oss-sec mailing list archives

Re: Fwd: ezmlm warning


From: Jeremy Stanley <fungi () yuggoth org>
Date: Sun, 31 Aug 2014 11:24:29 +0000

On 2014-08-31 01:10:54 +0000 (+0000), Jorge Manuel B. S. Vicetto wrote:
I'm forwarding this email to the ml as I just noticed this is the 3rd
time since Jun 19th that because of DMARC emails from some members are
being rejected by receivers domains, like gmail for me. As I don't
recall reading about this topic before in this ml, I'm raising the
issue in case others are unaware and start getting warnings for losing
emails or are surprised by some members not getting their emails.
[...]

As someone who helps operate a fairly large listserv myself, this
has been coming up a lot lately with our subscribers. The official
recommendations from the DMARC coalition (as far as I've been able
to tell) are published at http://www.dmarc.org/faq.html#s_3

The "solution" my fellow sysadmins and I have been leaning toward is
to unsubscribe and reject subscription requests for any address at
an obviously DMARC-enforcing domain, and start building a blacklist
(if someone else already has a DNS-based RBL for this, I'd be quite
interested to use and possible help maintain it as well). MTA
operators enforcing DMARC quite obviously wish to go play in their
own sandbox where a small (statistically, though still quite
important in my opinion) traditional E-mail use case is simply not
considered worth supporting. I'm personally perfectly happy if
nobody at one of those domains ever receives an E-mail message from
me again.
-- 
Jeremy Stanley


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