I

IEEE 1394

A standard of very fast data transfer that was developed specifically for use with digital cameras and other graphics peripherals. Also referred to as "FireWire."

IMAPv4

A method of storing and retrieving messages that allows a user to search through messages on a server and download only the items that he chooses.

incremental backup

A backup that uses a special bit called an archive bit to identify and copy all of the files that have changed since the last backup of any kind. The incremental backup clears the archive bit after it copies the files.

infrared (IR)

Communication or control using light that people cannot see because it is below the frequency of red light. Requires line-of-sight to work correctly.

input/output (I/O) device

Any device that can send and receive data to and from a computer.

Integrated Services Digital Network (ISDN)

An international standard for sending voice, data, and video over digital telephone lines. There are two types of ISDN: Basic Rate Interface (BRI) and Primary Rate Interface (PRI).

Internet Connection Firewall (ICF)

Firewall software that is built into the Windows XP operating system to block unwanted traffic that was not filtered by the corporate firewall. There is also an ICF on Windows Server 2003, although it is rarely used.

Internet Connection Sharing (ICS)

A service that allows you to connect one computer (the host computer) to a network (such as the Internet) and then connect other computers to that computer to provide access to the remote network as well.

Internet Control Message Protocol (ICMP)

A protocol that works at the Network layer of the OSI model and the Internet layer of the TCP/IP protocol suite to provide error checking and reporting functionality.

Internet Group Multicast Protocol (IGMP)

A protocol that works at the Network layer of the OSI model and is the standard for IP multicasting memberships and groups on TCP/IP networks.

Internet service provider (ISP)

An organization that provides connections to the Internet for its clients.

Internetwork Packet Exchange (IPX)

The protocol in the IPX/SPX suite that is responsible for logical network addressing, route selections, and connection services.

Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)

A proprietary suite of protocols developed by Novell for use with its NetWare server and Novell clients. (Today many Novell servers and clients use TCP/IP.)

intranet

A server or network of servers that are designed specifically for users of one organization to gain access through their browsers and other web-based software.

IP

The connectionless protocol in the TCP/IP protocol suite that is responsible for logical address assignment and for transporting data from one node of a network to another node. IP works at the Network layer (layer 3) of the OSI model.

IP address

A unique address assigned to each computer and interface within a network to allow the routing and delivery of messages throughout the network using the TCP/IP protocol.

ifconfig

A command-line tool that displays and configures network configuration values on Unix and Linux systems.

ipconfig

A command-line tool that can be used to determine the IP address, subnet mask, and default gateway of a computer's connection. You can also add switches to this command for other functions.

IPSec

A protocol designed to encrypt and secure data during communication between two computers. IPSec enables computers to negotiate to the most secure communication standards that each computer can support.

IPv6

The newest IP addressing scheme that uses a 128-bit hexadecimal address and makes available many more addresses than IPv4.