| A firewall for computer networks is much like a real | | | | what programs are allowed access to the Internet as |
| firewall that stops fire from spreading from one part of | | | | well as which traffic is allowed in and out of the |
| a building to another part. A firewall will control and limit | | | | system. |
| access from one side to the next. | | | | Network access is required by email programs, |
| A computer firewall works in the same way as a | | | | antivirus software, and Internet browsers. Personal |
| physical firewall does. It limits the movement of data | | | | firewalls can be put in place that allow some of this |
| and programs to and from a computer system. | | | | Internet traffic while disallowing others. |
| Firewalls for hardware are often used between | | | | A firewall is smart enough to know which programs |
| computer networks, such as between the Internet and | | | | are allowed access to the Internet and which are not. |
| a company network. The Internet is a complex system | | | | When a program first tries to get on to the Internet the |
| of networks that all cooperate together. Internet traffic | | | | firewall will signal the user. The user will either deny |
| that is incoming is restricted to access areas that are | | | | access or will modifiy the policy for the firewall to allow |
| public or to certain computers on the company | | | | access. The thing to remember is that if you don't |
| network. Company network computers are "behind" | | | | recognize a certain program you shouldn't give it |
| the firewall and can access other network computers | | | | access. Most software that you install will let you |
| as well as the Internet. | | | | know what firewall settings you need to set so that |
| Some companies also use internal network firewalls | | | | the program can run correctly. |
| so that certain resources are limited to certain | | | | Hackers will search through computer networks for |
| computer groups. Internal firewalls are also used to | | | | ports that are open so that they can get into your |
| prevent viruses from spreading through the network. | | | | computer. A port is an entry point between your |
| Personal firewalls, which are software firewalls, are | | | | computer and the Internet. When a hacker finds an |
| often used in PC computers that are connected to the | | | | open port they will use this port to send a worm which |
| Internet. A software firewall will be slower that a | | | | is carrying a payload to give the hacker complete |
| hardware firewall which has been specialized for just | | | | control over the PC. Firewalls are used to close any |
| that type of function. They also use some of the | | | | ports that aren't being used. |
| resources on the PC. | | | | Accessing the Internet without using a firewall is not |
| A firewall can prevent or limit access to computer | | | | advised. Always keep in mind that open ports will be |
| systems by viruses or hackers. It will manage both | | | | vulnerable to hackers. You need to protect your |
| outbound traffic and inbound traffic when a policy is | | | | firewall diligently so that incoming data and files are |
| put into place at the time the firewall is installed. These | | | | scanned for viruses. You should also avoid opening up |
| policies can also be configured later and will determine | | | | email attachments that you aren't expecting. |