Chapter 15

channel

A specific radio frequency within a broader frequency.

port forwarding

A technique that allows a computer on the Internet to reach a computer on a private network using a certain port when the private net- work is protected by a firewall device using NAT. Also called tunneling.

physical address

AKA MAC (Media Access Control)

adapter address

AKA MAC (Media Access Control) address.

best-effort protocol

AKA connectionless protocol.

global address

AKA global unicast address.

computer name

AKA host name

link-local address

AKA link-local unicast address.

local link

AKA link.

network adapter

AKA network interface card (NIC).

port address

AKA port

dynamic IP address

An IP address assigned by a DHCP server for the current session only, and is leased when the computer first connects to a network. When the session is terminated, the IP address is returned to the list of available addresses. Compare to static IP address.

loopback address

An IP address that indicates your own computer and is used to test TCP/IP configuration on the computer.

AES (Advanced Encryption Standard)

An encryption standard used by WPA2 and is currently the strongest encryption standard used by Wi-Fi.

gateway

Any device or computer that network traffic can use to leave one network and go to a different network.

intranet

Any private network that uses TCP/IP protocols. A large enterprise might support an intranet that is made up of several local networks.

classful subnet mask

In TCP/IP Version 4, the default subnet mask that is used if a network is not divided into subnets. It is called a classful subnet mask because the network portion of the IP address aligns with the class license. For example, 11111111.11111111.11111111.00000000 or 255.255.255.0 is the classful subnet mask for a Class C license.

classless subnet mask

In TCP/IP Version 4, the subnet mask takes some bits of the host portion of the IP address for the network ID and does not align the network portion of the IP address with the network octets assigned by the class license. The subnet mask can have a mix of zeroes and ones in one octet or can contain all ones in an octet that was not leased by the class license, for example, 11111111.111111 11.11110000.00000000 or 255.255.240.0.

interface

In TCP/IP Version 6, a node's attachment to a link. The attachment can be a physical attach- ment (for example, when using a network adapter) or a logical attachment (for example, when using a tunneling protocol). Each interface is assigned an IP address.

ISATAP

In TCP/IP Version 6, a tunneling protocol that has been developed for IPv6 packets to travel over an IPv4 network and stands for Intra-Site Automatic Tunnel Addressing Protocol.

global unicast address

In TCP/IP Version 6, an IP address that can be routed on the Internet. Also called global address.

link-local unicast address

In TCP/IP Version 6, an IP address used for communicating among nodes in the same link and is allowed on the Internet. Also called local address and link-local address.

interface ID

In TCP/IP Version 6, the last 64 bits or 4 blocks of an IP address that identify the interface.

subnet ID

In TCP/IP Version 6, the last block (16 bits) in the 64-bit prefix of an IP address. The subnet is identified using some or all of these 16 bits.

public IP address

In TCP/IP version 4, an IP address available to the Internet.

private IP addresses

In TCP/IP version 4, an IP address that is used on a private network that is isolated from the Internet.

octet

In TCP/IP version 4, each of the four numbers that are separated by periods and make up a 32-bit IP address. One octet is 8 bits.

link

In TCP/IP version 6, a local area network or wide area network bounded by routers. Also called local link.

multicast address

In TCP/IP version 6, an IP address used when packets are delivered to all nodes on a network.

6TO4

In TCP/IP version 6, an older tunneling protocol being replaced by the more powerful Teredo or ISATAP protocols. Tunnels are used by IPv6 to transport IPv6 packets over an IPv4 network.

multicasting

In TCP/IP version 6, one host sends messages to multiple hosts, such as when the host transmits a video conference over the Internet.

neighbors

In TCP/IP version 6, two or more nodes on the same link.

connection-oriented protocol

In networking, a TCP/ IP protocol that confirms a good connection has been made before transmitting data to the other end, verifies data was received, and resends it if it is not. An example of a connection-oriented protocol is TCP.

hardware address

See MAC (Media Access Control) address.

DMZ

Stands for "demilitarized zone" and refers to removing firewall protection from a computer or network within an organization of protected computers and networks.

HTTPS (HTTP secure)

The HTTP protocol working with a security protocol such as Secure Sockets Layer (SSL) or Transport Layer Security (TLS), which is better than SSL, to create a secured socket that includes data encryption.

HTTP (Hypertext Transfer Protocol)

The TCP/IP protocol used for the World Wide Web and used by web browsers and web servers to communicate.

802.11 a/b/g/n

The collective name for the IEEE 802.11 standards for local wireless networking, which is the technical name for Wi-Fi.

radio frequency (RF)

The frequency of waves gener- ated by a radio signal, which are electromagnetic frequencies above audio and below light. For example, Wi-Fi 802.11n transmits using a radio frequency of 5 GHz and 2.4 GHz.

default gateway

The gateway a computer on a network will use to access another network unless it knows to specifically use another gateway for quicker access to that network.

Service Set Identifier (SSID)

The name of a wireless network.

name resolution

The process of associating a character-based name with an IP address.

TCP (Transmission Control Protocol)

The protocol in the TCP/IP suite of protocols that works at the OSI Transport layer and establishes a session or connection between parties and guarantees packet delivery.

POP3 (Post Office Protocol, version 3)

The protocol that an email server and client use when the client requests the downloading of email messages. The most recent version is POP version 3. Compare to IMAP3.

Remote Desktop Protocol (RDP)

The protocol used by Windows Remote Desktop and Remote Assistance utilities to connect to and control a remote computer.

port filtering

To open or close certain ports so they can or cannot be used. A firewall uses port filtering to protect a network from unwanted communication.

client/server

Two computers communicating using a local network or the Internet. One computer takes on the role of making requests from the other computer. A computer making a request from another is called the client and the one answering the request is called the server.

anycast address

Using TCP/IP version 6, a type of IP address used by routers and identifies multiple destinations. Packets are delivered to the closest destination.

DNS client

When Windows queries the DNS server for a name resolution, which means to find an IP address for a computer when the fully qualified domain name is known.

port triggering

When a firewall opens a port because a computer behind the firewall initiates communi- cation on another port.

alternate IP address

When configuring TCP/IP in Windows, the static IP address that Windows uses if it cannot lease an IP address from a DHCP server.

port

(1) As applied to services running on a computer, a number assigned to a process on a computer so that the process can be found by TCP/IP. Also called a port address or port number. (2) A physical connector, usually at the back of a computer, that allows a cable from a peripheral device, such as a printer, mouse, or modem, to be attached.

DNS server

A Doman Name Service server that uses a DNS protocol to find an IP address for a computer when the fully qualified domain name is known. An Internet Service Provider is responsible for pro- viding access to one or more DNS servers as part of the service it provides for Internet access.

FTP (File Transfer Protocol)

A TCP/IP protocol and application that uses the Internet to transfer files between two computers.

connectionless protocol

A TCP/IP protocol such as UDP that works at the OSI Transport layer and does not guarantee delivery by first connecting and checking where data is received. It might be used for broadcasting, such as streaming video or sound over the web, where guaranteed delivery is not as important as fast transmission. Also called a best-effort protocol. Also see UDP (User Datagram Protocol).

NAT (Network Address Translation)

A TCP/IP protocol that substitutes the public IP address of the router for the private IP address of the other computer when these computers need to communicate on the Internet.

SMTP (Simple Mail Transfer Protocol)

A TCP/IP protocol used by email clients to send email mes- sages to an email server and on to the recipient's email server. Also see POP and IMAP.

Simple Network Management Protocol (SNMP)

A TCP/IP protocol used to monitor network traffic.

Secure FTP (SFTP)

A TCP/IP protocol used to trans- fer files from an FTP server to an FTP client using encryption.

DHCP client

A computer of other device (such as a network printer) that requests an IP address from a DHCP server.

router

A device that manages traffic between two or more networks and can help find the best path for traffic to get from one network to another.

DNS (Domain Name System or Domain Name Service)

A distributed pool of information (called the name space) that keeps track of assigned host names and domain names and their corresponding IP addresses. DNS also refers to the system that allows a host to locate information in the pool and the protocol the system uses.

multiple input/multiple output (MIMO)

A feature of the IEEE 802.11n standard for wireless networking whereby two or more antennas are used at both ends of transmissions to improve performance.

Quality of Service (QoS)

A feature used by Windows and network hardware devices to improve network performance for an application that is not getting the best network performance. VoIP requires a high QoS.

Hosts file

A file in the C:\Windows\System32\drivers\ etc folder that contains computer names and their associated IP addresses on the local network. The file has no file extension.

Internet Protocol version 4 (IPv4)

A group of TCP/ IP standards that uses IP addresses that have 32-bits.

Internet Protocol version 6 (IPv6)

A group of TCP/IP standards that uses IP addresses that have 128 bits.

subnet

A group of local networks when several net- works are tied together in a subsystem of the larger intranet. In TCP/IP Version 6, one or more links that have the same 64 bits in the first part of the IP address (called the prefix).

Class A

A license for a range of IPv4 IP addresses that defines a single octet, which is the network portion of the IP addresses in that license. The last three octets can be used for the host address or for subnetting the network.

Class C

A license for a range of IPv4 IP addresses that defines the first three octets, which is used for the network portion of the IP address.

Class B

A license for a range of IPv4 IP addresses that defines the first two octets, which is used for the network portion of the IP address. The last two octets can be used for the host address or for subnetting the network.

host name

A name that identifies a computer, printer, or other device on a network, which can be used instead of the computer's IP address to address the computer on the network. The host name together with the domain name is called the fully qualified domain name. Also called computer name.

domain name

A name that identifies a network and appears before the period in a website address such as google.com. A fully qualified domain name is sometimes loosely called a domain name. Also see fully qualified domain name.

local area network (LAN)

A network bound by routers or other gateway devices.

static IP address

A permanent IP address that is manually assigned to a computer.

Secure Shell (SSH)

A protocol that is used to pass login information to a remote computer and control that computer over a network using encryption.

Server Message Block (SMB)

A protocol used by Windows to share files and printers on a network.

DHCP (dynamic host configuration protocol)

A protocol used by a server to assign a dynamic IP address to a computer when it first attempts to initiate a connection to the network and requests an IP address.

IMAP4 (Internet Message Access Protocol, version 4)

A protocol used by an email server and client that allows the client to manage email stored on the server without downloading the email. Compare to POP3.

Lightweight Directory Access Protocol (LDAP)

A protocol used by various client applications when the application needs to query a database.

packet

A segment of data sent over a network as a unit that contains the data and information at the beginning of the segment that identifies the type of data, where it came from, and where it's going. Also called data packet or datagram.

protocols

A set of rules and standards that two entities use for communication. For example, TCP/IP is a suite or group of protocols that define many types of communication on a TCP/IP network.

SIM (Subscriber Identification Module) card

A small flash memory card that contains all the information a device needs to connect to a cellular network, includ- ing a password and other authentication information needed to access the network, encryption standards used, and the services that a subscription includes.

IP address

A 32-bit or 128-bit address used to uniquely identify a device or interface on a network that uses TCP/IP protocols. The first numbers identify the network; the last numbers identify a host. An example of a 32-bit IP address is 206.96.103.114. An example of a 128-bit IP address is 2001:0000:B80::D3:9C5A:CC.

MAC (Media Access Control) address

A 48-bit (6-byte) hardware address unique to each NIC or onboard network controller that is assigned by the manufacturer at the factory and embedded on the device. The address is often printed on the adapter as hexadecimal numbers. An example is 00 00 0C 08 2F 35. Also called a physical address, an adapter address, or a hardware address.

fully qualified domain name (FQDN)

Identifies a computer and the network to which it belongs and includes the computer name and domain name. For example, jsmith.amazon.com. Sometimes loosely referred to as a domain name.

Automatic Private IP Address (APIPA)

In TCP/ IP Version 4, IP address in the address range 169.254.x.y, used by a computer when it cannot successfully lease an IP address from a DHCP server.

subnet mask

In TCP/IP Version 4, 32 bits that include a series of ones followed by zeroes. For example, 11111111.11111111.11110000.00000000, which can be written as 255.255.240.0. The ones identify the network portion of an IP address, and the zeroes identify the host portion of an IP address. The subnet mask tells Windows if a remote computer is on the same or different net- work. Also see classless subnet mask and classful subnet mask.