RE: virus scanning

["Julian Mehnle" <lists@mehnle.net>]

Russell Coker wrote:
> > > However sending 550 codes is ideal for mail that goes direct.
> > 
> > How do you define "direct"?
> 
> TCP connection from viral infected machine to destination mail server
> without any redirection along the way.

By that definition (which is of course as good as any), a receiving mail server cannot reliably determine (if at all) whether an incoming connection is a "direct" one, can it?  Except of course by white-listing every single known-good mail server (hint SPF).