Chapter 12 - IPv6

Question 1

How many bits are in a IPv6 address?

Answer 1

128 bits.

Question 2

What is link local IPv6 address?

Answer 2

An address generated by the client for used only on the LAN. It starts with fe80::/64 prefix.

Question 3

Does broadcast exist in IPv6?

Answer 3

No, the idea of broadcast is abbandoned. IPv6 relies on multicast instead.

Question 4

What are the IPv4 and IPv6 multicast ethernet address reserved space?

Answer 4

IPv4 : 01-00-5e-xx-xx-xx
IPv6 : 33-33-xx-xx-xx-xx

Question 5

What is the all node IPv6 multicast address?

Answer 5

Ff02::1

Question 6

What is the all router IPv6 multicast address?

Answer 6

Ff02::2

Question 7

What is anycast?

Answer 7

When multiple server have the same IP address, the DNS can use an anycast uses BGP to determine the best option and only communicate with this one.

Question 8

What is link aggregation?

Answer 8

Link aggregation is an IPv6 feature were addresses have a logicial and geophysical sense. Through this feature clients, clients get a routeble public IP address from their router.

Question 9

What are the five IPv6 packet types?

Answer 9

Neighbor solicitation, neighbor advertisement, router solicitation, router advertisement and redirect.

Question 10

What are neighbor solicitation/advertisement?

Answer 10

It is the equivalent of ARP. When a IPv6 joins a network, it sends a neighbor solicitation to know who is on the network. When another computer answer’s the solicitation, it sends an advertisement.

Question 11

Why would someone still use DHCPv6 on a IPv6 network?

Answer 11

To send correct DNS information and gain a better control on the network. For a stateless DHCPv6 server, it rellys on router advertisement and only make small changes to ajust the DNS. For statefull, the DHCPv6 works in a very similar manner to the IPv4 DHCP.

Question 12

What are router solicitation/advertisement?

Answer 12

When a IPv6 device joins the network, it will look for a global address, default gateway, DNS, etc. It sends a router solicitation and wait for it to give this information. Contrary to IPv4 where NAT technologies where required, the global address will be directely routable on the internet (through link aggregation).

Question 13

What is 4to6?

Answer 13

It is a tunnel that encapsulate IPv4 information in IPv6.

Question 14

What is 6in4?

Answer 14

It is a tunnel that encapsulate IPv6 information in IPv4.

Question 15

What is Teredo?

Answer 15

A windows based technology to pass IPv6 packets on an IPv4 network. Most people prefer to skip Teredo and use its opensource equivalent, Miredo.

Question 16

What is ISATAP?

Answer 16

Intra-Site Automatic Tunnel Addressing Protocol. It appends the IPv4 address at the end of the IPv6 address.

Question 17

What is a tunnel broker?

Answer 17

A tunnel created through the internet by a company. It uses TSP (Tunnel Setup Protocol) and TIC (Tunnel Information Control protocol).

Question 18

What is an overlay tunnel?

Answer 18

Most router run a dual stack and can translate IPv6 to IPv4 and vice versa before sending it through the internet.

Question 19

What is NAT64?

Answer 19

IPv6 doesn’t need NAT to function on the public internet. However NAT64 encapsulate IPv4 packets in IPv6 packet for transmission.

Question 20

Which of the following address is a valid IPv6 address?

2001:bead:beef::1
2001:30f5::3d62::04ffe
192:168:1:4:ff45:129g:48fd:1
2001.0470.b33e.23f4.27de.d34a.aed2.1827

Answer 20

2001:bead:beef::1

Question 21

DHCP is required to receive an IPv6 address automatically?

Answer 21

False.

Question 22

What kind of DNS record do IPv6 addresses use?

Answer 22

AAAA

Question 23

Is NAT needed with IPv6?

Answer 23

NAT is no longer needed because of the massive name space of IPv6.

Question 24

What does a client need to access IPv6 content on the internet?

Answer 24

A global unicast address.

Question 25

What is the /16 prefix for all 6to4 addresses?

Answer 25

2002.