remote-debugging-azure.md

title	description	ms.date	ms.topic	author	ms.author	manager	ms.subservice
Remote Debug ASP.NET Core on IIS and an Azure VM	Learn how to set up and configure a Visual Studio ASP.NET Core app, deploy it to IIS using an Azure VM, and attach the remote debugger from Visual Studio.	04/23/2024	conceptual	mikejo5000	mikejo	mijacobs	debug-diagnostics

Remote Debug ASP.NET Core on IIS using an Azure VM from Visual Studio

This guide explains how to set up and configure a Visual Studio ASP.NET Core app, deploy it to IIS using an Azure VM, and attach the remote debugger from Visual Studio.

For IIS scenarios, Linux isn't supported.

To debug IIS on an Azure VM, follow the steps in this article. Using this method, you can use a customized configuration of IIS, but the setup and deployment steps are more complicated. If you don't need to customize IIS for your scenario, you might choose simpler methods to host and debug the app in Azure App Service instead.

For an Azure VM, you must deploy your app from Visual Studio to Azure and you also need to manually install the IIS role and the remote debugger, as shown in the following illustration.

Warning

Be sure to delete the Azure resources that you create when you have completed the steps in this tutorial. That way you can avoid incurring unnecessary charges.

These procedures have been tested on these server configurations:

• Windows Server 2022 and IIS 10
• Windows Server 2019 and IIS 10
• Windows Server 2016 and IIS 10

Prerequisites

Visual Studio 2019 or later versions is required to follow the steps shown in this article.

Network requirements

Debugging between two computers connected through a proxy isn't supported. Debugging over a high latency or low bandwidth connection, such as dialup Internet, or over the Internet across countries/regions isn't recommended and might fail or be unacceptably slow. For a complete list of requirements, see Requirements.

App already running in IIS on the Azure VM?

This article includes steps on setting up a basic configuration of IIS on Windows server and deploying the app from Visual Studio. These steps are included to make sure that the server has the required components installed, that the app can run correctly, and that you're ready to remote debug.

• If your app is running in IIS and you just want to download the remote debugger and start debugging, go to Download and Install the remote tools on Windows Server.

• If you want help ensuring your app is set up, deployed, and running correctly in IIS so that you can debug, follow all the steps in this article.

  • Before you begin, follow all the steps described in Create a Windows Virtual Machine, which includes steps to install the IIS web server.

  • Make sure you open port 80 in the Azure Network security group. When you verify that port 80 is open, also open the correct port for the remote debugger (4026, 4024, or 4022). That way, you don't have to open it later. If you're using Web Deploy, also open port 8172.

Create the ASP.NET Core application on the Visual Studio computer

1. Create a new ASP.NET Core web application.

   In Visual Studio, choose File > Start window to open the Start window, and then choose Create a new project. In the search box, type web app, then choose C# as the language, then choose ASP.NET Core Web Application (Model-View-Controller), and then choose Next. On the next screen, name the project MyASPApp, and then choose Next.

   Choose either the recommended target framework or .NET 8, and then choose Create. The version must match the version installed on the server.

2. Open the HomeController.cs file in the Controllers folder and set a breakpoint in the return View; statement in the Privacy method.

   In older templates, open the Privacy.cshtml.cs file and set a breakpoint in the OnGet method.

Update browser security settings on Windows Server

If you're using an older version of Windows Server, you might need to add some domains as trusted sites to enable you to download some of the web server components. Add the trusted sites by going to Internet Options > Security > Trusted Sites > Sites. Add the following domains.

• microsoft.com
• go.microsoft.com
• download.microsoft.com
• iis.net

When you download the software, you might get requests to grant permission to load various web site scripts and resources. Some of these resources aren't required, but to simplify the process, select Add when prompted.

Install ASP.NET Core on Windows Server

1. Install the .NET Core Hosting Bundle on the hosting system. The bundle installs the .NET Core Runtime, .NET Core Library, and the ASP.NET Core Module. For more in-depth instructions, see Publishing to IIS.

   For the current .NET Core hosting bundle, install the ASP.NET Core Hosting Bundle.

   [!NOTE] If you previously installed IIS, the ASP.NET Core IIS Module gets installed with ASP.NET Core. Otherwise, install the ASP.NET Core IIS Module manually.

   For .NET Core 2, install the .NET Core Windows Server Hosting.

   [!NOTE] If the system doesn't have an Internet connection, obtain and install the Microsoft Visual C++ 2015 Redistributable before installing the .NET Core Windows Server Hosting bundle.

2. Restart the system (or execute net stop was /y followed by net start w3svc from a command prompt to pick up a change to the system PATH).

Choose a deployment option

If you need help deploying the app to IIS, consider these options:

• Deploy by creating a publish settings file in IIS and importing the settings in Visual Studio. In some scenarios, this approach is a fast way to deploy your app. When you create the publish settings file, permissions are automatically set up in IIS.

• Deploy by publishing to a local folder and copying the output by a preferred method to a prepared app folder on IIS.

(Optional) Deploy using a publish settings file

You can use this option create a publish settings file and import it into Visual Studio.

Note

This deployment method uses Web Deploy, which must be installed on the server. If you want to configure Web Deploy manually instead of importing the settings, you can install Web Deploy 3.6 instead of Web Deploy 3.6 for Hosting Servers. However, if you configure Web Deploy manually, you will need to make sure that an app folder on the server is configured with the correct values and permissions (see Configure ASP.NET Web site).

Configure the ASP.NET Core web site

1. In IIS Manager, in the left pane under Connections, select Application Pools. Open DefaultAppPool and set the .NET CLR version to No Managed Code. This is required for ASP.NET Core. The Default Web Site uses the DefaultAppPool.

2. Stop and restart the DefaultAppPool.

Install and configure Web Deploy on Windows Server

[!INCLUDE install-web-deploy-with-hosting-server]

Create the publish settings file in IIS on Windows Server

[!INCLUDE install-web-deploy-with-hosting-server]

Import the publish settings in Visual Studio and deploy

[!INCLUDE install-web-deploy-with-hosting-server]

Note

If you restart an Azure VM, the IP address might change.

After the app deploys successfully, it should start automatically.

• If the app doesn't start after deployment, start the app in IIS to verify that it runs correctly.
• For ASP.NET Core, make sure the Application pool field for the DefaultAppPool is set to No Managed Code.

When you're ready, switch to a debug configuration.

Important

If you choose to debug a Release configuration, you disable debugging in the web.config file when you publish.

::: moniker range=">=vs-2022"

1. Select More Options > Edit to edit the profile, and then select Settings.
2. Select Save and then republish the app.
3. Select a Debug configuration, and then select Remove additional files at destination under the File Publish options. ::: moniker-end

::: moniker range="vs-2019"

1. Select Edit to edit the profile, and then select Settings.
2. Select Save and then republish the app.
3. Select a Debug configuration, and then select Remove additional files at destination under the File Publish options. ::: moniker-end

(Optional) Deploy by publishing to a local folder

You can use this option to deploy your app if you want to copy the app to IIS using PowerShell, RoboCopy, or you want to manually copy the files.

Configure the ASP.NET Core Web site on the Windows Server computer

If you're importing publish settings, you can skip this section.

1. Open the Internet Information Services (IIS) Manager and go to Sites.

2. Right-click the Default Web Site node and select Add Application.

3. Set the Alias field to MyASPApp and the Application pool field to No Managed Code. Set the Physical path to C:\Publish (where you later deploy the ASP.NET Core project).

4. With the site selected in the IIS Manager, choose Edit Permissions, and make sure that IUSR, IIS_IUSRS, or the user configured for the Application Pool is an authorized user with Read & Execute rights.

   If you don't see one of these users with access, go through steps to add IUSR as a user with Read & Execute rights.

(Optional) Publish and Deploy the app by publishing to a local folder from Visual Studio

If you're not using Web Deploy, you must publish and deploy the app using the file system or other tools. You can start by creating a package using the file system, and then either deploy the package manually or use other tools like PowerShell, Robocopy, or XCopy. In this section, we assume you're manually copying the package if you aren't using Web Deploy.

[!INCLUDE remote-debugger-deploy-app-local]

Download and Install the remote tools on Windows Server

Download the version of the remote tools that matches your version of Visual Studio.

[!INCLUDE remote-debugger-download]

Set up the remote debugger on Windows Server

[!INCLUDE remote-debugger-configuration]

Note

If you need to add permissions for additional users, change the authentication mode, or port number for the remote debugger, see Configure the remote debugger.

Attach to the ASP.NET Core application from the Visual Studio computer

::: moniker range=">=vs-2022"

Starting in Visual Studio 2022 version 17.10 Preview 2, the Attach to Process dialog box has changed. If you need instructions that match the older dialog box, switch to the Visual Studio 2019 view (upper left version selector in the article).

1. On the Visual Studio computer, open the solution that you're trying to debug (MyASPApp if you're following all the steps in this article).

2. In Visual Studio, select Debug > Attach to Process (Ctrl + Alt + P).

   [!TIP] In Visual Studio 2017 and later versions, you can reattach to the same process you previously attached to by using Debug > Reattach to Process... (Shift + Alt + P).

3. Set the Connection Type to Remote (Windows).

   The Connection Target option appears.

   Set the Connection Target to <remote computer name> and press Enter.

   Verify that Visual Studio adds the required port to the computer name, which appears in the format: <remote computer name>:port

   On Visual Studio 2022, you should see <remote computer name>:4026

   The port is required. If you don't see the port number, add it manually. ::: moniker-end

::: moniker range="vs-2019"

1. On the Visual Studio computer, open the solution that you're trying to debug (MyASPApp if you're following all the steps in this article).

2. In Visual Studio, select Debug > Attach to Process (Ctrl + Alt + P).

   [!TIP] In Visual Studio 2017 and later versions, you can reattach to the same process you previously attached to by using Debug > Reattach to Process... (Shift + Alt + P).

3. Set the Qualifier field to <remote computer name> and press Enter.

   Verify that Visual Studio adds the required port to the computer name, which appears in the format: <remote computer name>:port

   On Visual Studio 2019, you should see <remote computer name>:4024

   The port is required. If you don't see the port number, add it manually. ::: moniker-end

4. Select Refresh.

   You should see some processes appear in the Available Processes window.

   If you don't see any processes, try using the IP address instead of the remote computer name (the port is required). You can use ipconfig in a command line to get the IPv4 address.

   If you want to use the Find button, you might need to open outbound UDP port 3702 on the server.

5. Check Show processes from all users.

6. Type the first letter of your process name to quickly find your app.

   • If you're using the in-process hosting model on IIS, select the correct w3wp.exe process. Starting in .NET Core 3, this process is the default.

   • Otherwise, select the dotnet.exe process. (This is the out-of-process hosting model.)

   If you have multiple processes showing w3wp.exe or dotnet.exe, check the User Name column. In some scenarios, the User Name column shows your app pool name, such as IIS APPPOOL\DefaultAppPool. If you see the App Pool, but it's not unique, create a new named App Pool for the app instance you want to debug, and then you can find it easily in the User Name column.

   ::: moniker range=">=vs-2022" ::: moniker-end ::: moniker range="vs-2019" ::: moniker-end

7. Select Attach.

8. Open the remote computer's website. In a browser, go to http://<remote computer name>.

   You should see the ASP.NET web page.

9. In the running ASP.NET application, select the link to the Privacy page.

   The breakpoint should be hit in Visual Studio.

   If you're unable to attach or hit the breakpoint, see Troubleshoot remote debugging.

Troubleshooting IIS deployment

• If you can't connect to the host using the host name, try the IP address instead.
• Make sure the required ports are open on the remote server.
• For ASP.NET Core, you need to make sure that the Application pool field for the DefaultAppPool is set to No Managed Code.
• Verify that the version of ASP.NET used in your app is the same as the version you installed on the server. For your app, you can view and set the version in the Properties page. To set the app to a different version, that version must be installed.
• If the app tried to open, but you see a certificate warning, choose to trust the site. If you already closed the warning, you can edit the publishing profile, a *.pubxml file, in your project and add the following element (for test only): <AllowUntrustedCertificate>true</AllowUntrustedCertificate>
• After it's deployed, start the app in IIS to test that it deployed correctly.
• Check the Output window in Visual Studio for status information, and check your error messages.

Open required ports on Windows Server

In most setups, required ports are opened by the installation of ASP.NET and the remote debugger. However, if you're troubleshooting deployment issues and the app is hosted behind a firewall, you might need to verify that the correct ports are open.

On an Azure VM, you must open ports through:

• The Network security group.
• The firewall on Windows Server

Required ports:

• 80 - Required for IIS ::: moniker range=">=vs-2022"

• 4026 - Required for remote debugging from Visual Studio 2022 (see Remote Debugger Port Assignments for more information). ::: moniker-end ::: moniker range="vs-2019"

• 4024 - Required for remote debugging from Visual Studio 2019 (see Remote Debugger Port Assignments for more information). ::: moniker-end

• UDP 3702 - (Optional) The Discovery port enables you to the Find button when attaching to the remote debugger in Visual Studio. This must be an outbound port (outbound rule).

In addition, these ports should already be opened by the ASP.NET Core installation:

• 8172 - (Optional) Required for Web Deploy to deploy the app from Visual Studio