SYSTEM ADMINISTRATOR MOCK INTERVIEW EXAM

 

System Administrator Mock Interview Exam 

1. Which IP address is private?
A. 8.8.8.8
B. 172.16.5.4
C. 1.1.1.1
D. 192.0.2.1

2.What is the default port for HTTPS?
A. 80
B. 21
C. 443
D. 25

3.Which OSI layer handles routing?
A. Data Link
B. Network
C. Session
D. Transport

4.What does the CIA triad stand for?
A. Control, Integrity, Access
B. Confidentiality, Integrity, Availability
C. Control, Inspection, Audit
D. Confidentiality, Inspection, Access

5.In Linux, which command adds a user?
A. adduser
B. usermod
C. useradd
D. newuser

6.A subnet mask of 255.255.255.0 corresponds to which CIDR?
A. /16
B. /24
C. /8
D. /32

7.Which protocol uses port 22?
A. FTP
B. SSH
C. Telnet
D. SMTP

8.What is the main principle of Zero Trust?
A. Trust internal users
B. Trust verified devices
C. Never trust, always verify
D. Trust network perimeter

9.Which command shows running processes in Linux?
A. ps
B. ls
C. cat
D. who

10.Which command schedules jobs?
A. at
B. cron
C. schedule
D. jobrun

11.You cannot SSH into a server. What should you check first?
A. CPU usage
B. SSH service status
C. Disk size
D. User password length

12.Which tool is used for configuration management?
A. Docker
B. Ansible
C. Git
D. Apache

13.Which file stores user account info?
A. /etc/group
B. /etc/passwd
C. /etc/shadow
D. /etc/users

14.What does chmod 755 do?
A. Full access for all
B. Owner full, others read/execute
C. Read only
D. No access

15.Which port does DNS use?
A. 80
B. 53
C. 22
D. 25

16.Which command checks disk usage?
A. df
B. du
C. disk
D. usage

17.Which tool monitors system performance in real time?
A. ls
B. top
C. pwd
D. cat

18.A server is slow. What should you check first?
A. Background image
B. CPU, RAM, Disk
C. Username
D. IP address

19.Which protocol is connection-oriented?
A. UDP
B. TCP
C. ICMP
D. ARP

20.Which command installs packages in Ubuntu?
A. yum install
B. apt install
C. install pkg
D. dpkg start

21.What is the purpose of a firewall?
A. Encrypt data
B. Monitor CPU
C. Filter network traffic
D. Manage users

22.Which command creates a group?
A. addgroup
B. groupadd
C. newgroup
D. creategroup

23.Which Linux directory stores logs?
A. /home
B. /var/log
C. /etc/log
D. /logs

24.Which backup type copies only changed data since last backup?
A. Full
B. Incremental
C. Differential
D. Snapshot

25.What does ping test?
A. Disk
B. Connectivity
C. CPU
D. Memory


26.
Which command restarts a service?
A. service restart
B. systemctl restart
C. restart svc
D. reboot service

27.Which Kubernetes component schedules pods?
A. kubelet
B. scheduler
C. controller
D. proxy

28.What is least privilege?
A. Full access for admins
B. Minimum access required
C. Shared accounts
D. Guest access

29.Which command shows IP address?
A. ip a
B. ipconfig
C. netstat
D. route

30.Which tool is used for log analysis?
A. Splunk
B. Docker
C. Jenkins
D. Nginx

31.Which command checks open ports?
A. netstat -tuln
B. lsports
C. show ports
D. portlist

32.Which OSI layer handles encryption?
A. Application
B. Presentation
C. Network
D. Physical

33.A disk is full. What command helps find large files?
A. find / -size +100M
B. ls big
C. diskcheck
D. scan

34.What is RAID 1?
A. Striping
B. Mirroring
C. Parity
D. Backup

35.Which command changes file ownership?
A. chmod
B. chown
C. changeuser
D. ownfile

36.Which port is used by FTP?
A. 21
B. 22
C. 80
D. 110

37.Which tool visualizes metrics?
A. Grafana
B. Apache
C. Bash
D. Vim

38.What does systemctl do?
A. File editing
B. Service management
C. Networking
D. Disk management

39.Which command backs up files?
A. cp
B. rsync
C. mv
D. rm

40.Which type of attack floods a server?
A. Phishing
B. DoS
C. MITM
D. SQL Injection

41.Which file stores encrypted passwords?
A. /etc/passwd
B. /etc/shadow
C. /etc/security
D. /etc/auth

42.Which command edits crontab?
A. cronedit
B. crontab -e
C. editcron
D. jobedit

43.What is Kubernetes used for?
A. Database
B. Container orchestration
C. Firewall
D. Backup

44.Which protocol resolves IP to MAC?
A. DNS
B. ARP
C. TCP
D. HTTP

45.Which compliance framework is international?
A. NIST
B. ISO 27001
C. GDPR
D. Local Act

46.A user cannot access a file. What do you check first?
A. CPU
B. Permissions
C. Disk
D. Network

47.Which command shows memory usage?
A. free -m
B. memcheck
C. topmem
D. showmem

48.Which command tests DNS resolution?
A. nslookup
B. ping
C. route
D. netstat

49.Which is a secure authentication method?
A. Password only
B. MFA
C. Shared login
D. Plain text

50.Database backup in Linux commonly uses:
A. mysqldump
B. dbcopy
C. sqlsave
D. backupdb

 Answer.

1. B — 172.16.5.4
Private IP ranges include 172.16.0.0 – 172.31.255.255, so this falls within that range.

2. C — 443
HTTPS uses port 443 for secure encrypted communication (SSL/TLS).

3. B — Network
The Network layer (Layer 3) is responsible for routing packets between networks.

4. B — Confidentiality, Integrity, Availability
These are the three core principles of information security.

5. C — useradd
useradd is the standard low-level command for creating users in Linux.

6. B — /24
255.255.255.0 corresponds to 24 bits for network, hence /24.

7. B — SSH
SSH (Secure Shell) uses port 22 for secure remote access.

8. C — Never trust, always verify
Zero Trust assumes no user/device is trusted by default, even inside the network.

9. A — ps
ps displays running processes. Example: ps aux.

10. B — cron
cron schedules recurring jobs, while at is for one-time tasks.

11. B — SSH service status
First step: check if SSH daemon is running:
systemctl status sshd

12. B — Ansible
Ansible is widely used for automation and configuration management.

13. B — /etc/passwd
Stores user account details (not passwords). Password hashes are in /etc/shadow.

14. B — Owner full, others read/execute
755 =

Owner: rwx (7)
Group: r-x (5)
Others: r-x (5)

15. B — 53
DNS uses port 53 (UDP primarily, TCP for large queries).

16. A — df
df -h shows disk space usage per filesystem.

17. B — top
top shows real-time CPU, memory, and process activity.

18. B — CPU, RAM, Disk
These are primary performance bottlenecks to check first.

19. B — TCP
TCP is connection-oriented (reliable), unlike UDP.

20. B — apt install
Ubuntu/Debian use apt install for package management.

21. C — Filter network traffic
Firewalls allow/deny traffic based on rules.

22. B — groupadd
Creates new groups in Linux.

23. B — /var/log
System logs (auth, syslog, kernel logs) are stored here.

24. B — Incremental
Backs up only changes since last backup (efficient storage).

25. B — Connectivity
ping checks if a host is reachable over network.

26. B — systemctl restart
Used in modern Linux (systemd systems).

27. B — scheduler
Kubernetes scheduler assigns pods to nodes.

28. B — Minimum access required
Principle of least privilege reduces security risk.

29. A — ip a
Modern command to display IP addresses.

30. A — Splunk
Splunk is used for log analysis and SIEM.

31. A — netstat -tuln
Shows listening ports and services.

32. B — Presentation
Handles encryption, compression, data formatting.

33. A — find / -size +100M
Finds files larger than 100MB.

34. B — Mirroring
RAID 1 duplicates data across disks for redundancy.

35. B — chown
Changes file ownership.

36. A — 21
FTP control channel uses port 21.

37. A — Grafana
Grafana visualizes metrics (often with Prometheus).

38. B — Service management
systemctl manages services (start, stop, restart).

39. B — rsync
Efficient backup tool (incremental + remote sync).

40. B — DoS
Denial of Service overwhelms a system with traffic.

41. B — /etc/shadow
Stores hashed passwords securely.

42. B — crontab -e
Edits user cron jobs.

43. B — Container orchestration
Kubernetes manages containers at scale.

44. B — ARP
Maps IP addresses to MAC addresses.

45. B — ISO 27001
International standard for information security management.

46. B — Permissions
File access issues are usually permission-related.

47. A — free -m
Displays memory usage in MB.

48. A — nslookup
Used to query DNS servers.

49. B — MFA
Multi-Factor Authentication is more secure than passwords alone.

50. A — mysqldump
Common tool for MySQL database backups.