What does 'IISReset' do?

On IIS 6, what does an IIS reset do?

Please compare to recycling an app pool and stopping and starting an ASP.NET web site.

If you replace a DLL or edit/replace the web.config on an ASP.NET web site is that the same as stopping and starting that web site?

IISReset stops and restarts the entire web server (including non-ASP.NET apps)
Recycling an app pool will only affect applications running in that app pool.
Editing the web.config in a web application only affects that web application (recycles just that app).
Editing the machine.config on the machine will recycle all app pools running.

IIS will monitor the /bin directory of your application. Whenever a change is detected in those dlls, it will recycle the app and re-load those new dlls. It also monitors the web.config & machine.config in the same way and performs the same action for the applicable apps.

IISReset restarts the entire webserver (including all associated sites). If you're just looking to reset a single ASP.NET website, you should just recycle that AppDomain.

The most common way to reset an ASP.NET website is to edit the web.config file, but you can also create an admin page with the following:

public partial class Recycle : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        HttpRuntime.UnloadAppDomain();
    }
}

Here's a blog post I wrote with more info: Avoid IISRESET in ASP.NET Applications