Aaron Thomas [1/23/2004 8:28 AM] :
Sender Permitted From (http://spf.pobox.com/) attempts to eliminate Joe Dropping from domain.com by doing a look up on a TXT record similar to [...] As this project is fairly new, there aren't many large domains making use of it, and the tools available aren't mature enough for some email
What I described in my earlier email (helo filtering) is aimed at the same result. Only, it has to be done on a case by case basis. And it does allow road warriors. The second way (slightly more radical, prone to a little more collateral damage, but does stop a LOT of spam) - stop accepting mail from commonly forged freemail domains if the mail originates from an IP with either * no rDNS * generic (dialup / cable / dsl) pattern rDNS -- srs (postmaster|suresh)@outblaze.com // gpg : EDEDEFB9 manager, outblaze.com security and antispam operations