LEDMatrix/docs/archive/RECONNECT_AFTER_CAPTIVE_PORTAL_TESTING.md

Reconnecting to Internet After Captive Portal Testing

If captive portal testing fails or you need to reconnect to your normal network, here are several methods to get back online.

Quick Reference

Before testing: Always run sudo ./scripts/verify_wifi_before_testing.sh first!

If stuck: Run sudo ./scripts/emergency_reconnect.sh for automated recovery.

Quick Recovery Methods

Method 1: Via Web Interface (If Accessible)

If you can still access the web interface at http://192.168.4.1:5000:

1. Navigate to WiFi tab
2. Click "Scan" to find available networks
3. Select your network from the dropdown
4. Enter your WiFi password
5. Click "Connect"
6. Wait for connection - AP mode should automatically disable

Method 2: Via SSH (If You Have Direct Access)

If you have SSH access to the Pi (via Ethernet, direct connection, or still connected to AP):

# Connect via SSH
ssh user@192.168.4.1  # If connected to AP
# OR
ssh user@<pi-ip>      # If on same network

# Disable AP mode first
sudo systemctl stop hostapd
sudo systemctl stop dnsmasq

# Connect to WiFi using nmcli
sudo nmcli device wifi connect "YourNetworkName" password "YourPassword"

# Or if you have a saved connection
sudo nmcli connection up "YourNetworkName"

Method 3: Via API Endpoints (If Web Interface Works)

If the web interface is accessible but you can't use the UI:

# Connect to WiFi via API
curl -X POST http://192.168.4.1:5000/api/v3/wifi/connect \
  -H "Content-Type: application/json" \
  -d '{"ssid": "YourNetworkName", "password": "YourPassword"}'

# Disable AP mode
curl -X POST http://192.168.4.1:5000/api/v3/wifi/ap/disable

Method 4: Direct Command Line (Physical Access)

If you have physical access to the Pi or a keyboard/monitor:

# Disable AP mode services
sudo systemctl stop hostapd
sudo systemctl stop dnsmasq

# Check available networks
nmcli device wifi list

# Connect to your network
sudo nmcli device wifi connect "YourNetworkName" password "YourPassword"

# Verify connection
nmcli device status
ip addr show wlan0

Method 5: Using Saved Network Configuration

If you've previously connected to a network, it may be saved:

# List saved connections
nmcli connection show

# Activate a saved connection
sudo nmcli connection up "YourSavedConnectionName"

# Or by UUID
sudo nmcli connection up <uuid>

Step-by-Step Recovery Procedure

Scenario 1: Still Connected to AP Network

If you're still connected to "LEDMatrix-Setup":

1. Access web interface:

   http://192.168.4.1:5000
   

2. Go to WiFi tab

3. Connect to your network using the interface

4. Wait for connection - you'll be disconnected from AP

5. Reconnect to your new network and access Pi at its new IP

Scenario 2: Can't Access Web Interface

If web interface is not accessible:

1. SSH into Pi (if possible):

   ssh user@192.168.4.1  # Via AP
   # OR via Ethernet if connected
   

2. Disable AP mode:

   sudo systemctl stop hostapd dnsmasq
   

3. Connect to WiFi:

   sudo nmcli device wifi connect "YourNetwork" password "YourPassword"
   

4. Verify connection:

   nmcli device status
   ping -c 3 8.8.8.8  # Test internet connectivity
   

Scenario 3: No Network Access at All

If you have no network access (AP not working, no Ethernet):

1. Physical access required:

   • Connect keyboard and monitor to Pi
   • Or use serial console if available

2. Disable AP services:

   sudo systemctl stop hostapd
   sudo systemctl stop dnsmasq
   sudo systemctl disable hostapd  # Prevent auto-start
   sudo systemctl disable dnsmasq
   

3. Connect to WiFi manually:

   sudo nmcli device wifi list
   sudo nmcli device wifi connect "YourNetwork" password "YourPassword"
   

4. Restart network services if needed:

   sudo systemctl restart NetworkManager
   

Emergency Recovery Script

Create this script for quick recovery:

#!/bin/bash
# emergency_reconnect.sh - Emergency WiFi reconnection script

echo "Emergency WiFi Reconnection"
echo "=========================="

# Stop AP mode
echo "Stopping AP mode..."
sudo systemctl stop hostapd 2>/dev/null
sudo systemctl stop dnsmasq 2>/dev/null

# List available networks
echo ""
echo "Available networks:"
nmcli device wifi list

# Prompt for network
echo ""
read -p "Enter network SSID: " SSID
read -sp "Enter password: " PASSWORD
echo ""

# Connect
echo "Connecting to $SSID..."
sudo nmcli device wifi connect "$SSID" password "$PASSWORD"

# Wait a moment
sleep 3

# Check status
if nmcli device status | grep -q "connected"; then
    echo "✓ Connected successfully!"
    IP=$(ip addr show wlan0 | grep "inet " | awk '{print $2}' | cut -d/ -f1)
    echo "IP Address: $IP"
else
    echo "✗ Connection failed. Check credentials and try again."
fi

Save as scripts/emergency_reconnect.sh and make executable:

chmod +x scripts/emergency_reconnect.sh
sudo ./scripts/emergency_reconnect.sh

Preventing Issues

Before Testing

1. Save your current network connection:

   # Your network should already be saved if you've connected before
   nmcli connection show
   

2. Note your Pi's IP address on your normal network:

   hostname -I
   

3. Ensure you have alternative access:

   • Ethernet cable (if available)
   • SSH access via another method
   • Physical access to Pi

During Testing

1. Keep a terminal/SSH session open to the Pi
2. Test from a secondary device (not your main computer)
3. Have the recovery commands ready

After Testing

1. Verify internet connectivity:

   ping -c 3 8.8.8.8
   curl -I https://www.google.com
   

2. Check Pi's new IP address:

   hostname -I
   ip addr show wlan0
   

3. Update your SSH/config if IP changed

Troubleshooting Reconnection

Issue: Can't Connect to Saved Network

Solution:

# Remove old connection and reconnect
nmcli connection delete "NetworkName"
sudo nmcli device wifi connect "NetworkName" password "Password"

Issue: AP Mode Won't Disable

Solution:

# Force stop services
sudo systemctl stop hostapd dnsmasq
sudo systemctl disable hostapd dnsmasq

# Kill processes if needed
sudo pkill hostapd
sudo pkill dnsmasq

# Restart NetworkManager
sudo systemctl restart NetworkManager

Issue: WiFi Interface Stuck

Solution:

# Reset WiFi interface
sudo nmcli radio wifi off
sleep 2
sudo nmcli radio wifi on
sleep 3

# Try connecting again
sudo nmcli device wifi connect "NetworkName" password "Password"

Issue: No Networks Found

Solution:

# Check WiFi is enabled
nmcli radio wifi

# Enable if off
sudo nmcli radio wifi on

# Check interface status
ip link show wlan0

# Restart NetworkManager
sudo systemctl restart NetworkManager

Quick Reference Commands

# Disable AP mode
sudo systemctl stop hostapd dnsmasq

# List WiFi networks
nmcli device wifi list

# Connect to network
sudo nmcli device wifi connect "SSID" password "Password"

# Check connection status
nmcli device status

# Get IP address
hostname -I
ip addr show wlan0

# Test internet
ping -c 3 8.8.8.8

# Restart network services
sudo systemctl restart NetworkManager

Best Practices

1. Always test from a secondary device - Keep your main computer on your normal network
2. Have Ethernet backup - If available, keep Ethernet connected as fallback
3. Save network credentials - Ensure your network is saved before testing
4. Document your Pi's IP - Note the IP on your normal network before testing
5. Keep SSH session open - Maintain an active SSH connection during testing
6. Test during safe times - Don't test when you need immediate internet access

Recovery Checklist

• Stop AP mode services (hostapd, dnsmasq)
• Verify WiFi interface is available
• Scan for available networks
• Connect to your network
• Verify connection status
• Test internet connectivity
• Note new IP address
• Update any configurations that reference old IP