Network is the computer, so goes the slogan of a popular computer company. This statement has never been truer than now. All modern computers come with one or more devices that can connect it to other computers (Modem or a Network card). Some use their computers solely as a communication device. With all this recent emphasis on computer networks, it is no wonder that the Intranets are getting popular by the day. 

Intranets are an evolution of Computer Networks. With businesses needing a more efficient way of generating and maintaining information and a more efficient way of Internal communication, Intranets offered exactly the solution they were looking for. A typical Intranet offers at the least: 

1. Logically centralized access to information. The information itself could be stored in physically different places (or computers), but access to any information should be simple and should be from a common place.
2. Messaging within its users. The Intranet should allow efficient communication within the organization. This is typically accomplished by providing a local email service though other channels like audio conferencing and video conferencing are beginning to show up.
3. Secure and integrated access to outside world. A stand alone Intranet is of limited use much like a stand-alone computer. Businesses need access to resources on the Internet as also need to communicate with external entities (suppliers, clients, other branches) on the Internet. An Intranet should provide such access while ensuring that the internal data remains secure. This is typically accomplished by connecting to the Internet through a firewall. The firewall will typically disallow any communication requests from the outside world and allow only authenticated communication from within the Intranet.

Rainmail Server is Server software that helps an organization deploy an Intranet.