To run Mathematica using a network license, both the client machine and the license server must be on the network and MathLM must be running.
Alternatively, if you are running X, an additional menu folder named Wolfram has already been added to the desktop menu. In the folder, an item named Mathematica points to the most recently installed version of Mathematica. File associations have also been modified such that .nb files now associate with the most recently installed version of Mathematica.
Rather than installing Mathematica on every client machine, you can install Mathematica on a file server and export the installation directory to the clients. To display the front end, the clients must have access to the Mathematica fonts. For information about configuring the X server on the client machines to find the Mathematica fonts, see "Fonts on Linux". Once the fonts are properly configured, the client machines can run Mathematica as though it were a local installation.