1. What would it mean if I saw a lot of activity on port 53?

First of all you need to find what is the source of traffic. Try something like:

netstat -a -n -p|grep :53

or this:

lsof -p PID

2. What is the diff between http and html?

One is a protocol and one is a markup language

3. How do you list directories in Linux vs. Windows?

ls vs. dir

4. How would you defend a server in the dmz?

wrap it between two firewalls and add an IPS and anti-virus applications

5. Can you describe how you would teach how to bake a cookie? So I described how I would do sql injection.

6. What is the diff between asymmetric encryption and symmetric encryption?

If you can’t answer this, forget about getting hired. For some hiring managers, this is the icebreaker question on interviews. See this document for more information on encryptions.

7. At what level of the osi model is http?

8. At what level of the osi model is a switch?

9. What forensics tools have you used?

10. Can you describe a great achievement in your career?

11. Can you describe a time when you did something wrong?

12. Can you describe a time that was great but you would rather not talk about it?

13. What are some common vulnerabilities you would check for to harden a server?

14. How would you perform a pentest?