Wireless networks: Wi-Fi, WPA2/WPA3 and enterprise Wi-Fi
You learn Wi-Fi frequencies, channels and security, build an access point with hostapd, protect it with WPA2, WPA3 and 802.1X, and solve problems with iw and logs.
Level 201 · 16 lessons · 18 practice labs
Lessons
Radio basics
- Wi-Fi standards: 802.11n, ac, ax
- Frequency bands, channels and interference
- SSID, BSSID and roaming
- Scanning nearby networks with iw
- Short task: make a channel plan for three access points
The access point
- An access point with hostapd
- Connecting a client with wpa_supplicant
- Joining Wi-Fi to the wired network with a bridge and DHCP
- Short task: set up guest Wi-Fi on its own VLAN
Security
- WPA2-PSK and the four-way handshake
- WPA3-SAE and transition mode
- The risks of weak passphrases, WPS and old encryption
- Enterprise Wi-Fi: WPA2/3-Enterprise and RADIUS
- Detecting rogue access points and evil twins
- Short task: protect the staff network with 802.1X
Wrap-up
- Capstone: design and build secure Wi-Fi for an office
Practice labs
- An inventory of nearby networks: Scan the simulated radio environment with iw and produce a table of SSID, BSSID, channel, signal and encryption type for each network.
- Three access points are drowning each other: Identify three access points on overlapping channels, apply a non-overlapping 2.4 GHz channel plan and show the change with a fresh scan.
- The connection drops while roaming: Find from wpa_supplicant logs that roaming fails because two access points broadcasting the same SSID have different security and band settings, align them and show the client moving across without a drop.
- hostapd will not start: Fix the broken hostapd configuration (channel, country code, interface name), bring the access point up and show a client connecting.
- It connects but gets no address: Solve the DHCP problem caused by the wireless interface not being bridged to the wired network, and show the client getting an address from the wired server and reaching it.
- The guest network can see the staff network: Move Orchid Hotel’s guest SSID onto its own VLAN, enable client isolation and prove that a guest client reaches the internet but not the staff network.
- Move the access point to WPA3: Configure WPA3-SAE in hostapd, enable management frame protection and show from the log that a client connected using SAE.
- Old and new devices side by side: Set up WPA2/WPA3 transition mode and show two clients, one WPA2-only, both connecting, noting which method each used.
- Access point configuration review: Review the three given access point configurations against a security checklist, fix the missing settings and write a short report with the reason for each change.
- RADIUS is not answering: Fix the client definition and shared-secret mismatch between the access point and the RADIUS server and show a staff account joining the enterprise network.
- The client does not check the server certificate: Update the client profiles so they validate the RADIUS server certificate by CA and server name, and show they refuse a test server with the wrong certificate.
- VLAN assignment per user: At Atlas Clinic, place staff and device accounts in different VLANs through RADIUS replies and show two accounts receiving addresses from different subnets.
- An SSID plan for a small office: Prepare an SSID, VLAN and security-method table for Cinnamon Café covering staff, guest and device networks, justifying each choice in one sentence.
- Channel and power plan on two bands: Apply a 2.4 and 5 GHz channel and power plan for four access points in the simulated environment and show reduced overlap with scans.
- Build the wireless network for a new branch: Build staff (802.1X) and guest (isolated VLAN) networks for a Kuzey Logistics branch and document each network’s access boundaries with test results.
- Find the four-way handshake in a capture: In a capture of a client joining your own lab access point, find the four EAPOL messages and write to the answer file which side sent each one and in what order.
- Old encryption and WPS left switched on: Audit the configuration of Orchid Hotel’s lab access point, find WPS left on, the legacy cipher options and the weak passphrase setting, turn them off or renew them and show in a scan that only current protection is advertised.
- An access point on the same name that is not in the inventory: Scan the simulated radios in your own lab, identify from BSSID, channel and security-setting differences the access point that broadcasts the company network name but is not in the inventory, and write an audit script that compares a scan with the inventory and reports the unauthorised broadcast.
About this course
You learn Wi-Fi frequencies, channels and security, build an access point with hostapd, protect it with WPA2, WPA3 and 802.1X, and solve problems with iw and logs.
What you will learn
- Radio basics
- The access point
- Security
- Wrap-up
Prerequisites
Finishing the level 101 courses of the same path, or knowing those topics, is enough.
Lab environment
Lessons run in your own Kali Linux terminal in the browser, connected to a private lab network. Nothing to install.
Frequently asked questions
- Is this course right for my level?
- The course is at level 201; it assumes you know the topics of the lower-level courses.
- Is there anything to install?
- No. Every lesson runs in your own lab environment that opens in the browser.
- How do lessons work?
- Each lesson has 8 to 10 steps and a short quiz. Early steps show the command to type, later steps give less help; if two attempts fail, the solution opens.
- Can I try it for free?
- Yes. The first three lessons of every course are free.