Windows Firewall

What is a firewall?

A firewall is like locking the front door to your house—it helps keep intruders (in this case, hackers and malicious software) from getting in.

A firewall is software or hardware that checks information coming from the Internet or a network, and then either blocks it or allows it to pass through to your computer, depending on your firewall settings.

A firewall can help prevent hackers or malicious software (such as worms) from gaining access to your computer through a network or the Internet. A firewall can also help stop your computer from sending malicious software to other computers.

The following illustration shows how a firewall works.

Windows Firewall

Just as a brick wall can create a physical barrier, a firewall creates a barrier between the Internet and your computer. A firewall isn't the same thing as an antivirus program. To help protect your computer, you need both a firewall and an antivirus and anti-malware program.

To turn on Windows Firewall

Please note: the firewalls on university-owned computers are pre-configured and their configuration should not be changed. The following are instructions for personal (non-SMU) computers.

  1. Open Windows Firewall by clicking the Start button 
Windows Firewall, and then clicking Control Panel. In the search box, type firewall, and then click Windows Firewall.
  2. In the left pane, click Turn Windows Firewall on or off 
Windows Firewall. If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
  3. Click Turn on Windows Firewall under each network location that you want to help protect, and then click OK.

Windows Firewall


If you want the firewall to prevent all programs from communicating, including programs that you have previously allowed to communicate through the firewall, select the Block all incoming connections, including those in the list of allowed programs check box.

Firewall: frequently asked questions