Virtual Network Computing, VNC in short, is a type of software, which allows a computer or a mobile device to interact with another computer using the internet. The VNC is a Graphical User Interface (GUI), which uses the Remote Frame Buffer for the controlling of the remote computer. All the events generated by Keyboard and mouse are transmitted from one to another computer using VNC. The VNC software provides you cross platform and allows the remote control between various types of computers.
The VNC software is platform independent software i.e. a VNC user can access the VNC server irrespective of the operating system of either the server or client. VNC also has facility of connecting multiple users at a time. This program can be used for accessing files on network computers from your personal home PC.
History of VNC:
The VNC was originally created at AT&T lab. The name VNC was originated from the ATM (Asynchronous Transfer Mode) network computer. This computer is basically an LCD having a pen input. It should also have fast network connection using ATM. VNC basically only is a version of the ATM software.
Operation:
In operation, the VNC consists of a server, a client and a communication protocol.
The VNC server is software on the computer, which is sharing the screen; whereas the Client is one PC that interacts with the server when required. Moreover, the communication protocol is nothing but a simple graphical screen. In VNC, it is not necessary that the machine should have a physical display. Xvnc is one type of Unix VNC server that works as two servers in one i.e. for various applications you can use this as X server and it can also work as VNC server for remote VNC users. In the operation, the server sends frame buffer to the client. The VNC protocol requires a lot of bandwidth for communication. To reduce these communication overheads there are various methods for transfer the framebuffer in an efficient way called as encodings. The simplest way of encoding, raw encoding in this type of encoding pixel data is sent in scanline order from left to right and the rectangles are transmitted after the full screen. This type of encoding is very good for small changes in the screen but the bandwidth required will be very high for more changes in the pixels at a time.
Security:
VNC provides less security. In VNC, the passwords are not sent in plain text. Someone can sniff off the encoded password and the encryption key from the network and the security will be totally lost. To avoid this, it is strongly recommended that a password containing minimum 8 characters is to be used. On some of the VNC versions there is a limit on the number of characters in the password. In this case, if more than 8 character password is given then the VNC will automatically remove the excess characters and only first 8 characters will serve as the password.
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