Well....that simply means that the owner of that server has put in an alternate IP adress when reporting their stats to gotnap.com. I do the same thing with my server.
Let me explain this a little more and I don't expect anyone to understand unless you run a opennap or a slavanap server. In our settings on the server for reporting, it ask us to give us an IP# to report....but instead alot of us just simply enter in our DNS address. My server DNS address is 21.rockmep2p.com:8888, and I simply put s1.rockmep2p.com as the IP#. Causing it to show an altered or fake IP#.
Get it? Good