A security issue of a different kind.

[alan () manawatu gen nz (Alan Brown)]

Spam.

We've all seen it and we've all had it arrive in our mailboxes.

I get around 20 pieces a day, most of it from forged addresses or from
sites who have no business handling the originating domain.

Turning off your mail dameon's facility for being used as a mail relay
will help cut down on it by reducing the paths the spammers can use to
inject their poison into the mail system.

Sendmail 8.8.x has the facility to refuse mail from "bad domains" as well.

It's easy to do. Why does noone do it?

AB