It is important to know that there are different kinds of connection to the Internet which determine the way in which we will be able to work on it. In other words, connection to the Internet substantially affects its usefulness to the customer.
Local area networks can be attached to the Internet by installing TCP/IP networking software on the LAN server and obtaining connection between the LAN and the Internet. A wide range of different types of machines that are connected to the LAN can access the Internet, including DOS and windows-based personal computers (PCs) and UNIX workstations.
Basically, there are two fundamental methods of connection. They are full connection or terminal connection. In the case of full connection, there will be a permanent telecommunication link and the computer has a registered Internet name and address. The second type of connection is known as dial-up connection, via a temporary telecommunications link to a host machine that has full access. The third type of connection is known as gateway connection, where a connection is made through another network or service supplier" like 'Compu Serve'.
It is established either by direct connection such as used by universities or corporate bodies, where the machine or network of machines is permanently linked by dedicated line to the net, and has its own address; or remotely by using Serial Line Internet Protocol (SLIP) or Point to Point Protocol (PPP) connection to a directly connected machine. The advantage of having full connection is that, you can install any client software of your requirement on your machine and use all the facilities of the Internet.
On the other hand, if your local computer is connected to a host, which has a full connection, your machine acts only as a terminal to the host machine. You simply log on to the host and then access the Internet from the host. In this situation, you can avail only limited facilities depending upon the type of communication between your self and the host. It is the norm today for commercial hosts to provide SLIP/PPP connection, But this is not the case in those areas where telecommunications facilities are poor and the Internet is still developing.