🚀 go-pugleaf

In article <9804031938.45os@pierrot.co.uk>,
	tez@pierrot.co.uk (Terrance Richard Boyes) writes:

> Any chance that 5 can include the hostname as well as the address? Then
> some simple cross-validation of lines 5 [IP] and 6 [HELO information] (and
> the envelope from that you already provide with *ENV) will probably show
> up a lot of UCE.

There's no way you can check either the IP or HELO (which are from the
machine that sent the mail to demon's punts) against the envelope from
without losing lots of valid mail.

Checking the IP against the HELO will also fail for lots of PCs (why are
programmers of internet software for PCs incapable of doing things right?),
but this may not be a problem, as this kind of brain-dead software is
unlikely to be able to send directly anyway, but will instead be using a
smarthost, so by the time the mail gets to a demon machine it will hopefully
have something sensible. 

However, even if the HELO string is perfectly valid, lines 5 and 6 may not
be the same---the HELO string may forward resolve to the correct IP, but
that IP may reverse resolve to a different name.