[exim] Block dialup clients

Hi!

I'm tryng to block dialup users like the follow example:

ppp-*.libero.it

I'm using exim-4.44 with exiscan patch and I've try to use lsearch whit
a blacklist file but don't work.
I'm tryng to drop mail from hosts whit the follow example, but don't
work:

acl_smtp_connect:

  drop    message       = No mail from dialup connection
          hosts         = \N^ppp*\.libero.it$\N : \
                          \N^host*\.*pool.interbusiness.it$\N : \
                          \N^pc*\N : \

Have someone any idea to solve it?

Andrea