Re: [DNSOP] DNSOP Call for Adoption - draft-west-let-localhost-be-localhost

"John Levine" <johnl@taugh.com> Tue, 12 September 2017 22:21 UTC

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Date: 12 Sep 2017 22:17:38 -0000
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From: "John Levine" <johnl@taugh.com>
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Subject: Re: [DNSOP] DNSOP Call for Adoption - draft-west-let-localhost-be-localhost
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In article <CAHw9_iJL-Lc84GnMtOERM2oupVrMxKjoYGeumE9K77RwOE4uqQ@mail.gmail.com> you write:
>I think that this boils down to: It is an error to send a query for
>localhost (or anything under localhost) to the DNS. The main reason
>for this (at least from my reading of the thread) is a security
>argument -- you want to be completely sure that 'localhost' will
>always be 127.0.0.1 / ::1 / some local equivalent, and this is not a
>guarantee we can expect from the DNS[0]. Because of this it is better
>the have queries that accidentally *do* leak into the DNS get a
>failure (NXDOMAIN) - this avoids having (security important) cases
>work fine until there is an attacker.
>
>Is this a reasonable summary? Perhaps once we agree if *is* the
>behavior we want we'll have an easier time deciding exactly how...

Sounds right to me.

With respect to Tim's suggestion that we invent
localhost-we-really-mean-it-this-time, the existing localhost isn't
going away, and it is my impression that more often than not software
already does what this draft suggests.

R's,
John