[Pdns-users] Multipart TXT records

[Chris Sarginson]

I've now stuck a little bit in the FAQ with regards to this - hopefully any future users will be able to find this with minimal effort and prevent any lost time.

Chris

-----Original Message-----
From: pdns-users-bounces at mailman.powerdns.com [mailto:pdns-users-bounces at mailman.powerdns.com] On Behalf Of Augie Schwer
Sent: 08 March 2010 20:29
To: Pdns-users
Subject: Re: [Pdns-users] Multipart TXT records

Just wanted to confirm that this is spot on -- I ran into this same
thing a few weeks back and had to do the same head scratching, RFC
look-up, google, etc.

--Augie

On Mon, Mar 1, 2010 at 11:25 AM, Julian Mehnle <julian at mehnle.net> wrote:
> Leen Besselink wrote:
>
>> You can also see that here:
>>
>> http://doc.powerdns.com/changelog.html
>>
>> I'm unsure about what it does mean though.
>>
>> My first thought would be that it's code to split large TXT-records
>> over different TXT-records.
>>
>> Or just that multi TXT-records didn't work at all, a bug, as mentioned
>> in the log.
>
> I think pre-2.9.21, multi-"part" TXT records didn't work at all.
>
> Actually, RFC 1035 defines a TXT RR to be composed of "One or more
> <character-string>s" (not "parts", and a <character-string> as:
>
>    "a single length octet followed by that number of characters.
>    <character-string> is treated as binary information, and can be up
>    to 256 characters in length (including the length octet)".
>
> Thus the rationale for having more than one (character) strings in a
> single TXT RR is to build a TXT RR that is longer than 255 characters.
>
> The way TXT RRs work in the PowerDNS authoritative server is that each of
> a TXT RR's strings must be enclosed in double quotes, even if the TXT RR
> consists of only a single string.
>
> E.g.:
>
>  "foo bar quux"  (single string)
>
>  "foo " "bar " "quux"  (three strings)
>
> Those values still need to be quoted when specified in an SQL command.
> E.g.:
>
>  INSERT INTO dns_records (name, rrtype, content) VALUES (
>    'txt.example.com', 'TXT', '"foo bar quux")
>
>  INSERT INTO dns_records (name, rrtype, content) VALUES (
>    'txt.example.com', 'TXT', '"foo " "bar " "quux"')
>
> -Julian
>
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>
>



-- 
Augie Schwer    -    Augie at Schwer.us    -    http://schwer.us
Key fingerprint = 9815 AE19 AFD1 1FE7 5DEE 2AC3 CB99 2784 27B0 C072
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