use strict;
use warnings;
use Net::Netmask;

my $spec  = ...;
my $block = Net::Netmask->new2($spec) or die "bad spec";
my $base  = $block->base;
my $bcast = $block->broadcast;
my @ip    = $block->enumerate;

for (@ip) {

  next if @ip > 1 and $_ eq $base;
  next if @ip > 1 and $_ eq $bcast;

  ...

}