Difference between revisions of "What is a domain name?"
|Line 4:||Line 4:|
====How do I get one?====
====How do I get one?====
See [[Registering a domain]] for information on signing up for a domain name, and [[
See [[Registering a domain]] for information on signing up for a domain name, and [[Domains]] section for more information on transferring domains or using external domains.
Revision as of 12:56, 5 March 2008
Domain names are names that identify a particular computer on the internet. Examples are www.bravenet.com and www.google.com. They act as an alias for numeric IP addresses, but they are not permanently tied to a particular IP address. This means that you can change your domain name to point at a new IP address if you move your website from one computer to another.
By default, your website can be accessed at the sub-domain your_site_name.bravehost.com. If you have a professional account, you get one free domain name, and can purchase more as you need them. This means that you can have www.your_site_name.com point to your site.
How do I get one?
Why use domain names?
Domain names effectively translate the numeric IP addresses that relate to everything on the internet to alphabetical addresses. This makes websites easier to remember. Also, since one domain name can point to multiple IP addresses, and multiple domain names can point to one address, and that relationship can easily be changed, domain names allow flexible addresses on the internet. For example, if you wish to move your website www.example.com to another physical server, even though the IP will change, you can still refer to the same website with the same domain name.
Similarly, if the role of the server changes, you can adapt your domain names to suit the changes. For example, you start with a small website - www.example.com, and then add a forum at forum.example.com, and email services at email.example.com. Initially, all these addresses point to one server, but if you outgrow that server, it is easy to have email.example.com point to a different server.
Valid domain names:
Each string of letters, digits and hyphens between the dots is called a label in the world of the domain name system (DNS). Valid labels are subject to certain rules, which have relaxed over the history of the internet. Originally labels had to start with a letter, and end with a letter or digit; any intervening characters could be letters (a-z), digits (0-9), or hyphens ( - ). Currently it is possible for a label to start with a digit and have underscore ( _ ) characters in them, but support for these labels is uneven.
Labels must be at least 1 character, and under 64 characters long. Letters are ASCII, and allow both upper and lower case, but labels are compared case-insensitively - so www.BRAVENET.com and www.bravenet.com are considered the same. There is growing support for non-ASCII characters in domain names with some domain registrars, but it is still very highly recommended that you stick with the guidelines above, otherwise you stand the chance that large portions of the internet will not be able to visit your domain.
These are the rules imposed by the way names are looked up ("resolved") by DNS. Some top level domains (see below) impose more rules, such as a longer minimum length, on some labels.
How does it work?
When looking up a website (for example hostingwiki.bravenet.com) by domain name, the domain name is broken up into individual labels (in our example: hostingwiki, bravenet, com are the labels). Starting at the right-most label, your computer asks "who is responsible for this label?" There is an implied '.' at the end of the domain name, and that blank label, or root domain, is examined first.
There are a group of 13 root domain servers on the internet which your computer queries. Those root servers tell you where to check for more details about the "com" label - also known as a top level domain. The servers responsible for these top level domains, for example .com, .org, .net, or the country-based .ca, .uk, .tw and so on, then tell you where to look for more information about the label "bravenet". Your computer then queries the appropriate server, and is told to look at our DNS server to find information about the label "hostingwiki". Finally, your computer asks our server for the details for hostingwiki.bravenet.com - and it gets an IP address pointing to the exact right server for this wiki.
In reality, most of this information doesn't change very often, so it is cached at multiple levels. Your computer will never have to ask the root server, or even a top level domain server about this information, because your internet provider will likely have already gathered and stored that information for you.
How to Get There:
- Visit www.bravenet.com
- Log into your account, or create one if you don't have one yet
- Select the tab to manage your domains