use IO::Socket::Multicast;

  # create a new UDP socket ready to read datagrams on port 1100
  my $s = IO::Socket::Multicast->new(LocalPort=>1100);

  # Add a multicast group
  $s->mcast_add('225.0.1.1');

  # Add a multicast group to eth0 device
  $s->mcast_add('225.0.0.2','eth0');

  # now receive some multicast data
  $s->recv($data,1024);

  # Drop a multicast group
  $s->mcast_drop('225.0.0.1');

  # Set outgoing interface to eth0
  $s->mcast_if('eth0');

  # Set time to live on outgoing multicast packets
  $s->mcast_ttl(10);

  # Turn off loopbacking
  $s->mcast_loopback(0);

  # Multicast a message to group 225.0.0.1
  $s->mcast_send('hello world!','225.0.0.1:1200');
  $s->mcast_set('225.0.0.2:1200');
  $s->mcast_send('hello again!');
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update (broquaint): added <code> tags