[exim] Using local_host_blacklist

I'm trouble shooting my newly installed VestaCP, Exim4 on Ubuntu 14.

>From my reading I thought this would be simple BUT it seems not.

On Server-A - While monitoring */var/log/exim4/mainlog* with the tail cmd -
On Server-B - I sent an email to a testUser on Server-A
AND I watched as the email was logged.

The email included the From: IP Address.

So I placed the IP address in the file /etc/exim4/local_host_blacklist
and restarted exim4 via 'service exim4 restart' and watched restart get
logged.

THEN I repeated the above email send from Server-B expecting something
different would be logged on Server-A, i.e, the second email loging would
show some sort of rejection notification.

It was not rejected. Got a very similar logging as the first. The email
came through to the testUser's inbox. Clearly I am missing something.

At the moment I can not see where I went wrong, please advise.

Amanda