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62-473: Virtual private network ( VPN ) is a network architecture for virtually extending a private network (i.e. any computer network which is not the public Internet ) across one or multiple other networks which are either untrusted (as they are not controlled by the entity aiming to implement the VPN) or need to be isolated (thus making the lower network invisible or not directly usable). A VPN can extend access to

124-565: A computer keyboard . The actions in a GUI are usually performed through direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls . The term GUI tends not to be applied to other lower- display resolution types of interfaces , such as video games (where head-up displays ( HUDs ) are preferred), or not including flat screens like volumetric displays because

186-548: A web captive portal ). Remote-access VPNs, which are typically user-initiated, may use passwords , biometrics , two-factor authentication , or other cryptographic methods. People initiating this kind of VPN from unknown arbitrary network locations are also called "road-warriors". In such cases, it is not possible to use originating network properties (e.g. IP addresses) as secure authentication factors, and stronger methods are needed. Site-to-site VPNs often use passwords ( pre-shared keys ) or digital certificates . Depending on

248-474: A GUI and some level of a CLI, although the GUIs usually receive more attention. GUI wrappers find a way around the command-line interface versions (CLI) of (typically) Linux and Unix-like software applications and their text-based UIs or typed command labels. While command-line or text-based applications allow users to run a program non-interactively, GUI wrappers atop them avoid the steep learning curve of

310-455: A VPN works depends on which technologies and protocols the VPN is built upon. A tunneling protocol is used to transfer the network messages from one side to the other. The goal is to take network messages from applications on one side of the tunnel and replay them on the other side. Applications do not need to be modified to let their messages pass through the VPN, because the virtual network or link

372-410: A combination of technologies and devices to provide a platform that users can interact with, for the tasks of gathering and producing information. A series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with and use computer software. The most common combination of such elements in GUIs

434-415: A consistent VPN protocol across their products but do not open up for customizations outside the use cases they intended to implement. This is often the case for appliances that rely on hardware acceleration of VPNs to provide higher throughput or support a larger amount of simultaneously connected users. Whenever a VPN is intended to virtually extend a private network over a third-party untrusted medium, it

496-508: A grid of items with rows of text extending sideways from the icon. Multi-row and multi-column layouts commonly found on the web are "shelf" and "waterfall". The former is found on image search engines , where images appear with a fixed height but variable length, and is typically implemented with the CSS property and parameter display: inline-block; . A waterfall layout found on Imgur and TweetDeck with fixed width but variable height per item

558-460: A private network to users who do not have direct access to it, such as an office network allowing secure access from off-site over the Internet. This is achieved by creating a link between computing devices and computer networks by the use of network tunneling protocols . It is possible to make a VPN secure to use on top of insecure communication medium (such as the public internet) by choosing

620-506: A program was busy. Additionally, it was the first GUI to introduce something resembling Virtual Desktops . Windows 95 , accompanied by an extensive marketing campaign, was a major success in the marketplace at launch and shortly became the most popular desktop operating system. In 2007, with the iPhone and later in 2010 with the introduction of the iPad , Apple popularized the post-WIMP style of interaction for multi-touch screens, and those devices were considered to be milestones in

682-474: A retail store, airline self-ticket and check-in, information kiosks in a public space, like a train station or a museum, and monitors or control screens in an embedded industrial application which employ a real-time operating system (RTOS). Cell phones and handheld game systems also employ application specific touchscreen GUIs. Newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. A GUI uses

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744-539: A selection of VPN protocols which is subject to change over the years, as some have been proven to be unsecure with respect to modern requirements and expectations, and some others emerged. Desktop, smartphone and other end-user device operating systems do usually support configuring remote access VPN from their graphical or command-line tools. However, due to the variety of, often non standard, VPN protocols there exists many third-party applications that implement additional protocols not yet or no more natively supported by

806-414: A short sequence of words and symbols. Custom functions may be used to facilitate access to frequent actions. Command-line interfaces are more lightweight , as they only recall information necessary for a task; for example, no preview thumbnails or graphical rendering of web pages. This allows greater efficiency and productivity once many commands are learned. But reaching this level takes some time because

868-532: A significantly complex business network, may be combined to enable remote access to resources located at any given site, such as an ordering system that resides in a data center. Apart from the general topology configuration, a VPN may also be characterized by: A variety of VPN technics exist to adapt to the above characteristics, each providing different network tunneling capabilities and different security model coverage or interpretation. Operating systems vendors and developers do typically offer native support to

930-428: A system or moved about to different places during redesigns. Also, icons and dialog boxes are usually harder for users to script. WIMPs extensively use modes , as the meaning of all keys and clicks on specific positions on the screen are redefined all the time. Command-line interfaces use modes only in limited forms, such as for current directory and environment variables . Most modern operating systems provide both

992-579: A third-party, and might prefer a VPN implemented via protocols that protect the privacy of their communication. In the case of a Provider-provisioned VPN , the goal is not to protect against untrusted networks, but to isolate parts of the provider's own network infrastructure in virtual segments, in ways that make the contents of each segment private with respect to the others. This situation makes many other tunneling protocols suitable for building PPVPNs, even with weak or no security features (like in VLAN ). How

1054-409: A tunneling protocol that implements encryption . This kind of VPN implementation has the benefit of reduced costs and greater flexibility, with respect to dedicated communication lines, for remote workers . The term VPN is also used to refer to VPN services which sell access to their own private networks for internet access by connecting their customers using VPN tunneling protocols. The goal of

1116-403: A virtual private network is to allow network hosts to exchange network messages across another network to access private content, as if they were part of the same network. This is done in a way that makes crossing the intermediate network transparent to network applications. Users of a network connectivity service may consider such an intermediate network to be untrusted, since it is controlled by

1178-443: Is a form of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation . In many applications, GUIs are used instead of text-based UIs , which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on

1240-674: Is a related technology that promises to deliver the representation benefits of 3D environments without their usability drawbacks of orientation problems and hidden objects. In 2006, Hillcrest Labs introduced the first ZUI for television. Other innovations include the menus on the PlayStation 2 , the menus on the Xbox , Sun's Project Looking Glass , Metisse , which was similar to Project Looking Glass, BumpTop , where users can manipulate documents and windows with realistic movement and physics as if they were physical documents, Croquet OS , which

1302-429: Is desirable that the chosen protocols match the following security model: VPN are not intended to make connecting users neither anonymous nor unidentifiable from the untrusted medium network provider perspective. If the VPN makes use of protocols that do provide the above confidentiality features, their usage can increase user privacy by making the untrusted medium owner unable to access the private data exchanged across

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1364-417: Is especially common with applications designed for Unix-like operating systems. The latter used to be implemented first because it allowed the developers to focus exclusively on their product's functionality without bothering about interface details such as designing icons and placing buttons. Designing programs this way also allows users to run the program in a shell script . Many environments and games use

1426-457: Is made available to the OS. Applications that do implement tunneling or proxying features for themselves without making such features available as a network interface, are not to be considered VPN implementations but may achieve the same or similar end-user goal of exchanging private contents with a remote network. Virtual private networks configurations can be classified depending on the purpose of

1488-669: Is represented by rotating a cube with faces representing each user's workspace, and window management is represented via a Rolodex -style flipping mechanism in Windows Vista (see Windows Flip 3D ). In both cases, the operating system transforms windows on-the-fly while continuing to update the content of those windows. The GUI is usually WIMP-based, although occasionally other metaphors surface, such as those used in Microsoft Bob , 3dwm, File System Navigator, File System Visualizer , 3D Mailbox, and GopherVR . Zooming (ZUI)

1550-552: Is that they are point-to-point connections and do not tend to support broadcast domains ; therefore, communication, software, and networking, which are based on layer 2 and broadcast packets , such as NetBIOS used in Windows networking , may not be fully supported as on a local area network . Variants on VPN such as Virtual Private LAN Service (VPLS) and layer 2 tunneling protocols are designed to overcome this limitation. Network architecture In telecommunications ,

1612-440: Is the windows, icons, text fields, canvases, menus, pointer ( WIMP ) paradigm, especially in personal computers . The WIMP style of interaction uses a virtual input device to represent the position of a pointing device's interface , most often a mouse , and presents information organized in windows and represented with icons . Available commands are compiled together in menus, and actions are performed making gestures with

1674-460: Is the organization of nodes in peer-to-peer (P2P) services and networks . P2P networks usually implement overlay networks running over an underlying physical or logical network. These overlay networks may implement certain organizational structures of the nodes according to several distinct models, the network architecture of the system. Graphical user interface A graphical user interface , or GUI ( / ˈ ɡ uː i / GOO -ee ),

1736-555: Is usually implemented by specifying column-width: . Smaller app mobile devices such as personal digital assistants (PDAs) and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space and available input devices. Applications for which WIMP is not well suited may use newer interaction techniques , collectively termed post-WIMP UIs. As of 2011, some touchscreen-based operating systems such as Apple's iOS ( iPhone ) and Android use

1798-709: The Xerox Star . These early systems spurred many other GUI efforts, including Lisp machines by Symbolics and other manufacturers, the Apple Lisa (which presented the concept of menu bar and window controls ) in 1983, the Apple Macintosh 128K in 1984, and the Atari ST with Digital Research 's GEM , and Commodore Amiga in 1985. Visi On was released in 1983 for the IBM PC compatible computers, but

1860-584: The applications architecture of the public switched telephone network (PSTN) has been termed the Intelligent Network . There are a number of specific classifications but all lie on a continuum between the dumb network (e.g. the Internet ) and the intelligent network (e.g. the PSTN). A popular example of such usage of the term in distributed applications, as well as permanent virtual circuits ,

1922-501: The cursor (or rather pointer ) control: mouse , pointing stick , touchpad , trackball , joystick , virtual keyboards , and head-up displays (translucent information devices at the eye level). There are also actions performed by programs that affect the GUI. For example, there are components like inotify or D-Bus to facilitate communication between computer programs. Ivan Sutherland developed Sketchpad in 1963, widely held as

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1984-627: The 1970s, Engelbart's ideas were further refined and extended to graphics by researchers at Xerox PARC and specifically Alan Kay , who went beyond text-based hyperlinks and used a GUI as the main interface for the Smalltalk programming language , which ran on the Xerox Alto computer , released in 1973. Most modern general-purpose GUIs are derived from this system. The Xerox PARC GUI consisted of graphical elements such as windows , menus , radio buttons , and check boxes . The concept of icons

2046-513: The GUIs advantages, many reviewers questioned the value of the entire concept, citing hardware limits, and problems in finding compatible software. In 1984, Apple released a television commercial which introduced the Apple Macintosh during the telecast of Super Bowl XVIII by CBS , with allusions to George Orwell 's noted novel Nineteen Eighty-Four . The goal of the commercial was to make people think about computers, identifying

2108-479: The OS. For instance, Android lacked native IPsec IKEv2 support until version 11, and people needed to install third-party apps in order to connect that kind of VPNs, while Microsoft Windows , BlackBerry OS and others got it supported in the past. Conversely, Windows does not support plain IPsec IKEv1 remote access native VPN configuration (commonly used by Cisco and Fritz!Box VPN solutions) which makes

2170-558: The VPN is not fixed to a single IP address , but instead roams across various networks such as data networks from cellular carriers or between multiple Wi-Fi access points without dropping the secure VPN session or losing application sessions. Mobile VPNs are widely used in public safety where they give law-enforcement officers access to applications such as computer-assisted dispatch and criminal databases, and in other organizations with similar requirements such as field service management and healthcare. A limitation of traditional VPNs

2232-413: The VPN protocol, they may store the key to allow the VPN tunnel to establish automatically, without intervention from the administrator. A virtual private network is based on a tunneling protocol, and may be possibly combined with other network or application protocols providing extra capabilities and different security model coverage. Trusted VPNs do not use cryptographic tunneling; instead, they rely on

2294-522: The VPN. In order to prevent unauthorized users from accessing the VPN, most protocols can be implemented in ways that also enable authentication of connecting parties. This secures the joined remote network confidentiality, integrity and availability. Tunnel endpoints can be authenticated in various ways during the VPN access initiation. Authentication can happen immediately on VPN initiation (e.g. by simple whitelisting of endpoint IP address), or very lately after actual tunnels are already active (e.g. with

2356-401: The class of GUIs named post-WIMP. These support styles of interaction using more than one finger in contact with a display, which allows actions such as pinching and rotating, which are unsupported by one pointer and mouse. Human interface devices , for the efficient interaction with a GUI include a computer keyboard , especially used together with keyboard shortcuts , pointing devices for

2418-457: The command words may not be easily discoverable or mnemonic . Also, using the command line can become slow and error-prone when users must enter long commands comprising many parameters or several different filenames at once. However, windows, icons, menus, pointer ( WIMP ) interfaces present users with many widgets that represent and can trigger some of the system's available commands. GUIs can be made quite hard when dialogs are buried deep in

2480-413: The command-line, which requires commands to be typed on the keyboard . By starting a GUI wrapper, users can intuitively interact with, start, stop, and change its working parameters, through graphical icons and visual indicators of a desktop environment , for example. Applications may also provide both interfaces, and when they do the GUI is usually a WIMP wrapper around the command-line version. This

2542-571: The designer's work to change the interface as user needs evolve. Good GUI design relates to users more, and to system architecture less. Large widgets, such as windows , usually provide a frame or container for the main presentation content such as a web page, email message, or drawing. Smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a vertical market as application-specific GUIs. Examples include automated teller machines (ATM), point of sale (POS) touchscreens at restaurants, self-service checkouts used in

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2604-485: The development of mobile devices . The GUIs familiar to most people as of the mid-late 2010s are Microsoft Windows , macOS , and the X Window System interfaces for desktop and laptop computers, and Android , Apple's iOS , Symbian , BlackBerry OS , Windows Phone / Windows 10 Mobile , Tizen , WebOS , and Firefox OS for handheld ( smartphone ) devices. Since the commands available in command line interfaces can be many, complex operations can be performed using

2666-435: The display represents a desktop, on which documents and folders of documents can be placed. Window managers and other software combine to simulate the desktop environment with varying degrees of realism. Entries may appear in a list to make space for text and details, or in a grid for compactness and larger icons with little space underneath for text. Variations in between exist, such as a list with multiple columns of items and

2728-611: The first graphical computer-aided design program. It used a light pen to create and manipulate objects in engineering drawings in realtime with coordinated graphics. In the late 1960s, researchers at the Stanford Research Institute , led by Douglas Engelbart , developed the On-Line System (NLS), which used text-based hyperlinks manipulated with a then-new device: the mouse . (A 1968 demonstration of NLS became known as " The Mother of All Demos ".) In

2790-485: The interface found in current versions of Microsoft Windows, and in various desktop environments for Unix-like operating systems , such as macOS and Linux . Thus most current GUIs have largely common idioms. GUIs were a hot topic in the early 1980s. The Apple Lisa was released in 1983, and various windowing systems existed for DOS operating systems (including PC GEM and PC/GEOS ). Individual applications for many platforms presented their own GUI variants. Despite

2852-413: The kind of data they hold. The widgets of a well-designed interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows flexible structures in which the interface is independent of and indirectly linked to application functions, so the GUI can be customized easily. This allows users to select or design a different skin or theme at will, and eases

2914-402: The layer below it. On each layer, an instance provides services to the instances at the layer above and requests services from the layer below. In distributed computing , the network architecture often describes the structure and classification of a distributed application architecture, as the participating nodes in a distributed application are often referred to as a network . For example,

2976-435: The methods of 3D graphics to project 3D GUI objects onto the screen. The use of 3D graphics has become increasingly common in mainstream operating systems (ex. Windows Aero , and Aqua (MacOS)) to create attractive interfaces, termed eye candy (which includes, for example, the use of drop shadows underneath windows and the cursor ), or for functional purposes only possible using three dimensions. For example, user switching

3038-407: The network, or the usage of specific types of hardware links. The Open Systems Interconnection model (OSI model) defines and codifies the concept of layered network architecture. Abstraction layers are used to subdivide a communications system further into smaller manageable parts. A layer is a collection of similar functions that provide services to the layer above it and receives services from

3100-424: The open source code of the OS itself. For instance, pfSense does not support remote access VPN configurations through its user interface where the OS runs on the remote host, while provides comprehensive support for configuring it as the central VPN gateway of such remote-access configuration scenario. Otherwise, commercial appliances with VPN features based on proprietary hardware/software platforms, usually support

3162-461: The open source operating systems devoted to firewalls and network devices (like OpenWrt , IPFire , PfSense or OPNsense ) it is possible to add support for additional VPN protocols by installing missing software components or third-party apps. Similarly, it is possible to get additional VPN configurations working, even if the OS does not facilitate the setup of that particular configuration, by manually editing internal configurations of by modifying

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3224-403: The pointing device. A window manager facilitates the interactions between windows, applications , and the windowing system . The windowing system handles hardware devices such as pointing devices, graphics hardware, and positioning of the pointer. In personal computers , all these elements are modeled through a desktop metaphor to produce a simulation called a desktop environment in which

3286-465: The security of a single provider's network to protect the traffic. From a security standpoint, a VPN must either trust the underlying delivery network or enforce security with a mechanism in the VPN itself. Unless the trusted delivery network runs among physically secure sites only, both trusted and secure models need an authentication mechanism for users to gain access to the VPN. Mobile virtual private networks are used in settings where an endpoint of

3348-421: The specification of a network architecture may also include a detailed description of products and services delivered via a communications network, as well as detailed rate and billing structures under which services are compensated. The network architecture of the Internet is predominantly expressed by its use of the Internet protocol suite , rather than a specific model for interconnecting networks or nodes in

3410-517: The system never reached commercial production. The first commercially available computer with a GUI was the 1979 PERQ workstation , manufactured by Three Rivers Computer Corporation. Its design was heavily influenced by the work at Xerox PARC. In 1981, Xerox eventually commercialized the ideas from the Alto in the form of a new and enhanced system – the Xerox 8010 Information System – more commonly known as

3472-505: The term is restricted to the scope of 2D display screens able to describe generic information, in the tradition of the computer science research at the Xerox Palo Alto Research Center . Designing the visual composition and temporal behavior of a GUI is an important part of software application programming in the area of human–computer interaction . Its goal is to enhance the efficiency and ease of use for

3534-456: The underlying logical design of a stored program , a design discipline named usability . Methods of user-centered design are used to ensure that the visual language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI . Typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to

3596-451: The use of third-party applications mandatory for people and companies relying on such VPN protocol. Network appliances, such as firewalls, do often include VPN gateway functionality for either remote access or site-to-site configurations. Their administration interfaces do often facilitate setting up virtual private networks with a selection of supported protocols which have been integrated for an easy out-of-box setup. In some cases, like in

3658-470: The user-friendly interface as a personal computer which departed from prior business-oriented systems, and becoming a signature representation of Apple products. In 1985, Commodore released the Amiga 1000 , along with Workbench and Kickstart 1.0 (which contained Intuition ). This interface ran as a separate task, meaning it was very responsive and, unlike other GUIs of the time, it didn't freeze up when

3720-715: The virtual extension, which makes different tunneling strategies appropriate for different topologies: In the context of site-to-site configurations, the terms intranet and extranet are used to describe two different use cases. An intranet site-to-site VPN describes a configuration where the sites connected by the VPN belong to the same organization, whereas an extranet site-to-site VPN joins sites belonging to multiple organizations. Typically, individuals interact with remote access VPNs, whereas businesses tend to make use of site-to-site connections for business-to-business , cloud computing, and branch office scenarios. However, these technologies are not mutually exclusive and, in

3782-399: Was later introduced by David Canfield Smith , who had written a thesis on the subject under the guidance of Kay. The PARC GUI employs a pointing device along with a keyboard. These aspects can be emphasized by using the alternative term and acronym for windows, icons, menus, pointing device ( WIMP ). This effort culminated in the 1973 Xerox Alto , the first computer with a GUI, though

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3844-588: Was never popular due to its high hardware demands. Nevertheless, it was a crucial influence on the contemporary development of Microsoft Windows . Apple, Digital Research, IBM and Microsoft used many of Xerox's ideas to develop products, and IBM's Common User Access specifications formed the basis of the GUIs used in Microsoft Windows, IBM OS/2 Presentation Manager , and the Unix Motif toolkit and window manager . These ideas evolved to create

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