When you connect to the Internet to browse Web sites or to send emails, your PC needs to exchange information with various servers. You send emails and navigate to Web sites by entering email addresses and domain names. Computers, however, identify each other through a series of numbers, known as IP addresses.
What Are Domain Name Servers?
To translate these domain names into IP numbers and retrieve information, your computer sends a request to a Domain Name Server (DNS), provided by your Internet Service Provider. These servers contain databases of domain names and the IP addresses where they are found. They act as Internet directories for computers, redirecting requests to other DNS servers, known as root servers if the domain requested does not appear in their cache until the domain is resolved.
Where to Find your DNS Information
Most of the time all this looking up of domain names and transferring information happens behind the scenes, and it is not necessary to know which name servers your computer is using to fetch the Web sites you want to view, or to send email.
Even when you register a new domain name, unless you decide to do the hosting and administration yourself, you are unlikely to need to worry about the DNS settings for your domain. If you register your new domain with your Web host, they will automatically enter the name servers into your DNS records for you.
This name server information will be listed with other server information, and is often emailed to you shortly after registration. Typical name servers will look something like NS1.HOSTINDOMAIN.COM.
When to Change DNS Information
If you change your Web site hosting provider, you will have to transfer the files that comprise your Web site from your old host's servers to your new host. If you transfer your domain name registration to your new host as registrar at the same time, they will normally take care of the DNS updates as part of the transfer service.
In this case all you need to do is make sure your Web site is installed on your new server before the transfer completes. It's best to do this part way through a billing cycle so that the files exist on both your old and new servers during the transfer. This will minimize any down time as DNS servers across the Internet update their caches with your new server information.
If, on the other hand, you manage your domain separately from your hosting, when you transfer your site from one host to another, you will need to update the DNS server information manually with your domain registrar.
Your host will provide you will all the server names you need, and you will have to log in to your registrar's control panel and update the name server information. If you are in any doubt about which records you need to change, email your new Web host and ask them. If you have questions about where to enter the information your registrar's support desk is the best place to ask.