use strict;
use IO::Socket;

my $HOSTNAME = '127.0.0.1';
my $PORTNO = '27501';
my $length = 1024;

socket (SOCKET, PF_INET , SOCK_DGRAM, getprotobyname ('udp'))
or die "socket: $!";
my $ipaddr=inet_aton($HOSTNAME);
my $portaddr = sockaddr_in($PORTNO, $ipaddr) ;

my $msg = chr(0xff).chr(0xff)."Z".chr(0xff);

send (SOCKET, $msg, 0 , $portaddr) == length ($msg)
or die "cannot send to $HOSTNAME($PORTNO): $!";

my $rin = '';
vec($rin, fileno(SOCKET), 1) = 1;
my $rout;

while (select($rout = $rin, undef, undef, 10.0))
{
        $portaddr = recv(SOCKET, $msg , $length, 0)
        or die "recv: $!";
        
        ($PORTNO, $ipaddr) = sockaddr_in ($portaddr);
        my $host = gethostbyaddr ($ipaddr, AF_INET);

        print "$host($PORTNO) said $msg$/";
}