Extranets and Intranet


Over recent years, the terms intranet and extranet have established themselves firmly in the IT vocabulary. Even so, many people are still unsure about what exactly defines, or is defined by, either an intranet or an extranet.

Intranets

The term intranet is commonly used to describe a web-based application or system that provides tools for groups of people to work together collaboratively. The key element of an intranet is that only people within an organization can access it. Intranets are typically hosted, maintained, and operated completely independently from an organization's external Web presence, even though some of the information provided through both mechanisms might be the same. An example of an intranet is shown in Figure 8.4

Figure 8.4. An example of an intranet.


Intranet Technically speaking, any privately operated network to which external access is restricted could be considered an intranet. In common use terms, though, the description provided in this section is the most common interpretation of the term intranet.


Because they are typically accessed using Web browsers, and hosted by Web server applications, intranets rely on protocols such as the Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP).


Intranets are commonly identified by the following characteristics:

  • Limited access Access to an intranet is normally limited to users, or a sub-group of users, within the organization.

  • Browser based Most intranets operate as Web serverbased applications, and so are accessed through a Web browser.

  • Types of application Although no specific rules define what applications an intranet can host, the most common are collaborative, 'groupware' applications.

Extranets

Any network or application that is accessible from outside the physical and logical boundaries of an organization can be called an extranet. This means that any network on which remote access services are provided could, technically, be considered an extranet. Commonly, though, the term extranet is used to describe a system or application, hosted within an organization, which is securely made available to selected individuals or entire organizations outside of the hosting organization.

The key consideration to this model is that the company providing the system controls access to the extranet. In other words, only selected clients and associates are provided with access, and they might even be required to access the extranet over secure virtual private networking (VPN) links. Contrast this with the model used by, for example, online bookstores, where anyone can access the site, even though a username and password is subsequently required to place or track orders. Although the bookstore could decide to prevent a certain user from accessing the site, they are unlikely to do so. Figure 8.5 shows an example of an extranet.

Figure 8.5. An example of an extranet.


Extranets are commonly identified by the following characteristics:

  • Users are outside of the hosting organization Access to the extranet system is made available to individuals and organizations that are not directly affiliated with the host organization.

  • Only the owner of the system grants access Access to the extranet is normally granted and controlled by the operating organization.

  • Secure Extranets are typically secure, and connection to the extranet might require the use of secure communication channels such as a VPN.

Typically, though not exclusively, extranet applications, like intranet applications, are hosted on a Web server and accessed through a Web browser.



    Network+ Exam Cram 2
    Network+ Exam Cram 2
    ISBN: 078974905X
    EAN: N/A
    Year: 2003
    Pages: 194

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