use IO::Socket;
use IO::Select;
use IO::Handle;

$A = new IO::SOCKET::INET (LocalHost => 'localhost',
                           LocalPort => 1234,
                           Type      => SOCK_STREAM,
                           Proto     => "tcp",
                           Reuse     => 1,
                           Listen    => 5)
or die "A Server socket couldn't be created: $@\n";

$B_listen = new IO::SOCKET::INET (LocalHost => 'localhost',
                           LocalPort => 5555,
                           Type      => SOCK_STREAM,
                           Proto     => "tcp",
                           Reuse     => 1,
                           Listen    => 5)
or die "B Server socket couldn't be created: $@\n";

my $B_clients = new IO::Select();
my $pid = fork();

if ($pid) {        #PARENT
  while($A_sock = $A->accept()) {  #Will only have 1 connection
    while(defined($buf=<$A_sock>)){
      my @client_set = $B_clients->can_write;
      foreach my $client (@client_set) {
        print $client $buf;
      }
    }
  }
} else {           #CHILD
  while($B_sock = $B_listen->accept()) {
    $B_clients->add($B_sock);
  }
}