Chapter 12: IPv6 Addressing

Theses are the addresses of DNS servers and domain name

DNS addresses and domain name

Instead of a broadcast IPv6 has what?

IPv6 all nodes multicast address that essentially gives the same result.

What is the difference between a GUA address and a LLA addresses?

IPv6 global unicast addresses are globally unique and are routable on the IPv6 internet. LLAs are not unique and can be reused in different subnets and are not globally routable.

This uses the EUI-64 process or by generation a random 64-bit number, depending on the device operating system

Interface ID

Typically, which IPv6 address is used for the default gateway for other devices on the link?

It is the Link-local address

AN IPv6 Multicast address is used to send a single IPv6 packet to multiple destination.

Multicast

What does NAT64 stand for?

Network Address Translation 64

When an address begins with this hextext within the range of fe80 to febf, what parameter must follow the address?

link-local

For IPv6 it is strongly recommended that a prefix length of what is used for a GUA?

/64

What is the recommended IPV6 prefix length for LANs and most other types of networks?

/64

What is the recommended prefix length for most IPv6 subnets? /32 /48 /64 /128

/64

What is the prefix length range of an IPv6 address?

0-128

Breakdown how Method 2: SLAAC and Stateless DHCPv6 is used to receive IPv6 address information and DNS information.

1. The PC sends an RS to all IPv6 routers, I need addressing information 2. The router sends an RA message to all IPv6 nodes with Method 2 ( SLAAC and DHCPv6) specified. Here is your prefix , prefix length, and default gateway information. But you will need to get DNS information from DHCPv6 server. The PC sends a DHCPv6 Solicit message to all DHCPv6 servers. I used SLAAC to create my IPv6 address and get my default gateway address, but I need other information form a stateless DHCPv6 server.

An IPv6 anycast address is any Ipv6 unicast address that can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address.

Anycast

IPv6 does not have what type of address?

Broadcast

Why do you configure an LLA manually?

Configuring the LLA manually lets you create an address that is recognized and easier to remember.

Why is NAT problematic for many applications?

Creates latency Has Limitations that severely impede peer-topeer0 communications.

A GUA has three parts, what are they?

Global Routing Prefix Subnet ID Interface ID

What are the six different types of IPv6 unicast addresses?

Global Unicast Link-local Loopback Unspecified Address Unique Local Embedded IPv4

This is similar to a public IPv4 address. These are globally unique, internet-routable addresses. GUAs can be configured statically or assigned dynamically.

Global Unicast Address (GUA)

Unlike IPv4 devices that have only a single address, IPv6 addresses typically have two unicast addresses:

Global Unicast Address (GUA) Link-local Address (LLA)

Which part of a GUA is assigned by the ISP? Global Routing Prefix Global Routing Prefix and Subnet ID Prefix RIR Prefix

Global routing Prefix

For the Global Unicast Address, a device obtains the address dynamically through which version of the Internet Control Message Protocol version (ICMP)?

ICMPv6

What does LLA stand for?

Link-Local Address

When a device receives SLAAC information through Router Advertisement messages, by default, what does RA message suggest?

RA message suggests that the receiving device use the information in the RA message to create its own IPv6 GUA and all other necessary information.

A /64 subnet or prefix (Global Routing Prefix + Subnet ID) leaves 64 bits for the interface ID. This is recommended to allow what protocol to function?

SLAAC

Method 2 using SLAAC and stateless DHCPv6., the RA message suggests devices use the following:

SLAAC to create its own IPV6 GUA The router LLA, which is the RA source IPv6 address, as the default gateway address A stateless DHCPv6 server to obtain other information such as DNS server address and domain name

What does SLAAC stand for in IPv6?

Stateless Address Autoconfiguration

There are two ways in which a device can obtain an IPv6 GUA automatically:

Stateless Address Autoconfiguration Stateful DHCP

What does SLAAC protocol allow an device IPv6 enabled device to do?

Stateless Address Autoconfiguration (SLAAC) is a method that allows a device to create its own GUA without the services of DHCPv6.

This means the device has been manually configured.

Statically

There are two ways that a device can obtain an LLA:

Statically Dynamically

The IPv6 interface ID is equivalent to what form an IPv4 address?

The IPv6 interface ID is equivalent to the host portion of an IPv4 address.

If an LLA is not configured manually on an interface, the IPv6 enabled device will do what?

The device will automatically create its own without communicating with a DHCP server.

What is the global routing prefix?

The global routing prefix is the prefix, or network portion of the address that is assigned by the provider, such as an ISP, to a customer or site.

As shown in the figure, with this method, the RA message suggests devices use the following:

The router LLA, which is the RA source IPv6 address, for the default gateway address A stateful DHCPv6 server to obtain a GUA, DNS server address, domain name and other necessary information

What is the subnet ID portion of a GUA used to identify?

The subnet ID is used by an organization to identify subnets within its site.

How many hexadecimal digits in each hextet?

There are 4

Why is it beneficial to use LLAs on router interfaces?

This is beneficial because router LLAs are used as default gateways addresses and in router advertisement messages.

What does native IPv6 mean?

This means the customer network has an IPv6 connection to their ISP and is able to access content found on the internet over IPv6.

With SLAAC, the client device uses the information in the RA message to do what?

To create its own GUA

The router must be enabled for IPv6 routing, which is not enabled by default. How would you enable it on a router?

To enable a router as an IPV6 router, the ipv6 unicast-routing global configuration command must be used.

True or False: 4 out of 5 RIRs no longer have enough IPv4 addresses to allocate to customers on a regular basis. True False

True

True or False: A router interface can be configured to send an RA using stateful DHCPv6 only.

True

True or False: The size of the global routing prefix determines the size of the subnet ID.

True

Ture or False: IPv6 does not use the doted-decimal subnet mask notation.

True

True or False: Unlike IPv4, in IPv6, the all-0s and all-1s host addresses can be assigned to a device.

True, The all-1s address can be used because broadcast address are not used within IPv6. The all 0-s addresses can also be used, but is reserved as a Subnet-Router anycast address, and should be assigned only to routers.

What is tunneling?

Tunneling is a method of transporting an IPv6 packet over an IPv4 network. The ipv6 packet is encapsulated inside an IPv4 packet similar to other types of data.

If a device is using SLAAC to obtain IPv6 addressing information how are the devices receiving the SLAAC information?

Using SLAAC, a devices rely on the ICMPv6 RA messages of the local router to obtain the necessary information.

SLACC is stateless, which means what?

Which means there is no central server (for example, stateful DHCPv6 server) allocating GUAs and keeping a list of devices and their addresses.

Can you use the same LLA for all links on a router?

Yes, but for best practice it is better to use different ones for documentation purposes.

What is the most important motivating factor for moving to IPv6? better performance with IPv6 IPv6 addresses that are easier to work with better security with IPv6 depletion of IPv4 addresses

depletion of IPv4 addresses

Which of the following techniques use native IPv6 connectivity? dual stack tunneling translation all of the above

dual stack

What is the address range for IPV6 Unique Local addresses?

fc00::/7 to fdff::/7

What is the IPv6 address range for Link-local addresses?

fe80/10 - febf/10

What are the command to configure interface g0/0/0 with an IPv6 GUA of 2001:db8:acad:1::1/64?

interface g0/0/0 ipv6 address 2001:db8:acad:1::1/64 no shut down

How do you manually configure an IPV6 LLA on a router interface?

interface g0/0/0 ipv6 address fe80::1:1 link-local Note link local range is Fe80-FEBF

What does IPv6 use to represent the network portions of its addresses?

slash notation and is used to indicate the network portion of an IPv6 address.

IPv6 addresses are how many bits in length?

128 bits

2001:db8:acad::/48 From the above example what is the network portion of the IPv6 address?

2001:db8:acad::/48

For best practice what which IPv6 address should be used as the default gateway to a link or subnet?

Link-local Address

As with IPv4, there are different types of IPv6 addresses. In fact, there are three broad categories of IPv6 addresses:

Unicast Multicast Anycast

Breakdown how Method 3:Stateful DHCPv6 is used to receive IPv6 address information and DNS information.

1. The PC sends an RS to all IPv6 routers, I need addressing information 2. The router sends an RA message to all IPv6 nodes with Method 3 (Sateful DHCPv6) specified, I am your default gateway, but you need to ask a stateful DHCPv6 server for your IPv6 address and other addressing information 3. The PC sends a DHCPv6 Solicit message to all DHCPv6 servers, I received my default gateway address from the RA message, but I need an IPv6 address and all other addressing information form a stateful DHCPv6 server.

Given a /48 Global Routing Prefix and a /64 prefix, what is the subnet portion of the following address: 2001:db8:cafe:1111:2222:3333:4444:5555 cafe 1111 2222 3333 4444

1111

Your organization is issued the IPv6 prefix of 2001:db8:130f::/48 by your service provider. With this prefix, how many bits are available for your organization to create /64 subnetworks if interface ID bits are not borrowed? 16 128 80 8

16

What is the range for IPv6 Global Unicast address?

2000::/3 to 3fff::/3

What is the network address for the IPv6 address 2001:DB8:AA04:B5::1/64?

2001:DB8:AA04:B5::/64

What is the valid most compressed format possible of the IPv6 address 2001:0DB8:0000:AB00:0000:0000:0000:1234?

2001:db8:0:ab00::1234

What is the most compressed representation of the IPv6 address 2001:0db8:0000:abcd:0000:0000:0000:0001?

2001:db8:0:abcd::1

What is the prefix associated with the IPv6 address 2001:DB8:D15:EA:CC44::1/64?

2001:db8:d15:ea::/64

An EUI-64 Interface ID is represented in binary and is made up of three parts:

24-bit OUI from the Client MAC address, but the 7th bit (the Universally/Locally (U/L) bit) is reserved. this means that if the 7th bit is a 0, it becomes a 1. and vice versa The inserted 16-birt value ff fe (in hexadecimal) 24-bit Device Identifier from the client MAC address

Given a /32 Global Routing Prefix and a /64 prefix, how many bits would be allocated for the Subnet ID? 8 16 32 48 64

32

IPv6 are made up of how many hexadecimal numbers?

32

What is the drawback of using the dynamically assigned LLAs on Cisco routers?

A drawback to using the dynamically assigned LLA is its long interface ID, which makes it challenging to identify and remember assigned addresses.

What makes a DHCPv6 server stateful?

A stateful DHCPv6 server allocates and maintains a list of which device receives which IPv6 address. DHCP for IPv4 is stateful.

What do Stateless DHCPv6 do?

A stateless DHCPv6 server distributes DNS server addresses and domain names. It does not allocate GUAs.

Internet Control Message Protocol Version 6 can perform what two functions?

Address resolution Address autoconfiguration

What does dual stack migration technique allow on the network segment?

Allows IPv4 and IPv6 to coexist on the same network segment. Dual Stack devices run both IPv4 and IPv6 protocol stacks simultaneously.

What does NAT64 do?

Allows Ipv6-enabled devices to communicate with IPv4-enabled devices using translation technique similar to NAT for IPv4. An IPv6 packet is translated to an IPv4 packet and an IPv4 packet is translated to an IPv6 packet.

What does a LLA allow a device to do?

An IPv6 Link-local address enables a device to communicate with other IPv6-enabled devices on the same link and only on that link (subnet).

By default, what process does a Cisco IOS router use to generate the interface ID for all LLAs on IPv6 interfaces?

Cisco IOS routers use EUI-64 to generate the interface ID for all LLAs on ipv6 interfaces.

Cisco routers will do what whenever a GUA is assigned to the interface?

Cisco routers will automatically create an IPv6 LLA whenever a GUA is assigned to the interface.

A 16-bit subnet ID will create how many subnets?

Creates up to 65,536 subnets

To ensure the uniqueness of any IPv6 unicast address, the client may use a process known as what?

DAD or Duplicate Address Detection (DAD) Note: This is similar to an ARP request for its own address. If there is no reply, then the address is unique.

This is an IPv6 LLA, the source IPv6 address of the RA message

Default gateway address

The device identifier is a unique 24 bit (6 hexadecimal digits) value within a common OUI

Device Identifier

The IETF has created various protocols and tools to help network administrators migrate their networks to IPv6. The migration techniques can be divided into three categories:

Dual Stack Tunneling Translation

This means the device creates its own interface ID by using randomly generated values or using the Extended Unique Identifier (EUI) method, which uses the client MAC address along with additional bits.

Dynamically

What are the two methods a device can use to generate its own IPv6 interface ID? SLAAC stateless DHCPv6 Stateful DHCPv6 EUI-64 randomly generated

EUI-64 randomly generated

When will a router send out a Router Advertisement message?

Every 200 seconds automatically or when a host sends a Router Solicitation Message

What does EUI-64 stand for?

Extended Unique Identifier or modified EUI-64 process

True or False. RA messages are sent to all IPv6 routers by hosts requesting addressing information.

False

True or False: The Subnet ID field in a GUA must borrow bits from the Interface ID.

False

What is an example of a common Global Routing Prefix?

For example, it is common for ISPs to assign a /48 global routing prefix. The global routing prefix will usually vary depending on the policies of the ISP.

How will serial interfaces on Cisco routers generate an interface ID for IPv6?

For serial interfaces, the router will use the MAC address of the first Ethernet interface.

Stateful DHCPv6 is similar to DHCP for IPv4. A device can automatically receive what addressing information form a Stateful DHCPv6 server?

GUA prefix length and the addresses of DNS servers from a staeful DHCPv6 server

What two types IPv6 address will be okay for a default gateway?

GUA- Global Unicast Address LLA- Link local Address

What is the drawback of using the EUI-64 process?

However, this has caused privacy concerns among many users who worried that their packets could be traced to the actual physical computer. Due to these concerns, a randomly generated interface ID may be used instead.

When a router is set up for IPv6 what type of message will it periodically send out to all IPV6-enabled devices on the network?

ICMPv6 Router Advertisement messages

What is indicated by a successful pin on the ::1 IPv6 address? The link-local address is correctly configured All hosts on the local link are available. IP is properly installed on the host The default gateway address is correctly configured The host is cabled properly

IP is properly installed on the host

A source IPv6 address will always be what type of address?

IPv6 Unicast Address

The up/up output of the show ipv6 interface brief command indicates what?

Indicates the Layer1/Layer2 interfaces state

Where is the subnet ID located in GUA?

It is between the global routing prefix and the interface ID

To make it easier to recognize and remember LLAs on Cisco routers, what is the best practice?

It is common to statically configure IPv6 LLAs on routers.

What is the purpose of the command ping ::1? It tests the reachability of the default gateway for the network It tests the broadcast capability of all hosts on the subnet It tests the multicast connectivity to all hosts on the subnet It tests the internal configuration of an IPv6 host

It tests the internal configuration of an IPv6 host

What type of IPv6 address begins with fe80? GUA LLA multicast address None. an IPv6 address must begin with 2001

LLA

Which type of IPv6 unicast address is not routable between networks? Unique local address GUA embedded IPv4 address LLA

LLA

Which address type does not show in an IPv6 routing table?

LLAs because they are not routable

When DHCPv6 or SLACC is used, which IPv6 address will automatically be specified as the default gateway address?

Link-Local Address

This is required for every IPv6-enabled device. LLAs are used to communicate with other devices on the same local link. With IPv6, the term link refers to a subnet. LLAs are confined to a single link. Their uniqueness must only be confirmed on that link because they are not routable beyond the link. In other words, routers will not forward packets with a link-local source or destination address.

Link-local Address (LLA)

The GUA is not a requirement, however, every IPv6 enabled network interface must have what?

Link-local address

I have everything you need including the prefix, prefix length, and default gateway address

Method 1: SLAAC

Which dynamic addressing method for GUAs is the one where devices rely solely on the contents of the RA message for their addressing information? Method 1: SLAAC Method 2: SLAAC and Stateless DHCPv6 Method 3: Stateful DHCPv6

Method 1: SLAAC

What are the three methods for RA messages?

Method 1: SLAAC Method 2: SLAAC with Stateless DHCPv6 server Method 3: Stateful DHCPv6 (No SLAAC)

Which dynamic addressing method for GUAs is the one where devices get their IPv6 configuration in a RA message and request DNS information form a DCHPv6 server? Method 1: SLAAC Method 2: SLAAC and Stateless DHCPv6 Method 3: Stateful DHCPv6

Method 2: SLAAC and Stateless DHCPv6

Her is the information but you need to get other information such as DNS from a stateless DHCPv6 server

Method 2: SLAAC with sateless DHCPv6 server

Which dynamic addressing method for GUAs is the one where devices rely solely on a DHCPv6 server for their addressing information? Method 1: SLAAC Method 2: SLAAC and Stateless DHCPv6 Method 3: Stateful DHCPv6

Method 3: Stateful DHCPv6

I can give you your default gateway address. You need to ask a stateful DHCPv6 server for all you other information

Method 3: Stateful DHCPv6 (no SLAAC)

The ICMPv6 RA message is a suggestion to a device on how to obtain an IPv6 GUA. The ultimate decision is up to the device operating system. The ICMPv6 RA message includes the following:

Network prefix and prefix length Default gateway address DNS addresses and domain name

This tells the device which network it belongs to

Network prefix length and prefix length

Can packets with source or destination LLAs be routed?

No, packets with a source or destination LLA cannot be routed beyond the link from which the packet originated.

The OUI is a 24-bit (6 hexadecimal digits) vendor code assigned by IEE

Organizationally Unique Identifier (OUI)

Ethernet MAC addresses are usually represented in hexadecimal and are made up of two parts:

Organizationally Unique Identifier (OUI) Device Identifier

This is advertised in the RA message

Prefix

With SLAAC, the client device uses the information in the RA message to create its own GUA. As shown in the figure, the two parts of the address are created as follows

Prefix Interface ID

The EUI-64 process is illustrated in the figure, using the R1 GigabitEthernet MAC address of fc99:4775:cee0. Breakdown the process

Step 1: Divide the MAC address between the OUI and device Identifier Step 2: Insert the hexadecimal value fffe, which in binary is : 1111 1111 1111 1110 Step 3: convert the first 2 hexadecimal values of the OUI to binary and flip the U/L bit (bit 7). In this example, the 0 in bit 7 is changed to a 1 The result is an EUI-64 generated interface ID of fe99:47ff:fe75:cee0

Which field in and IPv6 GUA is used for subnetting? Prefix Network Global Routing Prefix Subnetting ID Interface

Subnetting ID

How many hosts does a 64-bit interface ID create?

Supports up to 18 quintillion hosts IPV6 addresses

Who defines the Extended Unique Identifier (EUI) or modified EUI-64 process?

The IEEE

What part of the Global Unicast Address is used to subnet IPv6 addresses?

The Subnet ID

What is the advantage of using of the EUI-64 to generate a interface ID?

The advantage of EUI-64 is that the Ethernet MAC address can be used to determine the interface ID. It also allows network administrators to easily track an IPv6 address to an end-device using the unique MAC address.

What is the advantage of a solicited-node multicast address?

The advantage of solicited-node multicast address is that it is mapped to a special Ethernet multicast address. This allows the Ethernet NIC to filter the frame by examining he destination MAC address without send it it to the IPv6 process to see fi the devices is the intended target for the IPv6 packet.

Why is the term interface ID used?

The term interface ID is used because a single host may have multiple interfaces, each having one or more IPV6 addresses.

How does the Extended Unique Identifier (EUI) or modified EUI-64 process generate a Interface ID for a GUA?

This process uses the 48-bit Ethernet MAC address of a client, an inserts another 16 bits in the middle of the 48-bit AMC address to create a 64-bit interface ID.

How do you determine the next available subnet when using IPv6 addressing?

To determine the next available subnet, just count up in hexadecimal.

True or False: Operating systems, such as windows, will typically use the same method for both a SLAAC-created GUA and a dynamically assigned LLA.

True

True or False? IPv6 was designed with subnetting in mind. True False

True

Ture or False: IPv6-enabled hosts create an IPv6 LLA even if the device has not been assigned a global unicast IPv6 address.

True, this allows IPv6-enabled devices to communicate with other IPv6-enabled devices on the same subnet. This includes communication with the default gateway (router)

True or False: The default gateway address can only be obtained dynamically from the RA message.

Ture, The stateless or stateful DHCPv6 server does not provide default gateway address

When is it recommended you configure a LLA statically?

Typically, it is only necessary to create recognizable LLAs on routers.

An IPv6 unicast address uniquely identifies an interface on an IPv6-enabled device

Unicast

A destination IPv6 address will be what type of address?

Unicast address Multicast Address

The IPv6 unique local addresses have some similarity to RFC 1918 private addresses for IPv4, but there are significant differences:

Unique local addresses are used for local addressing within a site or between a limited number of sites. Unique local addresses can be used for devices that will never need to access another network Unique local addresses are not globally routed or translated to a global IPv6 address

An assigned multicast address is a single address used to do what?

Used to reach a group of devices running a common protocol or service. Assigned multicast addresses are used in connect with specific protocols such as DHCPv6

What are well-known ipv6 multicast addresses?

Well-known IPv6 multicast addresses are assigned. Assigned multicast addresses are reserved multicast address for predefined groups of devices.

There are two types of IPv6 multicast addresses:

Well-known multicast addresses Solicited node multicast addresses

When will a PC use EUI-64 process or a random 64-bit number to generate an interface ID?

When the RA message is wither SLAAC or SLAAC with stateless DHCPv6, the client must generate its own interface ID.

Which windows operating systems use the EUI-64 process?

Windows XP and previous windows operating systems use EUI-64

Which windows operating systems use randomly generated interface IDs?

Windows vista and newer Notre: After the interface ID is established, either through the EUI-64 process or through random generation, it can be combined with an IPv6 prefix in the RA message to create a GUA, as shown in the figure

What is the interface ID of the IPv6 address 2001:DB8::1000:A9CD:47FF:FE57:FE94/64?

a9cd:47ff:fe57:fe94

What are the three parts of an IPv6 global unicast address? (Choose Three) an interface ID that is used to identify the local network for a particular host a subnet ID that is used to identify networks inside of the local enterprise site a global routing prefix that is used to identify the network portion of the address that has been provided by an ISP a global routing prefix that is used to identify the portion of the network address provided by a local administrator an interface ID that is used to identify the local host on the network

an interface ID that is used to identify the local host on the network a global routing prefix that is used to identify the network portion of the address that has been provided by an ISP a subnet ID that is used to identify networks inside of the local enterprise site

Which address type is not supported in IPv6? private broadcast unicast multicast

broadcast

Which IPv6 network prefix is only intended for local links and can not be routed? fe80::/10 2001::/3 fc00::/7 FF00::/12

fe80::/10

What is the range of IPv6 multicast addresses?

ff00::/8

This is a multicast group that all IPv6-enalbed devices join. A packet sent to this group is received and processed by all IPv6 interfaces on the link or network. This has the same effect as a broadcast address in IPv4. An ipv6 router send ICMPv6 RA messages to the all-nodes multicast group.

ff02::1 All-nodes multicast group

What are the two common IPv6 assigned multicast group?

ff02::1 All-nodes multicast group ff02::2 All-routers multicast group

This is a multicast group that all IPv6 routers join. A router becomes a member of this group when it is enabled as an IPv6 router with the ipv6 unicast-routing global configuration command. A packet sent to this group is received ad processed by all IPv6 routers on the link or network.

ff02::2 All-routers multicast group

At a minimum, which address is required on IPv6-enabled interfaces? unique local global unicast site local link-local

link-local

What type of address is automatically assigned to an interface when IPv6 is enabled on that interface? unique local global unicast link-local loopback

link-local

What type of IPv6 address is not routable and used only for communication on a single subnet? global unicast address unique local address link-local address loopback address unspecified address

link-local address

What are the three ways on a Cisco router to verify IPv6 address configuration?

show ipv6 interface brief show ipv6 route ping

Command can be used to verify that Ipv6 networks and specific IPv6 interface address have been installed in the Ipv6 routing table.

show ipv6 route

When pinging an LLA from a router, Cisco IOS will prompt the user for what?

the exit interface

What is the minimum configuration for a router interface that is enabled for IPv6? to have a self-generated loopback address to have both an IPv4 and IPv6 address to have both a link-local and a global unicast IPv6 address to have a link-local IPv6 address

to have a link-local IPv6 address