A low-down on.... Internet Domains and domain name levels

 

Gallery

Posted on 19 Feb 2002 at 17:02

Just how is the Internet organised? How does a .com address relate to a .fr address? What exactly is a second-level domain name? And where do the .biz, .info and .name addresses fit in? Time for a low-down on Internet domains.

The root of the Internet

Every computer user who has dealt with a file system is familiar with a hierarchical means of storage and division. The Internet follows this model, too. Sort of.

At the very top of the Internet system is the 'un-named root' (a logical starting point that provides access to the first level of domain names, a sort of Registry of Registries). Underneath this come the 'top-level' domain names (TLDs) - which originally consisted of seven generic suffixes (com, .net, .org, .edu .gov, .mil and .int) - and the geographically-specific two-letter country codes (ccTLDs).

The TLDs were intended to help designate the purpose of Web sites with .com representing commercial use of Web space, .org for organisations, .net for network providers, .edu for education, .gov for government sites, .mil for the military, and .int for international organisations.

Similarly, the ccTLDs help designate a site's country of origin: foodstore.nz would originate from New Zealand and alimentari.it from Italy.

The idea is that the naming scheme allows a choice between geographical or organisational naming systems. (You can check out the popularity of all the various country codes on the Net here).

New TLDs

In November 2000, ICANN (the Internet Corporation for Assigned Names and Numbers) decided to add seven new TLDs to help ease the 'crowding' around the .com namespace, i.e. people and organisations were using .com for want of a more suitable designation of the purpose of their Web site. The seven suffixes - .biz, .info, .name, .pro, .museum, .aero. and .coop - emerged from the forty-four serious applications (with .kids for children's content and .xxx for adult-oriented sites being among those rejected).

'This is a first giant step for domain-kind,' said Esther Dyson, chairman of ICANN, at the time. But subsequently there have been a number of delays and teething problems - mainly involving disputes over right of ownership - to the rollout of the new addresses. The .biz domain was particularly affected.

The second-level

Moving further down the pyramid, as it were, the structures found within the country codes vary. While, for example, you can have .co.uk or .gov.uk, you simply have .fr for France.

In theory, you could have a further geographic sub-division at the third level. Conceivably, if the national governing body so decided, the second-level domains could be further sub-divided - on a geographic basis, perhaps - underneath the second level. (Hypothetically, .co.uk could be preceded by county codes, to identify Northumbrian businesses from Cornish ones. Hypothetically, I repeat). In practice, this would only make administration of the domain more complex.

A good Web site for keeping track of the various country codes can be found here. Not only can you find out the letters associated with Israel or Australia, for example, you can find the details of the registrar with responsibility for that particular slice of Internet real estate.

As you are probably aware, you parse a domain name from left to right. Take the domain name pcpro.co.uk as an example. Taken hierarchically, in terms of how it would be considered by the naming system, 'pcpro.co.uk' is the lowest level domain, referring to the Web site for a particular magazine in the UK. The second level domain is '.co.uk', which is the domain for commercial operators within the UK, and the top level domain is the country code for Britain: .uk.