Chapter 12: IPv6 Flashcards
Define: IPv6 Address
A 128-bit address consisting of eight sets of four hexadecimal numbers, each number being a value between 0000 and ffff, using a colon to separate the numbers.
What two IPv6 addresses may not be used?
An all 0s and an all ffffs address.
What two parts are IPv6 addresses generally split into?
A 64-bit network prefix used for routing and a 64-bit interface ID, the user portion.
The network prefix of an IPv6 address gets split into what two parts?
A routing prefix and a subnet ID.
What are the IPv6 shorthand notation rules?
Leading zeroes can be dropped and only one group of contiguous zeroes can be represented by a double colon (::).
What does the IPv6 “/x” prefix length naming convention specify?
The number of bits in the network ID.
What is the IPv6 loopback address?
::1
Does a host have one or more IPv6 addresses?
It has more than one.
What is a link-local address and what is it used for?
The address that a computer running IPv6 gives itself after first booting. It is used for communicating on a local network.
What is the IPv6 link-local address?
The first 64 bits are always fe80::/64 (fe80:0000:0000:0000)
What are the two ways the 64-bit interface ID is generated in IPv6?
Most OSs generate a 64-bit random number. Older OSs and some devices may use the device’s MAC address to create a 64-bit number called an Extended Unique Identifier, 64-bit (EUI-64).
What is a unicast address in IPv6?
A unique address exclusive to that system in a LAN and is the link-local address.
What address type does a client need to access IPv6 content on the Internet?
A global unicast address
Does IPv6 use broadcast addresses or multicast addresses?
Multicast addresses
What is the all-nodes IPv6 multicast address?
ff02::1
The 2 (scope) indicates the local network segment.
The 1 (group) indicates all nodes within the scope.
What is the all-routers IPv6 multicast address?
ff02::2
The first 2 (scope) indicates the local network segment.
The second 2 (group) indicates all routers within the scope.
What is the solicited-node IPv6 multicast address?
ff02::1:ffxx:xxxx (The last six digits equal the last six digits of the corresponding unicast address).
What is the Ethernet address (MAC address) for IPv6 multicast traffic?
33-33-xx-xx-xx-xx
Define: IPv6 Anycast Address
A single IP address shared by multiple hosts.
Routers are configured to direct traffic destined for that single address to the closest system based on what routing metrics were chosen.
The ____ is an IPv6 protocol that performs the same functions as ARP in IPv4 and plays a role in features such as stateless address autoconfiguration (SLAAC).
NDP or Neighbor Discovery Protocol
What are NDP’s (Neighbor Discovery Protocol’s) five control message types?
Neighbor solicitation
Neighbor advertisement
Router solicitation
Router advertisement
Redirect
Hosts use ____ messages to request the MAC address of a target system, to inform the target system of their own MAC address, and to verify a system is still reachable. They also help IPv6 hosts detect duplicate addresses on the local network.
neighbor solicitation
What IPv6 multicast address does a host send a neighbor solicitation message to for finding out a MAC address?
The solicited-node multicast address
What is the neighbor discovery cache in IPv6?
A host’s list of known MAC addresses.
What are neighbor advertisement messages used for in IPv6?
To respond to neighbor solicitation messages with the host’s MAC address and to let the requesting system know that it is reachable.
These packets are sent via unicast addresses.
What are router solicitation messages used for in IPv6?
Nodes on the network send them to find any routers on the network.
These packets are always sent to the all-router multicast address.
Routers use ____ messages in an IPv6 network to send out important information such as their MAC and link-local addresses (default gateway), how hosts on the network should get a global unicast address, whether to use DHCP, and DNS server addresses.
router advertisement
What are redirect messages used for in IPv6?
They enable a router to tell a host that there is a better router to use for traffic to a given destination when multiple routers are available for a host to use.
What is stateless address autoconfiguration (SLAAC)?
A process that enables network clients to determine their own IPv6 addresses without the need for DHCP. SLAAC leans heavily on the neighbor discovery process supported by NDP.
What does a DHCPv6 server in stateful mode do?
It tells the host the full 128-bit address it should use and keeps track of the addresses it has passed out. It also gives out other information.
What does a DHCPv6 server in stateless mode do?
It lets hosts pick out their own IPv6 addresses using SLAAC (stateless address autoconfiguration) and gives out other information.
What is the main benefit of IPv6 aggregation?
Aggregation reduces the size and complexity of routing tables, allowing routers to work more efficiently.
As you get to the top of the Internet, the Tier 1 routers that connect to other Tier 1 routers can’t have any default route. These no-default routers make up the ____.
default-free zone (DFZ)
What is aggregation in IPv6?
Where every router underneath one router always uses a subset of that router’s existing routes.
What does the 4to6 IPv4-to-IPv6 tunneling standard do?
It encapsulates IPv4 traffic into an IPv6 tunnel to get it across the IPv6 gap to an IPv6-enabled router.
What is the 6in4 IPv6 tunneling protocol?
It is one of only two IPv6 tunneling protocols that can go through IPv4 NAT (called NAT traversal).
What service do tunnel brokers provide?
They create a tunnel and offer a custom-made endpoint client for users on IPv4 infrastructure to jump the gap between their computers and the IPv6 Internet routers.
What do Tunnel Setup Protocol (TSP) and Tunnel Information and Control (TIC) protocol do?
They set up IPv6 tunnels and handle configuration as well as login.
An ____ enables two IPv6 networks to connect over an IPv4 network by encapsulating the IPv6 packets within IPv4 headers, transporting them across the IPv4 network, then decapsulating the IPv6 data.
overlay tunnel
What is NAT64?
A transition mechanism that attaches the bytes of an IPv4 address onto the end of an IPv6 address for network traversal.
Is NAT needed with IPv6?
No, the address space is so large that rationing routable addresses is unnecessary.
Downstream routers may, in theory, do what if their upstream router suddenly changes the IPv6 prefix it delegates to them?
Send an all-nodes router advertisement so that clients can renumber.
