As part of an interview for a new system administration, we asked the following questions:
General:
- Background?
- With which Unix-like systems have you had experience?
- How many machines or users?
- Can you name some control panels? Which one have you supported?
Administration:
- Which filesystem does Linux use?
- What is journalling?
- What's an inode?
- What happens when you delete a file while an application has it opened?
- What is: NFS? NIS?
- What is Kerberos?
- Which webserver do you have experience with?
- What is a wildcard DNS entry? How would you configure Apache for that?
Network:
- Do you know how to tunnel traffic?
- Do you know what OSI layers are?
- Where does TCP fit in?
- What is ICMP? Where does it fit in?
Network above layer 4:
- What is SMTP?
- What's the difference between IMAP and POP3?
- Why are both protocols insecure? How to handle this?
- What's DNS?
- Did you administrate DNS servers?
- What does it mean when a server is authoritative for a domain?
- How do you look up the name servers for a domain?
- What are virtual hosts in the HTTP protocol?
Network layer 4 and below:
- What's the difference between UDP and TCP?
- What's a gateway?
- What's a multi-homed machine?
- If there are two network interfaces on a machine, how many IP addresses can you use?
Security:
- How do you stay up-to-date on security news?
- How do you check for open ports?
- What is jailing?
- What is selinux?
- When is a firewall called for, in your opinion?
- How would you go about setting up a firewall?
- What is intrusion detection?