OT: Seeking opinion about reverse-DNS lookups on SMTP HELO

[Scot L. Harris]

On Tue, 2004-12-14 at 07:02, HaJo Schatz wrote:
> To combat spam I have enabled reverse-DNS lookups of incoming SMTP 
> connections. If the FQDN does not match the HELO-Identity, I reject the 
> connection with a 550 Error.
> 
> I have now found that this breaks communication even with reputable 
> (well, an international bank that is) peers. Dunno how much more mail I 
> may have lost through this... How are you out there handling that, are 
> you doing reverse-lookups?

The best tool for combating spam that I have found so far is a
combination of greylisting and spamassassin.  Greylisting will block 95
to 98% of spam from ever getting on your sysstem.  Spamsassassin catches
most of the rest.

If you are using sendmail I have used the milter-greylist package to
provide greylisting.  There are many others as well as versions for
other MTAs.

Highly recommended.


-- 
Scot L. Harris
webid at cfl.rr.com

I have found little that is good about human beings.  In my experience
most of them are trash.
		-- Sigmund Freud