Re:My account is sending spam emails
by massaman_yams on Sunday April 22, 2018 @04:10PM
(#16898287)
ARC is the new standard designed to fix the DMARC edge case with forwarding. It's relatively new, though, so adoption isn't nearly as widespread as SPF, DKIM, or DMARC.
In this particular case, it seems the major issue is that spammers got access to 69.64.35.11, which is included in telus.com's SPF record. In the end, this will hurt deliverability for legitimate emails sent with telus.com in the return path, and I suspect telus.com's customer service will have some explaining to do for their customers.