Re: [TLS] DNS-based Encrypted SNI

Kazuho Oku <kazuhooku@gmail.com> Wed, 04 July 2018 01:37 UTC

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From: Kazuho Oku <kazuhooku@gmail.com>
Date: Wed, 4 Jul 2018 10:36:59 +0900
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To: Eric Rescorla <ekr@rtfm.com>
Cc: Paul Wouters <paul@nohats.ca>, "<tls@ietf.org>" <tls@ietf.org>
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Subject: Re: [TLS] DNS-based Encrypted SNI
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2018-07-04 0:55 GMT+09:00 Eric Rescorla <ekr@rtfm.com>;:
>
>
> On Tue, Jul 3, 2018 at 8:40 AM, Paul Wouters <paul@nohats.ca>; wrote:
>>
>> On Mon, 2 Jul 2018, Eric Rescorla wrote:
>>
>>>       It is strongly recommended not to use TXT records. Why not use a
>>> new
>>>       RRTYPE? Everything these days knows how to serve unknown record
>>> types
>>>       (see RFC 3597). The only possibly exception is provisioning tools
>>> of
>>>       small players, but this document starts of saying you basically
>>> need
>>>       to be on a bulk hosting provider anyway. They can properly
>>> provision.
>>>
>>> See:
>>>
>>> https://github.com/ekr/draft-rescorla-tls-esni/issues/7#issuecomment-388531906
>>
>>
>> [Can we keep the discussion within the IETF and the Note Well please. We
>>  also don't know what happens in 10 years with these links.]
>
>
> If you look carefully, you'll see that this discussion happened weeks ago. I
> was
> just pointing you at it because you asked why we did it the way we did.
>
> With that said,IETF policy does not prohibit having discussions on Github..
> We do it
> regularly in TLS and it's the standard policy in QUIC.
>
>
>>
>> quoting from that link:
>>
>>         These facts lead to the conclusion that if we choose RRtype as the
>>         method, there would often be cases where the DNS record of the
>> ESNIKey
>>         and the TLS server would be required to be operated by different
>>         entities.
>>
>> That seems to have confused two things with each other. I did not say
>> anything about the location of the DNS record, only of the RRTYPE.
>> Clearly, with the same location, it would be under control of the same
>> entity, so I don't understand why you bring this up as a reason against
>> using a dedicated RRTYPE.
>
>
> I'm just quoting Kazuho here, so I'll let him respond to himself.

The discussion was about comparing two approaches: a) use a new record
type without suffix, b) use TXT record type with suffix.

My argument was that we should select b because a has the
deployability issue in regard to APEX names.

It is true that the deployability issue is a concern related to the
non-use of prefix. It is _not_ related to the selection of the record
type.

OTOH, I think that the reliability issue related to using a new record
type exists, as others have pointed out.

>
> -Ekr
>
>
>
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-- 
Kazuho Oku