[exim] Too many Failed Recipients

I saw some code in the Exim Github and thought of putting that in to warn us
if we get a dictionary attack. However the following code, which I put in
does not work:



deny recipients = /usr/exim/deny_recipients

        message = rejected because the person is in the denied recipients
list

# warn if there are too many unknown recipients - and try to slow down

warn message = WARN - SPAM MAIL Failed Recipients - count = $rcpt_fail_count

      condition = ${if > {${eval:$rcpt_fail_count}}{3}{yes}{no}}

       !verify = recipients/callout=2m,defer_ok,use_sender

Exim version 4.80.1



Regards





Sujit Choudhury | IT Services

Birkbeck, University of London