---
title: "How to Enable Classic IIS App Pools With Retrace"
slug: "net-agent-installation-enable-classic-iis-app-pools"
description: "Ensure StackifyHttpModule is registered in IIS for Retrace or Prefix. Choose from two options to add the module to your app or server. "
updated: 2018-08-18T17:23:56Z
published: 2018-08-18T17:23:56Z
canonical: "docs.stackify.com/net-agent-installation-enable-classic-iis-app-pools"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stackify.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Enabling Classic IIS App Pools

When Stackify Retrace or Prefix is installed, StackifyHttpModule is registered in IIS. If you are using "classic" application pools, they will not automatically use Stackify's module. To fix this you can either add the module to your application's web.config and redeploy your app, or modify the master web.config on your server or PC to reference the module.

> Note: Some APM features may work without the module. Async requests and some other features may not work as expected.

## How to check the Pipeline mode of your App Pools

Open IIS Manager (Windows Feature) > Click App Pools. Here you can see the .NET version and the Pipeline Mode for you App pools.

![](https://support.stackify.com/wp-content/uploads/2017/10/EnablingAPM_ClassicAppPools.png)

## Option 1: Add StackifyHttpModule to your app and redeploy

You can install [the package from nuget](https://www.nuget.org/packages/StackifyHttpModule/) and then be sure to redeploy your app with the new dll and updated web.config.

```
PM> Install-Package StackifyHttpModule
```

You will then need to manually modify your web.config file to add the module under "system.web".

```xml
<system.web>
	<httpModules>
		<add name="StackifyHttpModule_Net40" type="StackifyHttpTracer.StackifyHttpModule,StackifyHttpTracer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=93c44ce23f2048dd" />
	</httpModules>
</system.web>
```

## Option 2: Add StackifyHttpModule to your server

*Note: If you added the module to your app and redeployed your app, you do not need to also reconfigure your server.*

### .NET 4.0 App Pools:

In both:

- C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\web.config
- C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\web.config

Find the location of `&lt;system.web&gt;&lt;httpModules&gt;` and add the following to register the module.

```xml
<add name="StackifyHttpModule_Net40" type="StackifyHttpTracer.StackifyHttpModule,StackifyHttpTracer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=93c44ce23f2048dd"/>
```

The file should similar to this:

```xml
<system.web>
	<httpModules>
        <!-- existing content -->
        <add name="StackifyHttpModule_Net40" type="StackifyHttpTracer.StackifyHttpModule,StackifyHttpTracer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=93c44ce23f2048dd"/>
    </httpModules>
</system.web>
```

Once the configuration changes have been made, save the change and recycle the app pool. This can be done in the IIS Manager.

![](https://support.stackify.com/wp-content/uploads/2017/10/EnablingAPM_ClassicAppPools2.png)

### .NET 2.0 App Pools:

In both:

- C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Config\web.config
- C:\Windows\Microsoft.NET\Framework\v2.0.50727\Config\web.config

Find the location of `&lt;system.web&gt;&lt;httpModules&gt;` and add the following to register the module.

```xml
    <add name="StackifyHttpModule_Net20" type="StackifyHttpTracer.StackifyHttpModule,StackifyHttpTracer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=23bb7f512c6bf076" />
```

The file should look like the example below:

```xml
    <system.web>
    	<httpModules>
            <!-- existing content -->
            <add name="StackifyHttpModule_Net20" type="StackifyHttpTracer.StackifyHttpModule,StackifyHttpTracer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=23bb7f512c6bf076" />
        </httpModules>
    </system.web>
```

Once the configuration changes have been made save the change and recycle the app pool. This can be done in the IIS Manager.

![](https://support.stackify.com/wp-content/uploads/2017/10/EnablingAPM_ClassicAppPools2.png)