See below

> On 10 Feb 2026, at 11:34, Tobias Fiebig <[email protected]> wrote:
> 
> Hello Gorry,
> 
> thank you for your feedback so far, and the additional comments under
> the ballot. We will address these in the next version. Comments on how
> we plan to do this are in this email.
> 
>> ---------------------------------------------------------------------
>> -
>> COMMENT:
>> ---------------------------------------------------------------------
>> -
>> 
>> Thank for writing this document and the work that went into
>> documenting DNS
>> IPv6 Transport and thank you to Martin Duke for a TSV-ART review. I
>> appreciate
>> the work to address the transport concerns and have updated the
>> position based
>> on rev -14.
>> 
>> # COMMENTS (non-blocking)
>> 
>> Please find below some non-blocking COMMENT points/nits (replies
>> would be
>> appreciated even if only for my own education).
>> 
>> ## Section 3.2:  I could not understand the "otherwise" in this:
>> "Otherwise, if the protocol is not
>>    resilient to IP layer fragmentation related issues by default, the
>>    above guidance for TCP and UDP based connections SHOULD be applied
>>    analogously."
>> - There is use of DNS over other transports and I do understand what
>> is being
>> called for by this requirement, please explain (and consider
>> rephrasing?).
> 
> The otherwise has been removed.
> 
> 
>> ## Section 4.1.  Guidelines for Authoritative DNS Server
>> Configuration:
>> "Every DNS zone SHOULD be served by at least two IPv4-reachable
>>       authoritative DNS servers to maintain name space continuity."
>> - Because this is a "SHOULD", please explain the implications when
>> the advice
>> is not followed. I then read, the following: " To reduce the chance
>> of DNS
>>    name space fragmentation, it is RECOMMENDED that at least two
>>    IPv4-reachable and two IPv6-reachable name servers are configured
>> for
>>    a zone."
>> - I think I may have been confused by the various recommendations and
>> tried to
>> see how to reconciled these two statements. I am a little concerned
>> that the
>> advice in this section might be complicated, and I wonder whether
>> these
>> (initial) statements are not intended to be normative, because the
>> following
>> bullets appear to define more specific requirements. More clarity
>> would be
>> appreciated.
> 
> This text has already been rewritten from the version quoted above in
> response to Eric's comments, who voiced similar concerns.
> 
>> ## Section 4.1.  fall back
>> " and providing TCP fall back options [RFC7766]."
>> -  Please be more specific to which section of RFC7766 is being
>> cited, I could
>> only find one that is normative (and one informative).
> 
> I clarified the text and specifically referred to Sec. 5 of 7766, which
> mandates TCP service availability (BCP14 MUST in 7766).
> 
>> ## Section 4.3: What is required?
>> “ When providing multiple DNS servers to stub resolvers, network
>>    operators SHOULD consider that various implementations can only
>>    configure a small set of possible DNS resolvers, e.g., only up to
>>    three for libc [MAN], and additional resolvers provided may be
>>    ignored by clients."
>> - What is the protocol requirement here? I can see consideration
>> might be
>> important, but I expect it isn't sufficient to think about the
>> problem and sort
>> sort of action might be required/desired?
> 
> I added text further clarifying this:
> 
> When providing multiple DNS servers to stub resolvers, network
> operators have to consider that various implementations can only
> configure a small set of possible DNS resolvers, e.g., only up to
> three for libc [MAN], and additional resolvers provided may be
> ignored by clients.  Hence, when providing more than three DNS
> servers to stub resolvers, operators SHOULD ensure that any random
> subset of three DNS resolvers from the provided list contains at
> least one recursive DNS server supporting DNS resolution via IPv4 and
> one DNS server supporting DNS resolution via IPv6.  A single
> recursive DNS server supporting dual-stack DNS resolution counts
> towards both requirements.  If this is not done, a client might
> select a subset of recursive DNS servers that leads to address family
> based namespace fragmentation.
> 
> ---
> 
> I would appreciate any opinions on these changes, either from you or
> other list participants. So far, these changes are staged in the
> following PR:
> 
> https://github.com/ietf-wg-dnsop/draft-ietf-dnsop-3901bis/pull/82
> 
> With best regards,
> Tobias
> 
> -- 
> Dr.-Ing. Tobias Fiebig
> T +31 616 80 98 99
> M [email protected]

All seems good, thanks

- I see you may wish to clarify (add current):
Current implementations can only configure ….

Gorry


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