New RFC draft
Hopefully it will be approved and become an extension/correction of RFC6761
A couple of nice excerpts (bold,italic, etc. by me)
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.
[RFC1537] suggests that this special-use top-level domain name has been implicitly mapped to loopback addresses for decades at this point, and that [RFC6761]'s assertion that developers may "assume that IPv4 and IPv6 address queries for localhost names will always resolve to the respective IP loopback address" is well-founded.
Unfortunately, the rest of that latter document's requirements undercut the assumption it suggests. Client software is empowered to send localhost names to DNS servers, and resolvers are empowered to return unexpectedly non-loopback results. This divide between theory and practice has a few impacts
Thank you for posting