You would think something as critical as finding which server your website is located on or where to deliver email for your domain would be well understood and straight forward. Well, like a lot of things it is and it isn’t. When you set it up the first time, everything seems pretty clear and it all works nicely. But, when it comes time to moving pieces of the puzzle around, there are a number of gotchas and potential pitfalls. I know, because we’ve had some clients who have had problems with these systems and they’ve come to us for help. One of the big problems is that most of the companies involved with domain names and websites play multiple roles.

First, let me explain the pieces of the puzzle.

Domain Names

Each domain name is registered somewhere. This is your registrar and common registrars are folks like GoDaddy and Network Solutions. But there are probably hundreds of registrars (many just resell services of other registrars). You may get your domain name for free from the company that hosts your website.

Registering a domain name is a way you claim ownership of that name (you are listed as the owner of your domain names right – be careful of anyone registering a domain name that doesn’t make you the registrar) and allows you to point that domain to your servers.

Name Servers

Name servers are pointed to by your domain name and they have all the information about how to find you. You can think of them as an entry in your contacts list. You may have the cell phone, home phone and home address of your friend stored there. Similarly a name server for a domain will know where your website is, where your email should be delivered to, etc. This information is called DNS information for Domain Name System information. Some of these records use IP addresses – which are like phone numbers – and some of the records use domain names that point to other registered domains.

When you enter a URL into your browser’s address bar, the browser uses the DNS information to find your web server. A simplified description is that It finds the name server for your domain, figures out what name servers have your website’s information and ask one of them where the URL can be found. Mail servers act in the same way to find where email should be delivered. (It’s actually a bit more complex than that because the DNS information is cached at servers all around the internet, but those caches have duplicated the information from the key DNS servers).

Web Servers and Email Hosts

We all know what web servers and email hosts do. They host our web sites and provide a location for email delivery. But sometimes they also provide your name servers and they may also be your domain name registrar.

Problems with Name Servers and Transferring Services

Now that we have the pieces, let’s see where problems arise when things are moved. The problem I generally see is disappearing Name Servers and there are several reasons for this. It’s almost always caused by not realizing that the Name Server service you were getting for free for was bundled with another service you were actually paying for.

When you transfer a domain name, the Name Servers don’t change. They just come along for the ride. But, if your Name Servers are being provided as part of your domain name registration, they probably will go away when the domain name is transferred. So it’s important, before you transfer a domain name, to ensure that the Name Servers it points to will still be around once the transfer is over.

This can also happen if you’re using the Name Servers of your web host and you move the website and cancel the account. Since you had the Name Server service as part of the hosting account, once you close it they probably will go away. Now, I will say I have seen some cases where Name Servers were still active when a client had no services with that company, but I can’t consider that a stable setup.

How to Prevent Problems

It’s important before you transfer any one of your services – Domain Name Registration, Name Servers, Web Hosting and Email Hosting – that you understand where each of those services are, how you are paying for them and how your moving of one service will affect any of the others.

More DNS Resources

Here are some useful resources that give you more information on DNS.

• FBI's Operation GhostClick Information Page
• Media Temple has a nice explanation of what DNS entries can contain.
• How Stuff Works has a more complete explanation of how DNS lookup works.
• Of course WikiPedia has more details on the history of domain names and DNS.