Starting an Online Business All-in-One For Dummies®, 3rd Edition

Adding Firewalls

One of the best lines of defense against viruses and intruders is having a firewall installed on your computer. Think of a firewall as a security guard standing watch at all the doors and windows of your computer. The firewall monitors the traffic, decides what's safe, and then gives permission to enter. Or, if the firewall detects a threat, it shuts the door and blocks the intruder.

Firewalls are particularly important because hackers are aggressive creatures. They actively search for networks that are unprotected or have disabled firewalls. To a Net-thief, that's the equivalent of having an open invitation to browse through all the files on your computer. The lack of firewalls also make it easy to install harmful programs that infect or shut down your computer or that — worse — scoop up and send out pertinent information to the hacker without your knowing, such as passwords and bank account numbers.

If a pesky virus manages to break through your front lines of defense, a firewall cannot remove or quarantine infected files. You still need to run antivirus software in addition to installing a firewall.

For added security, we recommend that you

• Enable individual firewalls. When your computer is part of a local area network (LAN), most routers have a firewall installed. For the best defense, though, enable a personal firewall on each computer.
• Add an enhanced firewall. ...