use IO::Socket;
use Storable;

my $dict = retrieve("hash.txt");

my $sock = IO::Socket::INET->new(
               LocalAddr => "localhost:8888",
                                     # any available port you like
               ReuseAddr => 1,
               Listen    => 2,
           ) or die "$0: can't create listening socket: $!\n";

while (1) {
    my $conn = $sock->accept();  # wait for connection

    next unless ref $conn;       # (just in case...)

    my $query = <$conn>;
    chomp $query;

    print STDERR "query: $query\n";   # just for debugging

    my $reply = (exists $dict->{$query}) ? "FOUND\n" : "NOT FOUND\n";
    print $conn $reply;

    close $conn;
}