Honestly, this "tutorial", should be removed from the site. I'm not trying to be mean or nasty but it is about 90% rubbish. There are plenty of sharp people here who wont be misled by the information, however, there are many more that could easily bust up a production web server (or any number of other services) by doing the things suggested by the poster. Security does not equal inoperability, which is exactly what will happen to *any* unix system you do these things to.

--TH13