# Broadcast:
14:40:09.490409 IP 192.168.0.14.5001 > 255.255.255.255.5000: UDP, length 16
14:40:09.491281 IP 192.168.0.15.5000 > 192.168.0.14.5001: UDP, length 16
# Unicast:
14:41:44.950375 IP 192.168.0.14.5001 > 192.168.0.15.5000: UDP, length 16
14:41:44.951275 IP 192.168.0.15.5000 > 192.168.0.14.5001: UDP, length 16

#!/usr/bin/perl
use strict;
use warnings;
use IO::Socket::INET;
use IO::Select;
$| = 1;
my ($socket,$select,$data,$peer_address,$peer_port);
$socket = new IO::Socket::INET (
    PeerAddr  => inet_ntoa(INADDR_BROADCAST),
#    PeerAddr   => '192.168.0.15',
    PeerPort  => '5000',
    LocalPort => '5001',
    Proto        => 'udp',
    Broadcast => '1',
) or die "ERROR in Socket Creation : $!\n";
$select = new IO::Select or die "no select: $!\n";
$select->add( $socket ) or die "no add socket: $!";
print "Start Client.\n";
$socket->send('data from client') or die "send faild: $!";
while ($select->can_read(2)){
    $socket->recv($data,128);
    $peer_address = $socket->peerhost();
    $peer_port = $socket->peerport();
    print "($peer_address:$peer_port) said: \"$data\"\n";
}
$socket->close();
print "Ende\n";

#!/usr/bin/perl
use strict;
use warnings;
use IO::Socket::INET;
$| = 1;
my ($socket,$received_data,$peer_address,$peer_port);
$socket = new IO::Socket::INET (
    LocalPort => '5000',
    Proto => 'udp',
    Broadcast => '1',
) or die "ERROR in Socket Creation : $!\n";
print "Start Server.\n";
while(1)
{
    $socket->recv($received_data,1024);
    $peer_address = $socket->peerhost();
    $peer_port = $socket->peerport();
    print "($peer_address:$peer_port) said: \"$received_data\"\n";
    $socket->send('data from Server') or print "Can't send data! $!\n";
}
$socket->close();