Hack to allow Pangolin tunnel over mobile hotspot on Windows.

pangolin-mobile-tunnel-fix.ps1

# Fixes Pangolin DNS issues with some mobile hotspots where they don't allow 1.1.1.1 or others and force device to use 172.20.10.1:53
# This patches olm config file on the fly to allow connection. Allows Pangolin tunnel over personal hotspot. uWu. 
# Run in elevated PowerShell terminal

# Get the active network's DNS server IP (excluding loopback and Pangolin itself)
$dnsServers = @(Get-DnsClientServerAddress -AddressFamily IPv4 | 
    Where-Object { $_.InterfaceAlias -ne "Pangolin" -and $_.InterfaceAlias -notlike "Loopback*" -and $_.ServerAddresses.Count -gt 0 } | 
    Select-Object -ExpandProperty ServerAddresses)

if ($dnsServers.Count -eq 0) {
    Write-Host "No active DNS server found. Are you connected to Wi-Fi/Ethernet?" -ForegroundColor Red
    exit
}

$activeDns = $dnsServers[0]
Write-Host "Detected active DNS Server: $activeDns" -ForegroundColor Green

$configPath = "C:\ProgramData\Pangolin\Tunnels\olm.json"

if (-not (Test-Path $configPath)) {
    Write-Host "Pangolin configuration file not found at $configPath." -ForegroundColor Red
    exit
}

# Stop the tunnel service
Write-Host "Stopping Pangolin tunnel service..."
Stop-Service -Name 'PangolinTunnel$olm' -ErrorAction SilentlyContinue

# Remove read-only attribute if present
if ((Get-Item $configPath).IsReadOnly) {
    Set-ItemProperty -Path $configPath -Name IsReadOnly -Value $false
}

# Read and modify config
$config = Get-Content $configPath -Raw | ConvertFrom-Json
$config.dns = $activeDns
$config.upstreamDns = @("$activeDns`:53")
$jsonText = $config | ConvertTo-Json -Depth 10 -Compress

# Write file without UTF-8 BOM to prevent Go parsing errors
[System.IO.File]::WriteAllText($configPath, $jsonText, [System.Text.UTF8Encoding]::new($false))

# Set back to read-only to prevent UI overwrite
Set-ItemProperty -Path $configPath -Name IsReadOnly -Value $true

# Start service
Write-Host "Starting Pangolin tunnel service..."
Start-Service -Name 'PangolinTunnel$olm' -ErrorAction SilentlyContinue

Write-Host "Pangolin DNS fix applied successfully!" -ForegroundColor Green