functions/Get-AzSRFreeIpAddress.ps1
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<#
.SYNOPSIS Find free IP addresses in a Azure Virtual Network .DESCRIPTION Returns a specified number or all free IP addresses from a specified Azure Virtual Network This allows easy IP address management if a static IP address should be used This function is different to Test-AzPrivateIPAddressAvailability since it returns all free IP addresses or a specified number. There is also no need to provide a IP address .PARAMETER NetworkName Name of the Virtual Network .PARAMETER ResourceGroupName Name of the Resource Group .PARAMETER SubnetName Name of the subnet .PARAMETER First Gets only the specified number of objects. Enter the number of objects to get. .EXAMPLE Find all free IP addresses in a specific Virtual Network Get-AzSRFreeIpAddress -NetworkName "MyVirtualNetwork" -ResourceGroupName "Subnet01" .EXAMPLE Find one free IP address in one of the available virtual networks Get-AzVirtualNetwork | Get-AzSRFreeIpAddress -First 1 .NOTES Copyright: (c) 2018 Fabian Bader License: MIT https://opensource.org/licenses/MIT #> function Get-AzSRFreeIpAddress { [CmdletBinding()] param ( [Alias('Name')] [Parameter(Mandatory = $true, ValueFromPipelineByPropertyName = $true)] [String]$NetworkName, [Parameter(Mandatory = $true, ValueFromPipelineByPropertyName = $true)] [String]$ResourceGroupName, [Parameter(Mandatory = $false)] [String]$SubnetName, [Int32]$First ) Begin { #region Check if logged in try { Get-AzCachedAccessToken | Out-Null } catch { throw $($_.Exception.Message) } #endregion } Process { $FoundIPAddress = 0 if ($SubnetName) { $SubnetConfiguration = Get-AzVirtualNetwork -ExpandResource "subnets/ipConfigurations" -Name $NetworkName -ResourceGroupName $ResourceGroupName | Select-Object -ExpandProperty Subnets | Where-Object { $_.Name -eq $SubnetName} } else { $SubnetConfiguration = Get-AzVirtualNetwork -ExpandResource "subnets/ipConfigurations" -Name $NetworkName -ResourceGroupName $ResourceGroupName | Select-Object -ExpandProperty Subnets } foreach ($Subnet in $SubnetConfiguration) { Write-Verbose "Check for free IP address in subnet:`t$($Subnet.Name)" if ( ( $PSBoundParameters.ContainsKey('First') ) -and ($FoundIPAddress -ge $First)) { # We have enough IP addresses break } Write-Verbose "Subnet address prefix:`t`t`t$($Subnet.AddressPrefix)" $PossibleIpAddresses = Get-SubnetAddress -Subnet "$($Subnet.AddressPrefix)" | Select-Object -ExpandProperty IPAddressToString $UsedIpAddresses = $Subnet.ipConfigurations.privateIPAddress if ([string]::IsNullOrEmpty($UsedIpAddresses)) { Write-Verbose "No IP addresses used" $FreeIPAddresses = $PossibleIpAddresses } else { $FreeIPAddresses = Compare-Object -ReferenceObject $PossibleIpAddresses -DifferenceObject $UsedIpAddresses | Where-Object { $_.SideIndicator -eq "<="} | Select-Object -ExpandProperty InputObject } Write-Verbose "Found $($FreeIPAddresses.Count) free IP addresses" foreach ($IPAddress in $FreeIPAddresses) { # First three address are reserved addresses in each subnet according to MSFT # https://docs.microsoft.com/en-us/azure/virtual-network/virtual-networks-faq#are-there-any-restrictions-on-using-ip-addresses-within-these-subnets if ($IPAddress -notin ( $PossibleIpAddresses | Select-Object -First 3 ) ) { Write-Verbose "$IPAddress is free" New-Object psobject -Property @{ "IPAddress" = $IPAddress "Subnet" = $Subnet.Name "VirtualNetworkName" = $NetworkName "ResourceGroupName" = $ResourceGroupName } $FoundIPAddress++ if ( ( $PSBoundParameters.ContainsKey('First') ) -and ($FoundIPAddress -ge $First)) { # We have enough IP addresses break } } else { Write-Verbose "$IPAddress is reserved" } } } } } |