martin f krafft:
> Authentication-Results: mx.google.com; dkim=pass (test mode)
> [email protected] header.s=2015-11-14 header.b=T7jbyqDv;
> spf=pass (google.com: best guess record for domain of
> [email protected] designates 2001:db8:bad::cafe:: as
> permitted sender) [email protected];
> dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=example.org
>
> What else can we do? How do you deal with this problem?
Perhaps the SMTP client IP address 2001:db8:bad::cafe:: has no PTR
record (or the name does not resolve to 2001:db8:bad::cafe::).
Wietse
