[ietf-dkim] Issue: Deployment Guide Section 6.1/6.5 (ADSP/Forwader) conflict
chl at clerew.man.ac.uk
Wed Oct 14 02:32:32 PDT 2009
On Tue, 13 Oct 2009 22:27:52 +0100, hector <gmail.sant9442 at winserver.com>
> Charles Lindsey wrote:
>> On Tue, 13 Oct 2009 02:24:56 +0100, hector
>> <gmail.sant9442 at winserver.com>
>>> The deployment guide section 6.5 writes:
>>> Any forwarder that modifies messages in ways that will break
>>> preexisting DKIM signatures SHOULD always sign its forwarded
>> But it should in addition say that it SHOULD also add an
>> Authentication-Results header for the signature it is about to break AND
>> include that A-R header within what it then signs. That will provide
>> more information to the ultimate recipient.
> But what is its not there? DKIM=DISCARDABLE provides a Domain
> Policy that mail must be signed and valid.
If a valid signature is absent, then indeed the listadmin should discard
it (maybe even with 'ALL'). But the case of most interest is when the
message arrives with a valid signature. In that case, the listadmin should
do his best to forward it, but what does he do if the list policy is to
munge? That is what we are discussing.
So he adds Authentication-Results and signs it. At least then the final
recipient can see that and decide to ignore the failure of the original
signature ("DISCARDABLE" or not), assuming he trusts the listadmin.
But if the final recipient sees that there was NO valid original signature
(nor any Authentication-Results in that case), then he should of course
Discard it (even if the original listadmin had not).
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131
Email: chl at clerew.man.ac.uk Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5
More information about the ietf-dkim