Martin G. Diehl wrote:
I understand that a series of requests must be made to
the DNS servers to read the records sequentially until
records with v=spf1 are read.
There is no such thing as requesting or reading DNS records sequentially.
Does that mean that a DNS inquiry cannot request the
next record that matches a specified string?
Correct. DNS queries can discriminate by record type (and a special
non-TXT SPF record type is proposed as part of the SPF specification
draft), but not by aspects of the record content.
But, if that could be done -- have the DNS server read
the records until the matching string was found (or the
end of the records for that domain) -- each inquiry
would return always return an SPF record wouldn't it?
Probably, but this is hypothetical as the DNS protocol doesn't support
that.