Microsoft’s OS Windows is checking online connectivity by doing two things:
- DNS-Lookup for dns.msftncsi.com
- result needs to be “131.107.255.255”
- 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 192.168.10.109
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=”192.168.10.109″ 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:
