Randy Bush writes on 12/1/2003 1:50 PM:
interesting but utterly irrelevant. the question was not how verison decided it was spam. the point was that their server returned a 450 as opposed to a 5xx (550 looks good), and this causes net damage.
They haven't yet determined that it is spam. So, RFC nitpicking wise, they are right.
On the other hand, from a mail operations standpoint, I personally feel that sender verification, graylisting and other methods that rely on 4xx'ing email are a bad idea, as they makes things inconvenient for a whole lot of ISPs ... and because these emails have to be either 5xx'd or trashed sometime sooner or later.
-- srs (postmaster|suresh)@outblaze.com // gpg : EDEDEFB9 manager, outblaze.com security and antispam operations
