To find out who the owner of a given domain is, and who the administrative contact is (typically this will be the registrar of the domain), you need to carry out a "Who Is" query. Many websites offer a "Who Is" lookup - for .uk domains, the Nominet website itself will provide this service whilst there are 3rd party websites available which also offer this service - for example DNSStuff.com - or simply type "who is" into a search engine. Remember, when typing your domain name into a "Who Is" query that your domain name is simply mycompany.co.uk and not www.mycompany.co.uk - the address including the "www" part is called a sub-domain.

DNS Management

When someone types "www.mycompany.co.uk" into their web browser, their computer needs to turn that domain name into an IP address in order to identify the web server to ask for the web page. DNS is all about providing the mechanism the translate domain names into IP addresses.

This happens by looking at the domain name record itself (as shown by the "Who Is" enquiry) and finding out what it's name server is. A name server is a server somewhere on the Internet that simply has vast lookup tables to indicate that a particular domain name is equivalent to a particular IP address. In fact there won't be a single entry but many since there will be one to indicate the IP address for www.mycompany.co.uk (generally refered to as the 'A' record), one for email (the MX record) and maybe others for things like remote.mycompany.co.uk and blog.mycompany.co.uk in the example above. The organisation that hosts these lookup tables on their servers is providing you with the DNS Management.

TTL ("Time To Live")

If your computer needed to look up the Names Server for your domain every time it wanted to load something from your website, it would introduce a massive overhead - since it would need to look up your domain to find your Names Server then look up your Names Server to find your web server - three lookups instead of one.

This means that when your computer looks up a name in a names server, it stores the results locally so it does not need to look them up again. This is called DNS Caching. It cannot store these details forever, though, since then it wouldn't know about changes (such as if you move your website to a new web server). Every DNS entry has a TTL, or Time To Live, associated with it and this tells any computers storing this information how long they can hold on to it before they need to go back to the Names Server to get updated information.

By default, this value is usually 24 or 48 hours.

For day-to-day purposes, this is fine but it does mean that if you are about to move your website, or launch a new one, then there will be a day or two when some people will see the old site and some people will see the new site. This is clearly very unsatisfactory so best practice is to reduce the TTL to, say, one minute a couple of days before the launch of the new site and then, once the transfer has taken place, put it back up. This way, everyone will pick up the new site almost immediately.

You cannot, of course, reduce the TTL to one minute immediately before updating the DNS entry since it will then be too late for the people that already have cached local copies that have a longer TTL associated with them.

Summary

Domain Management is all about looking after your ownership of your domain name but nothing to do with what it is used for.

DNS Management is all about configuring (and making available on the Internet) information about what a Domain Name is being used for, such as which server on the internet holds its website.

Both are required and are often provided by completely different organisations.