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TCP Traffic Stops
http://www.vistaarticles.com/articles/258/1/TCP-Traffic-Stops
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Published on 12/10/2006
 
After you enable both receive-side scaling and Internet Connection Sharing, TCP traffic stops. For example, the ping command does not work.

TCP Traffic Stops
To resolve this problem, disable either receive-side scaling or Internet Connection Sharing. Do not enable both receive-side scaling and Internet Connection Sharing at the same time.