430Understanding IPv6, Second Edition

MLD or MLDv2 Multicast Listener Report: Reports group membership for the specified multicast address

MLD Multicast Listener Done: Reports that there might not be any more members on the subnet for the specified multicast address

Chapter 8: Address Autoconfiguration

1.List and describe the states of an IPv6 autoconfigured address.

Tentative: The address is in the process of being verified as unique.

Valid: The address can be used for sending and receiving unicast traffic.

Preferred: The address is valid, and it can be used for unlimited communication.

Deprecated: The address is valid, but its use is discouraged for new communication.

Invalid: The address can no longer be used to send or receive unicast traffic.

2.What is the formula for calculating the amount of time an autoconfigured address remains in the deprecated state?

Valid Lifetime – Preferred Lifetime

3.How does a router obtain addresses other than link-local addresses? It obtains them through manual configuration.

4.According to RFC 4862, what addresses are autoconfigured for LAN interfaces on hosts when duplicate address detection for the EUI-64–derived link-local address fails? What is the behavior for the IPv6 protocol for Windows Server 2008 and Windows Vista?

No addresses are autoconfigured in this case.

If the link-local address is a duplicate, the IPv6 protocol for Windows Server 2008 and Windows Vista can continue with the receipt of a multicast Router Advertisement message containing non-link-local prefixes and automatically configure non-link-local addresses.

5.A host computer is running Windows Vista and is assigned the IPv4 address 172.30.90.65 on its single LAN interface. IPv6 on this computer starts up and receives a Router Advertisement message on its LAN interface that contains both a unique local prefix (FD0D:3A41:21D:29D8::/64) and a global prefix (2001:DB8:A3:29D8::/64), and both M and O flags are set to 0. List and describe the autoconfigured addresses for all the interfaces on this host.

LAN interface: FE80::[random permanent interface ID], FD0D:3A41:21D:29D8:[random permanent interface ID], 2001:DB8:A3:29D8:[random permanent interface ID], FD0D:3A41:21D:29D8:[random temporary interface ID], 2001:DB8:A3:29D8: [random temporary interface ID]

ISATAP tunneling interface: FE80::5EFE:172.30.90.65

Loopback Interface: ::1, FE80::1

6.Describe the difference between IPv6 stateful and stateless autoconfiguration. Describe the difference between DHCPv6 stateful and stateless operation.

IPv6 stateless autoconfiguration is done through the router discovery process and the receipt of a Router Advertisement message containing address prefixes, routes, and other settings. IPv6 stateful autoconfiguration is done through an address configuration protocol such as DHCPv6.

DHCPv6 stateful operation is when a DHCPv6 client requests IPv6 address configuration information in addition to other configuration settings. DHCPv6 stateless operation is when a DHCPv6 client requests only configuration settings.

7.List all the different ways that an IPv6 host running Windows Vista can be configured with IPv6 addresses.

Stateless address autoconfiguration DHCPv6 stateful operation

Manual configuration through the properties of the Internet Protocol version 6 (TCP/ IPv6) component in the Network Connections folder or at the Windows command prompt with commands in the netsh interface ipv6 context

Chapter 9: IPv6 and Name Resolution

1.Why is the DNS record for IPv6 name resolution named the “AAAA” record?

It is named the “AAAA” record because 128-bit IPv6 addresses are four times longer than 32-bit IPv4 addresses, which use a host (A) record.

2.A host computer running Windows Vista is assigned the IPv4 address 172.30.90.65 on its single LAN interface. IPv6 on this computer receives a Router Advertisement message on its ISATAP tunneling interface that contains both a unique local prefix (FD3A:47A1:2CB9:C140::/64) and a global prefix (2001:DB8:A3:C140::/64). List the IPv6 addresses for the AAAA records registered with DNS by this host.

FD3A:47A1:2CB9:C140::5EFE:172.30.90.65, 2001:DB8:A3:C140::5EFE:172.30 .90.65

3.Describe the importance of address selection rules for a node running both IPv4 and IPv6 that is using a DNS infrastructure containing both A and AAAA records.

Source and destination address selection determine the best source address to use with a destination address and the preference order for possible destination addresses. With a standard method to select source and destination addresses, applications do not need to include their own address selection algorithms, reducing the development burden on IPv6-capable applications.

432Understanding IPv6, Second Edition

4.Describe how LLMNR messages are the same as and different from DNS messages.

Same: LLMNR messages use Name Query Request and Name Query Response messages in a similar format as the corresponding DNS message.

Different: LLMNR messages can be multicast (DNS messages are unicast). LLMNR messages use a different port than DNS messages. LLMNR messages are exchanged by hosts. (DNS messages are between a DNS client and a DNS server.)

Chapter 10: IPv6 Routing

1.How does IPv6 on a router determine the single route in the routing table to use when forwarding a packet? How is the process different for an IPv6 sending host?

Based on the list of matching routes, the route that has the largest prefix length is chosen. If there are multiple longest matching routes, the router uses the lowest metric to select the best route. If there are multiple longest matching routes with the lowest metric, IPv6 can choose which routing table entry to use.

An IPv6 host first determines the source address and source interface. IPv6 on the host then performs either a constrained (for strong host, only routes with a next-hop interface of the source interface are considered) or unconstrained (for weak host, all routes are considered) route lookup to determine the closest matching route.

2.Describe the conditions that would cause a router to send the following ICMPv6 error messages.

ICMPv6 Packet Too Big The IPv6 MTU of the forwarding interface is lower than the size of the IPv6 packet being forwarded.

3.A host running Windows Vista receives a Router Advertisement message from a router advertising itself as a default router with the link-local address of fe80:: 2aa:ff:fe45:a431:2c5d, and containing a Prefix Information option to autoconfigure an address with the prefix 2001:db8:0:952a::/64 and a Route Information option with the prefix 2001:db8:0:952c::/64. Fill in the expected entries for the host based on this Router Advertisement message in the following abbreviated routing table.

4.Describe the differences between distance vector, link state, and path vector routing protocol technologies in terms of convergence time, ability to scale, ease of deployment, and appropriate use (intranet vs. Internet).

Distance vector: High convergence time; does not scale to large or very large networks; very easy to deploy; appropriate for use within a small intranet

Link state: Low convergence time; scales to large networks; more difficult to deploy; appropriate for use within an intranet consisting of a single autonomous system

Path vector: Low convergence time; scales to very large networks; difficult to deploy; appropriate for use between autonomous systems on the Internet

5.A static IPv6 router running Windows Server 2008 is configured with the following commands.

netsh interface ipv6 set interface “Local Area Connection” forwarding=enabled advertise=enabled

netsh interface ipv6 set interface “Local Area Connection 2” forwarding=enabled advertise=enabled

netsh interface ipv6 add route 2001:db8:0:1a4c::/64 “Local Area Connection” publish=yes

netsh interface ipv6 add route 2001:db8:0:90b5::/64 “Local Area Connection 2” publish=yes

With just these commands, will a host on the 2001:db8:0:90b5::/64 subnet have a default route? Why or why not? With just these commands, can a host on the 2001:db8:0:90b5::/64 subnet reach a host on the 2001:db8:0:1a4c::/64 subnet? If so, how?

No. For a static router running the IPv6 protocol for Windows Server 2008 or Windows Vista to advertise itself as a default router, it must have a default route that is configured to be published. For example, the command

netsh interface ipv6 add route ::/0 “Local Area Connection 2” FE80::2AA:FF:FE19:9B84 publish=yes

would add a publishable default route.