Bill,

If that's the case, then Microsoft appears to be at fault here. I'll try 
opening a ticket (I know. Windmills :)

 -mel

On Mar 29, 2017, at 8:13 AM, William Herrin 
<[email protected]<mailto:[email protected]>> wrote:

On Wed, Mar 29, 2017 at 3:04 AM, DaKnOb 
<[email protected]<mailto:[email protected]>> wrote:
Usually mailing lists act like e-mail spoofers as far as SPF and DKIM is 
concerned. These two systems above try to minimize spoofed e-mail by doing the 
following:

SPF: Each domain adds a list of IP Addresses that are allowed to send e-mail on 
their behalf.

DKIM: Each email sent by an "original" mail server is cryptographically signed 
with a key available, again, in the DNS.

When you send an e-mail to a list, you send it to the mailing list mail server. 
After that, of the server forwards that e-mail to the recipients, its original 
address is shown, therefore if Outlook checks for SPF records, that check will 
fail. An easy way to get around this is for the list to change the From field 
to something else, like "Mel Beckman via NANOG" and a local email address.

However, when you send that email, it may also be signed with DKIM: any change 
in subject (say "[NANOG]" is added) or the body (say "You received this email 
because you subscribed to NANOG" is appended) will also cause that check to 
fail.

Hello,

Both SPF and DKIM are meant to be checked against the domain in the envelope 
sender (SMTP protocol-level return address) which the NANOG list sets to 
[email protected]<mailto:[email protected]>. Checking against the 
message header "from" address is an incorrect implementation which will break 
essentially all mailing lists.

Regards,
Bill Herrin



--
William Herrin ................ [email protected]<mailto:[email protected]> 
 [email protected]<mailto:[email protected]>
Dirtside Systems ......... Web: <http://www.dirtside.com/>

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