A firewall is a barrier between a home or business network and the wider internet. It checks traffic and lets through what its rules trust, and it blocks what looks suspicious.
Two kinds
- Hardware firewalls. A physical device on the network that filters traffic there.
- Software firewalls. A program on a single device, with protection aimed at that device.
Both exist to keep out unauthorized access, attackers, and malware.
What a firewall does
Watch and filter traffic
It inspects packets, the small pieces of data sent across the internet. Using rules, it checks source, destination, and content, and it blocks a packet that does not meet the rules.
Block known threats
Many firewalls include lists of known malware and threats. When one of those shows up, the firewall blocks it before it reaches the device.
Split the network
A firewall can separate parts of a network. Examples include a business network kept apart from public access, and a guest Wi-Fi kept apart from company systems. If one part is compromised, the rest is harder to reach.
Control which programs connect
It can decide which applications are allowed on the network, so an unapproved program has a harder time doing damage.
Why they matter
- Personal information, such as financial details and login credentials, is a target. The firewall is another layer that blocks suspicious traffic before it reaches that data.
- Attackers try to break in and steal data. A firewall is a gate that stops many of those attempts.
- At work, some industries have to meet security rules, including healthcare and finance. Firewalls help by protecting sensitive information. One example is a company with patient records using a firewall to block unauthorized access and stay in line with a privacy law such as HIPAA. At home, a firewall can protect smart devices.
Firewalls are a first line of defense for a household or a business network: they filter traffic, block known threats, separate networks, and control which apps connect.
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