Security Hardware Problems caused by Devices

Web sites may fail due to outside attacks by hackers, who manage to gain access to the system and steal or corrupt data. Over the last few years there have been a number of attacks both in the private and the public sectors, which have increased concern about the importance of security hardware.

• What is security hardware?
  The security hardware's goal is to ensure that data stored in a computer cannot be accessed or altered by unauthorized users. To prevent unauthorized access to or from a private network, such as an intranet, a firewall server is used. The firewall is the first line of defense against unwanted users. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

1. client hardware: Desktop computer, network interface card, and modem
2. server hardware: A remote device shared by many users. It may store a particular resource, such as Web pages, or perform specific functions, such as forwarding and receiving email.
3. connectivity hardware: Allows a device or a program to link to other devices or programs.
4. security hardware: Firewall: ensures that data stored in a computer cannot be accessed by unauthorized users.
5. UPS: The uninterrupted power supply ensures that electrical power continues to be available during a power outage.

Firewalls are tools that can be used to enhance the security of computers connected to a network, such as a LAN or the Internet. A firewall separates a computer from the Internet, inspecting packets of data as they arrive at either side of the firewall ?

1. inbound to,
2. or outbound from,
3. your computer

to determine whether it should be allowed to pass or be blocked. Firewalls act as guards at the entry points of the computer (which are called "ports") where the computer exchanges data with other devices on the network. Firewalls ensure that packets that are requesting permission to enter the computer meet certain rules that are established by the user of the computer. Firewalls operate in two ways:

1. by either denying or accepting all messages based on a list of designated acceptable or unacceptable sources, or
2. by allowing or denying all messages based on a list of designated destination ports.

Although they sound complex, firewalls are relatively easy to install, setup and operate. This page is not intended to serve as a review of specific firewall products. Rather, it will serve as an overview of what firewalls are, how they work, and the different types of firewall technology and their suitability for small office and personal computer users.

In order to understand how firewalls work it is important to understand the basics of TCP/IP, the language or protocol which all computers on the internet use to communicate. If you are not at all familiar with concepts such as packets, ports and IP addresses, please refer to the following page on Transport Layer TCP/UDP.
If you are, the following section may seem elementary. However, it explains each of the aspects of TCP/IP as it relates specifically to firewalls. Let us start by saying that TCP/IP is a language that allows different computers to communicate. On the Internet, this language is spoken and understood by all different types of computers, even those using different operating systems such as Windows, Macintosh, or Unix.
There are three types of firewalls, varying in complexity and level of security. These are:

1. Packet-level gateway: The packet-level gateway is the most basic and inexpensive kind of firewall. It consists of a router configured with standard packet-filtering that scans each packet's header for authorized IP addresses and specified types of traffic. Unauthorized packets are simply discarded.
2. Application-level gateway: The application-level gateway (proxy server) is more secure than the packet-level gateway and harder to configure. It acts as an intermediary between clients and servers and uses server programs called proxies to examine external requests and forwards authorized requests to the appropriate internal host.
3. Circuit-level gateway: The circuit-level gateway relays TCP connections. It copies bytes back and forth from either side of the firewall creating a virtual circuit. It is best for trusted internal users who also need to do work outside the firewall. It's the safest of the three types of firewalls, but also the most difficult to configure.

Users may experience problems caused by their own security hardware. For example, a user may not be able to access or download from certain Web sites if the firewall configuration is faulty or if there is a router IP filtering problem. A faulty firewall configuration or the lack of sufficient client memory may also cause errors when the user attempts to download plug-ins.

• Three types of Firewalls There are three different types of firewalls. They vary in cost as well as level of configuration complexity and safety.
  From the simplest to the most complex, these firewalls are known as Packet-level gateways, Application-level gateways, and Circuit-level gateways. In the next lesson, you will learn about strategies for dealing with common hardware risks.