Transcript Virtual Network Computing (VNC)

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:
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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 GNU
General 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:
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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:
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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:
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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
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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