* Scott Kitterman:
One other consideration is that while the spec says that TXT and SPF
must be identical, receivers are explicitly NOT required to check
for this (and in fact, as I think you are arguing it would be a bad
idea).
One of us is misreading the spec, it seems. (It could well be me.)
Here's the relevant paragraph, I think:
| 4.5. Selecting Records
|
| Records begin with a version section:
|
| record = version terms *SP
| version = "v=spf1"
|
| Starting with the set of records that were returned by the lookup,
| record selection proceeds in three steps:
|
| 1. Records that do not begin with a version section of exactly
| "v=spf1" are discarded. Note that the version section is
| terminated either by a SP character or the end of the record. A
| record with a version section of "v=spf10" does not match and
| must be discarded.
|
| 2. If there are both SPF and TXT records in the set and if they are
| not all identical, return a "PermError".
|
| 3. If any records of type SPF are in the set, then all records of
| type TXT are discarded.
I *think* that this requires SPF clients to signal PermError in case
of a mismatch.