Changes

==Overview==

==Overview==

Technically, the second domain level is the data directly before the top-level domain ([[TLD]]).<ref>[http://www.giantgeek.com/blog/?p=97 What is a SLD]</ref>

Technically, the second domain level is the data directly before the top-level domain ([[TLD]]).<ref>[http://www.giantgeek.com/blog/?p=97 What is a SLD]</ref>

For example, in www.domainname.com, “domainname” represents the second level domain. Whereas the suffix "(dot)-com" represents the [[TLD]].  

For example, in www.domainname.com, “domainname” represents the second level domain, as the suffix "(dot)-com" represents the [[TLD]].  

Usually, the SLD is determined and defined upon registration of a domain name. More than one SLD can function on the same [[Internet Protocol|IP]] Address.<ref>[http://help.godaddy.com/article/335 SLD Definition]</ref>

Usually, the SLD is determined and defined upon registration of a domain name. More than one SLD can function on the same [[Internet Protocol|IP]] Address.<ref>[http://help.godaddy.com/article/335 SLD Definition]</ref>

===ccSLDs===

===ccSLDs===

A ccSLD, or Country Code Second Level Domain, refers to when an additional prefix is added to a ccTLD. An example of this would be .co.uk, where .uk is the (cc)TLD and .uk is the (cc)SLD. In this circumstance, the domain name ("example" in "example.co.uk") would be considered the third level domain, as it is in the third position.<ref>[http://www.igoldrush.com/reference/domain-glossary/c/ccsld-country-code-second-level-domain iGoldrush Domain Glossary]</ref> This can become confusing, as the domain name is commonly equated with the second level domain, and the [[Subdomain|subdomain]] is commonly equated with the third level domain.

A ccSLD, or Country Code Second Level Domain, refers to when an additional prefix is added to a ccTLD. An example of this would be .co.uk, where .uk is the (cc)TLD and .uk is the (cc)SLD. In this circumstance, the domain name ("example" in "example.co.uk") would be considered the third level domain, as it is in the third position.<ref>[http://www.igoldrush.com/reference/domain-glossary/c/ccsld-country-code-second-level-domain iGoldrush Domain Glossary]</ref> This can become confusing, as the domain name is commonly equated with the second level domain, and the [[subdomain]] is commonly equated with the third level domain. In these circumstances, the third level domain is sometimes referred to as a '''functional SLD'''.

 

A Functional SLD is a reasonable equivalent to an SLD in a namespace where domain names as second level domains are not permitted for policy reasons.

 

An example of a Functional SLD would be foo.com.au. While .com is the actual [[SLD]], [[.au]] policy does not permit the widespread registration of second level domains, thereby creating a proliferation of Functional SLDs (in this case .foo) in the [[.au]] namespace.<ref>[http://tools.ietf.org/html/draft-ietf-provreg-dn-defn-00 ietf.org]</ref>

 

[[IAHC]] strongly recommends the [[.us]] [[TLD]] to use the functional SLD.<ref>[http://potaroo.net/ietf/idref/draft-iahc-gtldspec/ potaroo.net]</ref>

==Valid Domain Names and SLDs==

==Valid Domain Names and SLDs==