Re: Bounce/System Notification Address Verification

> I am not rejecting anything. All I am suggesting is that when more than 
> one recipient is to be used for the message, to generate a separate copy 
> for each recipient (with only that recipient listed as the "To") so 
> there are separate copies (as would occur with multi-recipient [messages 
> where each recipient is in a different domain] at the MTA stage ).
Why should an MTA or MUA bother to do this?  This part of the SMTP 
standard has been stable since c. 1980 and it has _never_ required this.
> OK - Not a Rule but only the usual occurrence with <> messages such as 
> "can not deliver" messages. If those functions that generate 
> multi-recipient messages with a <> from would just create a separate 
> copy for each recipient it would make SPAM detection (of <> messages) 
> much easier 
no it wouldn't.  it would just mean that spammers would have to use 
another return address besides <> or send only one RCPT per session. 
it's not as if the check you propose imposes much of a hurdle for 
spammers to clear.
spammers have consistently shown themselves to be very flexible at 
adapting to far more substantial countermeasures.   and it's much easier 
for spammers to adapt than for the vast installed base to adapt.  it is 
counterproductive to impose meaningless restrictions on legitimate 
senders.  in the long term this only adds complexity and damages 
transparency of the mail system without doing anything to discourage spam.
Keith