[evilmoo]

Whilst interviewing SysAdmin candidates, I prefer an answer along the lines of: "I don't know, but I'd do x,y and z to find out"

Instead of guessing and potentially being very wrong and breaking things.

Be honest, but prove you're smart by showing how you'd get to the answer.

[jrussbowman]

This is exactly what I look for when interviewing sysadmin candidates as well. I'm not sure how well this transfers over to programming though. The actual question was't posted, but in general working with multi-dimensional arrays is a standard part of PHP programming in my opinion.

Therefore the interviewer could have decided that the applicant didn't have enough base experience for the position they were applying for because of that.

Translating this to a sysadmin candidate. If I were interviewing someone for a Systems Administrator III position focusing on Linux and they couldn't answer basic DNS questions, such as A vs CNAME record I'd be inclined to believe they haven't done enough server and application builds to qualify for a III. IF they were applying for a devops position and couldn't cover the basics of named based virtualhosts in apache, that might be another indicator.

I don't know is the right answer always. It's a lot worse for a company to hire you because you are able to fluff the answers in an interview and then not be able to perform once you have the job. It creates stress on you and on the team you join. It's especially more negative when you have to once again go looking for a job and explain why your most recent position experience was so short.

To the original poster, as others have said, you got a leg up here. You know specifically what you missed during the interview so now you have an opportunity to go focus on an are you've identified yourself as weak on so you can pass the next interview honestly.