Check if a port is active/open/listening in PowerShell.

IsPortActive.ps1

# Copy and paste the below function into PowerShell, then you can check if a port is active/open/listening by typing:
# IsPortActive -Port 22

function IsPortActive() {
    [CmdletBinding()]
    param (
        [Int32]$Port
    )

    # Check script elevation
    if (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")) {
        Write-Warning "Insufficient permissions to run this script. Open the PowerShell console as an administrator and run this script again."
        Break
    }

    # Get open ports
    $Results = Get-NetTCPConnection | Where-Object { $_.LocalPort -eq "$Port" } | Select-Object @{Name = "Process"; Expression = { (Get-Process -Id $_.OwningProcess).ProcessName } }, @{Name = "Path"; Expression = { (Get-Process -Id $_.OwningProcess).Path } }, LocalAddress, LocalPort, RemoteAddress, RemotePort, State

    # Return Results
    Write-Host
    if ($Results) {
        Write-Host "Port $Port is active!"
        $Results
    }
    else {
        Write-Host "Port $Port is NOT active"
        Write-Host
    }
}