Enabling Microsoft’s online-check

Microsoft’s OS Windows is checking online connectivity by doing two things:

  • DNS-Lookup for dns.msftncsi.com
    • result needs to be “”
  • Access URL http://www.msftncsi.com/ncsi.txt
    • result needs to be “Microsoft NCSI”

If the OS can’t do this, an exclamation mark is visible in the taskbar network icon:


If you have a webproxy with enabled authentication and/or blocking the category “Business”, the URL is not accessible. You can see this in the live log:

<M> utm:/var/log # tail -f http.log | grep
2015:07:22-10:21:19 utm-1 httpproxy[6194]: id=”0060″ severity=”info” sys=”SecureWeb” sub=”http” name=”web request blocked, forbidden category detected” action=”block” method=”GET” srcip=”″ dstip=”” user=”” ad_domain=”” statuscode=”403″ cached=”0″ profile=”REF_DefaultHTTPProfile (Default Web Filter Profile)” filteraction=”REF_DefaultHTTPCFFAction (Default content filter action)” size=”3184″ request=”0xe768e000″ url=”http://www.msftncsi.com/ncsi.txt” referer=”” error=”” authtime=”0″ dnstime=”0″ cattime=”100″ avscantime=”0″ fullreqtime=”1203″ device=”0″ auth=”0″ ua=”Microsoft NCSI” exceptions=”” category=”105″ reputation=”trusted” categoryname=”Business” reason=”category”

so you have to configure an exception for this file to skip checks for authentication, extension blocking and url filter:


now restart your network adapter. You can do this also with a shell command:

netsh interface set interface name=”Local Area Connection” admin=disabled && netsh interface set interface name=”Local Area Connection” admin=enabled

the exclamation will now disappear:


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