Need for securing a network:

security begins with an understanding how the system or network that needs to be secured works. This chapter uses the approach of analyzing potential threats to properly apply security.The network infrastructure can be divided into three layers-access,distribution and core.these layers contain all hardware that is necessary to control access from internal and external resources. Following are the core network components:

ROUTER:Routers are devices that forward data packets between computer networks, acting as traffic directors on the internet. They determine the best path for data to travel and ensure it reaches its destination efficiently.

FIREWALL: firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules. Its primary function is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet, to prevent unauthorized access and protect against cyber threats.

SWITCH:switch is a network device that connects multiple devices within a local area network (LAN), allowing them to communicate with each other.Switches are design to improve network performance to ease adminstration.For this reason we can easily configure a switch by sending specially formatted packets to it.