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RE: DMARC: perspectives from a listadmin of large open-source lists

2014-04-08 12:59:30
For mailman and DKIM problems (remote reject) 
Example:
2014-04-06 08:09:43 1WWkxK-0007jZ-T5 H=mail.ietf.org [4.31.198.44]:45557 
rejected DKIM : DKIM: encountered the following problem validating gmail.com: 
signature_incorrect

Fix:
In:
mm_cfg.py
Add:
REMOVE_DKIM_HEADERS = Yes





Alex Matias Ojeda Mercado
NOG CHILE
alex(_at_)nog(_dot_)cl
+56971922362


-----Mensaje original-----
De: ietf [mailto:ietf-bounces(_at_)ietf(_dot_)org] En nombre de 
ned+ietf(_at_)mauve(_dot_)mrochek(_dot_)com
Enviado el: martes, 08 de abril de 2014 12:53
Para: John R Levine
CC: IETF general list; Robin H. Johnson; zwicky(_at_)yahoo-inc(_dot_)com
Asunto: Re: DMARC: perspectives from a listadmin of large open-source lists

The problem described WILL vanish when all mailing list apps 
implement DMARC, but until then, it's really broken.

Mailing list apps can't "implement DMARC" other than by getting rid of 
every feature that makes lists more functional than simple forwarders.
Given that we haven't done so for any of the previous FUSSPs that 
didn't contemplate mailing lists, because those features are useful to 
our users, it seems unlikely we'll do so now.

Actually, mailing lists *can* implement DMARC, just not that way: Do a DMARC 
check on all incoming messages, and if the domain policy is one that is 
incompatible with the list's own policies - whatever they are - either change 
the list's policies to conform to that message or reject it outright, 
preferably with a nasty "find another a better mail provider" sort of message.

If the IETF wants to take a leadership position in regards to this issue, 
perhaps someone could set this up.

If receivers want to implement DMARC policy, they need to make their 
false alarm whitelist first.  This appears to be a substantial, 
perhaps insurmountable, hurdle.

At the same time, delaying mass usage of the reject policy would 
limit damage.

Reject policy is fine for domains that don't have individual human 
users, or for companies with firm staff policies that all mail goes 
through the company mail server, and employees don't join mailing 
lists and the like using company addresses, or the company provides a 
separate less strictly managed domain for its staff mail. Strict 
policies will never be appropriate for public webmail systems where 
the users will use their mail addresses any way one can use a mail 
address.  Yahoo appears to understand most of this, viz. the different domain 
for Elizabeth's company mail.

Which is why support for such policies is even in the specification. The 
problem is there's no way to stop inappropriate use of such politicies in 
advance of it happening. The best you can do is apply the clue-by-four later.

                                Ned