In <NGBBLEIJOEEEBMEIAPBKKEKAIMAA(_dot_)scott(_at_)kitterman(_dot_)com> Scott
Kitterman <spf2(_at_)kitterman(_dot_)com> writes:
-----Original Message-----
From: Mark Shewmaker [mailto:mark(_at_)primefactor(_dot_)com]
Sent: Wednesday, August 10, 2005 2:00 AM
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: [spf-discuss] Updating SPF type99 and TXT RR's: Simultaneity is
not guaranteed.
snip
(As a side note, there's another related, but far less serious issue:
If a domain publishes identical txt and spf rr's which include: a domain
that only publishes an SPF-type99 record, then recipients who check
TXT-only will return permerrors, while recipients who check either both
types or even just type99 will have no problems.)
Yes, but checking only one type isn't compliant with the current draft. In
this case if include:domain TXT returns nothing, then include:domain SPF
should be checked.
Checking for only one RR type is always compliant. See section 4.4:
4.4. Record Lookup
In accordance with how the records are published, see Section 3.1
above, a DNS query needs to be made for the <domain> name, querying
for either RR type TXT, SPF, or both. If both SPF and TXT RRs are
looked up, the queries MAY be done in parallel.
In particular, there is never any reason why you have to check for the
new SPF RR type. There are some situations where you simply can not
check for it.
In theory an SPF implementation can also skip checking for the TXT RR
and only check for the SPF RR type. I think this makes sense only if
the SPF RR type has become very popular.
-wayne