[SpamCop-List] Re: C/R systems

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in article MPG.1a9eec05ec559b3c98968d at news.spamcop.net, N. Miller at
tdy at blackhole.aosake.net wrote on 2/20/04 6:51 AM:

> In article <c12cu9$u81$1 at news.spamcop.net>, bar_n0ne at hotmail.com says...
>> I thought that a bounce of the type performed by the receiving MTA results
>> in the sending MTA actually sending the bounce, these would not be
>> mailwasher style bounces, I'd have thought. But I'm no expert so educate me.
>> Aren't those SMTP code 50## bounces like BL rejects OK?
> 
> Your original statement was ambiguous. "Presumably if intelligently done
> this could occur during the SMTP Envelope transaction...". This implies that
> the reject will go to the "envelope sender", which is not what you want to
> do, because the "envelope sender" may be forged.
> 
>> I don't propose that the receiving MTA receive and open the mail, just pass
>> back the deny reason and web site for C/R.
> 
> Actually, I think it is possible to receive DATA and still reject. The
> server would run the message through a content filter will the connection is
> still open. Then, if the content filter triggers a rule, the receiving
> server would send the 5xx code instead of the 2xx code. The sending server
> would have to deal with the 5xx reject.
> 
> What is harder is to perform a C/R reject. For the challenge to work, the
> C/R recipient must keep the message in quarantine, which means you can't
> reject the message, but have to accept it.

I don't understand why the DATA needs to be received at all, nor why the
email needs to be quarantined. the sender would have to gain admission via
c/r,, becomes whitelisted presumably, and then has to resend the original
message.

Berny