Windows NCSI

Network Connectivity Status Indicator (NCSI)

Before marking a network interface as available for applications, Windows tries to resolve hard-coded domain names, as well as retrieve the content of http://www.msftncsi.com/ncsi.txt.

If these names resolve or if the HTTP downloading succeeds, NCSI reports the network interface as "Internet access". Or, the network alert appears in the Task Bar saying "No connectivity" or "Limited Internet access" (depending on which requests failed). More details: NCSI active probes and the network status.

Using the captive portals feature

dnscrypt-proxy can return instant responses for NCSI domains using the captive portals feature. Enable it by uncommenting the following line in your dnscrypt-proxy.toml:

[captive_portals]

map_file = 'example-captive-portals.txt'

The provided example-captive-portals.txt already includes entries for Windows NCSI domains. See the captive portals documentation for details on the file format and additional platforms.

Configuring Windows to use global DNS

Additionally, change the system setting for NCSI to use global DNS, rather than Microsoft's proprietary DNS servers.