Failback

The process of moving resources, either individually or in a group, back to their original node after a failed node rejoins a cluster and comes back online.

Failover

The process of taking resource groups offline on one node, such as a failed node, and bringing them back online on another node.

Failover Pairs Configuration

A common N+I variation. Failover pairs are often used in clusters with four or more nodes, and they are ideal for ensuring performance consistency after failover. Failover policies can be defined so that each application can fail over between two nodes.

Failure Audit Event

An Event Viewer event that indicates the occurrence of an event that has been audited for failure, such as a failed logon when someone presents an invalid username and/or password. See also Event Viewer.

Failure Domain

The region in which a failure has occurred in a Token Ring. When a station gains information that a serious problem, such as a cable break, has occurred with the network, it sends a beacon frame that includes the station reporting the failure, its NAUN, and everything between. This defines the failure domain. Beaconing then initiates the procedure known as autoreconfiguration. See also Autoreconfiguration and Beacon.

Fallback

In ATM networks, this mechanism is used for scouting a path if it isn’t possible to locate one using customary methods. The device relaxes requirements for certain characteristics, such as delay, in an attempt to find a path that meets a certain set of the most important requirements.

False Negative

A false negative occurs when anti-virus software fails to indicate an infected file is truly infected. False negatives are more serious than false positives, although both are undesirable. False negatives are more common with anti-virus software because they may miss a new or a heavily modified virus. See also False Positive.

False Positive

A false positive error occurs when anti-virus software wrongly claims a virus infects a clean file. False positives usually occur when the string chosen for a given virus signature is also present in another program. See also False Negative.

Fast bcp

A form of importing data with the bcp utility that takes place where there are no indexes on the table being imported to, and when the Select Into/Bulk Copy database option is set.

Fast Ethernet

Any Ethernet specification with a speed of 100Mbps. Fast Ethernet is ten times faster than 10BaseT, while retaining qualities like MAC mechanisms, MTU, and frame format. These similarities make it possible for existing 10BaseT applications and management tools to be used on Fast Ethernet networks. Fast Ethernet is based on an extension of IEEE 802.3 specification (IEEE 802.3u). See also 100BaseT, 100BaseTX, and Institute of Electrical and Electronics Engineers.

Fast Ethernet Interface Processor (FEIP)

An interface processor employed on Cisco 7000 series routers, supporting up to two 100Mbps 100BaseT ports.

FASTHELP

Provides summary Help information for MS-DOS commands.

Fast Infector

Fast infector viruses, when active in memory, infect not only executed programs, but also those that are merely opened. Thus running an application, such as anti-virus software, which opens many programs but does not execute them, can result in all programs becoming infected. See also Slow Infector.

FASTOPEN

Decreases the amount of time needed to open frequently used files and directories.

Fast Serial Interface Processor (FSIP)

The Cisco 7000 routers’ default serial interface processor, it provides four or eight high-speed serial ports.

Fast Switching

A Cisco feature that uses a route cache to speed packet switching through a router.

FAT

See File Allocation Table.

FAT16

The 16-bit version of the File Allocation Table (FAT) system, which was widely used by DOS and Windows 3.x. The file system is used to track where files are stored on a disk. Most operating systems support FAT16. See also File Allocation Table.

FAT32

The 32-bit version of the File Allocation Table (FAT) system, which is more efficient and provides more safeguards that FAT16. Windows 9.x and Windows 2000 support FAT32. Windows NT does not support FAT32. See also File Allocation Table.

Fault Tolerance

Any method that prevents system failure by tolerating single faults, usually through hardware redundancy.

Fax Modems

Special modems that include hardware to allow the transmission and reception of facsimiles. See also Modem and Exchange.

Fax Service

Services providing a shared fax to many computers.

FC

Compares two files or sets of files, and displays the differences between them.

FDDI

See Fiber Distributed Data Interface.

FDISK

Configures a hard disk for use with MS-DOS.

FDISK /MBR

If you have MS-DOS version 5.0 or later, the command FDISK /MBR can remove viruses which infect the master boot sector but do not encrypt it. Using this command can produce unexpected results and cause unrecoverable damage.

FDM

See Frequency-Division Multiplexing.

FECN

See Forward Explicit Congestion Notification.

FEIP

See Fast Ethernet Interface Processor.

Fiber Distributed Data Interface (FDDI)

A Data Link layer that implements two counter-rotating token rings at 100 megabits per second. FDDI was a popular standard for interconnecting campus and metropolitan networks because it allows distant digital connections at high speed, but ATM is replacing FDDI in many sites. See also Asynchronous Transfer Mode and Data Link Layer.

Fiber-Optic Cable

A type of cable that uses light to transmit data.

File

A set of data stored on a mass storage device identified by a directory entry containing a name, file attributes, and the physical location of the file in the volume. See also Volume, Mass Storage Device, Directories, and File Attributes.

File Allocation Table (FAT)

The file system used by MS-DOS and available to other operating systems such as Windows (all variations), OS/2, and the Macintosh. FAT has become something of a mass storage capability standard because of its simplicity and wide availability. FAT has few fault tolerance features and can become corrupted through normal use over time. See also
File System, FAT16, and FAT32.

File Archiving

The movement of files to a near or off-line storage.

File Attributes

Bits are stored along with the name and location of a file in a directory entry to show the status of the file, such as archived, hidden, read-only, etc. Different operating systems use different file attributes to implement such services as sharing, compression, and security.

File Compression

A technique that shrinks program or data files so that they occupy less disk space. The file must then be extracted or decompressed before use. Some types of files, such as word processor documents, can be compressed by 50 percent or more. Recompressing an already compressed file usually makes the file slightly larger because of the compression overhead. File compression can be automatic and performed by the operating system, or it can be manual and performed by a file-compression program. See also File-Compression Program.

File-Compression Program

An application that compresses files so that they take up less space on the disk. Some file-compression programs are individual, stand-alone applications; others are built into the operating system.

File Extension

The three-letter suffix that follows the name of a standard file-system file. Using Group Policy and software management functionality, system administration can specify which applications are associated with which file extensions.

File List

A list of filenames contained in the active directory.

File-Level Security

Security applied to files and directories on NTFS partitions.

Filename

The name given to a file. It must not exceed 8 characters in length (except when using Windows ’95 long file names) and can have an extension of up to 3 characters.

File Replication Service (FRS)

The service used by the Distributed file system (Dfs) to automatically replicate Dfs shared folders. When changes are made to one shared folder, FRS updates the other shared folders to reflect the changes. See also Distributed File System and Dfs Shared Folder.

File Service

Services allowing for the storage and access of files.

Filespec

File specification made up of drive, path, filename and a three letter extension.

File System

A software component that manages the storage of files on a mass storage device by providing services that can create, read, write, and delete files. File systems impose an ordered database of files on the mass storage device, called volumes, that use hierarchies of directories to organize files. See also Mass Storage Device, File, Database, Volume, and Directories.

File Transfer

The moving of a file from one location to another.

File Transfer Protocol (FTP)

A simple Internet protocol that transfers complete files from an FTP server to a client running the FTP client. FTP provides a simple no-overhead method of transferring files between computers but cannot perform browsing functions. You must know the URL of the FTP server to which you want to attach. See also Internet and Uniform Resource Locator.

File-Update Synchronization

The updating of many copies of a file at once.

File Viruses

File viruses usually replace or attach themselves to COM and EXE files. They can also infect files with the extensions SYS, DRV, BIN, OVL and OVY. File viruses may be resident or non-resident, the most common being resident or TSR (terminate-and-stay-resident) viruses. Many non-resident viruses simply infect one or more files whenever an infected file runs. Also known as Parasitic Virus, File Infector and File Infecting Virus.

Filter Action

Associated with the use of filters. When you specify a filter action within a filter it dictates which action should be taken when a security filter match occurs.

Filtering

The process by which permissions on security groups are used to identify which Active Directory objects are affected by Group Policy settings. Through the use of filtering, systems administrators can maintain a fine level of control over Group Policy settings.

Filter List

Groups of individual filters that allow you to easily build rules that enforce complicated behavior, then distribute those rules throughout your network as necessary.

FIND

Searches for a text string in a file or files.

Firewall

A barrier purposefully erected between any connected public networks and a private network, made up of a router or access server or several routers or access servers, that uses access lists and other methods to ensure the security of the private network.

Firewall Chaining

The ability to arrange ISA Servers in a linked chain such that down-level servers can forward requests for external access to up-level servers that are closer or better connected to the Internet.

Firewall Client

Requires that the Firewall Client software be installed on the client computer. Allows for user-based access restrictions to be enforced.

Firmware

Software stored permanently in nonvolatile memory and built into a computer to provide its BIOS and a bootstrap routine. The entire operating system of simple computers may be built into firmware. See also Basic Input/Output System, Boot, and Software.

Fixed Disk

The hard disk of a computer.

Flame

A deliberately insulting e-mail message or post to a Usenet newsgroup, often containing a personal attack on the writer of an earlier post. See also Flame Bait and Flame War.

Flame Bait

An insulting or outrageous e-mail post to a Usenet newsgroup specifically designed to provoke other users into flaming the originator. See also Flame and Flame War.

Flame War

In a Usenet newsgroup, a prolonged series of flames, which may have begun as a creative exchange of views but which quickly descended into personal attacks and crude name-calling. See also Flame Bait.

Flash

Used to hold the Cisco IOS in a router by default. See Electronically Erasable Programmable Read-Only Memory.

Flash Memory

Developed by Intel and licensed to other semiconductor manufacturers, it is nonvolatile storage that can be erased electronically and reprogrammed, physically located on an EEPROM chip. Flash memory permits software images to be stored, booted, and rewritten as needed. Cisco routers and switches use flash memory to hold the IOS by default. See also Erasable Programmable Read-Only Memory and Electronically Erasable Programmable Read-Only Memory.

Flat-File Database

A database whose information is stored in files and is accessed sequentially. Examples of flat-file database programs include dBASE, Access, FoxPro, and other personal computer databases.

Flat Network

Network that is one large collision domain and one large broadcast domain.

Flexible Single Master Operation (FSMO)

A server that has the AD responsibilities that are handled in a single-master manner. Although this term is no longer used, it still appears in much of Microsoft’s documentation.

Flooding

When traffic is received on an interface, it is then transmitted to every interface connected to that device with exception of the interface from which the traffic originated. This technique can be used for traffic transfer by bridges and switches throughout the network.

Floppy Disk

The first convenient removable media mass storage device. Floppy disks typically store 1.4 MB of data magnetically on a thin mylar film coated with ferric particles encased in a protective plastic shell. Because floppy disks have been around longer than hard disk drives, most computers are capable of booting operating systems from a floppy disk. See also Mass Storage Device.

Flow Control

A methodology used to ensure that receiving units are not overwhelmed with data from sending devices. Pacing, as it is called in IBM networks, means that when buffers at a receiving unit are full, a message is transmitted to the sending unit to temporarily halt transmissions until all the data in the receiving buffer has been processed and the buffer is again ready for action.

Folder-Based Application

An application built within a public folder by customizing properties of the folder, such as permissions, views, rules, and the folder forms library to store and present data to users.

Folder Redirection

A Group Policy setting that automatically redirects special folders (such as My Documents) to an alternate location.

FOR

Runs a specified command for each file in a set of files.

Foreign Security Principals

Active Directory objects used to give permissions to other security principals that do not exist within an Active Directory domain. Generally, foreign security principals are automatically created by the services of the Active Directory.

Foreign System

A non-Exchange message system.

Forest

A collection of domains and domain trees. The implicit name of the forest is the name of the first domain installed. All domain controllers within a forest share the same configuration and schema naming contexts. To join an existing forest, the Dcpromo utility is used. The first domain within the forest cannot be removed.

Format

The process of preparing a mass storage device for use with a file system. There are actually two levels of formatting. Low-level formatting writes a structure of sectors and tracks to the disk with bits used by the mass storage controller hardware. The controller hardware requires this format, and it is independent of the file system. High-level formatting creates file system structures such as an allocation table and a root directory in a partition, thus creating a volume. See also Mass Storage Device and Volume.

FORMAT

Formats a disk for use with MS-DOS.

Formatting

The process of preparing a disk so that it can store information. During formatting, sectors, tracks, a directory, and the FAT are created on the disk.

Forward Caching

Used to provide internal clients access to web objects on the Internet. Retrieved web content is stored locally on the ISA Server’s hard drive. Additional requests for the same object are then fulfilled from the cached content without the need to return to the Internet.

Forwarder

Supplies directions for a service as to where it should pass on information requests when the service itself does not know the answer or have the information.

Forward Explicit Congestion Notification (FECN)

A bit set by a Frame Relay network that informs the DTE receptor that congestion was encountered along the path from source to destination. A device receiving frames with the FECN bit set can ask higher-priority protocols to take flow-control action is needed. See also Backward Explicit Congestion Notification.

Forwarding

The process by which a DNS server sends a request for name resolution to another DNS server. Forwarding is often used to improve performance and to restrict network traffic over slow connections.

Forward Lookup Zone

A name-to-address database that helps computers translate DNS names into IP addresses and provides information about available resources.

Forward-Only Server

A DNS server that is configured to use forwarders and that does not use recursion when forwarders fail, but instead fails the query.

FRAD

See Frame Relay Access Device.

Fragment

Any portion of a larger packet that has been intentionally segmented into smaller pieces. A packet fragment does not necessarily indicate an error and can be intentional. See also Fragmentation.

Fragmentation

The process of intentionally segmenting a packet into smaller pieces when sending data over an intermediate network medium that cannot support the larger packet size.

FragmentFree

LAN switch type that reads into the data section of a frame to make sure fragmentation did not occur. Sometimes called modified cut-through.

Frame

A data structure that network hardware devices use to transmit data between computer. Frames consist of the addresses of the sending and receiving computers, size information, and a checksum. Frames are envelopes around packets of data that allow the packets to be addressed to specific computers on a shared media network. See also Ethernet, Fiber Distributed Data Interface and Token Ring.

Frame Relay

Designed to support the Broadband Integrated Services Digital Network (B-ISDN). The specifications for Frame Relay address some of the limitations of X.25. As with X.25, Frame Relay is a packet-switching network service, but Frame Relay was designed around newer, faster fiber-optic networks.

Frame Relay Access Device (FRAD)

Any device affording a connection between a LAN and a Frame Relay WAN. See also Cisco Frame-Relay Access Device and Frame Relay Access Support.

Frame Relay Access Support (FRAS)

A feature of Cisco’s IOS software that enables SDLC, Ethernet, Token Ring, and Frame Relay-attached IBM devices to be linked with other IBM mechanisms on a Frame Relay network. See also Frame Relay Access Device.

Frame Relay Bridging

Defined in RFC 1490, this bridging method uses the identical spanning-tree algorithm as other bridging operations but permits packets to be encapsulated for transmission across a Frame Relay network.

Frame Type

An option that specifies how data is packaged for transmission over the network. This option must be configured to run the NWLink IPX/SPX/NetBIOS Compatible Transport protocol on a Windows 2000 computer. By default, the frame type is set to Auto Detect, which will attempt to automatically choose a compatible frame type for the network.

Framing

Encapsulation of the Data Link layer of the OSI model. It is called framing because the packet is encapsulated with both a header and a trailer.

FRAS

See Frame Relay Access Support.

FreeBSD

A free implementation of Unix for the Intel family of processors, derived from the 4.4BSD Lite releases. The distribution is free, but there may be a small charge to cover the distribution media and packaging. FreeBSD also includes XFree86, a port of the X Window system to the Intel processors. Most of FreeBSD is covered by a license that allows redistribution as long as the code acknowledges the copyright of the Regents of the University of California and the FreeBSD Project. Those parts of FreeBSD that include GNU software are covered separately by the Free Software Foundation license. See also copy left, Free Software Foundation, freeware, GNU, Linux, and open source software.

Free/Busy

Terminology used in the Microsoft Schedule+ application to denote an unscheduled period of time (i.e., free) or a scheduled period of time (i.e., busy).

Free Software Foundation

An organization founded by Richard Stallman that develops the freely available GNU software. The FSF philosophy is that all software should be free for everyone to use and that source code should always accompany the software. The theory being, that if you make a modification or fix an error, the change can be sent out to all other users, saving time and preventing duplication of effort. Also, any software developed under the FSF General Public License (GPL) must also be covered by the same terms of the GPL; in other words, you cannot use the free software to develop a commercial product for sale. For more information on the Free Software Foundation, see www.gnu.org/fsf. See also Copy Left, FreeBSD, Freeware, GNU, and Open Source Software.

Freeware

A form of software distribution in which the author retains copyright to the software, but makes the program available to others at no cost. The program cannot be resold by a third party for profit. See also Copy Left, Free Software Foundation, GNU, and Open Source Software.

Frequency

The repetition rate, usually of a signal, usually reported in cycles per second, or Hz.

Frequency-Division Multiplexing

A technique that permits information from several channels to be assigned bandwidth on one wire based on frequency. See also Time Division Multiplexing, Asynchronous Time-Division Multiplexing, and Statistical Multiplexing.

Front End

The client component of a client/server system. A front-end application works with a back-end component stored on a server.

Front-End/Back-End

An Exchange configuration in which clients access a bank of protocol servers (the front-end) for collaboration information, and these in turn, communicate with the data stores on separate servers (the back-end) to retrieve the physical data. A front-end/back-end configuration allows for a scalable, single point of contact for all Exchange-related data.

Front-End Program

A client application, usually running on a user’s workstation, that communicates with the back-end program, usually running on a server computer. Outlook is an example of a front-end program for Exchange Server, the back-end program. See also Back-End Program.

FRS

See File Replication Service.

FSIP

See Fast Serial Interface Processor.

FTP

See File Transfer Protocol.

Full Backup

Backs up all specified files.

Full-Duplex

A method of transmitting information over an asynchronous communications channel, in which signals may be sent in both directions simultaneously. This technique makes the best use of line time but substantially increases the amount of logic required in the primary and secondary stations.

Full Zone Transfers

A type of zone transfer in which the entire zone is propagated. Used in DNS under Windows NT 4 and higher. See alsoActive Directory Replication, Multimaster Replication Model, and Incremental Zone Transfers.

Full Mesh

A type of network topology where every node has either a physical or a virtual circuit linking it to every other network node. A full mesh supplies a great deal of redundancy but is typically reserved for network backbones because of its expense. See also Partial Mesh.

Fully Qualified Domain Name (FQDN)

The full DNS path of an Internet host. An example is “sales.dept4.widget.com”.

Functional Levels

Similar to modes in Windows 2000. Windows Server 2003 domain functional level includes all of the new features included in Windows Server 2003, but requires that all domain controllers run Windows Server 2003. The Windows 2000 native domain functional level offers all of the functionality of Native mode in Windows 2000, but all of the domain controllers must run either Windows Server 2003 or Windows 2000 Server. The Windows 2000 mixed domain functional level offers the least amount of functionality but supports domain controllers running Windows Server 2003, Windows 2000 Server, and Windows NT 4 Server.

Function Call

An instruction in a program that calls (invokes) a function. For example, MAPIReadMail is a MAPI function call.

Function Key

One of the series of 10 or 12 keys marked with the letter F and a numeral, used for specific operations.