As defined in Internet Information Services (IIS) an application Pool is a collection of one or more URLs that are serviced by one or a set of worker processes. After installation of SharePoint, open IIS Manager. You will notice application pools in iis.
You must select an existing Application Pool or create a new pool whenever you create a service or web application in SharePoint Server.
application pools in iis allow multiple SharePoint websites to run on a single server without the processes or code in one site interacting with any other sites. This is primarily a security benefit, since any outside intrusion on one site is isolated. Also, problematic or poor code running on one site is isolated so that other sites on the server are unaffected. For these reasons, you should plan to use dedicated application pools to isolate authenticated content and separate applications that contain password information.
we can run powershell command to get all application pools.
we can search one or more application pool directly by running the below command.
This issue usually occurs when a request from an authenticated user without local admin rights results in a failed read of the /BIN directory by the impersonating w3wp.exe (IIS worker process for ASP.NET) process.This behavior is typically associated with lack of permissions to the temporary folder /BIN where ASP.Net assemblies are Just In Time (JIT) compiled.
The solution is to ensure that the Authenticated Users or \Users group (which usually contains DOMAIN\Users group) has Read & Execute, List Folder Contents and Read permissions on the /BIN folder below
Follow the steps below to grant the required permissions:
Open Windows Explorer and navigate to the /bin directory of your web application
Right-click on the folder and click on Properties
Go to Security tab and click on Edit
Click on Add and add the local server group Authenticated Users or \Users (this usually contains DOMAIN\Users group).
Select the Read & Execute, List Folder Contents and Read permissions (if you are planning to add Everyone to the /bin folder, grant Read permissions only)
Click OK to apply the new settings
Refresh the page and we should be able to browse to the site.
If an administrator accesses the site/feature that caused the error, the subsequent requests from non-administrators would succeed. This behavior is typically associated with lack of permissions to the temporary folder where ASP.Net assemblies are Just In Time compiled.
The freb trace shows a 403.0 for ManagedPipelineHandler
It seems to go through quite a few ASPNet events – but happens during the ASPNetPageRender – it goes to the ASPNetPageRender Enter, then ASPNetHTTPHandler Leave.Only then does it get a 403.0 which is not an official RFC error. The first sub-status for 403 is 403.0.
Application pool in Classic or Integrated mode
Application Pool in Classic Mode – In this case, we can configure a Wildcard mapping for ASPNET_ISAPI.dll at the website level. That would propagate to child virtual directories. That should not need any further modifications at the virtual directory level.
Application Pool in Integrated Mode – In this case, all relevant virtual directories would need individual modifications. They need to be set for specific handler.