>> 2) What I want is to only allow relay of mail either to my domain from
>> anywhere, or from my domain to anywhere. Is the feature you refer
>> to what I want?
Philip> Yes. Set
Philip> sender_host_reject_relay = *
Philip> and that should do it. That will refuse any incoming MAIL FROM command
Philip> to a domain other than yours. It does not prevent mail to your domain
Philip> being sent out again if, for example, a user has a .forward file.
OK, let me clarify this. When you said "domain other than yours" what
is the precise definition? I'm asking because we relay mail to and
from both the domain comsat.com and the domain ctd.comsat.com.