#! perl
use strict;
use warnings;
use Net::IP;

my $one = Net::IP->new('0.0.0.1');
my $ip1 = Net::IP->new('192.168.0.0/24');
my $ip2 = Net::IP->new('172.168.0.0/16');
my $ip3 = Net::IP->new('10.0.0.0/24');

for my $ip ($ip1, $ip2, $ip3)
{
    print "\nStart IP    [", $ip->ip(),        "]\n";
    print   "Start mask  [", $ip->prefixlen(), "]\n";
    $ip->set($ip->last_ip());
    $ip = $ip->binadd($one);
    print   "Next subnet [", $ip->ip(),        "]\n";
}