Online Glossary of Security Terms

This glossary contains a list of terms, abbreviations, and acronyms frequently used when discussing networks, security, firewalls, and technical products.

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L

LAN (local area network)

A computer network that spans a relatively small area, generally confined to a single building or group of buildings.

LDAP (Lightweight Directory Access Protocol)

A protocol that helps manage information about authorized users on a network such as names, phone numbers, addresses, and what a user is and is not allowed to access. LDAP is vendor- and platform-neutral, working across otherwise incompatible systems.

LED (light-emitting diode)

A small indicator light on a networking device that indicates status and other information about the device.

link

See hyperlink.

Linux

An open source version of the UNIX operating system.

log host, logging host

A designated device for receiving and storing a record of events from another device or program (such as a SOHO, or ServerLock).

loopback interface

A special type of interface that allows you to make network connections to yourself, using IP. This convention, which all Internet-aware applications expect and utilize, has a variety of purposes, including routing and application testing.