.invalid
{{Short description|Reserved top-level domain}}
{{Infobox Top level domain
|name=invalid
|image=
|introduced=1999
|type=Reserved top-level domain
|status=Reserved to prevent conflict and confusion
|intendeduse=When necessary to show an address guaranteed to be invalid
|actualuse=Session Initiation Protocol, for identity protection; address munging e.g. on Usenet
|document={{IETF RFC|2606|3325}}
}}
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.{{Ref RFC|2606}}
Reserved DNS names
In 1999, the Internet Engineering Task Force reserved the DNS labels {{mono|example}}, {{mono|invalid}}, {{mono|localhost}}, and {{mono|test}} 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.{{Ref RFC|2606}} 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 {{mono|anonymous.invalid}} in a SIP URI indicates hiding of a caller's identity.{{Ref RFC|3325}}
References
{{reflist}}
{{GTLD}}
{{DEFAULTSORT:INVALID}}