Maybe it was listed in some errata list somewhere or else something has
changed in Exim since the publication of the book (2003-version):
On page 340 the second example under 14.8.17:
"deny sender" works only if you type it as "deny senders".
I could not find any "deny sender" in spec.txt.
Regards
Johann
--
Johann Spies Telefoon: 021-808 4036
Informasietegnologie, Universiteit van Stellenbosch
"Jesus said unto her, I am the resurrection, and the
life; he that believeth in me, though he were dead,
yet shall he live" John 11:25