PowerShell script to list all virtual machines and their public IP addresses across all Azure subscriptions in a specified tenant, using Managed Identity for authentication.

Detect-PublicIps.ps1

<#
    .SYNOPSIS
        This script lists all virtual machines in each Azure subscription and displays their public IP addresses.
    
    .DESCRIPTION
        The script authenticates using Managed Identity, sets the context to a specified tenant, retrieves all subscriptions 
        in that tenant, and then lists all virtual machines in each subscription along with their public IP addresses if available.
    
    .NOTES
        Ensure that the Managed Identity has sufficient permissions to access subscriptions and resources.
        
    AUTHOR
        Blake Drumm (blakedrumm@microsoft.com)
        
    CREATED
        July 8th, 2024

    MODIFIED
        July 15th, 2024
    
    .LINK
        Azure Automation Personal Blog: https://blakedrumm.com/
#>

# Disable automatic saving of Azure context to disk within the current process.
# This prevents using outdated context data and improves script performance by reducing disk operations.
# The output is directed to Out-Null to suppress any console output from this command.
Disable-AzContextAutosave -Scope Process | Out-Null

try
{
    # Authenticate to Azure using Managed Identity
    $x = Connect-AzAccount -Identity
    Write-Output "Authenticated to Azure with $($x.Context.Account.Type): $($x.Context.Account.Id)"
    
    # Define the tenant ID to set the context to
    # (the below line needs to be modified to your environment)
    $tenantId = '12345678-1234-1234-1234-123456789abc'
    
    # Set the context to the specified tenant
    Set-AzContext -TenantId $tenantId | Out-Null
    Write-Output "Context set to Tenant Id: $tenantId"
    
    # Get all Azure subscriptions for the tenant
    $subs = Get-AzSubscription
    if ($subs.Count -eq 0)
    {
        Write-Output "No subscriptions found for tenant: $tenantId"
        exit
    }
    else
    {
        Write-Output "Retrieved $($subs.Count) subscriptions"
    }
    
    foreach ($sub in $subs)
    {
        Write-Output "======================================================================"
        Write-Output "Processing subscription: $($sub.Name) ($($sub.Id))"
        
        # Set the context to the current subscription
        Set-AzContext -Subscription $sub.Name | Out-Null
        Write-Output "Context set to subscription: $($sub.Name)"
        
        # Get all virtual machines in the subscription
        $vms = Get-AzVM
        Write-Output "Retrieved $(($vms).Count) virtual machines in subscription: $($sub.Name)"
        
        foreach ($vm in $vms)
        {
            Write-Output "----------------------------------------------------------------------"
            Write-Output "Processing VM: $($vm.Name) in Resource Group: $($vm.ResourceGroupName)"
            
            if ($vm.NetworkProfile.NetworkInterfaces.Count -gt 0)
            {
                $nicId = $vm.NetworkProfile.NetworkInterfaces[0].Id # Assuming only one NIC per VM
                Write-Output "Retrieving Network Interface: $nicId"
                $nic = Get-AzNetworkInterface -ResourceId $nicId
                
                if ($nic.IpConfigurations.PublicIpAddress -ne $null)
                {
                    $publicIpName = $nic.IpConfigurations.PublicIpAddress.Id.Split('/')[-1]
                    Write-Output "Attempting to retrieve Public IP Address: $publicIpName in Resource Group: $($vm.ResourceGroupName)"
                    
                    # Check if the public IP address exists before retrieving
                    $publicIp = Get-AzPublicIpAddress -ResourceGroupName $vm.ResourceGroupName -Name $publicIpName -ErrorAction SilentlyContinue
                    
                    if ($null -ne $publicIp) 
                    {
                        Write-Output "VM Name: $($vm.Name)"
                        Write-Output "Resource Group: $($vm.ResourceGroupName)"
                        Write-Output "Public IP Address: $($publicIp.IpAddress)"
                        Write-Output ""
                    }
                    else
                    {
                        Write-Output "Public IP Address: $publicIpName not found in Resource Group: $($vm.ResourceGroupName)"
                    }
                }
                else
                {
                    Write-Output "VM Name: $($vm.Name) in Resource Group: $($vm.ResourceGroupName) does not have a Public IP Address."
                }
            }
            else
            {
                Write-Output "VM Name: $($vm.Name) in Resource Group: $($vm.ResourceGroupName) does not have a Network Interface."
            }
        }
    }
}
catch
{
    Write-Output "An error occurred: $_"
}
<#
    Copyright (c) Microsoft Corporation. MIT License
    
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#>