Here’s how you can access your computer from anywhere. Updated: January 24, 2020. Step 4: At this point, simply connect your Android device to your PC and the Android Control Screen will popup allowing you to control your device via your computer. While this solution will work for some, it is best suited to those who love coding and who have already installed USB debugging on your phone. View your connected computer's screen. After a brief moment, you'll see the first computer's screen appear in the TeamViewer window on the second computer's screen. Once you see the host computer's screen, you can interact with it as though it were your own computer. To disconnect, you'll click the X at the top of the TeamViewer window. Determines whether the remote session window appears full screen when you launch the connection. 1: The remote session will appear in a window - 2: The remote session will appear full screen: 2: Yes: smart sizing:i:value: Determines whether or not the local computer scales the content of the remote session to fit the window size.
Time Limit Manager v.10 (TLM) provides a convenient and reliable method to implement custom Usage Policies for public access computers, such as those currently deployed in public libraries.
TLM provides all necessary infrastructure to display a Usage Policy on each computer screen, to require and obtain patron’s digital assent to the Usage Policy prior to computer access, to enforce computer session time, to effect an orderly closing of all previous session applications, and to return to the Usage Policy display for the next patron.
Easily enforce usage policies
TLM is a mature product that can successfully help to implement a wide variety of Usage Policies with very little effort from administrators. Best of all, once TLM is monitoring the Usage Policy, librarians are free to attend to their important responsibilities rather than policing the fair and proper use of public access computers.
Use with Clean Slate to clear all user activity
Add Clean Slate security to Time Limit Manager to wipe all previous user mischief providing a hassle-free computer for each new user
When used with award-winning Clean Slate, all traces of user activity (cookies, history, mischief) are thoroughly cleared at the end of each session providing a clean computer for the next user.
Limit session time through reservation tickets
With Time Limit Manager installed, the computer displays an inviting entry screen with your organization’s own Usage Policy Statement. The screen prevents the computer from being used until a valid PIN is entered and the usage policy is accepted.
The valid PIN is distributed through the use of reservation tickets. Quickly and easily print the reservation tickets customized with your time limit policy. This is ideal for single public access computers or networks of thousands.
Easily view all computer activity on the network
TLM also provides for the remote observation of computer use. On a librarian’s computer TLM will display the status of every public access computer. This status includes which computers are in-use, idle, or off-line. Librarian’s can view screen shots, end sessions, and send messages reminding particular patrons of appropriate use.
Time clock displays session time remaining
Time Limit Manager can automatically stop computer use at, or prior to, library closing time
TLM displays an unobtrusive countdown timer on each public access computer indicating the time that the patron has remaining before all of their programs are automatically closed and the machine is prepared for the next user. At two intervals shortly before the session is to end, the patrons are given a prominent on-screen notice that their applications will soon be closed. Edgeview 2 1 980 – cutting edge image viewer reviews.
Automatically lock all computers at closing time
TLM can be used to effect the orderly ending of all computer sessions at a particular time prior to the library closing. This saves librarians from the unenviable task of walking around to each computer reminding patrons that the library is closing.
Virtual Network Computing logo
In computing, Virtual Network Computing (VNC) is a graphical desktop-sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer. It transmits the keyboard and mouse events from one computer to another, relaying the graphical-screen updates back in the other direction, over a network.[1]
VNC is platform-independent – there are clients and servers for many GUI-based operating systems and for Java. Multiple clients may connect to a VNC server at the same time. Popular uses for this technology include remote technical support and accessing files on one's work computer from one's home computer, or vice versa.
VNC was originally developed at the Olivetti & Oracle Research Lab in Cambridge, United Kingdom. The original VNC source code and many modern derivatives are open source under the GNU General Public License.
VNC in KDE 3.1
There are a number of variants of VNC[2] which offer their own particular functionality; e.g., some optimised for Microsoft Windows, or offering file transfer (not part of VNC proper), etc. Many are compatible (without their added features) with VNC proper in the sense that a viewer of one flavour can connect with a server of another; others are based on VNC code but not compatible with standard VNC.
VNC and RFB are registered trademarks of RealVNC Ltd. in the US and some other countries.
![Computer Computer](https://skp.samsungcsportal.com/upload/namo/FAQ/ca/20170714/20170714233926211_Z46D9ERC.png)
History[edit]
The Olivetti & Oracle Research Lab (ORL)[3] at Cambridge in the UK developed VNC at a time when Olivetti and Oracle Corporation owned the lab. In 1999, AT&T acquired the lab, and in 2002 closed down the lab's research efforts.
Developers who worked on VNC while still at the AT&T Research Lab include:[4]
- Tristan Richardson (inventor)
- Andy Harter (project leader)
- James Weatherall
Following the closure of ORL in 2002, several members of the development team (including Richardson, Harter, Weatherall and Hopper) formed RealVNC in order to continue working on open-source and commercial VNC software under that name.
The original GPLed source code has fed into several other versions of VNC. Such forking has not led to compatibility problems because the RFB protocol is designed to be extensible. VNC clients and servers negotiate their capabilities with handshaking in order to use the most appropriate options supported at both ends.
As of 2013, RealVNC Ltd claims the term 'VNC' as a registered trademark in the United States and in other countries.[5]
Etymology[edit]
The name Virtual Network Computer/Computing (VNC) originated with ORL's work on a thin client called the Videotile, which also used the RFB protocol. The Videotile had an LCD display with pen input and a fast ATM connection to the network. At the time, network computer was commonly used as a synonym for a thin client; VNC is essentially a software-only (i.e. virtual) network computer.[citation needed]
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Operation[edit]
- The VNC server is the program on the machine that shares some screen (and may not be related to a physical display – the server can be 'headless'), and allows the client to share control of it.
- The VNC client (or viewer) is the program that represents the screen data originating from the server, receives updates from it, and presumably controls it by informing the server of collected local input.
- The VNC protocol (RFB protocol) is very simple, based on transmitting one graphic primitive from server to client ('Put a rectangle of pixel data at the specified X,Y position') and event messages from client to server.
In the normal method of operation a viewer connects to a port on the server (default port: 5900). Alternatively (depending on the implementation) a browser can connect to the server (default port: 5800). And a server can connect to a viewer in 'listening mode' on port 5500. One advantage of listening mode is that the server site does not have to configure its firewall to allow access on port 5900 (or 5800); the duty is on the viewer, which is useful if the server site has no computer expertise and the viewer user is more knowledgeable.
The server sends small rectangles of the framebuffer to the client. In its simplest form, the VNC protocol can use a lot of bandwidth, so various methods have been devised to reduce the communication overhead. For example, there are various encodings (methods to determine the most efficient way to transfer these rectangles). The VNC protocol allows the client and server to negotiate which encoding they will use. The simplest encoding, supported by all clients and servers, is raw encoding, which sends pixel data in left-to-right scanline order, and after the original full screen has been transmitted, transfers only rectangles that change. This encoding works very well if only a small portion of the screen changes from one frame to the next (as when a mouse pointer moves across a desktop, or when text is written at the cursor), but bandwidth demands get very high if a lot of pixels change at the same time (such as when scrolling a window or viewing full-screen video).
VNC by default uses TCP port 5900+N,[6][7] where N is the display number (usually :0 for a physical display). Several implementations also start a basic HTTPserver on port 5800+N to provide a VNC viewer as a Java applet, allowing easy connection through any Java-enabled web-browser. Different port assignments can be used as long as both client and server are configured accordingly. A HTML5 VNC client implementation for modern browsers (no plugins required) exists too.[8]
Although possible even on low bandwidth, using VNC over the Internet is facilitated if the user has a broadband connection at both ends. However, it may require advanced NAT, firewall and router configuration such as port forwarding in order for the connection to go through. Users may establish communication through Virtual Private Network (VPN) technologies to ease usage over the Internet, or as a LAN connection if VPN is used as a proxy, or through a VNC repeater (useful in presence of a NAT).[9][10]
Xvnc is the Unix VNC server, which is based on a standard X server. To applications, Xvnc appears as an X 'server' (i.e., it displays client windows), and to remote VNC users it is a VNC server. Applications can display themselves on Xvnc as if it were a normal X display, but they will appear on any connected VNC viewers rather than on a physical screen.[11] Alternatively, a machine (which may be a workstation or a network server) with screen, keyboard, and mouse can be set up to boot and run the VNC server as a service or daemon, then the screen, keyboard, and mouse can be removed and the machine stored in an out-of-the way location.
In addition, the display that is served by VNC is not necessarily the same display seen by a user on the server. On Unix/Linux computers that support multiple simultaneous X11 sessions, VNC may be set to serve a particular existing X11 session, or to start one of its own. It is also possible to run multiple VNC sessions from the same computer. On Microsoft Windows the VNC session served is always the current user session.[citation needed] Cisdem appcrypt 4 6 1.
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Users commonly deploy VNC as a cross-platform remote desktop system. For example, Apple Remote Desktop for Mac OS X (and more recently, 'Back to My Mac' in 'Leopard' - Mac OS X 10.5) interoperates with VNC and will connect to a Unix user's current desktop if it is served with x11vnc, or to a separate X11 session if one is served with TightVNC. From Unix, TightVNC will connect to a Mac OS X session served by Apple Remote Desktop if the VNC option is enabled, or to a VNC server running on Microsoft Windows.[12]
In July 2014 RealVNC published a Wayland developer preview.[13][14]
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Security[edit]
By default, RFB is not a secure protocol. While passwords are not sent in plain-text (as in telnet), cracking could prove successful if both the encryption key and encoded password were sniffed from a network. For this reason it is recommended that a password of at least 8 characters be used. On the other hand, there is also an 8-character limit on some versions of VNC; if a password is sent exceeding 8 characters, the excess characters are removed and the truncated string is compared to the password.
UltraVNC supports the use of an open-source encryption plugin which encrypts the entire VNC session including password authentication and data transfer. It also allows authentication to be performed based on NTLM and Active Directory user accounts. However, use of such encryption plugins makes it incompatible with other VNC programs. RealVNC offers high-strength AES encryption as part of its commercial package, along with integration with Active Directory. Workspot released AES encryption patches for VNC. According to TightVNC,[15] TightVNC is not secure as picture data is transmitted without encryption. To circumvent this, it should be tunneled through an SSH connection (see below).
VNC may be tunneled over an SSH or VPN connection which would add an extra security layer with stronger encryption. SSH clients are available for most platforms; SSH tunnels can be created from UNIX clients, Microsoft Windows clients, Macintosh clients (including Mac OS X and System 7 and up) – and many others. There are also freeware applications that create instant VPN tunnels between computers.
An additional security concern for the use of VNC is to check whether the version used requires authorization from the remote computer owner before someone takes control of their device. This will avoid the situation where the owner of the computer accessed realizes there is someone in control of their device without previous notice.
See also[edit]
References[edit]
- ^Richardson, T.; Stafford-Fraser, Q.; Wood, K. R.; Hopper, A. (1998). 'Virtual network computing'(PDF). IEEE Internet Computing. 2: 33–38. CiteSeerX10.1.1.17.5625. doi:10.1109/4236.656066.
- ^The VNC family of Remote Control Applications: a list of VNC variants
- ^'VNC Frequently Asked Questions (FAQ)'. 1999. Archived from the original on 15 August 2000.
- ^RealVNC Executive Profiles
- ^Copyright and trademarks RealVNC. Accessed Feb 23, 2018.
- ^'RealVNC - Frequently asked questions'.
- ^'UltraVnc Configuration'.
- ^'noVNC'.
- ^'OpenWRT VNC repeater'.
- ^'uVNC repeater'.
- ^AT&T Laboratories Cambridge (1999). 'X-based VNC server'. Virtual Network Computing. Archived from the original on 19 March 2007. Retrieved 24 March 2007.
- ^'OnlineVNC Server for Windows OSes'.
- ^'VNC® Wayland Developer Preview'. 8 July 2014. Archived from the original on 14 July 2014. Retrieved 10 July 2014.
- ^'RealVNC Wayland developer preview email'. freedesktop.org. 9 July 2014.
- ^How secure is TightVNC? TightVNC Frequently Asked Questions. TightVNC.com Accessed Feb 23, 2018
External links[edit]
Wikimedia Commons has media related to VNC. |
Wikibooks has a book on the topic of: Internet Technologies/VNC |
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- AT&T VNC - Original AT&T-Cambridge VNC website
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