Английская Википедия:.invalid
Шаблон:Short description Шаблон:Infobox Top level domain
The name invalid is reserved by the Internet Engineering Task Force (IETF) as a domain name that may not be installed as a top-level domain in the Domain Name System (DNS) of the Internet.Шаблон:Ref RFC
Reserved DNS names
In 1999, the Internet Engineering Task Force reserved the DNS labels Шаблон:Mono, Шаблон:Mono, Шаблон:Mono, and Шаблон:Mono so that they may not be installed into the root zone of the Domain Name System.
The reasons for reservation of these top-level domain names is to reduce the likelihood of conflict and confusion.Шаблон:Ref RFC This allows the use of these names for either documentation purposes or in local testing scenarios.
Purpose
This top-level domain is sometimes used as a pseudo domain name in Uniform Resource Identifiers (URIs) to convey either an error condition or in use of privacy protection. A notable instance of this usage is in the Session Initiation Protocol (SIP) where the domain name Шаблон:Mono in a SIP URI indicates hiding of a caller's identity.Шаблон:Ref RFC
References
ja:トップレベルドメイン#特殊用途 sv:Toppdomän#Generiska toppdomäner
