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Oct 06, 2010 VNC Enterprise Edition is arguably the best free Mac OS X VNC client. VNC Enterprise Edition is a commercial product, from RealVNC, however licenses are only required for the VNC Server component - the viewer is free. Zhida Cheng mentioned Mac O. VNC, the Remote Frame Buffer protocol (RFB) allows a desktop to be viewed and controlled remotely over the Internet. A VNC server must be run on the computer sharing the desktop, a VNC client must be run on the computer that will access the shared desktop.
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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.
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]
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, including instant VPN applications (such as LogMeIn Hamachi) 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]
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]
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 are 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 make 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 a SSH connection (see below).
VNC may be tunnelled 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 |
- AT&T VNC - Original AT&T-Cambridge VNC website
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Virtual_Network_Computing&oldid=916580507'
You can set VMware Fusion so that any VNC client can access the virtual machine by connecting to your Mac.
Virtual network computing (VNC) software enables you to view and interact with one computer from any other computer or mobile device anywhere on the Internet. VNC software is cross-platform, allowing remote control between different types of computers.
There are three ways to have VNC set up, as described in Options for VNC. The option of using the VNC server provided by VMware Fusion is the subject of this help topic.
Zonealarm for mac. Description | |
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Remote Desktop, Screen Sharing, or Third-party VNC server on the Mac host | This enables controlling the entire host Mac, including VMware Fusion and any other applications. The connection to this server is made using the host's IP address or hostname. |
VNC server provided by VMware Fusion | This is available for each virtual machine, and must be set to unique ports that are not already in use, as described in the procedure in this help topic. Using the VNC server provided by VMware Fusion enables controlling the virtual machine whenever it is powered on, even before the guest operating system is running. The connection to this server is made using the host's IP address or hostname. |
VNC server inside the virtual machine's guest operating system | This VNC server is installed like any other application inside the virtual machine. How to get word and excel on mac for free. It allows controlling only the guest operating system, and it is only available once the guest operating system starts up. The connection to this server is made using the guest's IP address or hostname when using Bridged networking. |
The following procedure describes how to use the VNC server provided by VMware Fusion to enable a VNC Client to access the virtual machine remotely.
2 | In the Settings window, select Advanced. |
Click the Remote display over VNC checkbox. | |
4 | (Optional) Virtual machine software for mac. Type a password. Because data sent over VNC is unencrypted, do not use your regular password. |
Identify the port on the Mac. Microsoft office 2013 for mac os x torrent. The default port is 5900. If you enabled Screen Sharing on this Mac, port 5900 might already be in use and you must use a different port, like 5901. For multiple virtual machines, increment the port number for each additional virtual machine. |
Windows Vnc Client For Mac
Your virtual machine is visible to VNC clients.