Dave Crocker wrote:
So are you implying that we shouldn't worry about the SMTP transaction> 6. no negative feedback > > TCP has congestion control. ICMP "port unreachable", etc.YS> This also has to do with the fact that the body of the message and the> When SMTP messages are thrown away, they're often done so by the end > user. The recipient MTA usually doesn't know, and the originating MTA > doesn't know. So in the absence of negative feedback, spammers > increase their sending rates, in the hope that some messages will get > through.
YS> SMTP transaction are separate from each other.
Huh?
1. SMTP is equivalent to a link-level, point-to-point protocol. As
such, it has plenty of negative feedback and congestion control. The
larger mail service is a classic datagram model, like UDP. And, no,
it has no congestion control. However as one contemplates this
problem, keep in mind the challenge of doing meaningful end-to-end
congestion control in the face of multi-day latencies.
2. I think folks are trying to make the underlying transport service
be responsible for higher-level, user-to-user problems. Remember that
spam is a social problem, not a technical one. So, worry about the
end-to-end object/envelope, rather than the hop-by-hop transfer
protocool.
We do not want to reject all email from unknown senders since any> e.g. Messages from unknown senders should be treated with great > suspicion. Any and all available information should be used to > determine how to process the message.YS> A good example would be giving a higher value to unknown senders in YS> SpamAssasin. How is this different from whitelisting? How is it affected by spoofing?