Re: Whither OPES? [was: Antigen found W32/Hybris(_dot_)gen(_at_)MM (McAf

> I was speaking of the heuristic to invoke vectoring, not the
> application semantics.
"vectoring" is performed by MX records that cause incoming
mail to be directed to whatever SMTP servers the recipient's
domain wishes to process incoming mail.   

This was defined in RFC 974, and updated in RFC 2821.