Bands and Channels
2.4 GHz and 5 GHz channels shape coverage and noise — read them on YOUR lab AP only.
Visual · wireless_bands_channels
802.11 bands/channels literacy. Observe $LAB_SSID only. Original Cyberlium.
Channel numbers are not decorative — they are where your lab AP actually transmits.
802.11 uses 2.4 GHz and 5 GHz bands divided into channels. APs beacon their channel in management frames; overlapping 2.4 GHz channels cause interference; 5 GHz offers wider channels but shorter range. Defenders pick clean channels; attackers abuse crowded ones — you learn both as literacy on $LAB_SSID only. You will NOT scan neighbor channels to 'find weak APs.' You document YOUR lab AP channel plan. Next: BSS and ESSID.
1. 2.4 vs 5 GHz tradeoffs
2.4 GHz penetrates walls but shares crowded spectrum; 5 GHz is faster and wider but shorter range. Dual-band APs often run both; clients pick based on RSSI and capability.
Knowing band helps you interpret captures and write AP hardening checklists — not pick victim neighbors by signal strength.
Command guide
Try these commands — 2.4 vs 5 GHz tradeoffs
═══ TOOLS & WEBSITES ═══ Browse / read these (authorized learning only — stay in YOUR lab / program scope)
802.11 bands — https://www.wi-fi.org/knowledge-center/glossary Wireshark 802.11 — https://www.wireshark.org/docs/wsug_html_chunked/ChWirelessWLANTraffic.html
═══ INSTALL ═══
Linux (Debian/Ubuntu):
Command — copy this
sudo apt install iw sudo apt install network-manager
macOS: Prefer Linux lab VM for iw Use airport / System Settings
Windows: Use Kali VM / WSL with iw Use netsh wlan (built-in)
═══ LINUX / macOS ═══
Command — copy this
iw phy 2>/dev/null | grep -E 'Band|MHz' | head -10 || echo 'Band/channel literacy on YOUR adapter' nmcli -f CHAN,FREQ,SSID,SECURITY device wifi list 2>/dev/null | head -15
Primary tools to practice this lesson: iw, nmcli. Reference sites: 802.11 bands (https://www.wi-fi.org/knowledge-center/glossary); Wireshark 802.11 (https://www.wireshark.org/docs/wsug_html_chunked/ChWirelessWLANTraffic.html). Run every command in the box — install first, then the usage lines — only on YOUR lab / program scope.
2. Channel overlap and width
In 2.4 GHz, channels 1, 6, and 11 are common non-overlapping choices in many regions. 40/80 MHz widths in 5 GHz increase throughput but need clear spectrum.
On $LAB_SSID, record channel, band, and width as defender inventory — the habit blue teams use during site surveys.
3. Regulatory and lab boundary
Transmit power and allowed channels follow regional rules. Your lab AP stays in YOUR space; observing stranger channels on their BSSIDs is out of scope.
Ship: band/channel table for $LAB_SSID only. Next: BSS and ESSID.
4. What you ship: band/channel note for $LAB_SSID
Document band, channel, width for YOUR lab AP. No neighbor channel hunting. chmod 600.
5. What you record before the next lesson
Date. $LAB_SSID band/channel/width. NEVER neighbor surveys. File t15-m02-l01-bands-channels.txt chmod 600.
6. Wrong vs right: stranger SSIDs vs YOUR lab AP
Worked failure — same MSF word, opposite target. Right never needs a café Wi-Fi or classmate laptop.
- Wrong: Scan all channels listing every apartment SSID. Pick the neighbor channel because it has WPA2.
- Right: Record YOUR lab AP channel plan. Next: BSS and ESSID.
Mission: inventory YOUR lab AP channels
1) Record band and channel for $LAB_SSID. 2) Note overlap risk if on 2.4 GHz. 3) No neighbor SSID logging. Never wardrive channel lists.
Stuck? Ask Cyberlium AI Mentor
Regulatory domain affects allowed channels — lab docs should say which country profile your AP uses.
APPLY: Common non-overlapping 2.4 GHz choices in many regions:
APPLY: True or False: Strong neighbor signal authorizes capturing that SSID.
APPLY: 5 GHz vs 2.4 GHz generally: