Autotesting a network interface

I'm developing a software component responsible for testing if a network interface has conectivity with the internet. Think of it as the same test the XBOX360 does to inform the user if it's connected with the Live network (just as an example).

So far I figured the autotest would run as this:

1) Test the physical network interface (if the cable is conected, has up/downlink, etc...)

2) Test the logical network (has IP address, has DNS, etc...)

3) Connects to the internet (can access google, for example)

4) ???

5) Profit! (just kidding...)

My question relates to step 3: How can I detect, correctly, if my software has connection with the internet ? Is there any fixed IP address to ping ?

The problem is that I don't want to rely solely on google.com (or any other well-known address), as those can change in time, and my component will be embbeded on a mobile device,开发者_StackOverflow not easy to update.

Any suggestions ?

I suggest icann.org

Another question is if you really want to check if you have connection with the provider responsible to deliver internet connection. If that's the case you're test should be green even if the ISP is down.