How does Win7 know that network is limited?

Recently, the author is asking such a question when communicating with netizens. How does win7 know that your network is restricted? Your computer is equipped with win7 system, maybe you will notice that there is At this time, the system will issue a warning “Limited network connection”, which is mainly designed for international websites, as long as you visit international websites.

So the question is now very clear, is how Microsoft knows your network connection status? Here I will briefly explain the reasons for everyone, in fact, it is very simple.

Whenever a user connects to the network, the system automatically sends a domain name access request to Microsoft. The result of the access is the Network Connectivity Status Indicator (NCSI). In fact, Vista was the first to adopt this feature.

NCSI first performs a DNS query on dns.msftncsi.com and then requests access to the file. This is a plain text file containing only the text "Microsoft NCSI". Dns.msftncsi.com should resolve to 131.107.255.255, if the address does not match, then it will guess that the network connection is not working properly.

Edit Comment: For this feature of NCSI, some users may be concerned about privacy issues, because Microsoft will record the IP address of each connection in the website log. If you don't want Microsoft to know your network connection, you can modify the registry to disable the NCSI service, or modify it to access your own server.