In message <199806111949.PAA02739@luomat.peak.org>, Timothy J Luoma writes:
>
>How about requiring that people are sending mail from domains which actually e
>xist?
>
>That would stop some of it (ie john@3:16) at least, and is becoming more and  
>more common.

Sendmail 8.9.0 does this and more quite nicely.

Presumably qmail could do the same?