What is a Firewall?
A Firewall is a computer software program or piece of hardware that monitors incoming and outgoing network communication, keeping out communications that are deemed to be dangerous by a set of rules you or your network administrator sets up. Firewalls can be categorized as packet filtering, stateful inspection, or next-generation firewalls (NGFW).
Firewalls are often designed to be a system that mitigates the risks of data theft and unauthorised entry into personal devices, applications, and accounts. Firewalls also protect supply chain networks from cyberattacks that could compromise coordination of goods, services, pricing, and production from manufacturer to distributor, supplier, or consumer.
Generally, a firewall will examine each piece of data from an outside application or network device by looking at the unique headers in each data packet and matching it against a set of security rules. The first word in a firewall rule is “accept”, “reject”, or “drop” and specifies the action that the firewall will take if the packet matches a given rule. Firewall rules are grouped together into chains, with each subsequent rule checking against network traffic a little more thoroughly than the previous one.
The stateful inspection firewall is a type of firewall that keeps a list of open connections and compares new data packets against this list, trying to match each one to an existing connection in the database. This method of checking traffic is more sophisticated than the packet filtering technique, but it can be susceptible to denial-of-service attacks.