How does Win 7 determine internet connection?

I'm experiencing this problem on multiple Win 7 Home Premium, Win 7 Pro, and Server 2008 R2 machines. Network and Sharing Center and the Network Map shows the machine connected to the switch then my router but the router to the internet has no access. The network access will have an exclamation point. Now most of the time, I still do have internet access because I can open a browser and go places. Very rarely I really don't have access. Can anyone tell me exactly what Windows is doing to determine that I have access to the internet? Does it ping? Does it look for a web page? Does it do a DNS lookup? Does it.....

 

So starting at the beginning, what is between the machines and your ISP modem? Is this happening on all machines, or just one in general?

 

TW modem --> DLink DIR-655 --> Gig switch --> machines. I haven't done a complete inventory so I can't say all machines experience this but I can say at least 8 of the 16. They are a variety of Win 7, XP, and one Server 2008. One picture worth 1000 words - see Network.jpg. Just got this remoted into the server so I'm pretty confident the internet connection is up! :-D

 

What are you using the Windows server for? Do not go by what Microsoft Windows Networking map states. Something is causing a routing issue, so it is possible that the Server is causing the issue, so start looking in Network properties for each machine, and the hosts file.

What third party Internet Security software are you using, if any? There is a lot of good info over at http://www.ezlan.net