I have this strange problem that when I ping my local machine name, I get a General Failure. Forcing the ping to IPv4 with the /4 option works. I could live with that, but another side effect is that opening a http connection to my local IIS takes around 5 seconds to resolve the name. This is not acceptable.

It is even more strange that this problems stops as soon as I am on cabled network.

So this has something to do with IPv6 and Teredo and due to lack of time for finding the real reason, disabling Teredo worked for me.

netsh int teredo set state disabled

HTH