HTTPbis M. West Internet-Draft Google, Inc Updates: 6761 (if approved) September 27, 2016 Intended status: Standards Track Expires: March 31, 2017 Let 'localhost' be localhost. draft-west-let-localhost-be-localhost-02 Abstract This document updates RFC6761 by requiring that the domain "localhost." and any names falling within ".localhost." resolve to loopback addresses. This would allow other specifications to join regular users in drawing the common-sense conclusions that "localhost" means "localhost", and doesn't resolve to somewhere else on the network. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on March 31, 2017. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of West Expires March 31, 2017 [Page 1]

Internet-Draft let-localhost-be-localhost September 2016 3 . Recommendations Section 6.3 of [RFC6761] in the following ways: 1. Item #3 is changed to read as follows: Name resolution APIs and libraries MUST recognize localhost names as special, and MUST always return an IP loopback address for address queries and negative responses for all other query types. Name resolution APIs MUST NOT send queries for localhost names to their configured caching DNS server(s). 2. Item #4 is changed to read as follows: Caching DNS servers MUST recognize localhost names as special, and MUST NOT attempt to look up NS records for them, or otherwise query authoritative DNS servers in an attempt to resolve localhost names. Instead, caching DNS servers MUST generate an immediate negative response. 3. Item #5 is changed to replace "SHOULD" with "MUST": Authoritative DNS servers MUST recognize localhost names as special and handle them as described above for caching DNS servers. 4. Item #7 is changed to remove "probably" from the last sentence: DNS Registries/Registrars MUST NOT grant requests to register localhost names in the normal way to any person or entity. Localhost names are defined by protocol specification and fall outside the set of names available for allocation by registries/ registrars. Attempting to allocate a localhost name as if it were a normal DNS domain name will not work as desired, for reasons 2, 3, 4, and 5 above. 4 . Implementation Considerations 5 . References West Expires March 31, 2017 [Page 3]