In some cases, such as when you connect to a network that uses a proxy server to connect to the internet or when network restrictions prevent NCSI from completing its active probe process, Windows opens the MSN Portal page in the default browser. If you analyze a network trace on the computer, it shows an HTTP connection to that is followed by a connection to the MSN Portal. Windows opens this page for the benefit of the passive probe process. If the page loads, NCSI concludes that the computer has internet access. As the different probes fail and then succeed, the network status alert appears and then disappears.