Networking Basics · 8
📶 WiFi & Wireless Security
How wireless works — and why public WiFi is dangerous⏱ ~2 min
📻WiFi is like a walkie-talkie channel
Walkie-talkies work on a channel — everyone on channel 5 hears everything said on channel 5. Early WiFi (and open WiFi) works similarly: devices share a radio channel, and in theory, anyone listening could hear the conversations. Modern encryption (WPA3) is like adding a scrambler — even if someone hears the signal, all they get is noise.
WiFi Standards — how fast can we go?
| Standard | WiFi Name | Max Speed | Frequency | What's New |
|---|---|---|---|---|
| 802.11n | WiFi 4 | 600 Mbps | 2.4 / 5 GHz | Multiple antennas (MIMO) |
| 802.11ac | WiFi 5 | 3.5 Gbps | 5 GHz | Beamforming, MU-MIMO |
| 802.11ax | WiFi 6 | 9.6 Gbps | 2.4 / 5 GHz | OFDMA — handles crowded networks better |
| 802.11be | WiFi 7 | 46 Gbps | 2.4 / 5 / 6 GHz | Multi-Link Operation (2024+) |
2.4 GHz vs 5 GHz — pick the right lane
2.4 GHz
- •Longer range — penetrates walls better
- •Slower max speed
- •Very crowded — microwaves, baby monitors, Bluetooth also use it
- •13 channels, only 3 non-overlapping
- •Best for: devices far from the router
5 GHz
- •Shorter range — walls block it more
- •Much faster
- •Less crowded — cleaner signal
- •23+ non-overlapping channels available
- •Best for: streaming, gaming, devices close to router
WiFi Security Standards — know your encryption
- •❌ WEP (1997) — Completely broken. A hacker can crack it in under 60 seconds with free tools. Never use WEP.
- •⚠️ WPA (2003) — Better than WEP but still has known vulnerabilities. Avoid if possible.
- •✅ WPA2 (2004) — The current minimum standard. Uses AES encryption. Strong but vulnerable to KRACK attacks on older implementations.
- •🛡️ WPA3 (2018) — Latest and strongest. Protects against dictionary attacks even with weak passwords. Use this if your router supports it.
- •🔓 Open (No password) — Extremely dangerous. All traffic in plaintext. Anyone on the same network can read it.
★ FactWiFi 6 (802.11ax) introduced OFDMA — Orthogonal Frequency Division Multiple Access. Instead of one device using the whole channel at once, OFDMA splits the channel like a pizza, letting multiple devices send at the same time. This is why WiFi 6 routers are much better in crowded places like stadiums or apartment buildings.
🔒 SecurityEvil Twin Attack: An attacker sets up a fake WiFi access point with the same SSID as a legitimate one ('Airport_Free_WiFi'). When you connect, all your traffic flows through their device. They can read passwords, intercept emails, and inject malware — even if you see 'Connected.' Always verify you're connecting to the real network, and use HTTPS and a VPN.
🧠Quick Checkfirst try = +5 XP
You're at an airport and see two networks: 'Airport_WiFi' (open, no password) and 'Airport_WiFi_Secure' (WPA2). A cybersecurity concern with both is that you can't verify they're real. Which is the safer choice and why?
🎮 Practice what you learned
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