Re: CBV systems - was Re: SMTP Extensions - proper peply code for disabl

I could reply to your reply in detail but that would only distract from 
the important points in this debate.
the points are these:

if widely adopted CBV will impair the reliability of the mail system by 
causing delivery failures for legitimate messages in cases where 
delivery would otherwise have been successful (i.e. if the return-path 
field was invalid or not usable due to a configuration error or 
temporary failure)
since CBV is easily circumvented by spammers, in the long term CBV does 
no good - it only introduces overhead.