Hi

Could you please expand these PR URLS into this email thread?

thanks

  Geoff




> On 9 Jan 2026, at 8:35 pm, Tobias Fiebig <[email protected]> 
> wrote:
> 
> Good Morning,
> 
>> 1. Section 4.1, "IPv4 Adoption": "Given the IPv4 address scarcity,
>> operator MAY opt not to provide DNS services via IPv4, if they can
>> ensure that all clients expected to resolve this zone do support DNS
>> resolution via IPv6." In the context of the public Internet (which is
>> the intended context of RFC3901, and presumably the intended context
>> of this draft that proposes updating it), a DNS server is a
>> promiscuous server and SHOULD NOT assume that it can apply a
>> constraint or otherwise limit the clients that query it. The
>> conditional expression in this text relating to ensuring all client
>> can support DNS resolution via IPv6 transport appears to contradict
>> the context of the public Internet. This sentence appears to be out
>> of place in a BCP relating to the DNS on the public internet.
> 
> This point was already discussed in your prior review. This statement
> is the result of WG consensus; To cite Tommy Jensen in reply to the
> last review:
> 
> "I agree there are real situations where IPv6 connectivity can be
> guaranteed to be universally provided through an administered network
> that requires this. I equally strongly oppose removing this MAY given
> that this is only something a network operator can assert, not a
> resolver operator when the roles are distinct. I think it is already
> balanced."
> 
> We read the subsequent response of:
> 
> "I see that others have chimed on with responses to my DNSDIR review,
> and I don't propose to add to that conversation here."
> 
> As agreement to the WG's rational. Hence, we are somewhat confused to
> see this point being brought up again.
>   
>> 2. Section 4.1. "IPv6 adoption": "Authoritative DNS servers SHOULD
>> use native IPv6 addresses instead of IPv4-converted IPv6 addresses
>> for receiving queries." Neither RFC4291, nor RFC 6052 define a
>> "IPv4-converted IPv6 address." The draft should state that:
>> "Authoritative DNS servers SHOULD NOT use IPv4-Compatible IPv6
>> Addresses and IPv4-Mapped IPv6 Address [RFC4291]".
> 
> The prior instance of this comment was addressed by Med suggesting a
> definition to be added. We agree that explicit text provided might
> improve readability.
> 
> Please see the following PR:
> https://github.com/ietf-wg-dnsop/draft-ietf-dnsop-3901bis/pull/66
> 
>> 3. Section 4.2:  "..a configuration where it forwards queries.."
>> Embedding non-explicit forwarding of queries in the DNS resolution
>> process is not exactly an example of Best Current Practice. The DNS
>> has no form of query loop detection or excessive resolver query chain
>> detection, and application of this practice of query forwarding
>> between recursive resolvers is best avoided, as a general behaviour.
>> I suggest that all references to query forwarding by recursive
>> resolvers should be removed in Section 4.2.
> 
> As previously discussed on the same point, forwarding is effectively
> limited to one hop. An operator would have to consciously create a
> specific corner-case to cause loops, and then would also need to use a
> zone neither resolvable via IPv4 nor IPv6. This was already discussed
> in response to your last review.
> 
>> 4. Section 4.2: "when responding to recursive queries sent by stub
>> DNS". How can a recursive resolver know that a query has been sent by
>> a stub resolver?
> 
> RFC1035 defines an 'RD' bit in DNS queries. If it is present in a
> query, a recursive resolver can safely assume that the query has not
> been sent by a recursive resolver acting as a recursive resolver for
> this specific query.
> 
> We clarify this with the following PR:
> https://github.com/ietf-wg-dnsop/draft-ietf-dnsop-3901bis/pull/67
> 
>> 5. Section 5. Security Considerations: "introduce no new security
>> considerations into the DNS protocol." This reviewer differs with
>> respect to the recommendation that under certain circumstances a
>> recursive resolver may forward a query to another recursive resolver.
>> As already noted, the DNS resolution protocol has no form of query
>> loop detection or excessive resolver query chain detection, and there
>> is the potential for scenarios that can be used to launch a DOS
>> attacks on recursive resolvers. The authors should reconsider this
>> section in the light of the existing advice relating to resover-to-
>> resolver forwarding in this document.
> 
> We still argue that this is a corner case that would require an
> intentional misconfiguration on the recursive resolver operator's side.
> 
> Nevertheless, we added corresponding text to the section, see:
> https://github.com/ietf-wg-dnsop/draft-ietf-dnsop-3901bis/pull/68
> 
>> Also, I have seperately noted my reservation regading the
>> inappropriate use of Best Current Practice classification for
>> documents that do not describe what is understood to be current
>> operational practice, and for completeness I am repeating that
>> reservation here.
> 
> We hear the reviewers concerns. As already mentioned by Med earlier,
> per RFC2026, a BCP:
> 
>  "is a vehicle by which the IETF community can define and ratify 
>   the community's best current thinking on a statement of principle 
>   or on what is believed to be the best way to perform 
>   some operations or IETF process function."
> 
> The present document falls under the RFC2026 BCP definition.
> 
> With best regards,
> Tobias
> 
> -- 
> Dr.-Ing. Tobias Fiebig
> T +31 616 80 98 99
> M [email protected]
> Pronouns: he/him/his
> 
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