How a Computer Firewall Works - dummies

By Dan Gookin

What the firewall does is monitor both incoming and outgoing Internet traffic. When a firewall is properly configured, only the information you request from the Internet is allowed in. Outgoing information can also be filtered.

When information you didn’t request comes in, the firewall instantly squishes it, blocking the doors and windows, so to speak. Likewise, when information tries to sneak out, you can be queried about whether it’s okay for that information to be sent.

Generally speaking, the firewall prompts you with Allow or Deny types of messages. If you don’t want something coming in, you can choose to deny it by blocking it temporarily or permanently. The firewall can also learn from your choices so that after a few times, you aren’t bothered with the warnings.

Bottom line: To help keep your computer system secure, you need a firewall.

  • The first line of defense against Internet-spawned malware should be a firewall.

  • A firewall is a priority for broadband Internet users. The bad guys, who need the connection speed and storage that your compromised PC offers, covet those high-speed connections.

  • Two types of firewall are available for your computer: hardware and software.

  • A hardware firewall is an electronic gizmo installed between the broadband modem and your computer. It’s often included as part of the router. A hardware router monitors all incoming and outgoing Internet traffic. It’s a far more robust solution than a software firewall, though not as cheap.

  • A software firewall is a program running on your PC that monitors only the Internet traffic entering and leaving your computer.