Well maybe. If your client supports extra folders per each mailbox and you can access those folders, then yes. Most clients do have such folders, but the are designed to be used with "filters" built in the client. The filters probably aren't sophisticated enough to check DKIM or SPF, which is why plugins are used.
While readers of this list think filtering out email that fails ID is a great idea, the general public just wants the email to be delivered. I don't use Gmail, but I understand Google has implemented or is working on implementing a notification for email that fails DKIM and SPF. I would be interesting to get some stats on email passing both DKIM, each individually, or none at all. When I suggested a plugin for CLAWS email client to check DKIM and SPF, the silence was deafening. Original Message From: Chip Sent: Sunday, June 26, 2016 4:41 PM To: postfix-users@postfix.org Reply To: jeffsch...@gmail.com Subject: Re: DKIM/SPF failure to folder, not return to sender and other tricks Thanks, So it just may be easier to deliver all messages to a folder then have a cron job run some spf/dkim checking script against the emails. On 06/26/2016 05:53 PM, Bill Cole wrote: > On 26 Jun 2016, at 16:44, Chip wrote: > >> I'm wondering if Postfix can do the following easily. > > Nope, not *easily*. > >> It's a real dog to get this setup in Exim. > > Or Sendmail, or probably ANY MTA that isn't tightly integrated to > robust local delivery, mailstore, and mail access subsystems OR which > has a sophisticated flexible mechanism for arbitrary policy definition > and enforcement. So I guess if you wrote cf-ese by hand it might be a > cinch in Sendmail... But anyway: this is *out of scope* for a pure MTA. > > [details elided] > >> In other words, a database or text list of emails with corresponding >> acceptable senders needs to be maintained and referenced for each >> user, I believe, unless a guru here can tell me how to get the flow >> properly. > > To do this with Postfix, you need some sort of external program. The > traditional Postfix mechanism would be a policy daemon. In modern > Postfix you could do it in a milter such as MIMEDefang which provides > a framework for you to create and enforce any policy that you can > express in Perl. (which is easier than cf-ese, really...) > > Within Postfix proper, I suppose you could hypothetically do this with > restriction classes, but those don't scale well. If you had something > checking and tagging messages for SPF & DKIM authentication in Postfix > (e.g. any mechanism that hooks to SpamAssassin or specialized tools) > you could then do delivery via LMTP to something like Dovecot with its > Pigeonhole add-on and have all your per-user rules in Sieve rules. > > In short: there are many different ways to skin this cat, but they all > include the unpleasantry of skinning a cat. Ick. >
