12-02-2010, 11:52 AM
[attachment=1964]
ABSTRACT
VIRTUAL NETWORK COMPUTING
"Virtual Network Computing" is an application that is mainly intended for initiating and controlling remote desktop with in a network. The application also provides a facility to view and control the remote applications. Normally applications on a network can be accessed and executed by users as per the permissions assigned by the administrator. But unable to access the desktop. The "VNC" one such application that tries to provide facilities to initiate specific applications on a remote machine to be executed.
The purpose of the VNC is to view the desktop, the processes and the services that are running on a remote system on the network without being physically present there. The "VNC" consists of mainly two modules.
¢ Te Remote Host(Server)
¢ The User(Client) Remote host:
The Remote Host is the server, which could be any machine on a network. This machine is the one, which the user wants to retrieve. It runs the server module and opens a TCP/IP connection. The server machine will be polling at this socket connection looking for the client to connect. The User:
User, the client module, requests for a connection. When the connection is established the remote desktop is displayed at the client module interface, we can access and control the remote machines desktop from here.
Virtual network computing
1. INTRODUCTION:
"Virtual Network Computing" is a technology for remote desktop sharing. VNC was created as an open source research project in the late 1990s. Since that time, several mainstream remote desktop solutions have been created based on VNC. The original development team produces the RealVNC package. Other popular derivatives include Ultra VNC and TightVNC. VNC works similarly to the Remote Desktop application built into newer versions of Microsoft Windows. Unlike Windows Remote Desktop, VNC runs on older Windows computers, Linux/Unix and other non-Windows operating systems. VNC applications, however, are generally regarded as slower and offering fewer features and security options than Windows Remote Desktop. VIRTUAL NETWORK COMPUTING:
"Virtual Network Computing" is a tool to access another system's desktop at your machine. The Server module runs on the Remote machine and the Client module runs at your machine. This tool helps to invoke the application at desktop of Remote machine using the interface at your machine. The tool has feature of providing the color mode to view the desktop at different color setting. In order to provide the quick data transfer rate to the client machine the data send from the Remote Server machine is compressed. Remote Desktop Viewer and controller System is mainly intended for those scenarios, which runs on a client/server, Internet and Intranet worked environment.
The tool is implemented using TCP/IP network protocol, the server on the remote host machine initiate the connection, and waits for the Client request. The client machines specify the remote host address. When the connection is established the Client gets the View of the Remote host desktop. The activities at the remote machine are refreshed at the client at regular intervals. The information send over the network is compressed to enable quick data transfer. For this the Client can select various compression modes. This includes the Huffman's algorithm for data compression.
VNC stands for Virtual Network Computing. It 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. 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.
2. How can I use VNC?
Remote control software such as VNC has a variety of uses. It allows a person at a remote computer to assume control of another computer across a network, as if they were sitting in front of the other computer. For the individual user, one common scenario is using VNC to help troubleshoot the computer of a distant less-technically-savvy relative.Sitting at your desk in Baltimore, you could use VNC to take control of your mother's PC in London and show her how to install and use some new software package by actually doing it yourself.
For the business user, VNC can be used to provide a flexible hot-desking and road-warrior environment by allowing employees to access their office desktop and server machines from any machine in the company's offices or from other remote sites, regardless of the type of computers involved at either end. A popular business application of VNC is in remote system administration, where VNC is used to allow administrators to take control of employee machines to diagnose and fix problems, or to access and administer server machines without making a trip to the console.
VNC can also be used in educational contexts, for example to allow a distributed group of students simultaneously to view a computer screen being manipulated by an instructor, or to allow the instructor to take control of the students' computers to provide assistance .The variety of uses of VNC is really as diverse as the number of VNC users, a number which is big and growing all the time
What makes VNC different from other systems?
VNC differs from other remote display systems in three crucial ways:
¢ It is fully cross-platform. A desktop running on a Linux machine may be displayed on a Windows PC, any number of other architectures.
¢ There is. a Java viewer so that any desktop can be viewed with any Java-capable browser. There is a Windows server, allowing you to view the desktop of a remote Windows machine on any of these platforms using exactly the same viewer. The simplicity of the protocol makes it easy to port to new platforms and therefore ported VNC to a huge variety of platforms.
¢ It is small and simple.The Windows viewer is about 150K in size.The entire Java viewer is substantially less than 100K. and takes less time to download than the images on some web pages.
Virtual network computing
3. Overview-VNC:
VNC consists of two components. A server, which runs on the computer you want to remotely access, and a viewer, which runs on the computer you are sitting in front of. There are two important features of VNC:
¢ The server and the viewer may be on different machines and on types of computer. The protocol which connects the server and viewer is simple, open, and platform independent.
¢ No state is stored at the viewer. Breaking the viewer's connection to the server and then reconnecting will not result in any loss of data. Because the connection can be remade from somewhere else, you have easy mobility.
So to get started with VNC you need to run a server, and then connect to it with a viewer. Networking:
VNC software requires a TCP/IP connection between the server and the viewer. This is the standard networking protocol on LANs, WANs, broadband and dialup ISP. Each computer has a unique IP address and may also have a name in the DNS. You will need to know the IP address or name of the server when you connect a viewer to it. Sometimes the IP address is fixed, and sometimes it is issued to you dynamically by your ISP. If it is allocated dynamically, you might consider using a third party DNS management service.
The 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 framebuffer or RFB. In the past we have tended to refer to the VNC protocol as the RFB protocol, so you may have seen this term in other publications. The protocol simply allows a server to update the framebuffer displayed on a viewer. Because it works at the framebuffer level it is potentially applicable to all operating systems, windowing systems and applications. 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.
This is truly a "thin-client" protocol: it has been designed to make very few
requirements of the viewer. In this way, clients can run on the widest range of hardware, and the task of implementing a client is made as simple as possible.
Rectangular updates:
The display side of the protocol is based around a single graphics primitive: "put a rectangle of pixel data at a given x, y position". This might seem an inefficient way of drawing arbitrary user interface components. But because we have a variety of different encoding schemes for the pixel data, we can select the appropriate scheme for each rectangle we send, and make the most of network bandwidth, client drawing speed and server processing speed.
The lowest common denominator is the so-called raw encoding, where the
rectangle is simply pixel data sent in left-to-right scan line order. All clients and servers must support this encoding. However, the encodings actually used on any given VNC connection can be negotiated according to the abilities of the server, the client, and the connection between the two.
The copy rectangle encoding, for example, is very simple and efficient and can be
used when the client already has the same pixel data elsewhere in its frame buffer. The server simply sends an X, Y coordinate giving the position from which the client can copy the rectangle of pixel data. This means that operations such as dragging or scrolling a window, which involve substantial changes to the screen, may only require a few bytes. Most clients will support this encoding, since it is generally simple to implement and saves bandwidth.
A typical workstation desktop has large areas of solid colour and of text. Some of our most effective encodings take advantage of this by efficiently describing rectangles consisting of one majority (background) colour and 'sub-rectangles' of different colours. There are numerous other
Virtual network computing
possible schemes. We
might use a JPEG encoding for still images or MPEG for efficient transmission of moving images. An encoding which uses some kind of caching of pixel data would be good for rendering text, where the same character is drawn in the same font multiple times. Subsequent occurrences of the same character would be encoded simply by reference to the first occurrence.
Adaptive update protocol:
A sequence of these rectangles makes a framebuffer update (or simply update). An update represents a change from one valid framebuffer state to another, so in some ways is similar to a frame of video, but it is usually only a small area of the framebuffer that will be affected by a given update. Each rectangle may be encoded using a different scheme. The server can therefore choose the best encoding for the particular screen content being transmitted and the network bandwidth available.
The update protocol is demand-driven by the client. That is, an update is only sent by the server in response to an explicit request from the client. This gives the protocol an adaptive quality. The slower the client and the network are, the lower the rate of updates becomes. Each update incorporates all the changes to the 'screen' since the last client request. With a slow client and/or network, transient states of the framebuffer are ignored, resulting in reduced network traffic and less drawing for the client. This also improves the apparent response speed.
Output protocol:
The input side of the protocol is based on a standard workstation model of a keyboard and multi-button pointing device. Input events are sent to the server by the client whenever the user presses a key or pointer button, or whenever the pointing device is moved. These input events can also be synthesized from other non-standard I/O devices.
Connection Setup and Shutdown:
When the connection between a client and a server is first established, the server begins by requesting authentication from the client using a challenge-response scheme, which typically results in the user being prompted for a password at the client end. The server and client then exchange messages to negotiate desktop size, pixel format, and the encoding schemes to be used. The client then requests an update for the entire screen, and the session begins. Because of the stateless
Virtual network computing
nature of the client, either side can close the connection at any time without adverse consequences.
VNC Clients:
Writing a 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 framebuffer, or going through a windowing system). VNC clients exist for all flavors of UNIX, Windows, Macintosh, and Java and for smaller handheld appliances.
VNC Servers:
Writing a 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.
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 multi-user operation. Servers simply mirror the real display to a remote client, which means that the server is not 'multi-user'. It does, however, provide the primary user of a PC with remote access to their desktop.
INSTALLATION:
Running a Windows server:
Installing the Windows server, WinVNC, should create a RealVNC group in your Start... menu. Run the VNC server.
If this is the first time you've used a VNC server on this machine you'll be prompted to set a password, which you'll need when you connect to the machine from a remote location. A small icon will appear in the system tray, and by right-clicking on this you can control most aspects of the server.
Options... H
Add New Client Disconnect Clients;
Close VNC Server About...
16:19
The IP address of the computer running the VNC server can be found by hovering over the tray icon in the system tray. Unless this computer has a DNS name, you will need to specify this number to the viewer when you connect.
VNC Server (Service):192.168.0.103,172.16.76.1,172.16.209.1
«V2<YVS 17:33
r
You can now go to another machine and connect a viewer to the server.
Running a viewer:
You can run the Windows viewer the RealVNC group on the Start... menu.
In this case, you will be prompted for the host name (VNC server name) and display number:
VNC Viewer : Connection Details
V9
About.
Server: | my host, mydomain. cor~ ~~*\
OK
Encryption: [Always Off I Options...
Cancel
Enter it and click OK, and you will be prompted for your password, after which you should see the remote display. If you are connecting to a Windows or Mac server, the display number will be 0 unless you have explicitly changed it, and can be omitted. You can run the viewer on Unix and Windows by typing at the command line: vncviewer snoopy: 2
You need to specify the name of the VNC server and the number of the desktop. If, for example, you have started a server as display 2 on a machine called 'snoopy'. Remember that if you are connecting to a Windows or Mac server, the display number will be 0 unless you have explicitly changed it, and can be omitted. If the machine running the server does not have a DNS entry, you probably won't be able to use the name and will have to replace snoopy with its IP address, for example something that looks like 123. 456. 78. 9.
5. DATA FLOW DIAGRAM:
CLIENT SIDE
LOGIN
Fig: Level One DFD -Client Side
Compress Desktop Compressed data
SERVER SIDE:
Server PROGRAM
alizuW r
Fig: Level One DFD -Server Side
6.CONCLUSION:
VNC is a very impressive product, especially considering that it's free. Quite apart from that, its main advantage over its commercial competitors is that it is open source, so anyone with programming skills can contribute towards it and so make it an even better, more flexible product. Even in its current form, its remote control applications are almost limitless, and it wills no doubt find many uses and supporters in a typical support environment. Definitely a program to try out and evaluate for yourself. It is sharable. One desktop can be displayed and used by several viewers at once, allowing CSCW-style applications
With the VNC Proxy and guaranteeing QoS between the VNC server and VNC proxy, we achieved a higher number of screen updates on the VNC viewer. This clearly reflects the response-veness to user interactions on thin-client devices. Thus, making ultra-thin client systems more usable for mobile networking.
7.FUTURE ENHANCEMENT:
The developed system is flexible and changes can be made easily. The system is done with an insight into the necessary modifications that may be required in the future. Hence, the system can be maintained successfully without much rework.
VNC uses a random challenge-response system to provide the basic authentication that allows you to connect to a VNC server. This is reasonably secure; the password is not sent over the network. Once you are connected, however, traffic between the viewer and the server is unencrypted, and could be snooped by someone with access to the intervening network. Therefore recommend that if security is important to you, you 'tunnel' the VNC protocol through some more secure channel such as SSH So we can make VNC more secure using SSH
Now the derivations for VNC are available they provide more security than real VNC. They overcome the speed limitations of VNC. In future more powerful, secure and faster
VNC will be available on the market.
¢ realvnc.com
¢ google.com
¢ cl.cam.ac.uk
¢ pcsupportadvisor.com
8.BIBLIOGRAPHY:
CONTENTS
1. INTRODUCTION
2. HOW CAN IUSEVNC?
3. OVERVIEW-VNC
4. INSTALLATION
5. DATAFLOW DIAGRAM
6. CONCLUSION
7. FUTURE ENHANCEMENT
8. BIBLIOGRAPHY
ABSTRACT
VIRTUAL NETWORK COMPUTING
"Virtual Network Computing" is an application that is mainly intended for initiating and controlling remote desktop with in a network. The application also provides a facility to view and control the remote applications. Normally applications on a network can be accessed and executed by users as per the permissions assigned by the administrator. But unable to access the desktop. The "VNC" one such application that tries to provide facilities to initiate specific applications on a remote machine to be executed.
The purpose of the VNC is to view the desktop, the processes and the services that are running on a remote system on the network without being physically present there. The "VNC" consists of mainly two modules.
¢ Te Remote Host(Server)
¢ The User(Client) Remote host:
The Remote Host is the server, which could be any machine on a network. This machine is the one, which the user wants to retrieve. It runs the server module and opens a TCP/IP connection. The server machine will be polling at this socket connection looking for the client to connect. The User:
User, the client module, requests for a connection. When the connection is established the remote desktop is displayed at the client module interface, we can access and control the remote machines desktop from here.
Virtual network computing
1. INTRODUCTION:
"Virtual Network Computing" is a technology for remote desktop sharing. VNC was created as an open source research project in the late 1990s. Since that time, several mainstream remote desktop solutions have been created based on VNC. The original development team produces the RealVNC package. Other popular derivatives include Ultra VNC and TightVNC. VNC works similarly to the Remote Desktop application built into newer versions of Microsoft Windows. Unlike Windows Remote Desktop, VNC runs on older Windows computers, Linux/Unix and other non-Windows operating systems. VNC applications, however, are generally regarded as slower and offering fewer features and security options than Windows Remote Desktop. VIRTUAL NETWORK COMPUTING:
"Virtual Network Computing" is a tool to access another system's desktop at your machine. The Server module runs on the Remote machine and the Client module runs at your machine. This tool helps to invoke the application at desktop of Remote machine using the interface at your machine. The tool has feature of providing the color mode to view the desktop at different color setting. In order to provide the quick data transfer rate to the client machine the data send from the Remote Server machine is compressed. Remote Desktop Viewer and controller System is mainly intended for those scenarios, which runs on a client/server, Internet and Intranet worked environment.
The tool is implemented using TCP/IP network protocol, the server on the remote host machine initiate the connection, and waits for the Client request. The client machines specify the remote host address. When the connection is established the Client gets the View of the Remote host desktop. The activities at the remote machine are refreshed at the client at regular intervals. The information send over the network is compressed to enable quick data transfer. For this the Client can select various compression modes. This includes the Huffman's algorithm for data compression.
VNC stands for Virtual Network Computing. It 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. 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.
2. How can I use VNC?
Remote control software such as VNC has a variety of uses. It allows a person at a remote computer to assume control of another computer across a network, as if they were sitting in front of the other computer. For the individual user, one common scenario is using VNC to help troubleshoot the computer of a distant less-technically-savvy relative.Sitting at your desk in Baltimore, you could use VNC to take control of your mother's PC in London and show her how to install and use some new software package by actually doing it yourself.
For the business user, VNC can be used to provide a flexible hot-desking and road-warrior environment by allowing employees to access their office desktop and server machines from any machine in the company's offices or from other remote sites, regardless of the type of computers involved at either end. A popular business application of VNC is in remote system administration, where VNC is used to allow administrators to take control of employee machines to diagnose and fix problems, or to access and administer server machines without making a trip to the console.
VNC can also be used in educational contexts, for example to allow a distributed group of students simultaneously to view a computer screen being manipulated by an instructor, or to allow the instructor to take control of the students' computers to provide assistance .The variety of uses of VNC is really as diverse as the number of VNC users, a number which is big and growing all the time
What makes VNC different from other systems?
VNC differs from other remote display systems in three crucial ways:
¢ It is fully cross-platform. A desktop running on a Linux machine may be displayed on a Windows PC, any number of other architectures.
¢ There is. a Java viewer so that any desktop can be viewed with any Java-capable browser. There is a Windows server, allowing you to view the desktop of a remote Windows machine on any of these platforms using exactly the same viewer. The simplicity of the protocol makes it easy to port to new platforms and therefore ported VNC to a huge variety of platforms.
¢ It is small and simple.The Windows viewer is about 150K in size.The entire Java viewer is substantially less than 100K. and takes less time to download than the images on some web pages.
Virtual network computing
3. Overview-VNC:
VNC consists of two components. A server, which runs on the computer you want to remotely access, and a viewer, which runs on the computer you are sitting in front of. There are two important features of VNC:
¢ The server and the viewer may be on different machines and on types of computer. The protocol which connects the server and viewer is simple, open, and platform independent.
¢ No state is stored at the viewer. Breaking the viewer's connection to the server and then reconnecting will not result in any loss of data. Because the connection can be remade from somewhere else, you have easy mobility.
So to get started with VNC you need to run a server, and then connect to it with a viewer. Networking:
VNC software requires a TCP/IP connection between the server and the viewer. This is the standard networking protocol on LANs, WANs, broadband and dialup ISP. Each computer has a unique IP address and may also have a name in the DNS. You will need to know the IP address or name of the server when you connect a viewer to it. Sometimes the IP address is fixed, and sometimes it is issued to you dynamically by your ISP. If it is allocated dynamically, you might consider using a third party DNS management service.
The 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 framebuffer or RFB. In the past we have tended to refer to the VNC protocol as the RFB protocol, so you may have seen this term in other publications. The protocol simply allows a server to update the framebuffer displayed on a viewer. Because it works at the framebuffer level it is potentially applicable to all operating systems, windowing systems and applications. 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.
This is truly a "thin-client" protocol: it has been designed to make very few
requirements of the viewer. In this way, clients can run on the widest range of hardware, and the task of implementing a client is made as simple as possible.
Rectangular updates:
The display side of the protocol is based around a single graphics primitive: "put a rectangle of pixel data at a given x, y position". This might seem an inefficient way of drawing arbitrary user interface components. But because we have a variety of different encoding schemes for the pixel data, we can select the appropriate scheme for each rectangle we send, and make the most of network bandwidth, client drawing speed and server processing speed.
The lowest common denominator is the so-called raw encoding, where the
rectangle is simply pixel data sent in left-to-right scan line order. All clients and servers must support this encoding. However, the encodings actually used on any given VNC connection can be negotiated according to the abilities of the server, the client, and the connection between the two.
The copy rectangle encoding, for example, is very simple and efficient and can be
used when the client already has the same pixel data elsewhere in its frame buffer. The server simply sends an X, Y coordinate giving the position from which the client can copy the rectangle of pixel data. This means that operations such as dragging or scrolling a window, which involve substantial changes to the screen, may only require a few bytes. Most clients will support this encoding, since it is generally simple to implement and saves bandwidth.
A typical workstation desktop has large areas of solid colour and of text. Some of our most effective encodings take advantage of this by efficiently describing rectangles consisting of one majority (background) colour and 'sub-rectangles' of different colours. There are numerous other
Virtual network computing
possible schemes. We
might use a JPEG encoding for still images or MPEG for efficient transmission of moving images. An encoding which uses some kind of caching of pixel data would be good for rendering text, where the same character is drawn in the same font multiple times. Subsequent occurrences of the same character would be encoded simply by reference to the first occurrence.
Adaptive update protocol:
A sequence of these rectangles makes a framebuffer update (or simply update). An update represents a change from one valid framebuffer state to another, so in some ways is similar to a frame of video, but it is usually only a small area of the framebuffer that will be affected by a given update. Each rectangle may be encoded using a different scheme. The server can therefore choose the best encoding for the particular screen content being transmitted and the network bandwidth available.
The update protocol is demand-driven by the client. That is, an update is only sent by the server in response to an explicit request from the client. This gives the protocol an adaptive quality. The slower the client and the network are, the lower the rate of updates becomes. Each update incorporates all the changes to the 'screen' since the last client request. With a slow client and/or network, transient states of the framebuffer are ignored, resulting in reduced network traffic and less drawing for the client. This also improves the apparent response speed.
Output protocol:
The input side of the protocol is based on a standard workstation model of a keyboard and multi-button pointing device. Input events are sent to the server by the client whenever the user presses a key or pointer button, or whenever the pointing device is moved. These input events can also be synthesized from other non-standard I/O devices.
Connection Setup and Shutdown:
When the connection between a client and a server is first established, the server begins by requesting authentication from the client using a challenge-response scheme, which typically results in the user being prompted for a password at the client end. The server and client then exchange messages to negotiate desktop size, pixel format, and the encoding schemes to be used. The client then requests an update for the entire screen, and the session begins. Because of the stateless
Virtual network computing
nature of the client, either side can close the connection at any time without adverse consequences.
VNC Clients:
Writing a 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 framebuffer, or going through a windowing system). VNC clients exist for all flavors of UNIX, Windows, Macintosh, and Java and for smaller handheld appliances.
VNC Servers:
Writing a 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.
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 multi-user operation. Servers simply mirror the real display to a remote client, which means that the server is not 'multi-user'. It does, however, provide the primary user of a PC with remote access to their desktop.
INSTALLATION:
Running a Windows server:
Installing the Windows server, WinVNC, should create a RealVNC group in your Start... menu. Run the VNC server.
If this is the first time you've used a VNC server on this machine you'll be prompted to set a password, which you'll need when you connect to the machine from a remote location. A small icon will appear in the system tray, and by right-clicking on this you can control most aspects of the server.
Options... H
Add New Client Disconnect Clients;
Close VNC Server About...
16:19
The IP address of the computer running the VNC server can be found by hovering over the tray icon in the system tray. Unless this computer has a DNS name, you will need to specify this number to the viewer when you connect.
VNC Server (Service):192.168.0.103,172.16.76.1,172.16.209.1
«V2<YVS 17:33
r
You can now go to another machine and connect a viewer to the server.
Running a viewer:
You can run the Windows viewer the RealVNC group on the Start... menu.
In this case, you will be prompted for the host name (VNC server name) and display number:
VNC Viewer : Connection Details
V9
About.
Server: | my host, mydomain. cor~ ~~*\
OK
Encryption: [Always Off I Options...
Cancel
Enter it and click OK, and you will be prompted for your password, after which you should see the remote display. If you are connecting to a Windows or Mac server, the display number will be 0 unless you have explicitly changed it, and can be omitted. You can run the viewer on Unix and Windows by typing at the command line: vncviewer snoopy: 2
You need to specify the name of the VNC server and the number of the desktop. If, for example, you have started a server as display 2 on a machine called 'snoopy'. Remember that if you are connecting to a Windows or Mac server, the display number will be 0 unless you have explicitly changed it, and can be omitted. If the machine running the server does not have a DNS entry, you probably won't be able to use the name and will have to replace snoopy with its IP address, for example something that looks like 123. 456. 78. 9.
5. DATA FLOW DIAGRAM:
CLIENT SIDE
LOGIN
Fig: Level One DFD -Client Side
Compress Desktop Compressed data
SERVER SIDE:
Server PROGRAM
alizuW r
Fig: Level One DFD -Server Side
6.CONCLUSION:
VNC is a very impressive product, especially considering that it's free. Quite apart from that, its main advantage over its commercial competitors is that it is open source, so anyone with programming skills can contribute towards it and so make it an even better, more flexible product. Even in its current form, its remote control applications are almost limitless, and it wills no doubt find many uses and supporters in a typical support environment. Definitely a program to try out and evaluate for yourself. It is sharable. One desktop can be displayed and used by several viewers at once, allowing CSCW-style applications
With the VNC Proxy and guaranteeing QoS between the VNC server and VNC proxy, we achieved a higher number of screen updates on the VNC viewer. This clearly reflects the response-veness to user interactions on thin-client devices. Thus, making ultra-thin client systems more usable for mobile networking.
7.FUTURE ENHANCEMENT:
The developed system is flexible and changes can be made easily. The system is done with an insight into the necessary modifications that may be required in the future. Hence, the system can be maintained successfully without much rework.
VNC uses a random challenge-response system to provide the basic authentication that allows you to connect to a VNC server. This is reasonably secure; the password is not sent over the network. Once you are connected, however, traffic between the viewer and the server is unencrypted, and could be snooped by someone with access to the intervening network. Therefore recommend that if security is important to you, you 'tunnel' the VNC protocol through some more secure channel such as SSH So we can make VNC more secure using SSH
Now the derivations for VNC are available they provide more security than real VNC. They overcome the speed limitations of VNC. In future more powerful, secure and faster
VNC will be available on the market.
¢ realvnc.com
¢ google.com
¢ cl.cam.ac.uk
¢ pcsupportadvisor.com
8.BIBLIOGRAPHY:
CONTENTS
1. INTRODUCTION
2. HOW CAN IUSEVNC?
3. OVERVIEW-VNC
4. INSTALLATION
5. DATAFLOW DIAGRAM
6. CONCLUSION
7. FUTURE ENHANCEMENT
8. BIBLIOGRAPHY
