UdpClient can't receive after connect

Question

I'm using this code to listening on port 9999 udp.

   Dim remoteSender As New IPEndPoint(IPAddress.Any, 0)
   client = New UdpClient(9999)
   Dim state As New UdpState(client, remoteSender)
   client.BeginReceive(New AsyncCallback(AddressOf DataReceived), state)

It work perfectly, i received event fired on sub DataReceived() if i send a udp message to 127.0.0.1:9999.

However, because i want to create a program that connect to udp server and waiting for response from server. So i inserted a connect command after create the socket.

   Dim remoteSender As New IPEndPoint(IPAddress.Any, 0)
   client = New UdpClient(9999)
   client.Connect("127.0.0.1", 1000) 
   Dim state As New UdpState(client, remoteSender)
   client.BeginReceive(New AsyncCallback(AddressOf DataReceived), state)

But i cannot receive any response from server when server send packet back to 127.0.0.1:9999, event is not fired like the first code.

So what wrong with my code ? I know both C# and Vb.net so the answer is all fine from both language.

Answer 1

http://msdn.microsoft.com/en-us/library/c4w4cta7(v=vs.110).aspx:

If you call the Connect method, any datagrams that arrive from an address other than the specified default will be discarded.

The datagrams you wish to receive are coming from a different address. Maybe the sender is using the LAN or WAN IP address instead of the loopback (127.0.0.1) address.

If you do not need the Connect call, just remove it.