[Exim] Rejecting all connections from non-local hosts

Hello,

I'm sorry if this is a fairly basic question, but I can't find any
reference to it in the FAQ.

I have exim running on a workstation, and use it to send all my
outgoing mail, by using sendmail, and to collect incoming mail in
connection with fetchmail.

I want to reject all connections from non-local hosts, so that no-one
can connect to my computer to send me mail. Relaying is forbidden
already, but I can't work out how to reject all outside connections
without setting local_interfaces to 127.0.0.1, which seems messy to
me.

If anyone has any ideas I would be pleased to hear them.

Please CC me in replys because I have not subscribe to receive
messages from this list.

Tom Huckstep