Don't ask "trivia" questions - questions with a single, highly specific, answer. People can forget that kind of thing when under stress. If their job requires them to know which pin on a V.35 interface is used to transmit data, they can look it up when they have the job. General questions help you understand more about candidates than trivia ... We also dislike brain teasers.
The Practice of System and Network Administration
Ask different types of questions that will help you learn about the candidate. And how they will fit in with your workgroup. In the ancient days. Most SA were physicists, astronomers, mathematicians, and engineers. Why? Probably because the had excellent trouble shooting skills and took very good notes.
A few questions to ask:
- Describe to me, as if I knew nothing, how a TCP/IP network works.
- Describe to me, as if I knew nothing how a computer works (a basic Von-Neumann device)
- Draw me a simple network diagram: You have 20 systems, 1 router, 5 switches, 2 servers, and a small IP block. Go.
- Based on the job posting, what do you expect to be doing here?
- Describe to me what you hope to accomplish here.
- What is the best method to keep documentation up-to-date?
- What's the worst disaster recovery incident you have ever been involved in? Tell me what you did.
- Why do you like being a SA?
- How would you rate yourself as a SA?
- Do you believe that IT drives business or that business drives IT?
- What do you think about our current business model?
- What could you do to make us more profitable?
- How does IT interface with our company?
- What's your favorite joke?
- What book should I read tomorrow? Why? (then go to the library and skim it)
- Who is Thomas Limoncelli? (heh heh, GOTCHA!)
Most anyone can look good on paper. Some people can BS their way through technical discussions. And many people are poor public speakers. You must ask open ended questions. No "Yes or No", observe their thought processes, and their troubleshooting abilities. Most telling, are the metaphors they use to describe complex processes.
Hiring a SA is a very difficult task. It is unlikely that a technical interview will describe who you will be hiring. It's not so much what they know now. It's what they are willing to learn, and how quickly they will learn and apply it.