Remove duplicate firewall rules - Windows 10 or higher

dedupFirewall.ps1

Clear-Host
Write-Host "================================================================================================" -ForegroundColor Green
write-Host "`tDuplicate Firewall Rule Remover" -ForegroundColor Green
Write-Host "================================================================================================ `n`n`n" -ForegroundColor Green

Start-Process wf.msc

Start-Sleep -Milliseconds 800

Write-Host "Please export the policy, then close the Windows Firewall management console to continue." -ForegroundColor Red
while (Get-Process -Name "mmc" -ErrorAction SilentlyContinue) {
    Start-Sleep -Milliseconds 500
}
clear-host
Write-Host "Continuing script..."
Start-Sleep -Milliseconds 800
clear-host

# Grab all rules via netsh (much faster than Get-NetFirewallRule)
$raw = netsh advfirewall firewall show rule name=all verbose | Out-String
$sections = ($raw -split '(?m)^\s*$') -ne ''  # split on blank lines

$rules = foreach ($section in $sections) {
    $pairs = [ordered]@{}
    foreach ($line in $section -split '\r?\n') {
        if ($line -match '^-+$') { continue }
        if ($line -match '^(?<key>[^:]+):\s*(?<val>.*)$') {
            $key = ($matches['key'] -replace '\s+', '')  # normalize key
            $val = $matches['val'].Trim()
            $pairs[$key] = $val
        }
    }
    [PSCustomObject]$pairs
}

# Hash each rule based on key properties
$keys = 'RuleName', 'Program', 'Action', 'Profiles', 'RemoteIP', 'RemotePort', 'LocalIP', 'LocalPort', 'Enabled', 'Protocol', 'Direction'
$hashTable = @{}
$dupes = @()

foreach ($rule in $rules) {
    $keyString = ($keys | ForEach-Object { $rule.$_ }) -join '|'
    if ($hashTable.ContainsKey($keyString)) {
        $dupes += $rule
    }
    else {
        $hashTable[$keyString] = $true
    }
}

# Delete duplicates safely using PowerShell cmdlet (since netsh deletes all with same name)
foreach ($dup in $dupes | Group-Object RuleName) {
    $name = $dup.Name
    Write-Host "Removing duplicate rules for '$name'..." -ForegroundColor Yellow
    Get-NetFirewallRule -DisplayName $name -ErrorAction SilentlyContinue |
    Select-Object -Skip 1 |
    Remove-NetFirewallRule -ErrorAction SilentlyContinue
}
if ($dupes.Count -eq 0) {
    Write-Host "No duplicate firewall rules found." -ForegroundColor Green
}
else {
    Write-Host "Removed $($dupes.Count) duplicate firewall rules." -ForegroundColor Green
}