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Table of Contents
Microsoft DNS
From here.
NCSI active probes and the network status alert
The active probe process consists of the following steps:
Windows 10 or later versions
- NCSI sends a DNS request to resolve the address of the
www.msftconnecttest.comFQDN. - If NCSI receives a valid response from a DNS server, NCSI sends a plain HTTP GET request to
http://www.msftconnecttest.com/connecttest.txt. - If NCSI successfully downloads the text file, it makes sure that the file contains Microsoft Connect Test.
- NCSI sends another DNS request to resolve the address of the dns.msftncsi.com FQDN.
If any of these requests fails, the network alert appears in the Task Bar (as described in Symptoms). If you hover over the icon, you see a message such as “No connectivity” or “Limited Internet access” (depending on which requests failed).
If all of these requests succeed, the Task Bar shows the usual network icon. If you hover over the icon, you see a message such as “Internet access.”
Windows 8.1 or earlier versions
- NCSI sends a DNS request to resolve the address of the
www.msftncsi.comFQDN. - If NCSI receives a valid response from a DNS server, NCSI sends a plain HTTP GET request to
http://www.msftncsi.com/ncsi.txt. - If NCSI successfully downloads the text file, it makes sure that the file contains Microsoft NCSI.
- NCSI sends another DNS request to resolve the address of the dns.msftncsi.com FQDN.
If any of these requests fails, the network alert appears in the Task Bar (as described in Symptoms). If you hover over the icon, you see a message such as “No connectivity” or “Limited Internet access” (depending on which requests failed).
If all of these requests succeed, the Task Bar shows the usual network icon. If you hover over the icon, you see a message such as “Internet access.”