If you put an ASP.Net app on the Internet it's guaranteed you will start to get hackers making automated attempts to control the server.

ASP.Net is pretty good at catching these attempts but if you log errors you'll see them clutter up your event logs and be generally disturbing.

I've written a small app that sets up IIS to block about 90% of these attacks before they even to get to your site:

http://www.hdgreetings.com/ecards/block-ip-iis/

Just run the app, click on a bad address list, and click block.

Regards,

LTG