Save time by using IIS instead of Cassini

I’m always looking for ways (whether or big or small) to make the software development process faster, and here’s a real easy win — use IIS instead of Cassini. Cassini was a good idea in concept (allows you to develop web applications without IIS), but it’s also really slow. If you’ve used it, you know what I’m talking about — every time you debug your application, you have to wait 20 seconds for Cassini to start up. Fortunately there is a better way, and that way is to use IIS instead.

The first thing is that you need to be developing a web application, not a web site. I can’t think of any reason to use a web site over a web application. So I’m going to assume that you already have a web application. I’m also using IIS 7. If you’re using IIS 6, you can still do all of the same things, but you have a different IIS console. But you should still be able to figure it out.

Step 1: Create a new application pool by right-clicking on “Application Pools” in the IIS management console. I suppose you could use an existing application pool, but I always like to make a new one. This way, you don’t have one application pool being used for multiple sites, because then you can’t change the application pool settings without affecting all of those sites. After you create the new application pool, click Start in the panel on the right to start the app pool.

Create a new application pool

Step 2: Right click on “Sites” in the IIS management console and select Add New Site. The physical path should be the local path on your drive to the folder that contains the web.config file for your site. In the “Host name” text box, just make up some host name. For example, “”. It doesn’t matter what you pick, just pick a host name that doesn’t actually exist. Also, click the “Select” button at the top and select your application pool.

Add Web Site

Step 3: Edit your “hosts” file. This file can be found at C:\Windows\System32\drivers\etc\hosts. Enter this line at the bottom of the file:

Use the host name that you entered when you created the new web site.

Step 4: Browse to the URL that you assigned to the site. In my case, Your website should come up! Win!

Debugging your site using IIS is slightly different. In Visual Studio, edit the project properties for your web site and select the Web tab. Click on the “Use Local IIS Web Server” radio button and enter your custom URL as the Project Url (e.g. Notice that there is also a checkbox that says, “Apply server settings to all users”. Ideally everyone on your team will set up IIS (because this way is much faster), but if that is not the case, you will want to uncheck that checkbox.


You can also debug your site by doing Tools / Attach to Process in Visual Studio (that’s Ctrl-Alt-P) and connecting to the w3wp.exe process (aspnet_wp.exe if you’re on Windows XP). If you don’t see w3wp.exe in the list, make sure that you check the “Show processes in all sessions” checkbox in the Attach to Process dialog box.

Happy debugging!