In <20040311194015(_dot_)GB56829(_at_)Space(_dot_)Net> Markus Stumpf
On Thu, Mar 11, 2004 at 11:02:28AM -0800, Hallam-Baker, Phillip wrote:
2) TXT record with prefix label, e.g. _spf, _ep
This fills all the requirements, with the possible exception
of (1) since some DNS configurations reject labels with
underscores. I think in the context of an IETF proposal we
can get these fixed.
This is not a problem at all, as this kind of notation is already widely
used and well defined for SRV records.
The last time the SPF folks investigated where to place their TXT
record, it was determined that a non-trivial number of web-based DNS
administration systems (registrars, DNS providers, etc.) could not
handle the underscore. Some can not deal with adding TXT records, and
most do not allow you to add arbitrary RRs.
I agree with Phillip here. I think that in the context of an IETF
proposal, we can get these fixed, but there ARE problems that need to
be fixed. Last fall, when it looked like SPF deployment would be
going a lot slower, it was decided that using an underscore would
be too much of a hurdle for rapid adoption. It was also determined
that the usage of TXT records is low enough that there wasn't a need
to place them in a subdomain in order to keep the DNS queries under