"What is a URL?"

Universal Resource Locator. You can usually think of this as a web address, (which is more specifically a "web site URL").

A resource is an additional designation applied to a domain name at the DNS level to allow a single domain name to perform multiple functions and to be mapped to multiple sites and IP addresses. If you've used the Internet at all, you have already encountered resource identifiers such as www., mail., ftp. and others used in conjunction with a domain name. Most of these are simply conventions, albeit well established ones. These are not part of your domain name per se, and are not asked for when you register a name. You can specify any identifier you want (like sales., or home., or members.) and sometimes these are called subdomains. The following resources are universally understood:

• www. to identify a world wide web site
• mail. to identify an e-mail server
• ftp. an ftp (file transfer) site
• ns. or dns. to identify a name server

A URL is a unique identifier. Several web sites can have the same domain name, no two web sites can have the same URL. For example, www.corenic.net and www.whois.corenic.net are two URLs using the same domain name but having different web addresses. This is all programmed into DNS, and illustrates the versatility of a single domain name.