Node.js Socket Server 如何知道客户端连接到哪个 IP 或域?

如何知道客户端在 node.js TCP Server 中连接到哪个 IP/主机名?

How can I know which IP/hostname the client connect to in node.js TCP Server?

var server = net.createServer(function (stream) { 
    // The server is behind a firewall,
    // how can I know how the client connect to this server?
    console.log(stream.localAddress);
});
server.listen(21, '0.0.0.0');

谢谢