Get-RandomIP.ps1

function Get-RandomIP {
    <#
    .SYNOPSIS
        Function to generate random IPs.
    .DESCRIPTION
        Generate Random IPs with optional ability to target public/private IP space
    .PARAMETER ExcludePrivate
        Specifies to exclude IANA reserved IP addresses (see: https://en.wikipedia.org/wiki/Reserved_IP_addresses) (default: false)
	.PARAMETER ExcludePublic
        Specifies to exclude publicly routable IP addresses (see: https://en.wikipedia.org/wiki/Reserved_IP_addresses) (default: false)
    .PARAMETER Count
        Number of IPs to generate (default: 1)

    .EXAMPLE
        PS C:\> Get-RandomIP
        Generates a single publicly routable IPv4 addressd
    .EXAMPLE
        PS C:\> Get-RandomIP -Count 2000
        Generates 2000 publicly routable IPv4 addressd
    #>
    
    param(
        [Switch]
        $ExcludePrivate,

        [Switch]
        $ExcludePublic,

		[String]
        $Count
    )
    
    ## Declare helper function to check an IP and see if it is private
    function Get-IsPrivate{
        param(
            [String]
            $Address
        )
        $octets = $Address -split "\."
        if($Address -eq "255.255.255.255"){
            return $true
        }
        if($octets[0] -eq "0"){
            return $true
        }
        if($octets[0] -eq "10"){
            return $true
        }
        if($octets[0] -eq "127"){
            return $true
        }
        if($octets[0] -in (224..239)){
            return $true
        }
        if($octets[0] -in (240..255)){
            return $true
        }
        if($octets[0] -eq "100"){
            if($octets[1] -in (64..127)){
                return $true
            }
        }
        if($octets[0] -eq "169"){
            if($octets[1] -eq "254"){
                return $true
            }
        }
        if($octets[0] -eq "172"){
            if($octets[1] -in (16..31)){
                return $true
            }
        }
        if($Address -match "192\.88\.99\.*"){
            return $true
        }
        if($Address -match "192\.168\.*\.*"){
            return $true
        }
        if($Address -match "198\.18\.*\.*"){
            return $true
        }
        if($Address -match "198\.19\.*\.*"){
            return $true
        }
        if($Address -match "198\.51\.100\.*"){
            return $true
        }
        if($Address -match "203\.0\.113\.*"){
            return $true
        }
        return $false
    }

    ## Set count to default value
    if(!$Count){
        $Count = 1
    }
    $continue = $true
    ## Sanity check that we can generate IPs based off user supplied switches...
    if($ExcludePrivate -and $ExcludePublic){
        Write-Host "You cannot exclude both Public and Private IP address space"
        $Count = 0
    }

    while($Count -gt 0){
        $octetValues = (0..255)
        $o1 = $octetValues | Get-Random
        $o2 = $octetValues | Get-Random
        $o3 = $octetValues | Get-Random
        $o4 = $octetValues | Get-Random
        if($o1 -ne 0){
            $isPriv = Get-IsPrivate -Address "$o1.$o2.$o3.$o4"
            if($ExcludePrivate){
                if($isPriv -eq $false){
                    Write-Output "$o1.$o2.$o3.$o4"
                    $Count = $Count - 1
                }
            }
            if($ExcludePublic){
                if($isPriv -eq $true){
                    Write-Output "$o1.$o2.$o3.$o4"
                    $Count = $Count - 1
                }
            }            

        }
    }


}