Hardening Linux

I came across a 3 part article written by Æleen Frisch of Linux Mag.
It was very useful to me as a newbie/intermediate to hardening a linux box. These articles aren't aimed at the newbie, but at a more intermediate user. I had to look up several of the things that they suggested, just so I could understand it all. Anywho, just wanted to share with those who are interested.

Hardening Linux Part 1
Hardening Linux Part 2
Hardening Linux Part 3

Enjoy!