I am going to show you how to change Apache's source code before compiling and installing so that it always shows a different name while using the technique described here. I have used Apache version 2.0.59 for this tutorial. Assuming that you have already downloaded the source code and extracted all the files in httpd-2.0.59, 'cd' into httpd-2.0.59 and use 'nano' (or your favourite text editor) to open the file (httpd-2.0.59/server/core.c) containing the Apache label.
If you want to compile and install Open Source Software on your MacOS X machine then you should install MacOS X's Xcode tools. Xcode tools provide the compilers and other software development kits (SDKs) to enable you to compile and install open source software on your computer.
Before you proceed, please note that this method may not work at all times because some websites hide their server information. Also, this method should be used to find out more about your site's security and should not be used for any other purposes.
All the instructions below are tested on Ubuntu Linux Server but should work fine on other platforms running telnet.