Which two statements about 6to4 tunnels are true?

Which two statements about 6to4 tunnels are true? (Choose two.)
A. They encapsulate IPv6 packets, which allows the packets to travel over IPv4 infrastructure.
B. They support point-to-multipoint traffic.
C. They support OSPF and EIGRP traffic.
D. They support point-to-point traffic.
E. They allow IPv4 packets to travel over IPv6 infrastructure without modification.
F. They generate an IPv6 prefix using a common IPv4 address.

cisco-exams

9 thoughts on “Which two statements about 6to4 tunnels are true?

  1. Correct answer A B

    6to4 tunnels and manually configured tunnels is that the tunnel is not point-to-point; it is point-to-multipoint. In automatic 6to4 tunnels, routers are not configured in pairs because they treat the IPv4 infrastructure as a virtual nonbroadcast multiaccess (NBMA) link. The IPv4 address embedded in the IPv6 address is used to find the other end of the automatic tunnel.
    https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/interface/configuration/xe-3s/ir-xe-3s-book/ip6-6to4-tunls-xe.html

  2. A – definitely, that’s the whole point of this
    B – Automatic 6to4 tunnels are inherently p2m in nature – So yeah
    F – also seems to be valid. I would choose F also if 3 questions would be correct. If only 2, I guess there is some trickery with the “generate IPv6 prefix” or “common IPv4 address” wording, but other than that:

    “These tunnels determine the appropriate
    destination address by combining the IPv6 prefix with the globally unique destination 6to4 border
    router’s IPv4 address, beginning with the 2002::/16 prefix, in this format:
    2002:border-router-IPv4-address::/48
    This prefix-generation method leaves another 16 bits in the 64-bit prefix for numbering networks
    within a given site.”

  3. Automatic 6to4 tunnels are inherently point-to-multipoint in nature. These tunnels treat the underlying IPv4 network as an NBMA cloud

    Answer: A and B

  4. From the same page:

    IPv6 manually configured tunnels can share the same source interface because a manual tunnel is a “point-to-point” link, and both the IPv4 source and IPv4 destination of the tunnel are defined.

    This question doesn’t say anything about Automatic 6to4 tunnels.

    1. Also the statement you cited says nothing about 6to4 tunnels. Manual IPv6 tunneling is a different tunneling method.
      There is no “Manual 6to4 tunneling”. So the point-to-point is not correct.

Leave a Reply

Your email address will not be published. Required fields are marked *


The reCAPTCHA verification period has expired. Please reload the page.