What Is a Firewall?
A firewall is a device that filters incoming and outgoing data to contain security threats. It is either hardware or software, or a combination of both and can be installed on user devices or within networks.
Firewalls are a network’s last line of defense against cyberattacks, which can result in identity theft, financial loss and more. As the threat landscape continues to evolve, it’s important to keep your Next Generation Firewall (NGFW) equipped with the latest features.
The first firewalls were invented in the 1980s and allowed or blocked individual data packets based on their context. The current, more advanced versions of firewalls are able to read multiple layers of information from packets and use that information to make better decisions about allowing or blocking traffic.
For example, a packet-filtering firewall looks at the contents of each data packet, including its IP address and port number. It also checks whether the packets are related to each other – similar to looking at the “to” and “from” sections of an email.
Another type of firewall, stateful inspection, keeps track of each individual data packet and its connections. It uses this state table to make filtering decisions based on both its own rules and the patterns it has “learned” from previous interactions. Finally, proxy firewalls act as a bridge between each network and the internet and use application-level packets to check for things like protocol types and other data traits. They are unique in their ability to read and filter applications.