Re: [core] Feedback on DNS over CoAP - draft-lenders-dns-over-coap

Martine Sophie Lenders <> Wed, 01 September 2021 13:38 UTC

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To: Carsten Bormann <>
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From: Martine Sophie Lenders <>
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Date: Wed, 1 Sep 2021 15:37:55 +0200
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Subject: Re: [core] Feedback on DNS over CoAP - draft-lenders-dns-over-coap
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Hi Carsten,

Am 01.09.21 um 15:19 schrieb Carsten Bormann:
> [...]
>> On 1. Sep 2021, at 13:52, Martine Sophie Lenders <> wrote:
>>   (c) There is one concern regarding FETCH. Various CoAP implementations
>> do not support FETCH [4] (maybe because FETCH was added later to CoAP).
>> This could hinder deployment of DoC or could lead DoC implementations
>> that are not spec-compliant, because implementers just use GET or POST
>> when FETCH is not available.
> CoAP implementations that do not support FETCH need to be fixed.
> If applications were to wait until everyone has implemented FETCH, there never would be an application that uses FETCH, so there would be no need to implement it.
> Since implementing FETCH is near trivial if you already have implemented POST, maybe getting a list of CoAP implementations that still don’t do FETCH and generating fixes for them would be a good parallel activity to standardising DoC.

I came prepared [1] (but did not want to include this table initially to 
not overwhelm everyone with the info dump ;-))! Our preliminary 
judgement call was that there are for the most part 2 types of CoAP 
implementations that are in that state: (1) who have a stale development 
status anyways (last change >1 year ago) or (2) where it is not needed 
fort the use-case anyways (e.g. wakaama). Of the one remaining, I agree 
with your proposal to generate fixes for FETCH support down the line.

Best Regards,

> Grüße, Carsten