I had a customer with all their Windows 7 PC’s intermittently reporting ‘No Internet Access’.
The PC’s did actually have internet access.
I found that the website used to determine this is www.msftncsi.com/ncsi.txt.
If this doesn’t respond, Windows 7 reports no internet access. I found that a slow connection to this website can also cause this error.
The msftncsi.com website is hosted on www.akamai.com (new window) servers. In this instance, all other content stored on Akamai servers was also very slow. Ping times to www.msftncsi.com, www.microsoft.com, and www.abc.net.au were all in excess of 200 ms. Ping times to www.adobe.com, www.yahoo7.com.au were all reasonable.
Investigation found that the IP addresses being resolved for the Akamai servers was hosted in the US, not Australia.
After changing the DNS from Google (126.96.36.199 and 188.8.131.52) to the local ISP DNS servers, the IP addresses for the Akamai servers were now resolved to the local Australian servers, and the ping times to the above websites were all reasonable. The Windows 7 PC’s all reported they now had internet access.