[dmarc-discuss] mailing lists, was SPF pass / fail

[John R Levine]

> If the only thing you have to assert is 'the domain enforces DMARC, so
> they already rejected everything that should be', then it's a lot less
> ambiguous.

I'm still confused.  How do you know that?  If the domain just asserts it, 
they're probably lying or mistaken.  I suppose you could have a DMARC checker 
tbat sent probe mail to see what happens, but it would be hard to do that in a 
way that isn't trivilally faked out by bad guys who figure out where the probes 
come from.

Even though my mail system isn't very big, I've still had to whitelist places 
like NANOG and the IETF to keep spamassassin from catching their mail.  I 
suspect that anyone with filtering sophisticated enough to worry about DMARC 
and lists probably has the resources to figure out whare the lists are.

Regards,
John Levine, johnl at iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. http://jl.ly