Given a subnet mask like 10.0.1.0/24, will return the lowest and highest addresses across the range

Get-SubnetRange.ps1

<#
    .DESCRIPTION
        Given a subnet mask, will return the lowest and highest addresses within the range of the mask.
        For example, given 10.1.4.0/24, will return @{"lowest"="10.1.4.0", "highest"="10.1.4.255"}

    .EXAMPLE
        Get-SubnetRange -SubnetMask '10.1.4.0/24'
#>
function Get-SubnetRange
{
    param (
        [Parameter(Mandatory=$true)]
        [ValidateNotNullOrEmpty()]
        [string]
        $SubnetMask
    )

    # split for ip and number of 1 bits
    $split = $SubnetMask -split '/'
    $ip = $split[0]
    $ip_parts = $ip -isplit '\.'
    $bits = [int]$split[1]

    # generate the netmask
    $network = @("", "", "", "")
    $count = 0

    foreach ($i in 0..3)
    {
        foreach ($b in 1..8)
        {
            $count++

            if ($count -le $bits)
            {
                $network[$i] += "1"
            }
            else
            {
                $network[$i] += "0"
            }
        }
    }

    # covert netmask to bytes
    0..3 | ForEach-Object {
        $network[$_] = [Convert]::ToByte($network[$_], 2)
    }

    # calculate the bottom range
    $bottom = @(0..3 | ForEach-Object { [byte]([byte]$network[$_] -band [byte]$ip_parts[$_]) })

    # calculate the range
    $range = @(0..3 | ForEach-Object { 256 + (-bnot [byte]$network[$_]) })

    # calculate the top range
    $top = @(0..3 | ForEach-Object { [byte]([byte]$ip_parts[$_] + [byte]$range[$_]) })

    return @{
        'lowest' = ($bottom -join '.');
        'highest' = ($top -join '.');
        'range' = ($range -join '.');
        'netmask' = ($network -join '.');
        'ip' = ($ip_parts -join '.');
    }
}