Agreed that this is an area we should improve the wording on.
I think the intent is:
* within a resource record in the RRset, concatenate the
<character-string>s to obtain the TXT-DATA and treat that as a "domain
validation string"
* individual resource records are independent domain validation strings.
The change from -07 to -09 to stop referencing RFC1464 was the biggest one
which should have gone to the list and didn't (apologies!).
In particular, RFC1464 didn't meet the needs by itself here we need
groupings of {token=..., expires=...} to be paired together.
Having a bag of {token=..., expires=..., token=..., expires=...} in the
RRset as was the result of the text in -07 would not have met the needs
here.
Erik
On Mon, Jul 21, 2025 at 3:35 PM Joe Abley <jabley=
[email protected]> wrote:
> Hi Shumon,
>
> On 21 Jul 2025, at 14:28, Shumon Huque <[email protected]> wrote:
>
> > Yes, it means that you should concatenate multiple RDATA strings within
> the same TXT record.
> > We'll fix the wording here shortly.
>
> If we retreat briefly to the warm comfort of RFC 1035, a single resource
> record includes a single field called RDATA, so "multiple RDATA strings
> within the same TXT record" is a strange phrase.
>
> RFC 1035 section 3.3.14 defines a field TXT-DATA as "one or more
> <character-string>s". <character-string> is "a single length octet followed
> by that number of characters". Also "<character-string> is treated as
> binary information, and can be up to 256 characters in length (including
> the length octet)".
>
> The draft currently contains many examples of the word "RDATA". I haven't
> looked closely at every occurance in context, but I suspect it might be a
> good idea to define a new phrase like "domain validation string" to use in
> most or all of those casses, and to define it carefully, e.g. so that it's
> clear how to interpret something like this:
>
> _example_service-challenge.example. TXT "token=" "3419" "this" "is an "
> "example\0 of a"
> _example_service-challenge.example. TXT "token=3420 enormous pile of"
> "token=3419"
> _example_service-challenge.example. TXT "token=3419 confusing" " situation"
>
> (I think it's somewhat clear how to interpret that nonsense right now, but
> I think the document could be clearer.)
>
>
> Joe
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