Solving the Mystery of the Dead Teredo Interface

imageYou’ve deployed DirectAccess on your network as a pilot project for your IT group over the holidays and everything is working great. When the users are behind a wide open NAT device, they use Teredo to connect to the UAG DirectAccess server. When they’re behind a port-restricted firewall or web proxy only, then they fall back to IP-HTTPS. Of course, you’d prefer that they use Teredo because it’s better performance. But IP-HTTPS connectivity is better than no connectivity at all.

Then it happens – the unthinkable!

Performance seems to slow down. You do an ipconfig and find that the Teredo interface isn’t starting up and only IP-HTTPS is being used. You move the client around, first behind a wide open NAT device and nothing changes. Then you disable the 6to4 interface and connect the client directly to the Internet. Still, only the IP-HTTPS interface comes up.

What’s up with that?

Here are some hints:

First, check out

Next, check out the graphic below:


Finally, check Ben Lee’s blog where he puts all the pieces together to come up with a solution over at



Tom Shinder
Principal Knowledge Engineer, Microsoft DAIP iX/Forefront iX 
UAG Direct Access/Anywhere Access Group (AAG)
The “Edge Man” blog (DA all the time):
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