CTI-120-01BL Network & Sec Foundations Chapter 6

Chapter 6

6to4

An IPv4-to-IPv6 transition protocol that provides automatic tunneling of IPv6 traffic over an IPv4 network. It can handle host-to-router or router-to-host tunneling but is most often used to create a router-to-router tunnel.

address registry

A regional organization that administers IP addresses.

all DHCP servers multicast group

An IPv6 multicast address with the value ff02::1:2. Packets with this destination address are processed by all DHCPv6 servers on the subnet.

all nodes multicast group

An IPv6 multicast address with the value ff02::1. Packets with this address in the IPv6 destination address field are processed by all IPv6 nodes on the subnet. This multicast address replaces the broadcast address found in IPv4

anycast addresses

An address type used in IPv6 to allow a one-to-many relationship between source and destination; the packet is delivered to only one of the possible destination computers.

automatic private IP addressing (APIPA)

A process that uses a private range of IP addresses assigned to an APIPA-enabled computer automatically when an IP address is requested via DHCP, but no DHCP server responds to the request.

CIDR notation

A method of expressing an IP address in the format A.B.C.D/n; n is the number of 1 bits in the subnet mask or the number of bits in the network ID.

classful addressing

The use of IP addresses with their default subnet masks according to their address class: A, B, or C.

classless interdomain routing (CIDR)

A method of IP addressing in which the network and host IDs are determined by a prefix number that specifies how many bits of the IP address are network bits; the remaining bits are host bits.

content delivery networks (CDNs)

A group of servers that are geographically dispersed that cache Internet content for quick delivery to users.

dotted decimal notation

The format for expressing an IPv4 address; it’s four decimal numbers separated by periods.

dual IP layer architecture

The current architecture of the IPv6 protocol in Windows, in which both IPv4 and IPv6 share the other components of the stack.

duplicate address detection (DAD)

An IPv6 function that uses NDP to determine if an address is already in use by another node.

extended unique identifier (EUI)-64 interface ID

An autoconfigured IPv6 host address that uses the MAC address of the host plus an additional 16 bits.

global IPv6 unicast adresses

IPv6 addresses that are accessible on the public Internet and can be routed.

host address space

The number of addresses available in an IP network number that can be assigned to hosts.

intra-site automatic tunnel addressing protocol (ISATAP)

An automatic tunneling protocol used to transmit IPv6 packets between dual IP layer hosts across an IPv4 network.

IP prefix

A value used to express how many bits of an IP address are network ID bits. The value is usually preceded by a forward slash (/), as in 192.168.1.24/27; in this example, 27 is the IP prefix.

IPv4 address

A 32-bit dotted decimal address containing a network ID, which specifies the network the computer is on, and a host ID, which uniquely identifies the computer on that network.

link-local address

An IP address that can be used to communicate only on the local subnet. It can’t be routed to other networks.

link-local IPv6 address

Similar in function to the IPv4 APIPA addresses, link-local IPv6 addresses begin with fe80, are self-configuring, and can’t be routed.

local host

A reserved name that corresponds to the loopback address in an IP network.

logical AND operation

A binary operation in which there are two operands; the result is 0 if either operand is 0 and 1 if both operands are 1.

loopback address

An address that always refers to the local computer; in IPv4, it’s 127.0.0.1, and in IPv6 it’s ::1. This address is used to test TCP/IP functionality on the local computer.

metric

A numeric value that tells the router how “far away” the destination network is. It can be composed of values such as the bandwidth of links between the source and destination, the hop count, and the link’s reliability.

multicast address

An address that identifies a group of computers running a multicast application.

multicasting

A network communication in which a packet is addressed so that more than one destination can receive it.

multihomed server

A server with two or more NICs, each attached to a different IP network. Each NIC is assigned a network connection and requires its own IP address.

neighbor discovery protocol (NDP)

An IPv6 protocol based on ICMPv6 that is used to discover the MAC address of IPv6 devices on the local subnet.

network address translation (NAT)

A service that translates a private IP address to a public IP address in packets destined for the Internet, and then translates the public IP address in the reply to the private address. Used to allow using private IP addresses while connected to the Internet.

octect

An 8-bit value; a number from 0 to 255 that’s one of the four numbers in a dotted decimal IP address.

port address translation (PAT)

An extension of NAT, and a service that allows several hundred workstations to access the Internet with a single public Internet address by using Transport-layer port numbers to differentiate each host conversation.

router advertisement

An IPv6 multicast message sent to all nodes on the subnet letting the nodes know about IPv6 address information. Can be sent in response to a router solicitation or periodically by the router.

router solicitation

An IPv6 multicast message sent by an IPv6 node to all routers on the subnet so the node can get information about IPv6 address configuration from the router. Routers respond with a router advertisement.

solicited-node IPv6 multicast

An IPv6 multicast address with the format ff02::1:ffxx:xxxx. The xx:xxxx is the last 24 bits of the target node’s IPv6 address. The packet is delivered to all nodes on the subnet, but only the node that has an IPv6 address that matches the last 24-bits of the multicast will process the request and respond by replying with its MAC address.

stateful autoconfiguraton

An IPv6 address autoconfiguration mode in which a node contacts a DHCPv6 server to get its IPv6 address configuration information, It is called stateful because the DHCPv6 server keeps track of the addresses assigned to nodes.

stateless autoconfiguration

An IPv6 address autoconfiguration mode in which a node listens for router advertisement messages from a local router to discern its IPv6 address configuration information. It is called stateless because there is no device keeping track of node address configuration.

subnet

A subdivision of an IP network address space.

submask

A 32-bit dotted decimal number, consisting of a contiguous series of binary 1 digits followed by a contiguous series of binary 0 digits, that determines which part of an IP address is the network ID and which part is the host ID.

subnetting

A process that reallocates bits from an IP address’s host portion to the network portion, creating multiple smaller address spaces.

supernetting

A process that reallocates bits from an IP address’s network portion to the host portion, effectively combining smaller subnets into a larger supernet.

teredo

An automatic IPv6-over-IPv4 tunneling protocol that solves the problem of 6to4’s requirement of a public IPv4 address and the inability to traverse NAT routers.

tunneling

A network protocol technique that allows transmitting a packet in a format that would otherwise be incompatible for the network architecture by encapsulating the packet in a compatible header format.

unicast address

An address in a unit of network data intended for a single destination device.

unique local IPv6 address

An address for devices on a private network that can’t be routed on the Internet.