public static IPAddress GetExternalAddress()
{
IPHostEntry entry = Dns.GetHostEntry (stunServer);
IPEndPoint endPoint = new IPEndPoint (entry.AddressList [0], 3478);
UdpClient client = new UdpClient ();
client.Connect (endPoint);
MessageHeader header = new MessageHeader ();
header.MessageType = MessageType.BindingRequest;
byte[] bytes = header.GetBytes ();
client.Send (bytes, bytes.Length);
bytes = client.Receive (ref endPoint);
header = new MessageHeader (bytes);
if (header.MessageType == MessageType.BindingResponse) {
foreach (MessageAttribute attribute in header.MessageAttributes) {
if (attribute is MappedAddressAttribute) {
return (attribute as AddressAttributeBase).Address;
}
}
throw new Exception ("Resposne was missing Mapped-address!");
} else {
throw new Exception ("Wrong response message!");
}
}