use IO::Socket;
use Net::IP;


my $port = 80;
my $start_ip = "88.198.240.123";
my $end_ip = "88.198.255.254";

my $ip_string =  $start_ip." - ".$end_ip;

my $ip = new Net::IP ($ip_string) or die;

        do {
                my $temp_ip = $ip->ip();
                
                print "Info: Connecting to... [$temp_ip]\n";
            my $socket = IO::Socket::INET->new( PeerAddr  => $temp_ip, 
                                                                                        PeerPort  => $port, 
                                                                                        proto  => 'tcp', 
                                                                                        Timeout  => 0 ); 
                unless($socket) {
                        print STDERR "Info: ... FAILED! Can't bind: $@\n";
        }
                
        $socket->close();
        print "Info: ... OK!\n";

        } while (++$ip);

Info: Connecting to... [88.198.240.123]
Info: ... FAILED! Can't bind: IO::Socket::INET: connect: Unknown error
Can't call method "close" on an undefined value at ...