Volume 1 - Chapter 28: Implementing IPv6 Addressing on Hosts

Question 1

What feature of NDP allows an IPv6 host to learn the MAC address of other hosts in the LAN?

Answer 1

Neighbor MAC Discovery.

Question 2

What feature of NDP allows an IPv6 host to learn the MAC address of routers in the same subnet?

Answer 2

Router Discovery.

Question 3

What feature of NDP allows an IPv6 host to learn the subnet prefix that routers expect to exist on the link?

Answer 3

Prefix Discovery.

Question 4

Describe the function of DAD in regard to NDP.

Answer 4

Duplicate Address Detection is used to verify that no other host is using the same IP address before the host is assigned it.

Question 5

Describe the function of the NDP NS message.

Answer 5

Functions similarly to an IPv4 ARP Request.

The IPv6 Neighbor Solicitation request is used to request the MAC address of a host on the same subnet.

Question 6

Describe the function of the NDP NA message.

Answer 6

Functions similarly to an IPv4 ARP Reply.

The IPv6 Neighbor Advertisement is the response to the NS request containing the IPv6 address and MAC address

Question 7

What multicast address is used for sending an unsolicited IPv6 neighbor advertisement?

Answer 7

FF02::1

Question 8

What service can a technician use to prevent NDP neighbor solicitation messages from being flooded out to all hosts, and to only be sent to the intended host?

Answer 8

Multicast Listener Discovery (MLD)

Question 9

What is the multicast address used for hosts to discover routers using a router advertisement?

Answer 9

FF02::2

Question 10

Describe the differences between how hosts calculate routes in IPv4 versus IPv6

Answer 10

IPv4 hosts calculate the subnet and range of address using their IP address and subnet mask

IPv6 hosts build their routing table using a prefix advertised to them using NDP.

Question 11

When using IPv6, how does a host send information to its default gateway when trying to reach an exterior subnet?

Answer 11

The host will create a default route to its gateway using the routers LLA.

Question 12

Describe the process of an IPv6 host using DAD.

Answer 12

Step 1) The host wants to use an IPv6 address, so it sends a NS request with the destination IP as the one it wants to use

Step 2) If a host already that IP, it responds back with a NA containing its IP and MAC

Step 3) The original host receives the NA response and determines it cannot use that IP

Question 13

Describe how stateful DHCPv4 and stateful DHCPv6 differ

Answer 13

With stateful DHCPv4 the DHCP server provides the IP address, subnet mask, gateway, and DNS servers.

With stateful DHCPv6 the server only provides the unicast address and DNS servers. The host will use NDP requests for the prefix length and default router

Question 14

What process does IPv6 use for DHCP?

Answer 14

SARR

Solicit, Advertise, Request, and Reply

Question 15

What destination address is used for “all DHCP agents”?

Answer 15

The link-local scope multicast address FF02::1:2

Question 16

What is the command to set the DHCP relay address for an interface?

Answer 16

ipv6 dhcp relay destination address

Question 17

Describe how a host uses SLAAC to generate an IP address.

Answer 17

Step 1) The host uses NDP Router Solicitation/Advertisement messages to learn the prefix
Step 2) Make up the IID randomly or using EUI-64
Step 3) Use DAD to ensure the address isn’t in use

Question 18

Describe how a host gets its necessary IP configuration when utilizing stateless DHCP with SLAAC.

Answer 18

The host creates the IID
The host uses NDP messages to get the prefix, prefix length, and gateway
The stateless DHCP server provides the DNS servers

Question 19

Describe the differences between a stateful and stateless DHCP server.

Answer 19

The stateful DHCP server provides all IP addressing information to the host and actively tracks what host has an address.

The stateless DHCP server only provides the DNS server and does not provide or track any other information.

Question 20

Describe the purpose of RDNSS.

Answer 20

RA-based DNS Servers are used for hosts to dynamically learn DNS servers without the use of a stateless/stateful DHCP server.

The router’s interfaces are configured with DNS server addresses which are advertised via Router Advertisement (RA) messages.

Question 21

An IPv6 address that is configuring using SLAAC, but has a fixed time before it is changed is referred to as a?

Answer 21

Temporary SLAAC Address

Question 22

An IPv6 address that is configuring using SLAAC, but does not have an expiry is referred to as?

Answer 22

Permanent SLAAC Address

Question 23

Describe the stages of a SLAAC IPv6 temporary address

Answer 23

Preferred: The address is valid and can be used to established connections

Valid: No new connections can be established using this address, but existing connections can be completed

Deprecated: Address is not used at all

Question 24

What command can be used in Windows to display the current IPv6 addresses?

Answer 24

netsh interface ipv6 show address

Question 25

What command can be used in Linux to display the current IPv6 addresses?

Answer 25

show -6 address

Question 26

What command can be used in MacOS to display the current IPv6 addresses?

Answer 26

ifconfig -aL inet6

Question 27

What commands are used in Linux to perform IPv6 pings and traceroutes?

Answer 27

ping6 & traceroute6

Question 28

What is the command to clear all existing NDP neighbor entries from a router?

Answer 28

clear ipv6 neighbor