[Mimedefang] $helo versus $ip

[Joseph Brennan]

--On Tuesday, February 3, 2004 12:41 PM +1100 Jack Olszewski 
<jacek at hermes.net.au> wrote:

> In the archives of this list I can't find anything on possible checks
> of $helo versus $ip in filter_relay. What about finding the address of
> the host given as $helo, and matching it against $ip? Would it be safe
> to reject the message if they do not match? For instance (not tested
> in mimedefang-filter yet):


This test has been suggested many times.  You will reject plenty of legit 
mail
if you do it.

If you want to check, put in a test that logs but does nothing else, and 
check
what it found after a day, or a week.  On my site, I could tell it was a 
bad idea
within an hour or two :-)

Joseph Brennan
Academic Technologies Group, Academic Information Systems (AcIS)
Columbia University in the City of New York