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IPv6 Questions

March 16th, 2020 Go to comments

Question 1

Question 2

Question 3

Explanation

The short syntax of static IPv6 route is:

ipv6 route <destination-IPv6-address> {next-hop-IPv6-address | exit-interface}

Question 4

Explanation

Floating static routes are static routes that have an administrative distance greater than the administrative distance (AD) of another static route or dynamic routes. By default a static route has an AD of 1 then floating static route must have the AD greater than 1. Floating static route has a manually configured administrative distance greater than that of the primary route and therefore would not be in the routing table until the primary route fails.

Question 5

Explanation

A IPv6 Unique Local Address is an IPv6 address in the block FC00::/7. It is the approximate IPv6 counterpart of the IPv4 private address. It is not routable on the global Internet.

Note: In the past, Site-local addresses (FEC0::/10) are equivalent to private IP addresses in IPv4 but now they are deprecated.

Link-local addresses only used for communications within the local subnet. It is usually created dynamically using a link-local prefix of FE80::/10 and a 64-bit interface identifier (based on 48-bit MAC address).

Question 6

Explanation

The “ipv6 address autoconfig” command causes the device to perform IPv6 stateless address auto-configuration to discover prefixes on the link and then to add the EUI-64 based addresses to the interface. Addresses are configured depending on the prefixes received in Router Advertisement (RA) messages. The device will listen for RA messages which are transmitted periodically from the router (DHCP Server). This RA message allows a host to create a global IPv6 address from:
+ Its interface identifier (EUI-64 address)
+ Link Prefix (obtained via RA)
Note: Global address is the combination of Link Prefix and EUI-64 address

Although answer B seems to be correct but it is missing the prefix-length /64:

ipv6_address_eui_64.jpg

Question 7

Explanation

FF00::/8 is used for IPv6 multicast and this is the IPv6 type of address the question wants to ask.

FE80::/10 range is used for link-local addresses. Link-local addresses only used for communications within the local subnetwork (automatic address configuration, neighbor discovery, router discovery, and by many routing protocols). It is only valid on the current subnet. It is usually created dynamically using a link-local prefix of FE80::/10 and a 64-bit interface identifier (based on 48-bit MAC address).

Question 8

Explanation

When an interface is configured with IPv6 address, it automatically joins the all nodes (FF02::1) and solicited-node (FF02::1:FFxx:xxxx) multicast groups. The all-node group is used to communicate with all interfaces on the local link, and the solicited-nodes multicast group is required for link-layer address resolution. Routers also join a third multicast group, the all-routers group (FF02::2).

Comments (4) Comments
  1. KiLLaX
    April 14th, 2020

    Question 6 is incorrect.

    C. ipv6 address autoconfig
    – discovers the preview through a solicit

    B. ipv6 address 2001:068:5:112::64 eui-64
    – This is the correct answer as it lets you specify a prefix as required in the question.

  2. 9tut
    April 15th, 2020

    @KiLLaX: That command is missing the prefix-length /64. We have just updated our explanation so please check again.

  3. KiLLaX
    April 16th, 2020

    @9tut, Thanks for the clarification. Without the /64 answer B is incorrect.
    Answer C is the best choice, though I read the question as a prefix should be “specified” not discovered, that is not what is stated in the question. Thanks again.

  4. D@n@k@
    May 17th, 2020

    Q4 .. answer is A & E or B & E..
    Please explain

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