Oh wow, where do I begin? First, through a recruiter, phone interview (screening). Then another a phone interview with an HR person there very similar to the screening. In both interviews your basic knowledge is tested in Networking, Security and Linux. I finally had an official interview with the folks there.
I have to admit, it was a bit intense. The environment was a bit intimidating in that the interviewers are all staring at you with dim light above. If it wasn't for my humor to have some control to the interview, I would've been very nervous. Then again, the position itself is intense and I felt the interview was to test your personality for the position.