I have 2 computers in a homegroup at home (Windows 7 Ultimate 64 bits and Windows 7 Home Basic 32 bits), behind a TP-Link TL-WR740N router (and ZoneAlarm Free

Both computers have Teredo enabled, but the Ultimate one is always running ("qualified"), whereas the Home basic one is mainly "dormant", unless, of course, I try to reach a website which "triggers" Ipv6 (e.g. "Test your IPv6").

Trying to figure out why the Ultimate computer had the Teredo connection always "qualified" led me to dig deep into the Teredo Tunneling issue, and I became somewhat scared of the security risks in using it.

Apart from opening a "hole" in the router and assigning a global IPv6 address to the computer, the traffic in the tunnel is really IPV6 encapsulated in a IPv4 packet, so the firewall won't be able to filter it properly, applying the desired security policy.

So, here are the 2 questions:

1) In a nutshell, how safe is Teredo? I could just disable it, but it seems that homegroup in Windows 7 requires it.

2) I know that the latest Zonealarm version has IPv6 enabled. Is it effective against potential security threats in Teredo traffic?

Looking forward to hearing your opinions!

Thanks in advance!