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How does a firewall protect a network?

A firewall protects a network by checking every piece of incoming and outgoing traffic against a set of rules, then allowing or blocking it. Like a security guard at a gate, it stops unauthorized or suspicious connections while letting safe traffic pass.

See it in motion.
Watch a 2-minute animated lesson that shows exactly how a firewall works.
▶ Watch the visual lesson

Step by step

  • 1It inspects traffic entering and leaving a network.
  • 2It allows or blocks based on security rules.
  • 3It stops unauthorized or malicious connections.
  • 4It's a frontline defense in network security.

Frequently asked questions

How does a firewall work?
It checks network traffic against rules and blocks anything unauthorized or suspicious while allowing safe traffic.
What can a firewall block?
Unwanted connections, known malicious addresses, suspicious ports, and traffic that breaks its rules.
Is a firewall enough to stay secure?
It's essential but not sufficient alone — it works best alongside antivirus, updates, and good practices.

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