Suresh> How big a site do you think we are? 30 million users.
Suresh> We use fake EHLO as one of our most effective filters.
Suresh> Mail from a non yahoo IP (say a taiwanese DSL line) saying
Suresh> HELO yahoo.com? Or better still, HELOing to us with the name
Suresh> of one of our own hosts or IPs? Cast iron spamsign.
one caveat: you make to make sure that you don't apply this rule to
your relaying clients. Using port 587 for mail submission rather than
port 25 makes this an awful lot easier.
