This module eases the task of checking if a given host is in the list.
The methods available are described below:

`->new(suffix)'
    Creates a list handle. The `suffix' parameter is mandatory and
    specifies which suffix to append to the queries.

`->check($host)'
    `$host' can be either a hostname or an IP address. In the case of an
    IP Address, any trailing netmask (anything after a '/' character)
    will be ignored. In the case of a hostname, all the IP addresses
    will be looked up and checked against the list. If any of the
    addresses is in the list, the host will be considered in the list as
    a whole.