When you connect your Windows PC to any network whether through a LAN cable or through a WiFi adapter, it shows if the network has an active internet connection or not. If the computer is able to access the internet through an existing network to which it is connected, then Windows shows a normal networking icon in the system tray. If there is no active internet access available, then the network icon is shown with a yellow exclamation icon. The magic behind it is that Windows keeps probing some of the Microsoft servers to check if internet is reachable or not. In the process, it checks the IPv4 and IPv6 address of dns.msftncsi.com (the servers of Microsoft NCSI – network connectivity status indicator) and matches them with the hardcoded values. It also tries to read a small text file “ncsi.txt” from the msftncsi.com servers that contains the text “Microsoft NCSI”. Upon success of these operations, it declares an active internet connection else thinks that Windows has no internet access.
If you do not want Windows to probe the Microsoft server every time you connect to a network, then you can easily disable it using the following steps:
- Press the Win+R hotkey to bring up the Windows’ Run dialog. In the Run dialog, type regedit and press Enter. This will open the Windows Registry Editor.
- In the Windows Registry Editor window, navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internet
- Find the value named EnableActiveProbing, double-click on it and change its value from 1 to 0.
- Close the Windows Registry Editor. Try reconnecting to the internet (by replugging the ethernet cable or restarting the router). Now Windows will no longer probe Microsoft NCSI servers.
Alternatively, if you do not want to go through all these manual steps, then you can download disable-msft-ncsi.zip, extract the files to a folder and double-click on disable-network-probing.reg and proceed with prompts. Similarly, the enable-network-probing.reg file is meant to restore the default values for NCSI.