uniquely identifies an Internet site (original) (raw)

A domain name is a name that uniquely identifies a site (e.g., web site or ftp site) on the Internet or other TCP/IP network.

Domain names are actually user-friendly substitutes for IP addresses. Addressing on the Internet or other TCP/IP networks is based on IP addresses, each of which is a unique numeric identifier for a computer or other device on the network. TCP/IP (transmission control protocol/Internet protocol) is the set of protocols (i.e., agreed upon formats) that is used for the Internet as well as for most LANs (local area networks) and other computer networks.

It is difficult for humans to remember IP addresses, which can contain as many as 12 digits under the currently mainstream IPv4 addressing scheme (or as many as 32 hexadecimal digits under the next-generation IPv6 addressing scheme). However, it is relatively easy for them to remember domain names, which typically use alphabetic characters and consist of words, abbreviations or acronyms.

Domain names are hierarchical in nature and consist of at least two levels. Each level is separated by a single period. The part on the left is the most specific, and the part on the right is the most general. For example, Mitsubishi Corporation's personnel department might use the domain name personnel.mitsubishi.com.

Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited number of such domains, which is always either one of a several general names (e.g., .com, .org, .edu or .gov) or a two-character country code (e.g., .uk, .de or .fr).

The domain name forms a part of the URL. In the case of The Linux Information Project, for example, the URL, server name and domain name are as follows:

URL: http://www.bellevuelinux.org/linfo.html
Server name: www.bellevuelinux.org
Domain name: bellevuelinux.org

The domain name for a large organization will point to multiple computers belonging to that organization because of load balancing. Load balancing is the dividing of a task, such as serving a particular website, among two or more computers so that more work gets done in the same amount of time and, in general, all users get served faster. Also, a given computer can have more than one domain name, a common example being computers used by ISPs (Internet service providers) to host multiple websites.