Skip to toolbar

Education & Training

Office of Information Security


Guard your personal information from cyber criminals. Use firewalls.

what are firewalls


Every Internet-connected computer is vulnerable to automated attack tools seeking ways to break into and take over your system. Attackers may crash your system, spawn new attacks, or even steal passwords and credit card information.

Firewalls provide virtual barriers that filter out potentially dangerous connection attempts to your device. Network firewalls (firewalls designed to help protect multiple computers in a university department or a home or apartment complex network) and properly configured host-based firewalls (firewalls you can enable on your personal computer) can each provide effective security to suit various needs.

what are firewalls


Network firewalls are used to provide protection for one or more computer networks. These firewalls are normally placed between a trusted internal network and untrusted external network (for example, between Penn State and the Internet).

Network firewalls should be in place in front of Penn State internal networks. According to the Network Security Standard, denying all inbound network traffic by default is required. Allowed traffic is allowed by exception only. Denying outbound network traffic by default is either recommended or required based on the classification of the data being transferred (see University Policy AD95). This is best accomplished with a network firewall. Many networks at Penn State are behind the Enterprise Firewall (EFW). This is a central firewall service offered through ENCS. For more information on the EFW please visit their website.

Network firewalls are also recommended for home networks to provide protection for your personal devices.

what are firewalls


Host-based firewalls come included with desktop and server operating systems. These firewalls should be enabled to provide another layer of protection for your systems. This is also true for home systems or mobile devices that can connect to public networks or networks that otherwise do not have any type of firewall installed. More information about the host-based firewalls included with Windows, macOS, and Linux are below:

  • Windows Firewall
  • macOS Firewall
  • Ubuntu Uncomplicated Firewall (An example for Linux, if you use a different version you can find documentation specific to that version)