How to extract used or free ips for all vnet with ip address space in powershell script

Question

Extract used or free ips for all vnet with subnet and also giving the ip address space for bith vnet by using powershell. and also get the result for extracting output in CSV file.

Answer 1

you can modify the following

Connect-AzAccount

# Get all VNets
$vnets = Get-AzVirtualNetwork

# Initialize an empty array for the results
$results = @()


foreach ($vnet in $vnets) {

    foreach ($subnet in $vnet.Subnets) {

        $usedIPs = (Get-AzNetworkInterface -VirtualNetwork $vnet).IpConfigurations | Where-Object { $_.Subnet.Id -eq $subnet.Id } | Select-Object -ExpandProperty PrivateIpAddress


        $ipAddressSpace = [System.Net.IPAddress]::Parse($subnet.AddressPrefix.Split("/")[0])
        $subnetMask = [Convert]::ToInt32($subnet.AddressPrefix.Split("/")[1])
        $ipRange = 1..([Math]::Pow(2, (32 - $subnetMask)) - 2)


        $freeIPs = $ipRange | ForEach-Object { $ipAddressSpace.Address += 1; $ipAddressSpace } | Where-Object { $_.ToString() -notin $usedIPs }


        $results += [PSCustomObject]@{
            "VNetName"        = $vnet.Name
            "VNetAddressSpace" = ($vnet.AddressSpace.AddressPrefixes -join ', ')
            "SubnetName"      = $subnet.Name
            "SubnetAddressSpace" = $subnet.AddressPrefix
            "UsedIPs"         = ($usedIPs -join ', ')
            "FreeIPs"         = ($freeIPs -join ', ')
        }
    }
}

# Export the results to a CSV file
$results | Export-Csv -Path "VNetIPReport.csv" -NoTypeInformation

Answer 2

@Anonymous

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to know the number of Available IP Addresses and used IP Addresses in a subnet in VNet.

# Get the VNet
$resourceGroupName = "<RG Name>"
$virtualNetworkName = "<VNET Name>"


$virtualNetwork = Get-AzVirtualNetwork `
    -Name $virtualNetworkName `
    -ResourceGroupName $resourceGroupName

#Loop through the VNet for individual Subnets

foreach ($subnet in $virtualNetwork.Subnets)
{
$subnetMask = $subnet.AddressPrefix.Split("/")[1]

$netmaskLength = [Math]::Pow(2, 32 - [int]$subnetMask)

$availableIpAddresses = $netmaskLength - 5 - $subnet.IpConfigurations.Count

Write-Host "Subnet Name: " $subnet.Name
Write-Host "Address Range: " $subnet.AddressPrefix
Write-Host "Total usable IP Addresses in this Subnet: " ($netmaskLength - 5)
Write-Host "Used IP Addresses: " $subnet.IpConfigurations.Count
Write-Host "Available IP Addresses: " $availableIpAddresses
Write-Host "`n"

}

Kindly let us know if this helps or you need further assistance on this issue.

Thanks,

Kapil

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