1. Reserved DNS names

2. Conventional use

3. References

The name localhost is reserved by the Internet Engineering Task Force (IETF) in {{IETF RFC|2606}} (June 1999) as a domain name label that may not be installed as a top-level domain in the Domain Name System (DNS) of the Internet.^[1]

Reserved DNS names

In 1999, the Internet Engineering Task Force reserved the DNS labels {{mono|localhost}}, {{mono|example}}, {{mono|invalid}}, 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.^[1] This allows the use of these names for either documentation purposes or in local testing scenarios.

Conventional use

The name localhost is a commonly defined hostname for the loopback interface in most TCP/IP systems, resolving to the IP addresses 127.0.0.1 in IPv4 and ::1 for IPv6. As a top-level domain, the name has traditionally been defined statically in host DNS implementations with address records (A and AAAA) pointing to the same loopback addresses. Any other use conflicts with widely deployed algorithms relying on this convention.

References

• Cycling at the 2002 Asian Games - Men's team pursuit
• Cycling at the 2002 Asian Games - Men's team sprint
• Cycling at the 2002 Asian Games - Women's 500 metres time trial
• Cycling at the 2002 Asian Games - Women's cross-country
• Cycling at the 2002 Asian Games - Women's downhill
• Cycling at the 2002 Asian Games - Women's individual pursuit
• Cycling at the 2002 Asian Games - Women's individual time trial
• Cycling at the 2002 Asian Games - Women's points race
• Cycling at the 2002 Asian Games - Women's road race
• Cycling at the 2002 Asian Games - Women's sprint
• Cycling at the 2002 Central American and Caribbean Games
• Cycling at the 2004 Summer Olympics - Men's individual road race
• Cycling at the 2004 Summer Olympics - Women's individual road race
• Cycling at the 2004 Summer Paralympics - Men's individual pursuit
• Cycling at the 2006 Asian Games - Men's 1 kilometre time trial
• Cycling at the 2006 Asian Games - Men's individual pursuit
• Cycling at the 2006 Asian Games - Men's individual time trial
• Cycling at the 2006 Asian Games - Men's keirin
• Cycling at the 2006 Asian Games - Men's madison
• Cycling at the 2006 Asian Games - Men's points race
• Cycling at the 2006 Asian Games - Men's road race
• Cycling at the 2006 Asian Games - Men's sprint
• Cycling at the 2006 Asian Games - Men's team pursuit
• Cycling at the 2006 Asian Games - Men's team sprint
• Cycling at the 2006 Asian Games - Men's team time trial