CCST Cheat Sheet 2026

The 30 highest-yield CCST facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Identify which of the services below uses both TCP and UDP ports. → DNS
2. What is the CIDR prefix length for the subnet mask 255.255.252.0? → /22
3. A network for connecting personal devices, like Bluetooth. → PAN (Personal Area Network)
4. Which of the following security controls is primarily used to enforce the principle of confidentiality? → AES encryption
5. Which class of IPv4 addresses uses the default subnet mask of 255.255.0.0? → Class B
6. Which well-known port does the SMTP protocol use to send outgoing email between mail servers? → 25
7. Which Ethernet switching method would you use if low latency is of utmost importance? → Cut-through
8. Which Cisco IOS command can a support technician use to verify the IP configuration on a router interface? → show ip interface brief
9. What is the wildcard mask corresponding to the subnet mask 255.255.255.240? → 0.0.0.15
10. A technician needs to transfer a router's IOS image using a lightweight protocol that requires no authentication and uses UDP. Which protocol should they use? → TFTP
11. What does a Layer 2 switch use to make forwarding decisions? → MAC addresses
12. Which tool would a technician use to test whether a specific TCP port (e.g., port 443) is open on a remote server? → telnet or Netcat (nc)
13. What distinguishes a crossover cable from a straight-through cable? → Crossover cables swap transmit and receive pairs at one end for connecting similar devices
14. Which Network Layer protocol handles error reporting and diagnostics? → ICMP
15. Which command can a technician use on a Cisco IOS device to verify current active connections and listening TCP ports? → show ip sockets
16. Which PDU is associated with the Transport Layer? → Segments
17. Which statement about NTP is true? → NTP authentication is disabled by default.
18. How many subnets can be created by borrowing 3 bits from the host portion of a subnet? → 8
19. What is the function of a host-based intrusion detection system (HIDS)? → To monitor system activities and file changes to detect intrusion or policy violations
20. Each operating system has built-in tools for configuring and troubleshooting network connectivity. → Networking utilities
21. What is the administrative distance of a directly connected route? → 0
22. What does CIDR stand for in networking? → Classless Inter-Domain Routing
23. What is the importance of separating hot and cold air in a networking equipment room? → To prevent the mixing of hot and cold air, increasing equipment cooling efficiency
24. A network administrator needs subnets from 192.168.5.0/24 that each support exactly 14 usable hosts. Which subnet mask should be used? → /28
25. Which fiber connector features a push-pull latching mechanism and small form factor? → LC (Lucent Connector)
26. Provides virtualized computing resources over the internet. → IaaS (Infrastructure as a Service)
27. How are IPv6 addresses typically represented in human-readable format? → Eight hexadecimal numbers separated by colons.
28. What is the primary purpose of a default gateway in a network? → To forward traffic destined for networks outside the local subnet
29. What is the primary function of the Common Vulnerability Scoring System (CVSS)? → To offer a standardized framework for rating the severity of security vulnerabilities.
30. A technician suspects a DNS issue. Which tool can be used to query a DNS server for hostname-to-IP resolution? → nslookup