Re: [dnsext] loads of TXT records for fun and profit

[Doug Barton <[e-mail]>]

On 05/03/2013 02:01 PM, David Conrad wrote:
> Phil,
>
> On May 3, 2013, at 1:39 PM, Phil Pennock <[e-mail]> wrote:
>> That is not my understanding as a reader of RFC4408 and as someone who
>> worked with the coder (and documented the results) for the handling of
>> TXT records in a widespread MTA to be as flexible as possible and to
>> support SPF-style lookups.
>
> Last sentence of RFC 4408, section 3.1.3:
>
> "  SPF or TXT records containing multiple strings are useful in
>     constructing records that would exceed the 255-byte maximum length of
>     a string within a single TXT or SPF RR record."
>
> Sure sounds to me like 4408 anticipates multiple TXT RRs.

Yeah, this is not theoretical. They show up in practice for 
organizations with larger mail infrastructures. IIRC the source for 
libspf2 has some info on this as well.

Doug