The Facts

• Virtual network computing, or VNC, is a software standard for connecting to computers remotely over the Internet or a local area network. With VNC, the monitor of the remote computer is shown in a window on your screen, and any mouse movement or keystrokes you make are transmitted back to the server. VNC is exceptionally useful for a single administrator who must manage multiple computers in varied locations.
  
  

Types

• Most VNC installations connect to normal workstations and servers, which are set up with monitors and keyboards of their own. A "headless" server is any server which is not connected to a monitor (and usually lacking a keyboard) because it is rare that someone needs to physically interact with it. "Headless VNC" is therefore using VNC to connect to a headless server. Multiple servers can be controlled with a hardware "KVM" switch, connecting multiple incoming cables to the same keyboard and monitor. VNC is a software method of accomplishing the same.
  
  

Features

• The advantage of VNC over individual hardware or a KVM switch is the ability to avoid having even a single monitor or keyboard installed in the server room. Headless VNC also allows for remote administration from any network location.
  
  

Considerations

• The primary disadvantage of headless VNC is the lag time from the moment a keystroke or a mouse command is sent to the server, and the response time of the screen displaying the result of the command. Over a local area network this time is typically short, but over the Internet it can be long enough to slow down your work.
  
  

Benefits

• Because headless VNC is run entirely by software, it has lower initial expense than hardware solutions. It also considerably reduces the amount of heat produced by many monitors and switches running in a small server space without adequate ventilation.