How does Windows know when your Internet connection (but not your LAN connection) goes down?

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Chapters
00:00 How Does Windows Know When Your Internet Connection (But Not Your Lan Connection) Goes Down?
01:07 Accepted Answer Score 11
01:47 Thank you

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Full question
https://superuser.com/questions/269633/h...

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Tags
#windows7 #internet

#avk47

ACCEPTED ANSWER

Score 11

This behavior is activated by setting the DWORD value EnableActiveProbing in

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internet

to the value 1, and respectively 0 to disable it.

On certain events like login or connection problems it checks DNS with nslookup dns.msftncsi.com and verifies that it returns 131.107.255.255, then to test your HTTP it tries to download ncsi.txt from msftncsi.com. It should contain Microsoft NCSI, which stands for Network Connectivity Status Indicator...

More information can be read in the Microsoft Technical Library.