use Net::Netmask;
use strict;
use warnings;
my $b = new2 Net::Netmask( '218.0.0.0 - '.shift(@ARGV).'.255.255.255')
  or die "Argh: $Net::Netmask::error";
print map "$_\n", $b->base, $b->mask, $b->size, $b->next;