Re: [exim] Spam Blocking idea

Marc Perkel wrote:
> Just a thought ....
>
> You extract the registrar barrier part of the host name and the same for
> the helo. Many hosts that send good email this would match. For example
> yahoo.com would have yahoo.com in both the host and the helo.
>
> Then after tracking these and developing a list of hosts that do this
> then we see a host that the helo claims to be yahoo.com but the rdns
> says otherwise. The idea is that if they are on the list of having
> matched then when they don't match it might be a spam indicator?

This fails in exactly the same ways as spf, with the added bonus that
the owner of the domain doesn't even get to tell us when they've changed
their architecture so that they should be removed from your list.

- Marc