There were at least 20 questions. Some are easy and some I wasn't able to answer. Just be honest upfront that you cannot answer the question. Here are some that I can remember. 1. What command checks for running processes? 2. What is TCP and UDP? 3. You said that in TCP, connection is established, how is this done? 4. What command shows the hops between two networks? 5. How does traceroute command obtain these hops? 6. What is MTU? 7. What command checks for open ports? 8. What does the inode command do? 9. How do you edit the file descriptor? 10. How do you open files of a specific process? 11. What command checks the routing table in Linux? 12. Which directory are log files stored? 13. Which directory are third party software stored? 14. What is DNS? 15. Tell me about the DNS process. (The entire technical process) 16. What is DHCP. 17. Tell me about the DHCP process. (The entire technical process) 18. Tell me examples of TCP. 19. Tell me examples of UDP. 20. What command checks port connection? Then there were two behavioral questions: 1. When was the time you worked out of scope from your responsibilities? Tell me about it. 2. Tell me about a time with the most difficult customer.