[net-dns-users] Bug with large txt RR ?

[Håkon Alstadgeum]

7. okt. 2026 22:54:36 Felipe Gasper <felipe at felipegasper.com>:

>
>
>> On Oct 7, 2026, at 2:08 PM, Håkon Alstadheim <hakon at alstadheim.priv.no> wrote:
>>
>>
>> Den 07.10.2026 19:32, skrev Felipe Gasper:
>>>> On Oct 7, 2026, at 12:17 PM, Håkon Alstadheim via net-dns-users <net-dns-users at lists.nlnetlabs.nl> wrote:
>>>>
>>>>
>>>> Den 07.10.2026 18:07, skrev Håkon Alstadheim:
>>>>> Den 07.10.2026 01:38, skrev Doug Barton via net-dns-users:
>>>>>> …
>>>>> Sorry I'm having such a hard time getting this across, my presentation was probably confusing because I've tried many of the various ways to get at the txt contents.
>>>>>
>>>> Looks like I mixed my examples again. First example, with quotes on *some* for the chunks and others naked, is from using rdstring, txtdata gives just extra spaces.
>>> Every TXT record is a *list* of strings, each capped at 255 bytes.
>>>
>> I know this.
>>> Any application that models TXT record as a single string must define logic for splitting & joining across the TXT record’s individual pieces.
>>> DKIM, for example, (IIRC) simply joins the segments end-to-end.
>>>
>>> Scalar-context Net::DNS::RR::TXT::txtdata(), on the other hand, joins the segments with a space.
>>
>> Fine, so I should work with rdstring, which *should* return the segments in "quotes", except that *one* segment gets printed unquoted! So programmatically glueing it together becomes rather random.
>>
>> "v=spf1 [...totally fine string...]ip4"   ":160 [...totally fine string...]include:478860"    1.spf03.hu "bspotemai[...totally fine string...]p.com -all"
>>
>> What is 1.spf03.hu doing unquoted?
>
> Going by the documentation, rdstring() is defined (on the base class, not on ::TXT) as just “a string representation of the RR-specific data”. It doesn’t seem to define a quoting mechanism, or even guarantee that the returned string is round-trippable.
>
> Are you able to do the quoting yourself? That might solve the issue.
Maybe I can rely on my *guess* (realized just recently) that strings with spaces will be double-quoted, and any naked text is a segment without spaces to be used verbatim until the next space, I gess I'm good. I think actual double-quotes are illegal in spf1. If those  two things hold, I'm good. I'll try it and see  :) .

>
> Alternatively, LDNS might be closer to what you want.
>
> -FG

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