When physically securing a building from break-ins, the goal is to prevent any unauthorized person from ever gaining access to the building, so the company's assets will remain safe. The concept of network security is the same. The security administrator's goal is to restrict access to
and from the compant's network.
A firewall is a secure computer system placed between a trusted network and one that is not trusted, such as the Internet. On one side of a firewall is a company's production network that is supervised, controlled, and protected by the network administrator. The other side contains a public network, such as the Internet.
This module discusses the mechanisms used to shield the internal network from unwanted activity.
By the end of this module, you will be able to:
Define and describe firewalls
Describe the role a firewall plays in a company's security policy
Define common firewall terms
Describe packet filter use as a first line of defense
Describe and configure proxy servers
Describe circuit-level gateways and their features
Describe application-level gateways and their features