Windows has a cool feature that allows you to tell if your computer has Internet connectivity when you are connected to a network (see image below). This feature is called Network Connectivity Status Indicator (NCSI) it uses a combination of DNS and/or HTTP look ups to tell if you are connected to the Internet. The way does this is either via a HTTP request for http://www.msftncsi.com/ncsi.txt or a DNS look up for dns.msftncsi.com that resoles to 188.8.131.52
However if you find this error message really annoying there is now a Windows 7 group policy will turn it off. This is a machine setting so edit a Group Policy Object that is applied to all the workstations you want to turn this message off. Then navigate to Computer Configuration > Policies > Administrative Templates > Network Connections and enabled the â€œDo not show the â€œlocal access onlyâ€ network iconâ€ policy setting.
TADAâ€¦ Now you will no longer see the exclamation icon on the network icon.
For more information on how NCSI works and this Windows 7 policy see http://technet.microsoft.com/en-us/library/ee126135(WS.10).aspx
Unfortunately Windows Vista does not have the same Group Policy however there is a registry key that can be applied using Group Policy Preferences that has the same affect.
Data: 1 (REG_DWORD) = Enabled
Data: 0 = Disabled
Step 1. Edit a Group Policy Object that is applied to all the workstation you want this Browser Ballot disabled.
Step 2. Navigate to Computer Configuration > Preferences > Windows Settings > Registry and create a â€œNew Registry Itemâ€
Step 3. Type â€œSYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internetâ€ in the Key Path then type â€œEnableActiveProbingâ€ in the Value name, then select REG_DWORD as the value type â€œ0â€ in the value data and then click â€œOKâ€.
For more information on how NCSI works and this Windows Vista policy see http://technet.microsoft.com/en-us/library/cc766017(WS.10).aspx