What is a Firewall?
Firewall protects the data moving to, from and within a network by screening for malicious actors. It blocks or allows network data based on a pre-defined or dynamic set of rules that can be customized to match specific threats.
Data travels to and from computers over the internet in small pieces called packets. Each packet has a destination address, port number and application that it is associated with. Firewalls use packet filtering to examine each of these elements to determine if the data is safe. If it is not, the firewall will discard the data packet.
To prevent malware from stealing sensitive information or causing other attacks, firewalls can monitor each car (data packet) on your digital highway, determining which ones should be allowed to pass based on pre-established rules and filters. A well-trained IT staff can create these rules – known as policies – to block the most common threats, such as backdoors, denial of service attacks, macros, remote logins and viruses.
A hardened firewall is a powerful tool but requires a deep understanding of your infrastructure. At Boston University, IS&T security staff can help you build a comprehensive and effective firewall policy using the Windows Firewall Control Panel and other graphical interfaces. We can also assist with more complex Unix or Linux firewall software that may not offer these simpler graphical interfaces. Our team can also combine firewall logs with other security tools to evaluate and understand a network’s health.