Re: misconception in SPF

>I think this makes sense, but I think it would make more sense if there was
>a way to just specify in the SPF record for, for example, twitter.com, that
>all legit senders for all subdomains are included in the highest level SPF
>record.  

This sort of thing has been proposed before.  It turns out that
anything in the DNS that starts "all names below this node ..." is
astonishingly hard to implement.

(Yes, I know about zone cuts.)

I do agree that it would have been really nice if the SMTP fallback
from MX to A records had been deprecated and killed back in the 1980s.
I tried to get RFC 5321 not to add fallback to AAAA but the powers
that be insisted that it was already too late.