Domain Names Trivia

Here is some interesting information on domain names.

Domain Names are Case Insensitive

We often use inter-capping to emphasize the meaning of a domain name, for example, GetUpFresh.com. However domain names are case insensitive and in some cases can be misinterpreted when the caps are removed. For example, a well intended TheTherapistFinder.com becomes therapistfinder.com and ExpertsExchange.com becomes expertsexchange.com!

A domain name consists of one or more parts, which are conventionally concatenated, and delimited by dots, such as example.com. The right most label .com is the top level domain. The hierarchy of domains descends from the right to the left label in the name. Each label to the left is a sub-domain of the domain to the right.

For example, "example" is the sub-domain to the top level domain "com" in example.com. And "www" is a sub-domain of example.com in the domain name, www.example.com.

Length of Domain Names

This tree of sub-domains can go on for up to 127 levels while each sub-domain can be up to 63 characters. However the full domain name may not exceed a total of 263 characters. In practice the limits imposed by registries may be much shorter.

Here is an example of a very long domain name.

http://thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com

Period of registration

The maximum period of registration for a domain name is 10 years. Some registrars offer longer periods of up to 100 years. This involves the registrar keeping a record and renewing the registration for their customer. The 100-year registration would not be in the official registration database.

Reserved Domain Names

To avoid confusion and conflict, four top-level domain names are reserved for various specific purposes. They are .examples, .invalid, .localhost and .test. Example is reserved for examples while invalid for obviously invalid domain names. Localhost is reserved to avoid conflict with the traditional use of localhost as a hostname while test is reserved for use in tests. They are reserved with the intention that these should not occur in production networks within the global domain name system.

In addition, The Internet Assigned Numbers Authority (IANA) also currently reserves a few second level domain names for use as examples. They are example.com, example.net and example.org.

Evolution of Top Level Domains

The first Internet top-level domain is ".arpa". It was intended to be used only temporarily but after it had been used for reverse DNS lookup, it was found impractical to retire it. Today it is used today exclusively for Internet infrastructure purposes such as in-addr.arpa for IPv4 and ip6.arpa for IPv6 reverse DNS resolution.

In the early days of the Internet, top level domains were associated with organizations. There were .arpa, .csnet, .bitnet and .uucp. On January 28, 1986, the four organizations met and agreed to restructure the domain name space into the following eight subject-specific top-level domains namely:-

.bitnet - used by computers on the BITNET network
.com - originally for commercial sites but now use for any kind of site
.int - used by "International" sites, such as NATO sites
.edu - used for educational institutions like universities and colleges
.gov - used for US Government sites.
.mil - used for US Military sites.
.net - originally intended for sites related to the Internet itself, but now used for a wide variety of sites
.org - originally intended for non-commercial organizations, but now used for a wide variety of sites

In December 2002, after a long debate, ICANN approved the following additional top-level Internet domains: .aero, .biz, .coop, .info, .museum, .name, and .pro.

In October, 2004, ICANN approved the top-level domains .travel and .post. Periodically new top level domains continue to be approved.

With the new ICANN ruling on new Generic Top Level Domains (gTLD) that came into effect in 2008, you should expect many more top level domains.

Fancy Multi Level Domains

Take the example "mail.example.com".

"com" is the top level. "example" is the second level while "mail" is the third level.

You can create fanciful domain names by carefully combining first, second and third level names.

For example if you want the word physiognomy as a domain name. You can register "physiogno" with the ".my" Malaysia country code to get "physiogno.my" or "siogno" with ".my" and later adding the sub-domain "phy" to give "phy.siogno.my".

A real life fancy domain name example is "who.is".

Domain Statistics

According to a report release by Verisign in early 2010, around 11 million domain names were registered during the last quarter of 2009 pushing the total number of domain name registrations to 192 million domain names.

The renewal rate of domain names is approximately 70% which means that nearly 30 percent of all domain names registered are allowed to expire.

The most popular Top level domains after .com are the country code domains for China (.cn), Germany (.de) and UK (.co.uk) respectively. The Verisign report also reveal that 37 percent of domains either point to a single page (the homepage) or point to nothing at all.

Furthermore, the DNS (Domain Name System) structure apparently receives roughly 52 million requests every day, that's roughly 2.1 million requests every hour and is more than twice the volume in 2008.

For daily domain statistics (registration, transfer and expiry) visit the links below

http://www.domaintools.com/internet-statistics/
http://www.whois.sc/internet-statistics/