Internet
The Internet is a global system of
interconnected computer networks. It is not controlled by a central entity and
therefore relies on network devices and accepted conventions and protocols to
relay the data traffic until it gets to its destinations. Some countries have
imposed rules to censor or otherwise control what kind of content is accessible
by its citizen (i.e. China). However, except for the management of Internet
Protocol addresses and the Domain Name System by ICANN (the Internet
Corporation for Assigned Names and Numbers), the Internet remains unregulated
and uncensored.
The beginnings of the Internet can
be traced back to the 1960s when the United States funded research by its
military agencies to develop a fault-tolerant and robust distributed network of
computers. The Internet is now global and in theory can be accessed by anyone
who can get access from an Internet service provider.
Intranet
On the other hand, an intranet is a
private network that is setup and controlled by an organization to encourage
interaction among its members, to improve efficiency and to share information,
among other things. Information and resources that are shared on an intranet might include: organizational
policies and procedures, announcements, information about new products, and
confidential data of strategic value.
An intranet is a restricted-access
network that works much like the Internet, but is isolated from it. As is the
case with the Internet, an intranet is based on TCP/IP protocols. Therefore, a
web page in an intranet may look and act just like any other webpage on the
Internet, but access is restricted to authorized persons and devices. In some
cases, access to an intranet is restricted by not connecting it to other
networks, but in other cases a firewall is used to deny access to unauthorized
entities.
The difference between an intranet
and the Internet is defined in terms of accessibility, size and control. Unless
content filters are being used or the government is censoring content, all the
Internet’s content is accessible to everyone. On the other hand an intranet is
owned and controlled by a single organization that decides which members are
allowed access to certain parts of the intranet. In general, an intranet is
usually very small and is restricted to the premises of a single organization.
Extranet
An extranet is an extended intranet.
In addition to allowing access to members of an organization, an extranet uses
firewalls, access profiles, and privacy protocols to allow access to users from
outside the organization. In essence, an extranet is a private network that
uses Internet protocols and public networks to securely share resources with
customers, suppliers, vendors, partners, or other businesses.
Both intranets and extranets are
owned, operated and controlled by one organization.
However, the difference
between intranets and extranets is defined in terms of who has access to the
private network and the geographical reach of that network. Intranets allow
only members of the organization to access the network, while an extranet
allows persons from outside the organization (i.e. business partners and
customers) to access the network. Usually, network access is managed through
the administration of usernames and passwords, which are also used to determine
which parts of the extranet a particular user can access.
Summary
The Internet, extranets, and
intranets all rely on the same TCP/IP technologies. However, they are different
in terms of the levels ofaccess they allow to various users inside and outside
the organization and the size of the network. An intranet allows for restricted
access to only members of an organization; an extranet expands that access by
allowing non-members such as suppliers and customers to use company resources.
The difference between the Internet and extranets is that while the extranet
allows limited access to non-members of an organization, the Internet generally
allows everyone to access all network resources.
