IIS doesn't interpret a php file

I have a IIS webserver (v 6.1) with a webpage which is accessable from other devic开发者_JAVA百科es in the LAN. If I try to access a php-page via the IP address I can only download the file. IIS doesn't interpret the PHP.

When I access the page locally (with a specified hostname like 'http://test.app') everything works fine.

Are there any settings to control this behaviour?

In default IIS server doesn't parse php content and

you must configure your IIS server to parse and render PHP content.

Please read this setup tutorial

or just google for configuring iis for php

The problem lies within the PHP file as it returns JSON or JavaScript.