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Virtual Network Computing (VNC). Dave Grizzanti Steve Curti. Backround. VNC is remote control software which allows you to view and interact with one computer (the "server") using a simple program (the "viewer") on another computer anywhere on the Internet. . Backround.
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Virtual Network Computing (VNC) Dave Grizzanti Steve Curti
Backround • VNC is remote control software which allows you to view and interact with one computer (the "server") using a simple program (the "viewer") on another computer anywhere on the Internet.
Backround • The two computers don't even have to be the same type, so for example you can use VNC to view an office Linux machine on your Windows PC at home. • VNC is freely and publicly available and is in widespread active use by millions throughout industry, academia and privately.
Backround • VNC differs from other remote display systems in three crucial ways: • It is fully cross-platform. • It is small and simple. The Windows viewer, for example, is about 150K in size and can be run directly from a floppy. • It is free! You can download it, use it, and redistribute it under the terms of the GNUGeneral Public License.
VNC Protocol • The protocol simply allows a server to update the frame buffer displayed on a viewer. Because it works at the frame buffer level it is potentially applicable to all operating systems. • This includes X/Unix, Windows, and Macintosh, but might also include PDAs, and indeed any device with some form of communications link. The protocol will operate over any reliable transport such as TCP/IP.
VNC Protocol • The VNC protocol is a simple protocol for remote access to graphical user interfaces. It is based on the concept of a remote frame buffer or RFB.
VNC Clients • Writing an VNC viewer is a simple task, as it should be for any thin-client system. It requires only a reliable transport (usually TCP/IP), and a way of displaying pixels (either directly writing to the frame buffer, or going through a windowing system). • VNC clients exist for all flavours of Unix, Windows, Macintosh, Java and for smaller hand-held appliances.
VNC Servers • Writing an VNC server is slightly harder than writing a client for a number of reasons. The protocol is designed to make the client as simple as possible, so it is usually up to the server to perform any necessary translations. • For example, the server must provide pixel data in the format the client wants. There are servers Unix, Windows and Macintosh platforms A Unix machine can run a number of Xvnc servers for different users, each of which represents a distinct VNC desktop. • Each VNC desktop is like a virtual X display, with a root window on which several X applications can be displayed.
VNC Servers • The Windows server (WinVNC) is a little more difficult to create, because there are fewer places to insert hooks into the system to monitor display updates, and a less clearly-defined model of multiuser operation. • Servers simply mirrors the real display to a remote client, which means that the server is not 'multiuser'. It does, however, provide the primary user of a PC with remote access to their desktop.
Servers and Viewers • RealVNC http://www.realvnc.com/ • TightVNC http://www.tightvnc.com/ • UltraVNC http://ultravnc.sourceforge.net/ • Chicken of the VNC http://sourceforge.net/projects/cotvnc/ • OSXvnc http://www.redstonesoftware.com/vnc.html
Installation • Windows: • Download a copy of RealVNC. • You can choose between installing the just the viewer or both the server and viewer. • Install the program. • Set password and chosen options.
VNC – Java viewer • An machine running a VNC server can be connected to by any other machine running a web browser and connected to the Internet. • Example
Installation • Linux: • rpm -q vnc vnc-server. • Download latest version from RealVNC (RPM and GZip). • Run RPM and unpackage Gzip into appropriate folder. • Edit files according to http://fedoranews.org/tchung/vnc/index.shtml
Error Log • What went wrong: • TightVNC – Compatibility issues with Fedora, Xwindows. Attempted to install new version of Xwindows. Resulted in failed GUI. • RealVNC – Packages from RealVNC were misleading. Only installed server but not the viewer. Had to download packages for viewer from fedora mirror. http://fedora.officepark.ru/3/i386/os/Fedora/RPMS/?C=N;O=D
Notes • Windows vs. Linux • When logging into Windows machines viewer only requires IP address. • Linux requires IP address plus session number. (i.e. 134.198.161.104:1) • Computer can be logged out (not turned off) but vncserver must be running.
References • http://www.realvnc.com - RealVNC • http://www.tightvnc.com - TightVNC • http://fedoranews.org/tchung/vnc/index.shtml - Fedora News.org