Cannot connect to local Webserver IPAD

I got a local test environment which runs IIS 7.0. I can call the local webserver from PC's via http://demo-pc/ and get the website to show. If I use the same URL on the IPad or IPhone or IPod Touch I get an error "address is not available". I tried installing the Opera browser on the IPad and still get the same problem.

Is there a solution to the problem. I saw some solution postings related to macbooks, but nothing on the iOS so far.