X Window System ORAFACT The X Window System

X Window System ORAFACT

The X Window System The graphical environment for Linux is not a core part of the operating system. Rather, it is a service provided by a running process much like a Web server GUI infrastructure for UNIX and Linux systems • Created in 1984 • Both a Protocol and an Implementation Advantages of X • Operating System Independent • Modular and Extensible • Client-server (Network Transparent!) XFree 86 • Original Free Open Source implementation of the X Window System X. Org • Forked XFree 86 with a more open development model ORAFACT

X. Org Drivers Binary modules (drivers) for different video chipsets • Drivers, in theory, are platform-neutral Advanced features such as 3 D acceleration are supported Drivers for most newer video cards are available Some features require proprietary drivers ORAFACT

Starting X X already running in runlevel 5 with a graphical login From a text virtual terminal login, use startx • startx is a shell script that eventually runs xinit • can run xinit manually, but all that gets started is an X server ORAFACT

X Access Control xhost The xhost command can be used to control host-based access control. $ xhost +bar. example. com # bar. example. com can access the server $ xhost + # anyone can access the server $ xhost # bar. example. com can still access the server $ xhost -bar. example. com # bar. example. com can� t access the server ORAFACT

Insecure Remote X On the Local System - Determine Display Name On the Remote System - export DISPLAY of 2 $ hostname of 2. orafact. com of 2 $ echo $DISPLAY : 0. 0 of 2 $ telnet of 4. orafact. com Trying 192. 168. 1. 4. . . Connected to of 2. orafact. com (192. 168. 1. 4 ). . . snip. . . login: guest Password: welcome of 4 $ export DISPLAY=of 2. orafact. com: 0 of 4 $ xclock ORAFACT

Alternative Remote Graphical Protocols VNC • Cross-platform • Open source can be found at http: //www. realvnc. com/. ORAFACT