John Leslie wrote:
Doug Otis and I have been working up a proposal for a SMTP extension to
shift some of the burden of spam abatement away from the receiving SMTP
servers towards the originator. It is now published at:
In essence it holds the originator responsible for maintaining the copy of
the message until a receiving Mail User Agent determines that it should be
delivered to the recipient.
They enforce this patents and its follow-ons very aggressively.
2. At best, this reduces total bytes over the but the requirement for a
notification message does not reduce the number of network 'transactions' --
in fact it increases them by 100% or more.
3. This presumes that making a real-time decision is a current problem, when
it is not generally held to be a major factor among the anti-abuse community.
Sure, it would be nice to be able to do it, but it's a long way from the top
of the list.
4. It presumes that users can make the right decision. Experience is pretty
clear that that's too often not a correct presumption. In addition, having
users be required to make this decision burdens them far more than is felt to
be useful. (This is a derivation of the transaction cost item, above, except
that it moves the decision-making from a receive-side front-end filter to the
human user. And of course, it them requires them to wait for the message to
5. Doesn't work so well for disconnected users.