Dispositivo físico de acceso a un medio: p.e. una tarjeta de red.
    Tiene asociada una dirección unica que lo identifica en el medio. De este modo, el resto de los componentes que tienen acceso a ese medio pueden identificarlo: a la hora de recibir datos de él o tener que enviarselos.

    The MAC address is the unique physical address embedded in each network adapter.

MMC            Microsoft Management Console

It is Microsoft's new interface for machine and application management and allows the user to create a custom console with "snap-ins" loaded. MMC provides a shell with no functionality, a 'snap-in' provides the functionality, such as DNS management, and while a number of default console configurations will be supplied with certain snap-in's pre loaded you will be able to create your own console with one or more snap-ins loaded.

The main MMC window has the 'Console' menu, which is used to add and remove snap-ins to the console and to also save the configuration to enable you to reload any useful snap-in combinations.

Future Microsoft applications, such as Exchange 6.0 (Platinum) will use MMC snap-ins instead of normal applications and other software providers will follow suit with snap-ins for most application management interfaces.

The MMC is core in Windows 2000 and was first seen in NT 4.0 with Option Pack 4, Internet Information Server 4.0 and Service Pack 4's Security Configuration Editor.

MPR            Multiple Provider Router
MUP              Multiple Universal namig convention Provider

Access to network resources is provided through one of these two components.
MUP supports applications that use UNC names and selects the appropiate provider to them.
MPR was created to support applications that use WNet APIs (Win32 network APIs).

MTF            Master File Table
    En esta tabla, el sistema NTFS mantiene un registro de cada fichero.

MTU          Maximum Transfer Unit

Es el tamaño máximo que un paquete, dentro de un determinado medio, puede tener.
La capa de enlace (layer link) del modelo OSI es la responsable de conocer este tamaño e informarlo a los protocolos que pretenden utilizarlo.