Hey Dave,
On Monday 19 October 2009 12:22:20 Dave CROCKER wrote:
Barry Leiba wrote:
I suggest that ADSP-compliant mailing lists should be
advised to reject "discardable" messages whether or not they will be
breaking the signature.
rejection is really only needed if they break the signature which should be
evident by their settings. The point of DKIM is to preserve integrity however
the bank statement is a confidentiality issue.
For instance I manage a private maillist of board members that receive paypal
notices. 100% DKIM validation pass rate. The maillist is configured to not
modify the message so the final recipients could validate it too if they
wanted.
Yes, this is a reasonable idea.
The question is whether it is the /right/ idea.
Another reasonable idea is that the mailing list should ignore ADSP, since
ADSP is really meant for final recipients;
As the mailing list is probably the last place to see a valid signature
evaluating the ADSP there is the best idea. The mailing list verifier has a
greater confidence in rejecting broken signatures there than the final
recipient. The final recipient could deploy some whitelisting model based on
the behaviour of the list with minimal risk.
note that ADSP only comes into
play for recipients who support it. (Well, that is at least one model.)
And there are no doubt lots of other reasonable ideas.
At this stage, I believe rightness depends entirely on market preferences.
Do we have any empirical data of ADSP use which experiences the problem
being covered here,
Some was described here;
http://mipassoc.org/pipermail/ietf-dkim/2009q4/012596.html
resolves it in the way being suggested,
dkim=discard is the easy case.
and garners receiver support?
at the moment receivers who care about dkim whitelist domains/ip or if they
wish to accept some risk, rely on domain reputation.
Absent any of that, this discussion is purely academic.
Each proposal like this is expensive. It takes time to discussion, run
through the process, test, deploy and use. We should let private
experiments determine the preferred handling, before we seek to
standardize a solution.
Particularly since we seem to have only and exactly one market-based
organization experiencing the problem.
given the level of ADSP deployment it is hardly unexpected that only one
organisation that this group collectively knows about has disclosed a problem.
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