Disguise a Server

Yeah you can simply use SINFP to change the OS reporting for the TCP Stack:

http://www.gomor.org/cgi-bin/sinfp.pl?mode=view;page=sinfp_description

I'm confused.  SINFP seems to be another program like nmap that tries and detects what OS a computer is running.

I don't think you want to change your Linux box to look like a Windows box.  What software does to try and finger print a OS is to look at how the IP stack responds to specific situations.  In order to make your Linux box look like it Windows you would need to change the IP stack code to respond as if it were Windows.  Which means changing the IP source code.

I agree with what giltjr suggest that you "do not" want to make your Linux boxes look like a Windows boxes and it is probably no way to do that.  There are however, a few ways that I knew from an old article (http://insecure.org/nmap/misc/defeat-nmap-osdetect.html) that you can foil nmap OS fingerprinting.  They are written at the time of 2.2 / 2.4 series of kernels.  I am not sure if there exists anything for kernel 2.6.

As posted in your other comment, you tune the OS area of the TCP stack.

http://www.zog.net/Docs/nmap.html

Thanks for all of the input.  I posted this question for a friend who was given this assignment by her instructor in a security class with very little explanation, but it sounds as if you are all on the right track with your suggestions.  I will pass this info along to her and try to close out this question or post additional information ASAP.

My apologies for failing to get back on this.  My friend dropped the issue because her instructor didn't seem to even know the answer and wasn't sure what the results were supposed to be.  Based on what I could glean from the limited information, I think everyone was basically on the correct path.  Because kblack05 posted the most thorough information, I have accepted that as the solution.