What is w3wp.exe?

Question

I have a WCF service running under a service user on my local system. Every time I try to debug it is giving me a message Attach Security warning.

In Visual Studio, by default (even without attaching), I get this error:

Attaching to this process can potentially harm your computer. If the information below looks suspicious or you are unsure, do not attach to this process

Name: C:\Windows\System32\inetsrv\w3wp.exe

What is w3wp.exe? According to a Google search, I think it is related to IIS. But what does it do? What setting should be changed so that this won't give this message everytime I try to debug on my local system?

Solution 1

An Internet Information Services (IIS) worker process is a windows process (w3wp.exe) which runs Web applications, and is responsible for handling requests sent to a Web Server for a specific application pool.

It is the worker process for IIS. Each application pool creates at least one instance of w3wp.exe and that is what actually processes requests in your application. It is not dangerous to attach to this, that is just a standard windows message.

Solution 2

Chris pretty much sums up what w3wp is. In order to disable the warning, go to this registry key:

HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\10.0\Debugger

And set the value DisableAttachSecurityWarning to 1.

Solution 3

• A worker process runs as an executables file named W3wp.exe

• A Worker Process is user mode code whose role is to process requests, such as processing requests to return a static page.

• The worker process is controlled by the www service.

• worker processes also run application code, Such as ASP .NET applications and XML web Services.

• When Application pool receive the request, it simply pass the request to worker process (w3wp.exe) . The worker process“w3wp.exe” looks up the URL of the request in order to load the correct ISAPI extension. ISAPI extensions are the IIS way to handle requests for different resources. Once ASP.NET is installed, it installs its own ISAPI extension (aspnet_isapi.dll)and adds the mapping into IIS.

• When Worker process loads the aspnet_isapi.dll, it start an HTTPRuntime, which is the entry point of an application. HTTPRuntime is a class which calls the ProcessRequest method to start Processing.

For more detail refer URL http://aspnetnova.blogspot.in/2011/12/how-iis-process-for-aspnet-requests.html

Comments

[Chris Kooken]

This talks about debugging, I really don't think it is off-topic.

[Gaʀʀʏ]

After trying to search for a w3wp description, I was unable to find any. It is a good question.

[Leniel Maccaferri]

Just check the tag info now: stackoverflow.com/tags/w3wp/info

[Brook]

Each application pool creates ^at least one, possibly more depending on how it's configured^ instance of this.

[Jonny]

@ChrisKooken is it possible to have an Application pool with no worker processes? I have 4 application pools all started in IIS 6. However I can only see to 2 w3wp processes in task manager

[Chris Kooken]

@Jonny They only spin up when a request is made. If there are no requests for a long period of time, they will shut down.

[Mukus]

Chris Kooken had answered this three years before your answer. What does IIS pool being shutdown have to do with the secure running of the PC?

[SparK]

For curiosity, the name is a reduction of: World Wide Web Worker Process I guess they didn't like w4p or it would lose the meaning of www...