Understanding Firewalls

Backdoor program

A program installed by hackers that allows them to take almost complete control of your computer without your knowledge

Black-hat hacker

Hackers who use their knowledge to destroy information or for illegal gain

White-hat hacker

A hacker who breaks into systems just for the challenge of it (and who don’t wish to steal or wreak havoc on the systems)

Botnet

A large group of software programs (called robots or bots) that runs autonomously on zombie computers

Zombie

A computer that a hacker controls; often used to launch denial-of-service (DoS/DDoS) attacks on other computers

Denial-of-Service (DoS) attack

An attack where legitimate users are denied access to a computer system because a hacker is repeatedly making requests on that computer system through a computer they have taken over as a zombie

Distributed Denial-of-Service (DDoS) attack

An attack launched from more than one zombie (sometimes thousands of zombies) at the same time and is more difficult to stop

Firewall

A program or hardware device designed to protect computers from hackers

Hacker

Anyone who unlawfully breaks into a computer system— either an individual computer or a network

Identity theft

Characterized by someone using personal information about you (such as your name, address, or SSN) to assume your identity for the purpose of defrauding others

Internet Protocol address (or IP address)

For the Internet to share information seamlessly, data packets must have a way of getting to their correct locations; a unique address every computer connected to the Internet has

Logical port blocking

The process where a firewall is configured to ignore all incoming packets that request access to port 21 (the port designated for FTP (file transfer protocol) traffic) thereby allowing no FTP requests to get through to the computer.

Logical ports

Digital pathways that allow computers to send and receive data for specific services, like FTP or web browsing

Network Address Translation (NAT)

NAT assigns internal IP addresses to devices on a network, keeping them safe from hackers by making them invisible outside the network.

Packet

Data travels through the Internet in small pieces, each called a packet. The packets are identified with an IP address, in part to help identify the computer to which they are being sent.

Packet filtering

The process where firewalls can be configured so that they filter out packets sent to specific logical ports

Packet sniffer

A computer program deployed by hackers that looks at (or sniffs) each packet as it travels on the Internet— not just those that are addressed to a particular computer, but all packets

Personal firewall

A firewall specifically designed for home networks

Script kiddies

Amateur hackers that use tools created by skilled hackers that enable unskilled novices to wreak the same havoc as professional hackers

Static addressing

When your IP address is always the same and is assigned by your ISP (internet service provider)

Trojan horse

A malware program that appears to be something useful or desirable (like a game or a screen saver), but while it runs it does something malicious in the background without your knowledge

What Risks Firewalls Protect Against

Even if you don’t store proprietary files on your home computer, hackers can still use it for other illegal activities, such as to commit identity theft, to launch a Trojan horse, to launch a denial-of-service attack, or to launch a distributed denial-of-service attack

How Firewalls Work

A firewall protects a computer by screening data coming into the computer’s logical ports. Logical ports allow a computer to organize requests for information from other networks or computers. Unless you take precautions to restrict access to your logical ports, hackers may be able to access your computer through them

Types of Firewalls

Firewalls can be either software programs or hardware devices, both of which are equally effective. Personal firewalls are software programs or hardware devices specifically designed to keep home computers safe from hackers

Installing and Testing Firewalls

Although some people prefer to have a professional install and test their firewall, even home users can install and test a firewall by following the instructions provided in the user manual. Unfortunately, not all firewalls come with software that allows you to test whether the firewall is working correctly. The best solution is to test the firewall with a testing agent such as ShieldsUP or LeakTest