Unable to reach other 6to4 sites or the 6bone by using the 6to4 router.
Cause: Your firewall or Internet router is dropping IPv4 traffic that has the IP Protocol field value set to 41.
Solution: All IPv6 traffic that is encapsulated (tunneled) inside of an IPv4 header has the IPv4 Protocol field in the header set to 41. IPv6 tunneled traffic includes traffic that uses IPv4-compatible addresses, 6over4 addresses, and 6to4 addresses. To allow IPv6 tunneled traffic to be forwarded, configure your firewall or Internet router to pass IPv4 traffic that has the Protocol field set to 41.
Cause: You are unable to resolve the DNS name 6to4.ipv6.microsoft.com.
Solution: By default, the 6to4 service attempts to first resolve the name 6to4.ipv6.microsoft.com to its IPv4 addresses and then choose a relay router. If you cannot resolve the name 6to4.ipv6.microsoft.com, a relay router is not configured and you cannot reach any locations on the 6bone. Type ping 6to4.ipv6.microsoft.com to determine whether you can resolve the name 6to4.ipv6.microsoft.com.
Cause: You do not have the correct route.
Solution: View the display of the ipv6 rt command. You should see a 2002::/16 -> 3 route. This route causes all 6to4 traffic to be sent by using the 6to4 tunneling interface.
Cause: You do not have the correct address.
Solution: Verify that you have a 6to4 address assigned before attempting to reach a destination. For example, without a 6to4 address, you might be using a link-local address to reach a 6to4 global address. Use the display of the ipv6 if command to determine your address configuration.