[Mimedefang] Yahoo! DMARC and smfi_chngfrom was Yahoo DMARC

Kevin A. McGrail KMcGrail at PCCC.com
Tue Apr 15 09:35:19 EDT 2014

On 4/14/2014 10:06 PM, David F. Skoll wrote:
>> Specifically, here's a test from my Yahoo! account to an autism
>> mailing list. Even though smfi_chgfrom appears to have worked, when
>> the email is parsed by mailman, it does not appear to reflect the
>> changed sender. Any thoughts appreciated...
> smfi_chgfrom only changes the envelope sender.  I think Mailman (and
> possibly Yahoo?) might be looking at the From: header instead.
Thanks.  I think I also need to exempt emails to -owner, etc.  Need to 
look at that.
> With regards to the MIMEDefang list, I don't plan on doing anything
> special.  If Yahoo wants to break legitimate mailing lists for its
> users, that's Yahoo's problem, not mine.  Luckily, I do not depend
> on being able to reach Yahoo subscribers for my business to be viable,
> so... meh.
The article might not be doing a good job of explaining the basic, 
real-world issue:

- Yahoo user sends email to list
- List resends email to all members
- All the various recipients that acknowledge p=reject reject the mail 
as forged
- You look like a spammer
- Recipient ISPs blacklist you
- Members on some lists (like mailman) are unsubscribed for reaching 
bounce thresholds


More information about the MIMEDefang mailing list