IIS 5.0 (default on Windows/2000) will not co-reside with 
another web server on the same machine without the 
following fix.  

With initial versions of IIS5.0 this would only affect 
another web server (like Screensurfer) if that server 
wanted to listen on port 80, on a different IP address than 
IIS (multi-homed).

It now appears that the Windows/2000 SP2 build has 
introduced some kind of port listener which will create 
problems even for ports 82 and 83 (the typical alternate SS 
ports).

Here is the information and fix:
From MS knowledge base article Q259349:
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IIS Binds To All Available IP Addresses When It Starts 
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The information in this article applies to:

Microsoft Internet Information Services version 5.0
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SYMPTOMS
When you start Internet Information Services (IIS)