For testing applications that send or receive HTTP messages, i.e., HTTP clients, you can use suitable tools for logging HTTP traffic, such as Wireshark (http://www.wireshark.org/) or Fiddler (http://www.fiddler2.com/). However, before issuing HTTP requests to a real web service out in the wild, you may want to know beforehand exactly what you would send. A simple test server is often all that you need. You run your client program (e.g., Example 7-1), on your Netduino Plus, and you run a .NET test server that logs an incoming request on your development PC.
In your client program for the Netduino Plus, change the request URI to something like this:
192.168.5.100 with the Internet ...