For IPv6 addresses, you can use two periods to indicate a string of consecutive 16-bit groups with a value of zero.

33. (p. 358) For IPv6 addresses, you can use two periods to indicate a string of consecutive 16-bit groups with a value of zero.
FALSE

                                                                       

34. (p. 358) An IPv6 address cannot be all zeroes, and it cannot be all ones.
TRUE

35. (p. 359) Like IPv4, IPv6 uses link-local addressing.
FALSE

36. (p. 361) With link-local addressing, you need to type in a subnet mask.
FALSE

37. (p. 363) Your gateway router determines the prefix it receives.
FALSE

38. (p. 368) NAT is a very important part of IPv6.
FALSE

39. (p. 372) It is impossible to run IPv4 and IPv6 on your computers and routers at the same time.
FALSE

40. (p. 373) ISATAP uses conventional IPv6 addresses for the tunnel endpoints.
FALSE

41. (p. 373) The tunneling protocol your tunnel broker provides is usually invisible to you.
TRUE

42. (p. 376) There is a firm date for the switchover from IPv4 to IPv6.
FALSE

43. (p. 361) Multicasts exist in IPv4.
TRUE

44. (p. 361) Multicasts have replaced broadcasts in IPv6.
TRUE

Fill in the Blank Questions
 

45. (p. 358) In an IPv6 address, each group is a 16-bit hexadecimal number with a value between _______________ and _______________.
0000; FFFF

46. (p. 358) A complete IPv6 address always has _______________ groups of four hexadecimal characters.
eight

47. (p. 358) The IPv6 address, 2001:0000:0000:0000:00CF:0000:BA98:1234, can be shortened to _______________.
2001::CF:0:BA98:1234

48. (p. 359) To show the subnet for an address, IPv6 uses the "/X" _______________ nomenclature.
Classless Inter-Domain Routing (CIDR)

49. (p. 359) The first 64 bits of a link-local address are always _______________.
FE80:0000:0000:0000 or FE80::/64

50. (p. 360) In IPv6, all computers except dedicated servers will use _______________ addressing.
link-local

51. (p. 361) IPv6 has eliminated the idea of _______________ addressing.
broadcast

52. (p. 363) The last 64 bits of an IPv6 address are generated using _______________.
the MAC address of the NIC

53. (p. 357) IANA passes out _______________ subnets to big ISPs and end users who need large numbers of addresses.
/32

54. (p. 361) The majority of IPv6 subnets are between _______________ and _______________.
/48; /64

55. (p. 363) You receive a global address from your _______________.
default gateway router

56. (p. 364) The top-tier routers are also called the _______________ routers.
no-default

57. (p. 364) Using IPv4, a typical _______________ on the Internet has between 30,000 and 50,000 routes.
no-default router

58. (p. 364) Your gateway router receives a(n) _______________ from your ISP's router.
48-bit prefix

59. (p. 365) IANA does not pass our IPv6 prefixes; the five _______________ perform this task.
Regional Internet Registries

60. (p. 364) IPv6 addresses begin at the very top of the Internet from the _______________ servers.
no-default

61. (p. 374) The fastest way to verify if your system runs IPv6 is to use the _______________ command at the command prompt.
ipconfig

62. (p. 368) IPv6's address space makes hackers' address-scanning programs _______________.
obsolete

63. (p. 369) DHCP for IPv6 is called _______________ to distinguish it from IPv4 DHCP.
DHCPv6

64. (p. 369) The _______________ mode of DHCP for IPv6 is expected to be the norm in an IPv6 world.
stateless

65. (p. 370) If _______________ information is added to IPv6 router advertisements, the need for DHCP in IPv6 could diminish.
DNS server

66. (p. 370) One way to avoid using a DHCP server for IPv6 is to manually add _______________ information to IPv6 clients.
DNS

67. (p. 369) An IPv6 DHCP server that only passes out optional information (mainly DNS server addresses) is a(n) _______________ DHCPv6 server.
stateless

68. (p. 369) An IPv6 DHCP server that only passes out all IP configuration information, including IPv6 address, subnet mask, and optional information, is a(n) _______________ DHCPv6 server.
stateful

69. (p. 370) All the root _______________ servers presently support IPv6 resolution.
DNS

70. (p. 371) If you needed to add an IPv6 DNS server to Vista's configuration, you would enter this in the _______________.
Internet Protocol Version 6 (TCP/IPv6) Properties dialog box

71. (p. 370) If you were the administrator of a DNS server in a network that is primarily running IPv4, you would recognize the IPV6 hosts' records by their IPv6 addresses and the unique _______________ record type.
AAAA

72. (p. 370) To get around using a DHCPv6 server, you can manually add _______________ information to each IPv6 client.
DNS server

73. (p. 373) To avoid the complexity of setting up a IPv6 tunnel, use a(n) _______________.
tunnel broker

74. (p. 374) Once you have made a tunnel connection to the IPv6 network, _______________ an IPv6-only Web site to test the connection.
ping

75. (p. 361) Only specifically-configured systems can use _______________.
multicasts

76. (p. 361) In __________, multicasts used Class D addresses (224.0.0.0/4)
IPv4

Essay Questions
 

77. (p. 357-358) Explain the shortcut you may to use in IPv6 address notation that involves the use of colons. 

In IPv6, you may represent a string of consecutive 16-bit groups with a value of zero with a pair of colons (::). For example, 2001:0000:0000:3210:0800:200C:00CF:1234 can be written in shortcut form as 2001::3210:0800:200C:00CF:1234. You may not use more than one instance of the double colon in a single IPv6 address.

78. (p. 357) Discuss briefly the reasons for the development of IPv6 to replace IPv4. 

Although IPv4 theoretically provides over 4 billion addresses, only about 1.7 billion are available, and many of those are wasted by the way they were allocated. This means that we will soon run out of IP addresses using the current IPv4 specification.

79. (p. 358) Explain the shortcut you may use in IPv6 address notation that involves leading zeroes. 

When writing IPv6 addresses, you can drop leading zeroes from any group. Therefore, the address used in Question 1 can be further shortened to 2001::3210:800:200C:CF:1234.

80. (p. 361) What occurs when a system sends out a multicast to the address FF02::2? 

When a system sends out a multicast to the address FF02::2, only routers read the message, and all other systems ignore it.

81. (p. 361) What computers can read an all nodes multicast? 

Only the computers that are members of a particular group will read an all nodes multicast.

82. (p. 361) Explain the difference between a multicast and a broadcast. 

With IPv6, only the computers defined by the IPv6 multicast address receive a multicast message. With broadcast, all computers in the broadcast domain receive the broadcast message.

83. (p. 362) Why would you need an anycast address? 

You need an anycast address when you have a number of computers (or clusters of computers) at various geographic locations that you want to appear as a single computer with a single IPv6 address. A top-tier router will recognize an anycast address, and somehow have the smarts to send the packets to the computer closest to the router.

84. (p. 362) What does an anycast address look like? 

An anycast address looks like a unicast address and is only recognized as an anycast address by the top-tier Internet routers.

85. (p. 363) Explain the process of receiving a global unicast address. 

As your computer boots up, it sends out a router solicitation message to multicast address FF02::2 looking for a router. Your gateway router, on hearing this message, sends your computer the network ID and subnet mask, together called the prefix. Your computer then generates the last 64 bits to create a global address.

86. (p. 363) What do the last 64 bits of a global unicast address look like? 

The last 64 bits of a global unicast address look like the last 64 bits of the link-local address for that same NIC.

87. (p. 363) Explain how, at least for the near future, you can recognize a global address. 

Presently, IANA is only passing out global addresses beginning with 2. Therefore, it is easy to recognize a global address.

88. (p. 359 and 363) Compare the current global addresses with link-local addresses. 

Global addresses begin with 2, while link-local addresses begin with FE80:0000:0000:0000.

89. (p. 364) Define aggregation. 

Aggregation occurs when each router that is below another router uses a subnet of the higher-level router's existing route.

90. (p. 364) Explain the purpose of aggregation. 

The purpose of aggregation is to reduce the size and complexity of routing tables and to make the Internet faster.

91. (p. 364-366) Explain why aggregation is not used for IPv4 addresses on Internet routers. 

Aggregation might have worked with IPv4 addresses if they had not been allocated in a very inefficient way. At this point, many organizations would have to give up their class licenses, and they simply will not do that. Even if it were possible to take back class licenses and reallocate them in a way to support aggregation, it would require a huge amount of joint effort and would bring down the Internet for some time. [Not stated in the chapter: the new IPv6 has many features, in addition to built-in aggregation, that make it worth migrating to, rather than "fixing" IPv4.]

92. (p. 365) List the five Regional Internet Registries (RIRs) and the geographic areas each covers in its job of passing out IPv6 prefixes. 

The five RIRs are: American Registry for Internet Numbers (ARIN) — North America
RIPE Network Coordination Centre (RIPE NCC) — Europe, the Middle East, and Central Asia
Asia-Pacific Network Information Centre (APNIC) — Asia and the Pacific region
Latin American and Caribbean Internet Addresses Registry (LACNIC) — Central and South American and parts of the Caribbean
African Network Information Centre (AfriNIC) — Africa

93. (p. 365) Your ISP has no control over the IPv6/32 prefix it receives from its upstream router. Explain who controls the next 16-bit subnet. 

The person setting up the ISP's router adds a 16-bit subnet to the prefix received from the upstream router.

94. (p. 366) Explain what keeps IPv6 aggregation intact when there are changes upstream. For instance, what happens if your ISP changes to another upstream ISP? 

If your ISP changes to another upstream ISP, the new ISP passes out a different 32-bit prefix. Your ISP's router, in turn, changes the 48-bit prefix it sends downstream to include the new upstream prefix. The downstream routers make an "all nodes" multicast, and the downstream clients get new IP addresses. This process keeps aggregation intact.

95. (p. 368) Experts will tell you that NAT is obsolete in an IPv6 network. Explain why anyone would even consider a NAT program for IPv6, such as NAPT-PT. 

The NAT program NAPT-PT lets a private IPv6 network use a single IPv4 address. I assume this is to access the IPv4 Internet. Therefore, it is not really working in an IPv6 world, but is just something to use during the transition to IPv6. If the IPv6 network were connecting to another IPv6 network, it would not use NAT.

96. (p. 368-369) If using NAT to hide IPv6 addresses will not be a practical option, what should we do to protect our private IPv6 networks that will connect to the IPv6 Internet? 

Knowing that NAT is obsolete, the best options for securely connecting a private IPv6 network to another IPv6 network are a very good firewall and IPSec.

97. (p. 369) Since IPv6 routers give out the prefixes for IPv6 addresses and provide subnets to IPv6 clients, why is DHCP necessary at all for IPv6? 

While it is true that routers give clients the IPv6 prefix, to which the client adds the remaining 64 bits, a DHCPv6 server is necessary to give out the other IP configuration information, such as DNS server address, and so on.

98. (p. 371) What is the state of IPv6 security right now, and what would you recommend to anyone wanting to connect to the IPv6 Internet just to learn more about using it? 

The IPv6 Internet still has security risks, and operating systems may have less-than-perfect support for IPv6. Therefore, the recommendation is not to connect to the IPv6 Internet on a mission-critical computer.

99. (p. 369) When might it be helpful to use a stateful DHCPv6 server? 

It might be helpful to use a stateful DHCPv6 server for internal networks that do unconventional things with IP addresses, such as using subnets greater than/64 (which is impossible on the IPv6 Internet) or in a stateless environment.

100. (p. 372) Describe the IPv6 gap. 

While there is support for IPv6 on individual computers, and on the root DNS servers and most tier 1ISP routers, a gap is created by the lack of support for IPv6 on the routers and DNS servers that exist between individual IPv6-capable computers.

101. (p. 367) Describe the IPv6 status of Macintosh OS X. 

Macintosh OS X has complete support for IPv6 in all versions, and IPv6 is active on default installs.

102. (p. 372) Describe the function of an IPv4-to-IPv6 tunnel. 

An IPv4-to-IPv6 tunnel spans the IPv6 gap by encapsulating IPv6 traffic into an IPv4 tunnel to get to an IPv6-capable router.

103. (p. 373) How can you set up an IPv4-to-IPv6 tunnel? 

Assuming you have obtained an IPv6 tunnel client, install the client, start it up, and make the tunnel connection.

104. (p. 373) Describe the main tasks in setting up an IPv6 tunnel. 

To set up an IPv6 tunnel, you must find someone willing to host the far endpoint, and then you must connect to the endpoint, and you must know the tunneling standard the far endpoint requires.

105. (p. 373) Why are other tunneling standards gaining ground on Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)? 

Other IPv6 tunneling standards are gaining ground on ISATAP because this protocol uses nonstandard addresses, rather than the IPv6 addressing structure.

106. (p. 373) What services does a tunnel broker normally provide? 

A tunnel broker creates the tunnel and normally offers a custom-made endpoint client that is easy to use.

107. (p. 361) Explain the use of multicasts in both IPv4 and IPv6. 

Multicasts have been around for a while; they existed in IPv4 and currently exist in IPv6. In IPv4, multicasts used Class D addresses (224.0.0.0/4), and a computer had to be part of a multicast group and configured with the appropriate multicast address to receive them. Only specific applications used multicasts. Multicasts work differently in IPv6, as IPv6 has replaced the concept of broadcasting with multicasting. Several IPv6-only multicast addresses have been added, such as those used by specific services (for example, router messages).