>Ok, I have found how to simulate that. Basically, if someone sends a URL to my server with a .SVC file, this causes an error message in the event viewer. I just don't understand why someone sending a bad URL to my server would cause such error. What would be the best approach to avoid that? I guess I should just handle that extension as part of an exception list.

You can check to see if IIS has .SVC mapped. Go into IIS, right-click on the website, select Properties. Click on Home Directory tab. Click on Configuration. Then see if .SVC is in the application extension mappings - if it is, you can just remove it.