What happens in IIS?
Wanna know in depth on how request and response are processed: go to this link..
http://msdn.microsoft.com/en-us/magazine/cc188942.aspx
IIS (Internet Information Server) is one of the most powerful web servers from Microsoft that is used to host your ASP.NET Web application. IIS has it’s own ASP.NET Process Engine to handle the ASP.NET request. So, when a request comes from client to server, IIS takes that request and process it and send response back to clients.
When client request for some information from a web server, request first reaches to HTTP.SYS of IIS. HTTP.SYS then send the request to respective Application Pool. Application Pool then forward the request to worker process to load the ISAPI Extension which will create an HTTPRuntime Object to Process the request via HTTPModule and HTTPHanlder. After that the ASP.NET Page LifeCycle events starts.
Worker process(w3wp.exe) runs the web application in the web server.
Application pool is the container of the worker process.
HTTP.sys
HTTP.SYS is Responsible for pass the request to particular Application pool. Whenever we creates a new Application Pool, the ID of the Application Pool is being generated and it’s registered with the HTTP.SYS. So whenever HTTP.SYS Received the request from any web application, it checks for the Application Pool and based on the application pool it send the request.
Now the control request from the remote user moves from http.sys to the application pool and then to the worker process as discussed.
This is just the basic understanding and the birds eye view of the request processing in IIS.
-Yuva
Yuva's blog 