[Exim] blocking spam in ACL

I constantly see harvesting attempts with the following two log entries:

    H=(mail.nowhere.com)  F=<joe@???>

Would the appropriate RBL entry look like:

deny senders = joe@???


is it that simple?

--
Jim Pazarena  Box 550                 mailto:paz@qcislands.net
              Queen Charlotte  BC     http://www.qcislands.net/paz
              CANADA   V0T 1S0        phone:250 559 7777