BASIC NETWORKING CONCEPTS

Introduction

Networks connect computers together. The Merits of networking include communication with other users, sharing resources such as printers and software, centralization of software and account maintenance, and mobility of users. These concepts are independent of the type of computer workplace or its operating system.

Local Area Networks (LANs)

Generally a LAN is a network which connects computers of various types, and various sub-networks (within a small geographical area). The purpose of a Local Area Connection is usually to share the computing resources of a group of users. LAN supports various functions such as the system database, dial-in modem, data processing functions, etc.

Wide Area Networks (WANs) and the Internet:

A Wide Area Network (WAN) connects several networks of computers of various types over a wide geographical area. One of the best example for WAN is world wide internet

FIREWALL

Firewall is nothing but a security device which is configured in such a way to permit, proxy data through a network.

1. First generation:

It is also called as the Packet Filters. It is a highly technical internet security device. This type of firewall inspects the packets during the data transfer between the computers on the internet. Only if the packet matches the rules of the filter the packet will be transferred or otherwise it will discard the packet with an error message.

2. Second Generation:

It is also called as the Stateful Filter. This type of Filter thoroughly checks all the contents of each packet individually and it maintains the records for all the connections through the firewall. This type of filter will determine whether the packet is a new connection or a part of an existing one.

3. Third Generation:

It is otherwise called as the Proxy filters. This type of filter is an application layer filtering and one of the advantages is that this will identify certain protocols and applications and it will discard the unwanted protocols being transferred through.