On Nov 21, 2010, at 6:43 PM, Tsuneki Ohnishi wrote: > > Thanks, Bill, Mark and Byung-Hee for the warm welcome. > > Yes, we gotta start something somewhere and glad to > let you know that we are staring something here. > If possible, let's work together for the spread out > in eastern asia, Byung-Hee. > > Well, let me give you the first feedback of what's > been discussed at the point of implementation here, > and I would like to ask your opinions. > > Here is our stuation. Members of dkim.jp so far circulate > somewhat like 30% of domestic emails and a lot more forged > emails coming from overseas, especially forged @yahoo.co.jp > and @rakuten.co.jp. So with the initiative of those two > companies and others, we got together to get rid of those > forged emails. > > Senders in dkim.jp are committed to attach DKIM signature > withing 6 months, and possibly ready to write their ADSP > "discardable". Since we have major ISPs on our member list > and they are very willing to discard unveryfied emails, > no surprise about it :-), we are trying to inch up to the > level where all domestic emails are signed and verified. > > But there is a small problem. It is rather polical. > We have a telecommunication law that allows ISPs to discard > forged email, but our Ministry so far does not acknowledge > that failure of DKIM verification immediately equals to > forgery, because there could be other reasons to fail.
That's not political, that's technical. Mail that is validly DKIM signed when it's sent may not be DKIM signed when it is received. If you discard mail that isn't DKIM signed just because you expected it to be DKIM signed, you'll end up discarding quite a lot of email. And the errors aren't likely to be terribly random, rather they'll be related to particular mail paths, so some people will see a lot of mail wrongly discarded. ADSP is better than SPF, but it's still not something anyone should consider deploying widely as a primary means of deciding to discard inbound email. > We can fight about it taking time to get through to dull > Japanese bureaucracy, but I think there is a faster way. > It is to let senders to have an option to declare that > if there is no DKIM signature at all, verifiers can discard > those messages. Then we can shut their mouths insisting > there could be other reasons. > > So, my point is that what do you think of the idea to have > an new entry in ADSP "discard-if-no-sig", which allows > senders to declare messages without DKIM signature should > be discarded? If you're just trying to stop email such as virus blowback then something simple like that will work OK, some of the time. It's more complex, and less effective, than other approaches so it's not a really good idea. But if you're trying to stop mail that's being sent by a bad actor... give up on this approach, as it's trivial to add a "fake" DKIM header that will not authenticate. Also, it may discard quite a bit of legitimate email, if any of your users subscribe to mailing lists (some mailing list managers are likely to strip out DKIM headers in the cases where they know they'll invalidate them). Cheers, Steve _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
