#!/usr/bin/perl
use IO::Socket;
my $port = 1;

$file = "/home/retail/perl/ports.txt";

while ($port <= 10000) {
  $sock = IO:Socket::INET->new(PeerAddr => '172.21.101.11', PeerPort => $port, Proto => 'tcp', Timeout => '1');

  open (LIST, ">>$file");
    if ($sock) {
      close ($sock);
      print "$port -open\n";
      print LIST "$port -open\n";
      $port = $port + 1;
    }
    else {
      print "$port -closed\n";
      $port = $port + 1;
    }
}
close (LIST);