A network license permits a specified number of copies of Mathematica to run concurrently on a network, making Mathematica available to multiple users and machines. Mathematica system administration in a network license environment involves setting up two separate components. First, the Mathematica license manager, MathLM, is installed on the license server to handle the details of license activity. Then, Mathematica is installed as a client of MathLM.
By contrast, single-machine licenses are used for standalone installations of Mathematica (those that do not connect to a license server). See your license certificate for details. For environments with single-machine licenses, Mathematica system administration consists of installing and customizing Mathematica. Here are basic instructions as well as advanced information for administrators of large sites.