find_netmask.ps1

find_netmask.ps1

function Convert-PrefixToNetmask {
    param (
        [Parameter(Mandatory = $true)]
        [int]$PrefixLength
    )
    
    # Create a binary mask string with 1's for the prefix and pad with 0's
    $binaryMask = ("1" * $PrefixLength).PadRight(32, "0")
    $octets = @()
    
    # Convert each 8-bit block to a decimal number
    for ($i = 0; $i -lt 4; $i++) {
        $octetBinary = $binaryMask.Substring($i * 8, 8)
        $octets += [convert]::ToInt32($octetBinary, 2)
    }
    return $octets -join "."
}

# Example usage:
$interface = "Ethernet"
$ipConfig = Get-NetIPConfiguration -InterfaceAlias $interface
$prefixLength = $ipConfig.IPv4Address.PrefixLength
$netmask = Convert-PrefixToNetmask -PrefixLength $prefixLength

Write-Output "Prefix Length: $prefixLength"
Write-Output "Netmask: $netmask"