L
LAN – Local Area Network; two or more computers connected, either physically or wirelessly, and able to share resources.
Layer-2 Tunnelling Protocol (L2TP) – security for transmission of sensitive information over unprotected networks.
Layered security – multiple layers of security technology and administrative processes working together to provide a level of protection appropriate to the asset being protected; multiple barriers and inbuilt limits to possible damage form part of such a defence in depth. Larger organisations, in particular, need to deploy layered security architectures.
Legislation – legal requirements applicable in the jurisdiction in which you operate. Reference to various pieces of legislation is contained in this glossary.
LFM – log file monitor. See Intrusion detection.
Licences – any software that is being used is potentially subject to copyright restrictions and it is essential that organisations ensure they have the correct type and number of licences for each software program they use. There are two types of user licence. The first is known as a ‘per seat’ licence, the second is for ‘concurrent users’. Per seat requires there to be a licence for every installation, or instance, of the software; typically, Microsoft Office licences, for instance, are supplied on this basis. Concurrent user allows for a maximum number of simultaneous users and is more normal for shared software, such as some database applications. This enables the client software to be installed on many machines, but typically the server software is set so that it will not allow more than the licensed number of users to work simultaneously.
Linux – open source software, originally aimed at desktop workstations.
Log files – files that contain logs of specific activity types.
Logical – objects and methods that are apparent to users and/or applications, as opposed to the physical objects and methods upon which they are based; you have to have physical access to a computer before you can have logical access to its folders.