[Asrg] Meta channel, not bounces (was: Re: where the message originated)

[David Wilson]

On Thu, 2009-01-15 at 10:45 -0500, Rich Kulawiec wrote:
> Bounces are a bad idea because they add still more SMTP traffic, they
> can easily be abused to conduct DDoS attacks, and because of the
> situation outlined above.
> 

Something on which we are agreed!

However, what I have been saying is that rejecting using 5xx will
generate a bounce if the reject is sent as a response to an intermediate
MTA.

If the message is very likely to be dangerous, rather than just
inconvenient, any bounce containing the message is itself dangerous. No
doubt, most such dangerous messages come directly from some compromised
PC, and a 5xx response will not give a bounce. But there will be some
proportion which come via an intermediate MTA, which will.