wlan0 - Wireless Interface (WiFi Access Point)

Overview

The wlan0 interface provides wireless access point functionality for WiFi client devices. It creates a local wireless network for mobile devices, laptops, and other WiFi-enabled devices requiring network access.

Current Configuration

• Type: WiFi Access Point
• Mode: Master (AP)
• IP Address: 192.168.77.1/24
• Network: 192.168.77.0/24 (WiFi subnet)
• Broadcast: 192.168.77.255
• MAC Address: b8:27:eb:85:bf:e4
• Hardware: Built-in WiFi (Raspberry Pi 3B+)

WiFi Access Point Settings

• Channel: Auto-selected (typically 6 or 11)
• Security: WPA2-PSK
• Country Code: UA (Ukraine)
• Max Clients: 30 concurrent connections
• DHCP Range: 192.168.77.100-200 (served by Pimeleon device)

Device Classification

• Security Zone: Standard
• Device Types: Smartphones, tablets, laptops, IoT devices
• Access Level: Internet access + limited local services
• Filtering: DNS filtering, content filtering, parental controls

Sample Hostapd Configuration

# /etc/hostapd/hostapd.conf
interface=wlan0
driver=nl80211
ssid=YourNetworkName
hw_mode=g
channel=6
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=YourWiFiPassword
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
country_code=UA

Monitoring Commands

# Interface status
ip addr show wlan0

# Access point status
systemctl status hostapd

# Connected clients (if hostapd_cli available)
hostapd_cli all_sta

# WiFi interface information
iw dev wlan0 info

# Interface statistics
ip -s link show wlan0

# DHCP client leases (WiFi devices)
cat /var/lib/dhcp/dhcpd.leases | grep 192.168.77

Troubleshooting

Clients Cannot Connect

1. Check hostapd service: systemctl status hostapd
2. Verify interface is up: ip link show wlan0 (should show UP,LOWER_UP)
3. Test configuration: hostapd -dd /etc/hostapd/hostapd.conf (debug mode)
4. Check DHCP service: Ensure DHCP server is running for 192.168.77.0/24
5. Restart services:

   sudo systemctl restart hostapd
   sudo systemctl restart dhcpcd  # or dhcp service
   

Poor WiFi Performance

1. Check for interference: Scan for competing networks on same channel
2. Verify channel selection: Consider switching to less congested channel
3. Check power settings: Ensure WiFi adapter is not in power-save mode
4. Monitor client count: High client count can impact performance
5. Physical placement: Ensure Pimeleon router has good physical placement

Access Point Not Broadcasting

1. Check wlan0 interface: ip addr show wlan0 (should have 192.168.77.1)
2. Verify hostapd config: Check /etc/hostapd/hostapd.conf syntax
3. Check kernel modules: lsmod | grep brcm (for Pi WiFi driver)
4. Review system logs: journalctl -u hostapd -f

Hardware Limitations

• Pi 3B+ WiFi: 802.11n (2.4GHz only), theoretical max ~150 Mbps
• Concurrent clients: Performance degrades with >15-20 active clients
• Range: Limited by Pi's built-in antenna (consider external antenna for better range)
• Channel support: 2.4GHz channels 1-13 (Ukraine regulations)

Related Documentation:

• Network Topology - Overall network architecture
• IP Allocation - Network addressing and DHCP configuration
• eth1 - LAN Interface - LAN interface configuration
• eth0 - WAN Interface - WAN interface configuration

← Network Topology | ← Network Interfaces