Test if a IP address is part of the Office 365 endpoints

Test-IsO365IpAddress.ps1

[CmdletBinding()]
param (
    # IP Address to check against Office 365 Range
    [Parameter(Mandatory = $true,
        ValueFromPipeline = $true,
        Position = 0)]
    $IPAddress,

    # Port to check
    [Parameter(Mandatory = $false,
        Position = 1)]
    $Port
)

Begin {
    #region Functions

    # http://www.gi-architects.co.uk/2016/02/powershell-check-if-ip-or-subnet-matchesfits/
    # Please note i took inspiration form www.padisetty.com
    # The function will check ip to ip, ip to subnet, subnet to ip or subnet to subnet belong to each other and return true or false and the direction of the check
    #////////////////////////////////////////////////////////////////////////
    function checkSubnet ([string]$addr1, [string]$addr2) {
        # Separate the network address and lenght
        $network1, [int]$subnetlen1 = $addr1.Split('/')
        $network2, [int]$subnetlen2 = $addr2.Split('/')


        #Convert network address to binary
        [uint32] $unetwork1 = NetworkToBinary $network1

        [uint32] $unetwork2 = NetworkToBinary $network2


        #Check if subnet length exists and is less then 32(/32 is host, single ip so no calculation needed) if so convert to binary
        if ($subnetlen1 -lt 32) {
            [uint32] $mask1 = SubToBinary $subnetlen1
        }

        if ($subnetlen2 -lt 32) {
            [uint32] $mask2 = SubToBinary $subnetlen2
        }

        #Compare the results
        if ($mask1 -and $mask2) {
            # If both inputs are subnets check which is smaller and check if it belongs in the larger one
            if ($mask1 -lt $mask2) {
                return CheckSubnetToNetwork $unetwork1 $mask1 $unetwork2
            } else {
                return CheckNetworkToSubnet $unetwork2 $mask2 $unetwork1
            }
        } ElseIf ($mask1) {
            # If second input is address and first input is subnet check if it belongs
            return CheckSubnetToNetwork $unetwork1 $mask1 $unetwork2
        } ElseIf ($mask2) {
            # If first input is address and second input is subnet check if it belongs
            return CheckNetworkToSubnet $unetwork2 $mask2 $unetwork1
        } Else {
            # If both inputs are ip check if they match
            CheckNetworkToNetwork $unetwork1 $unetwork2
        }
    }

    function CheckNetworkToSubnet ([uint32]$un2, [uint32]$ma2, [uint32]$un1) {
        $ReturnArray = "" | Select-Object -Property Condition, Direction

        if ($un2 -eq ($ma2 -band $un1)) {
            $ReturnArray.Condition = $True
            $ReturnArray.Direction = "Addr1ToAddr2"
            return $ReturnArray
        } else {
            $ReturnArray.Condition = $False
            $ReturnArray.Direction = "Addr1ToAddr2"
            return $ReturnArray
        }
    }

    function CheckSubnetToNetwork ([uint32]$un1, [uint32]$ma1, [uint32]$un2) {
        $ReturnArray = "" | Select-Object -Property Condition, Direction

        if ($un1 -eq ($ma1 -band $un2)) {
            $ReturnArray.Condition = $True
            $ReturnArray.Direction = "Addr2ToAddr1"
            return $ReturnArray
        } else {
            $ReturnArray.Condition = $False
            $ReturnArray.Direction = "Addr2ToAddr1"
            return $ReturnArray
        }
    }

    function CheckNetworkToNetwork ([uint32]$un1, [uint32]$un2) {
        $ReturnArray = "" | Select-Object -Property Condition, Direction

        if ($un1 -eq $un2) {
            $ReturnArray.Condition = $True
            $ReturnArray.Direction = "Addr1ToAddr2"
            return $ReturnArray
        } else {
            $ReturnArray.Condition = $False
            $ReturnArray.Direction = "Addr1ToAddr2"
            return $ReturnArray
        }
    }

    function SubToBinary ([int]$sub) {
        return ((-bnot [uint32]0) -shl (32 - $sub))
    }

    function NetworkToBinary ($network) {
        $a = [uint32[]]$network.split('.')
        return ($a[0] -shl 24) + ($a[1] -shl 16) + ($a[2] -shl 8) + $a[3]
    }
    #////////////////////////////////////////////////////////////////////////
    #endregion

    # Generate GUID to query
    $GUID = [guid]::NewGuid()
    # Retreive
    $Office365IPRanges = Invoke-RestMethod -Method Get -UseBasicParsing -Uri "https://endpoints.office.com/endpoints/worldwide?clientrequestid=$GUID&NoIPv6"
    $IPAddressInSubnet = $false
    $AllIPAddresses = $Office365IPRanges.ips | Select-Object -Unique
}

Process {
    foreach ($Subnet in $AllIPAddresses) {
        if ( (checkSubnet $IPAddress $Subnet).Condition ) {
            Write-Verbose "$IPAddress is part of $Subnet"
            $IPAddressInSubnet = $true
            break
        }
    }
    if ($IPAddressInSubnet) {
        $MatchingServices = $Office365IPRanges | Where-Object { $Subnet -in $_.ips } | Add-Member -NotePropertyName "Subnet" -NotePropertyValue $Subnet -PassThru | Select-Object serviceAreaDisplayName, category, subnet, tcpPorts, required, @{e={"$IPAddress"};n="IPAddress"}
    }
    if ( $PSBoundParameters.ContainsKey('Port')) {
        $MatchingServices = $MatchingServices | Where-Object { $_.tcpPorts -match $port -or $_.udpPorts -match $port }
    }
    # Output result
    if ($MatchingServices) {
        $MatchingServices
    } else {
        Write-Host -ForegroundColor Yellow "Did not find $IPAddress"
    }
}