OT - blocking mail from specific email addresses

[Sam Varghese <sam@gnubies.com>]

hi

i help to run a potato server for a group of elderly/disabled people.
we use exim 3.12 as the MTA.

some of our members have been getting offensive email from a
certain person and i would like to block this. the problem is
that i cannot block mail from the domain as it is a fairly
public one.

i would be grateful if any of the assembled could advise me 
or point me to docs to find out what syntax to use in the exim.conf 
to block email from specific email addresses.

i have looked at the exim docs and searched with google;
there is plenty on how to keep out mail from a particular domain 
but nothing on blocking email from a particular user.

sam
-- 
(Sam Varghese)
http://www.gnubies.com