2.3 Network Security

Firewalls control traffic flow

A firewall filters incoming and outgoing network traffic based on a set of security rules, blocking unauthorized access while allowing legitimate communication. Firewalls can be hardware devices, software programs, or both, and they act as a barrier between a trusted internal network and untrusted external networks like the internet.

Wireless networks need extra protection

Wireless networks broadcast signals through the air, making them vulnerable to eavesdropping. Protections include WPA (Wi-Fi Protected Access) encryption, strong passwords, hiding or renaming the default SSID (Service Set Identifier), and disabling remote administration to reduce the attack surface available to nearby attackers.

Segmentation and monitoring limit damage

Network segmentation divides a network into smaller isolated zones so that if one segment is compromised, attackers can't easily reach the rest. Tools like IDS (Intrusion Detection Systems) and IPS (Intrusion Prevention Systems) monitor traffic for suspicious activity, alerting admins or automatically blocking threats in real time.

Key terms

Firewall

A hardware or software system that filters network traffic based on security rules.

WPA

Wi-Fi Protected Access — a protocol that encrypts wireless network traffic.

SSID

Service Set Identifier — the name of a wireless network, which can be hidden or renamed for security.

Network segmentation

Dividing a network into smaller, isolated zones to limit the impact of a breach.

IDS vs. IPS

IDS detects and alerts on suspicious activity; IPS detects AND actively blocks the threat.

Try an AP-style question

What does a firewall do?

1. Encrypts all stored files
2. Assigns IP addresses
3. Removes viruses from files
4. Filters traffic using rules