On Mon, 23 Aug 2004, Jim Lyon wrote:
I believe that the latest Protocol draft (draft-ietf-marid-protocol-03)
contains changes that don't correctly reflect the consensus of the group
concerning DNS record types. Briefly, it states:
1. Publishers MUST publish using the new SPF2 record type.
2. Publishers MAY also publish using TXT records.
3. Consumers MUST do lookups using the new SPF2 record type.
4. Consumers MAY also do lookups using TXT records.
5. Consumers MAY do both lookups (3 and 4) in parallel.
6. If consumers receive records from both lookups, they SHOULD use
the SPF2 record and ignore the TXT record.
These are all in section 2.1.1 of the Protocol doc.
The problems with the above are:
a. It's not what was previously debated / agreed to.
It has been debated, but it may not have been agreed to by all.
b. Anyone who can't publish an SPF2 record cannot comply with this spec.
That will case those who can not publish SPF2 record to make their service
compliant to be able to fully supportthe spec. However you maybe right
that its too strong to say they are can not comply with spec at all.
c. Anyone who can't look up an SPF2 record cannot comply with this spec.
Same as above, but here I feel more strongly that everyone should provide
ability to read the records and those that dont are not compliant. And
even with microsoft system dns problems (which btw means microsoft software
is not compliant with some dns specs...), I've not seen any argument
that microsoft software can not read new/unknown record types - it can do
it given DNS type number, it just does not know how to interprete it as part
of the library and that would be up to software to do, which I dont think
is that hard given text format of SPF records.
d. Publishers who take the "MAY" in step 2 above to heart and don't
publish TXT records will have their record be completely invisible
to consumers that can't query for the new record type.
I respectfully request that the above requirements be replaced with:
1.Pushblishers SHOULD publish using the new SPF2 record type,
if they are able to do so.
This seems acceptable to me.
2. Regardless of whether they published using the SPF2 record
type, publishers MUST publish a TXT record.
This is not acceptable. If somebody can publish SPF2 record, they MUST do
it and MAY publish TXT record.
2a.The contents of the SPF2 record and TXT record MUST be identical.
Agreed. This is reasonable to avoid problems for those who requested both
TXT and SPF2 records and got TXT first.
3. Consumers SHOULD check for the new SPF2 record type, if they
are able to do so.
I would be ok with SHOULD here, although I feel slightly better if it was
MUST.
4. Consumers who either cannot query for SPF2 records or who find
that a domain hasn't published any SPF2 records MUST query for
a TXT record.
I remind that its optional for consumer to decide to use or not use MARID.
record. So I do not believe that we should force them to query second time
(just like they are not forced to do it the first time and do it by their
own choice) for TXT if they dont want to and are willing to leave with
consequences and consider the domain as if it did not publish MARID record.
I don't think this would be norm though and I think most will for considered
period of time will choose to query both SPF2 and TXT records.
5. Consumers MAY do both lookups (3 and 4) in parallel.
Agreed.
6. If consumers receive records from both lookups, they SHOULD use
the SPF2 record and ignore the TXT record.
Agreed.
Brief Discussion:
It's undisputed that the world would be a better place if everyone uses
the new record type. However, it's also undisputed that many players
won't be able to publish and/or consume the new record type until new
software is installed.
As such everybody should be encoraged to upgrade their software to be
fully compliant with the specs (as well as for many other reasons it also
good to regularly do os and major packages upgrades), but for those who
did not they can still rely on TXT records for considerable time
understanding however that they are not fully compliant and may possible
loose some records the longer they continune to use non-ugpraded software.
--
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net