> As we all know, Unix systems run their daemons under various users (root, > nobody etc). Since any of such users can be used to spam systems (because
> they appear to be local users, and hence CAN send email), I am wondering if
> there is a way where I can set up a router or director which will allow
> those users to ONLY send email within the local host, i.e
> nobody@??? can send email only to users within the host itself.
It's much more interesting to refuse mail FOR them. How can
I?