Windows check a Microsoft site for connectivity, using the Network Connectivity Status Indicator site. NCSI performs a DNS lookup on www.msftncsi.com and sends a DNS lookup request for dns.msftncsi.com.
You can block this probe by adding the content of the data/<type>/extra.txt hosts file.
But you will have a "No Internet access" warning in your system tray.
To solve this problem you can use the alternative WindowsSpyBlocker NCSI by executing WindowsSpyBlocker.exe and select NCSI > Apply WindowsSpyBlocker NCSI:
Then you can test your internet connection the Microsoft way:
