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Are there any security concerns having IPv6 and Teredo tunneling enabled in Win Vista/7? AFAIK, using Teredo basically allows bypassing of the firewall, as the firewall cannot really filter the contained IPv6 packets. (By firewall, I refer to the network firewall, not the personal Windows firewall.)

If upgrading the firewall is not an alternative, what can be done to keep the network as secure as possible?

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It appears you can shut off Teredo's UDP port in the firewall.

Also, are you sure the firewall would not be effective once traffic leaves the tunnel? This article says you are protected.

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I think simon is referring to the network level firewall.

In any case Teredo and ISATAP are not easily blocked by firewalls (by design).

A much better idea is to start rolling out IPv6, even if only on the LAN with no Internet connectivity. These days only servers and Linux systems will really encounter v6 hosts in the world, although more web sites are becoming available on v6 every day.

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