What is Extranet?

Question

I know subnet mask is used to separate network byte and host byte but what if my subnet mask is not configured properly.

E.g.
In my environment i need to use 255.255.254.0 as a subnet but i mistakenly configured 255.255.252.0 but still I am able to receive and send data from my system, Then what is the use of using correct subnet?

Answer 1

In Summary an Extranet is an Intranet which is partially accessible to authorized outsiders users. In technical implementation server which hosts the which hosts the web pages remains behind a firewall which helps to control access between the Intranet and Internet permitting access to the Intranet only to authorized users.
The level of access can be set to different levels for individuals or groups of outside users. The access can be based on a username and password or an IP address.

Advantages (Source: Wiki)
Exchange large volumes of data using Electronic Data Interchange (EDI)
Share product catalogs exclusively with external trade partners
Collaborate with other companies on joint development efforts
Jointly develop and use training programs with other companies
Provide or access services provided by one company to a group of other companies, such as an online banking application managed by one company on behalf of affiliated banks

Disadvantages
Extranets can be expensive to implement and maintain within an organization (e.g., hardware, software, employee training costs), if hosted internally rather than by an application service provider.
Security of extranets can be a concern when hosting valuable or proprietary information.

Answer 2

An extranet is a private network that uses Internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses. An extranet can be viewed as part of a company's intranet that is extended to users outside the company. It has also been described as a "state of mind" in which the Internet is perceived as a way to do business with other companies as well as to sell products to customers.

An extranet requires security and privacy. These can include firewall server management, the issuance and use of digital certificates or similar means of user authentication, encryption of messages, and the use of virtual private networks (VPNs) that tunnel through the public network.

Companies can use an extranet to:
• Exchange large volumes of data using Electronic Data Interchange (EDI)
• Share product catalogs exclusively with wholesalers or those "in the trade"
• Collaborate with other companies on joint development efforts
• Jointly develop and use training programs with other companies
• Provide or access services provided by one company to a group of other companies, such as an online banking application managed by one company on behalf of affiliated banks
• Share news of common interest exclusively with partner companies