#1, Yup. That'd be Rule 4 to the SPF - and to top it off, NW Admin/Host Named DNS Operators need to square it up and add _eps zones and proper SPF TXT Records, soon - as well, they'd better be certain they are the authoritative delegates for both forward and reverse lookups for all assigned address spaces they answer for. Similarly, business DNS and mail server admins need to ensure the same, or have their host named providers add at least proper reverse DNS records for all Domains they answer for.
If not, properly configured and serviced mail systems will reject their traffic.
Say goodbye to SPAM that is largely sent behind one masquerade or another.
It won't truly end though, until carriers lean "hard" on the hosts of target sites serviced by SPAM - stiff fines ought to cover that.
|