10 - IPv6 Flashcards

1
Q

What was IPv4 ARP replaced with in IPv6?

A

NDP (Neighbor Discovery Protocol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the Prefix / prefix length in IPv6?

A

Number of bits that make up the prefix, which is the equivalent of a SubnetID in IPV4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a Global Unicast address similar to from IPv4?

A

Public IPv4 address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a Global Routing Prefix?

A

A reserved block of IPv6 addresses that only one company can use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the first hex digits for IPv6 Unique Local addresses?

A

FD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the first hex digits for IPv6 Multicast addresses?

A

FF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the first hex digits for IPv6 Link Local addresses?

A

FE80

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the three parts to an IPv6 address?

A
  • Global Routing Prefix
  • Subnet
  • Interface ID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many bits is the Subnet section of an IPv6 address?

A

64 - Prefix Length bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two components of a Prefix/Subnet ID?

A
  • Global Routing Prefix

- Subnet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the formal name for the Subnet ID in IPv6?

A

Prefix ID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is another name for the IPv6 Subnet ID / Prefix ID?

A

Subnet Router Anycast Address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is SLAAC?

A

Stateless Address Autoconfiguration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are Unique Local unicast addresses?

A

Private IPv6 addresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How many bits is the Global ID in a Unique Local Unicast address?

A

40 bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the three components of the first 64bits of a Unique Local address?

A
  • First 8 bits must be FD
  • 40 bit Global ID
  • 16 bits Subnet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the three components of the first 64bits of a Unique Local address?

A
  • First 8 bits must be FD
  • 40 bit Global ID
  • 16 bits Subnet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

True/False: You can leave a space between the address and the /prefix length when entering the command on the device

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you enable IPv6 routing?

A

ipv6 unicast-routing

interface> ipv6 address …

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is an alternative method to static assignment for an IPv6 interface ID?

A

EUI-64 autoconfiguration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the steps EUI-64 autoconfiguration uses to build the interface ID?

A
  1. Split the 6byte MAC address of the interface into two halves
  2. Insert FFFE in the middle
  3. Invert the 7th bit of the resultant interface ID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How would you configure an interface using EUI-64?

A

ipv6 address 2001:DB8:1111:4::/64 eui-64

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What command is used to override the burned in MAC address for an interface?

A

mac-address 0201.AA00.0001

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

True/False: You must only enter the prefix and not the full address when configuring an interface address in eui-64 mode or else the command will fail

A

False. IOS automatically converts the address to the matching prefix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are two ways Cisco routers support to allow a router interface to dynamically learn an IPv6 address?

A
  • Stateful DHCP

- SLAAC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do you configure a router interface to use DHCP?

A

ip address dhcp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How do you configure a router interface to use SLAAC?

A

ip address autoconfig

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are IPv6 Link Local addresses used for?

A

Not used for normal packet flows containing application data. They are used for overhead protocols and for routing e.g. next hop IP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

True/False: NDP uses link-local addresses

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What command could you use to show the link-local address of a neighboring router?

A

show ipv6 route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

True/False: Link-local addresses can represent more than one host

A

False. They are Unicast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

True/False: Link-local addresses can be automatically generated

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the forwarding scope for link-local addresses?

A

Only the link itself. Routers do not forward packets with link-local destination addresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What do link local addresses always start with? (Including the 54 bits after the first 10)

A

FE80:0:0:0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What three ways can the second half (interface ID) of the link local address be created?

A
  1. Randomly generated
  2. EUI-64
  3. Manually configured
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What command would you use to manually configure a link local address?

A

ipv6 address [address] link-local

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the valid starting prefixes for link-local addresses?

A

FE8
FE9
FEA
FEB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

True/False: If not manually configured IOS automatically calculate the link-local address using EUI-64 rules

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What rules does SLAAC use when calculating the interface ID?

A

EUI-64

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What does the ipv6 enable command do?

A

Enable IPv6 processing on an interface and adds a link-local address but no other unicast IPv6 addresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What kind of link would you only need a link-local address on?

A

WAN links

42
Q

What is the IPv6 Multicast address for OSPFv3 ‘all OSPF routers’?

A

FF02::5

43
Q

What is the IPv6 Multicast address for OSPFv3 ‘all DR routers’?

A

FF02::6

44
Q

What are the IPv4 and IPv6 Multicast addresses for ‘all nodes’?

A

224.0.0.1 / FF02::1

45
Q

What are the IPv4 and IPv6 Multicast addresses for ‘all router interfaces’?

A

224.0.0.2 / FF02::2

46
Q

What is the Multicast address FF02::A used for?

A

To address all EIGRPv6 routers

47
Q

What does Interface-local scope mean?

A

Packet remains within the device e.g. sending to services running on the same host

48
Q

What does Site-local scope mean?

A

Routers can forward packets in this scope but usually not across WAN links

49
Q

What prefix do Link-local Multicast packets start with?

A

FF02

50
Q

What prefix do Link-local Unicast addresses start with?

A

FE80

51
Q

Why is NDP an improvement over the MAC discovery process (ARP)?

A

By sending IPv6 Multicast packets that can be processed by the correct host but discarded with less processing the other hosts in the subnet

52
Q

What is a Solicited-Node Multicast Address used for?

A

Obtaining the L2 address of a node in NDP

53
Q

What is a Solicited-Node Multicast Address?

A

A special address derived from the last 24 bits (6 hex digits) of each Unicast address on an interface

54
Q

What is the format of a Solicited-Node Multicast Address?

A

FF02::1:FF–:—- where the last 6 characters are the last 24 bits of the original Unicast address

55
Q

What special IPv6 address represents unknown (unspecified) address?

A

:: or all 0s

56
Q

What is the loopback IPv6 address?

A

::1

57
Q

What is an IPv6 Anycast address?

A

An address that can be configured on a number of router interfaces and causes a packet to be delivered to the closest one

58
Q

What prefix are Anycast address routes advertised as?

A

128 bits (as a host route)

59
Q

How do you configure an IPv6 Anycast address on a router interface?

A

ipv6 address 2001:1:2:99/128 anycast

60
Q

What is the Subnet Router Anycast address?

A

One special Anycast address in each subnet, reserved by routers as a way to send a packet to any router on the subnet. Effectively the network address of that subnet (all 0s in host)

61
Q

What is the value of the Subnet Router Anycast address?

A

Same prefix/number as the SubnetID address, all 0s on the interface ID

62
Q

True/False: Routers add connected or local IPv6 routes for link-local addresses

A

False

63
Q

What two routes will routers make for each Unicast IPv6 address on an interface (excluding link-local addresses)?

A
  • A connected route for the subnet

- A host route for the interface address

64
Q

What command would you use to show all Local IPv6 routes?

A

show ipv6 route local

65
Q

What command would you use to show all Connected IPv6 routes?

A

show ipv6 route connected

66
Q

How would you configure a static IPv6 route by specifying an outgoing interface?

A

ipv6 route 2001:DB8:1111:2::/64 s0/0/0

67
Q

How do you show a particular route to a specified destination?

A

show ipv6 route [ip]

68
Q

Why must you specify both an outgoing interface and link-local address when using a link-local address as the next-hop for a static IPv6 route?

A

Because the link-local address by itself does not tell the local router which outgoing interface to use

69
Q

How would you configure a static route using a link-local next-hop address?

A

ipv6 route [dest] [outgoing interface] [link-local next-hop]

70
Q

What must you always do when configuring a static route that uses an Ethernet interface?

A

Include a next-hop IP address. You cannot only specify an outgoing interface

71
Q

What is the IPv6 default route?

A

::/0

72
Q

How would you make a floating static route?

A

ipv6 route [destination] [next-hop] [metric]

73
Q

What is a floating static route?

A

A static route with a custom administrative distance value that floats in / out of the routing table depending what better (lower) routes exist with lower administrative distance

74
Q

What is the default administrative distance for connected routes?

A

0

75
Q

What is the default administrative distance for NDP learned routes?

A

2

76
Q

What is the default administrative distance for OSPF routes?

A

110

77
Q

What is the default administrative distance for RIP routes?

A

120

78
Q

When using SLAAC how does the host learn the subnet (prefix) and prefix length used on the link ?

A

NDP

79
Q

What is DAD and how do hosts perform it?

A

Duplicate address detection.

Hosts use NDP to ensure no other hosts uses the same IPv6 address before attempting to use it

80
Q

True/False: NDP is part of ICMPv6

A

True

81
Q

What replaces ARP Request and Reply messages in NDP?

A

Neighbor Solicitations and Neighbor Advertisements

82
Q

What does a Neighbor Solicitation (NS) message do?

A

Asks the host with a particular IPv6 address to reply with an NA that lists its MAC

83
Q

What is the destination address of a NS message?

A

Solicited Node Multicast address associated with the target address.

Therefore the message is only processed by hosts whose last six hex digits match the address being queried

84
Q

What does a Neighbor Advertisement (NA) message do?

A

Lists the senders IPv6 and MAC.

Sent in reply to an NS or can be sent as an unsolicited NA, announcing its addresses to all IPv6 hosts

85
Q

What is the destination address of an unsolicited Neighbor Advertisement?

A

FF02::1

This is the ‘all IPv6 hosts’ local-scope multicast address

86
Q

What is the NDP neighbor table?

A

The equivalent of the IPv4 ARP cache

87
Q

What is the multicast address for all IPv6 hosts local scope?

A

FF02::1

88
Q

How can hosts learn the identity of a default gateway differently in IPv6?

A

Using NDP with RS and RA messages

89
Q

What is a Router Solicitation (RS) message?

A

A message sent to all IPv6 routers on the local link to ask for their details

90
Q

What is the destination address of a Router Solicitation message?

A

FF02::2

This is the ‘all IPv6 routers’ local-scope multicast address

91
Q

What is a Router Advertisement (RA) message?

A

Lists facts about the router, either in response to an RS or by itself e.g. link-local address

92
Q

True/False: An RA does not list more than one prefix or default routers to be listed

A

False. IPv6 allows multiple prefixes and multiple default routers to be listed in RA messages

93
Q

True/False: IPv6 does not use Broadcasts

A

True. It uses Multicast instead

94
Q

What alternative to DHCP does IPv6 support for dynamic address assignment?

A

SLAAC

95
Q

What are the three steps involved in SLAAC?

A
  1. Learn the IPv6 prefix used on the link from any router using NDP RS/RA
  2. Build an address from the prefix + interface ID, using a random value or EUI-64 rules
  3. Use DAD before using the address
96
Q

When do hosts use DAD?

A

Anytime the interface initializes

  • End of SLAAC
  • Static address configuration
  • DHCP
97
Q

What are the initial 104bits of a Solicited Node Multicast Address?

A

FF02::1:FF

98
Q

What kind of route is this?

ipv6 route 200.:db8:a::/32 fastethernet0/1 2001:db8:b::1

A

This is a fully specific static route. It contains the destination network, outbound interface, and next-hop IPv6 address are all configured directly.

99
Q

What kind of route is created from the following command:

ipv6 route 200.:db8:a::/32 fastethernet0/1

A

This command creates a a directly attached static route. When a directly connected static route is configured, the router assumes that any packet that matches the destination network is reachable through a specified outbound interface.

100
Q

What kind of route is created from the following command:

ipv6 route 200.:db8:a::/32 2001:db8:b::1

A

This command creates a recursive static route. The router assumes the outbound interface to be the interface which the next hop is either directly or indirectly connected. The next-hop IPv6 address must be resolvable through the outbound interface.