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DNS - technical definition
- Domain Name System.The naming convention that divides the Internet into logical domains identified in Internet Protocol version 4 (IPv4) as a 32-bit portion of the total address.The standard convention is user@organization.domain, where user is the name of the end user, organization is the name of the enterprise or other organization owning or sponsoring the address, and domain is the type of entity owning or sponsoring the address.The administration of the DNS is the responsibility of Internet Corporation for Assigned Names and Numbers (ICANN). See also domain, ICANN, Internet, and IPv4.
- Domain Name Server. All Internet domain names are maintained in mirrored databases on root servers distributed around the world. These servers are updated by the domain registrars. Thousands of Domain Name Resolvers (DNRs) located strategically with Internet Service Providers (ISPs) and institutional networks periodically download database updates from the root servers. See also database, DNR, Internet, ISP, root, and server.
See DNS in Computer
(Domain Name System) A system for converting host names and domain names into IP addresses on the Internet or on local networks that use the TCP/IP protocol. For example, when a Web site address is given to the DNS either by typing a URL in a browser or behind the scenes from one application to another, DNS servers return the IP address of the server associated with that name.
A Hierarchy
The DNS system is a hierarchy of database servers that start with the root servers for all the top level domains (.com, .net, etc.). The root servers point to authoritative servers residing within ISPs and companies that resolve the host names to complete the name resolution. Using the example WWW.COMPANY.COM, COMPANY.COM is the domain name, and WWW is the host name. The domain name is the organization's identity on the Web, and the host name is the name of the actual Web server within that domain (see WWW). See DNS records, reverse DNS, DDNS, HOSTS file, mDNS, ping, root server and WINS.
Getting a Web Page
Turning a URL in a Web browser into an IP address can take numerous queries. This is a simplified diagram because the original requester actually talks to each name server in turn, and there can be more name servers in between. A request can also be satisfied from a DNS cache along the way and not need to reach the authoritative server.
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