Chapter 13 - IPv6

Question 1

How long is a IPv6 address and how many possiblities are there?

Answer 1

Ipv6 is a 128-bit address allowing up to 2^128 (3.4x10^38) addresses.

Question 2

What is one advantage of IPv6

Answer 2

IPSec is a standard part of every IPv6 stack meaning every packet sent from a NIC is encrypted. Also provides more efficient routing scheme by using aggregation

Question 3

Give an example of an IPv6 address and explain the structure

Answer 3

2001: 0000:0000:3210:0800:200C:00CF:1234
- Quartet/Hextet = each group of numbers
- Numbers between 0000:FFFF
- Eight groups of 4 characters

Question 4

IPv6 addresses can be hard to read, what is a way to simplify them?

Answer 4

Leading zeroes can be shortened to '::'
2001:0000:0000:3210:0800:200C:00CF:1234
now becomes
2001:0:0:3210:800:200C:CF:1234
and can now become
2001::3210:800:200C:CF:1234
NOTE: '::' can only be used to represent the zeroes once
FEDC:0000:0000:0000:00CF:0000:BA98:1234
becomes
FEDC::CF:0:BA98:1234

Question 5

What is the IPv6 loopback address

Answer 5

::1

Question 6

How does one determine an IPv6 address is link-local

Answer 6

The first 64 bits will start with FE80::/10 followed by 54 zero bits.
FE80:0000:0000:0000
The second 64 bits are the ‘Interface Identifier’ and is generated by either
- Systems post-vista or OSX, and linux will generate a random number
- Legacy systems like XP will use the MAC

Question 7

How does subnetting happen in IPv6 and who passes them out?

Answer 7

Because the last 64 bits are generated by the NIC, the subnet mask is a maximum /64
IANA passes out /48 subnets to big ISPs, and /16 for smaller ISPs who will then pass out /64 subnets

Question 8

Define unicast address (IPv6)

Answer 8

This is the systems link-local address

Question 9

Define Multicast address (IPv6)

Answer 9

a set of reserved addresses designed to go only to certain systems. Individual addresses are assigned to specific applications.

Question 10

What address is used to encapsulate IPv6 multicast packets

Answer 10

33-33-xx-xx-xx-xx

Question 11

What is the function of the address FF02::1

Answer 11

All nodes address

Question 12

Waht is the function of the address FF02::2

Answer 12

All routers address

Question 13

What is the function of the address FF02::1:FFxx:xxxx

Answer 13

Solicited-Node Address

Question 14

Where does a DNS server keep the IP addresses of the root servers

Answer 14

Root Hints file

Question 15

Define ‘Anycasting’

Answer 15

Starts by giving a number of computers the same IP address. Routers use BGP to determine which computer or cluster is closest. The router then send the packet to the closest root DNS server.

Question 16

How does a system get on the internet with IPv6

Answer 16

It needs a Global Unicast address and is only given out by the default gateway

Question 17

Explain the process, in detail, of getting a Global Unicast Address

Answer 17

1. Computer sends out a solicitation message on boot
2. IPv6 Router sends prefix to computer
3. Computer adds interface identifier or EUI64 to prefix
   4.

Question 18

Define prefix delegation

Answer 18

tells the router to go upstream and get a prefix to hand out to clients

Question 19

Define no-default routers

Answer 19

tier-one routers that connect to other tier one routers. They can not have a default route

Question 20

Define aggregation

Answer 20

Every router underneath one router uses a subset of that routers existing routes.

Question 21

Give the formula for a IPv6 address

Answer 21

48 bit from upstream router + 16-bit from default gateway + 64 bit unique number

Question 22

What are the two modes that DHCPv6 uses?

Answer 22

Stateful - passes out IPv6 addresses, subnet masks, and defualt gateways, DNS, and TFTP server addresses.
Stateless - passes out only optional information (default)

Question 23

How does a DNS server store a IPv6 record

Answer 23

Storing it in a record type of AAAA

Question 24

Define 4 to 6 tunnel

Answer 24

encapsulating IPv6 traffic into a IPv4 tunnel

Question 25

Define 6 to 4 tunnel

Answer 25

Enables IPv6 traffic to use the IPv4 internet. Generally used to connect two routers.

• Always start with 2002::/16
• 192.88.99.1 is the 6to4 anycast address

Question 26

Define 6in4

Answer 26

one of two tunneling protocols that can go through a NAT

Question 27

Define Teredo

Answer 27

IPv6 tunneling protocol
Start with 2001:0000:/32
Built into windows

Question 28

Define Miredo

Answer 28

Open source version of Teredo for linux

Question 29

Define Intra-site automatic tunnel addressing protocol

Answer 29

ISATAP
Designed to work within an IPv4 network by adding IPv4 address to an IPv6 prefix.
ex. 2004:DB8::98CA:200:131.107.28.9

Question 30

What is TSP and TIC

Answer 30

Tunnel Setup Protocol and Tunnel Information and Control are used to take advantage of automatic configuration

Question 31

Define Overlay tunnel

Answer 31

enables two IPv6 netowrks to connect over an existing IPv4 infrastructure

Question 32

What ius a manual tunnel used for

Answer 32

Creates a simple point to point connectionbetween the two IPv6 networks

Question 33

How does a IPv6 multicast fiffer from broadcasts

Answer 33

Both broadcasts and multicasts are sent to all network nodes but in multicast only the destination nodes process the incoming packets