[Linux-aus] PSA: Messages sent through LA mailing lists being classified as SPAM

[Joel W. Shea]

On Thu, Jan 14, 2016 at 10:13:18AM +1000, Rob Thomas wrote:
>
> [...] The firs one I found was from Andrew Bartlett, and was bounced
> because of SPF errors:

Excuse the pedantry; not bounced, and not because of SPF errors, per se.

But rather it was marked as spam, by enforcing samba.org's DMARC
quarantine policy, when failing the DMARC check.

$ dig +short TXT _dmarc.samba.org
"v=DMARC1\; p=quarantine\; [...]"

> [...]
> Authentication-Results: mx.google.com;
>   spf=pass (google.com: domain of linux-aus-bounces at lists.linux.org.au
>   designates 192.55.98.181 as permitted sender)
>   smtp.mailfrom=linux-aus-bounces at lists.linux.org.au;      

As you can see, it passed SPF… 

>   dkim=neutral (body hash did not verify) header.i=@samba.org;
>   dmarc=fail (p=QUARANTINE dis=QUARANTINE) header.from=samba.org
> [...]

but fails DMARC, because;

a) DKIM authentication fails, as the body hash verification fails (since
the mailing list modified the body by appending a footer)

*and/or*

b) According to DMARC, the domain in the "From:" header must match the
domain used to validate SPF (hence not an SPF error, per se)

Although this might be desired behaviour, it's possible the strict
policy may have been set while overlooking this unanticipated
consequence.
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