Friends -
Contributors
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The authors of the DMP, RMX and Vixie proposals are listed in the
references section. Is that not enough?
New RR
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The wording an design of this section was done in conjunction with DNS
guru types. It doesn't include the stronger language they desired
which would have made the new RR type required for both publishers and
receivers.
It is by design that publishers can choose not to publish the TXT
format if they wish. One can only hope for a day when deployment makes
this a reasonable option.
It is also by design that which order to query the types isn't
specified. Implementations may choose to query both simultaneously.
Repeated Modifiers
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Section 4.6.3 says "The same key MUST NOT appear in more than one
modifier in a record." The intent is that modifiers cannot be
repeated, and any repetition results in a syntax error (PermFail).
As this is a specification, it should not sanction tolerance of
non-well-formed records, or records with ambiguous semantics (such as
having two "exp=" sections). Implementations, will of course, vary in
their degree of strictness.
Case Sensitivity
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Since the specification is defined using the ABNF of RFC 2234, all
alphabetic literal characters (those in double quotes) in the syntax
are case insensitive. So, yes, "v=spf1" and "V=SPF1" and "v=SpF1" are
technically all legal and the same. Similarly, "+a" and "+A" are the
same. On the other hand, the characters that make up domain-spec and
macro-string, as they are specified with percent notation (as in
%x30-7E), are case sensitive.
I have long suspected that this is NOT really agreed upon understanding
of SPF v1. Comments?
- Mark