Cisco CCNA Study Guide 2026
Everything you need to pass the Cisco CCNA exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 Cisco CCNA Exam Format at a Glance
📚 Cisco CCNA Topics to Study (21)
✍️ Sample Cisco CCNA Questions & Answers
1. Which SNMP version introduced authentication and encryption for secure management communications?
SNMPv3 added user-based security with MD5/SHA authentication and DES/AES encryption, replacing the community-string model.
2. Which attack does DHCP snooping protect against on a switched network?
DHCP snooping prevents rogue DHCP servers by only forwarding DHCP offers from trusted (uplink) ports, blocking unauthorized IP assignments.
3. Which command disables CDP on a specific Cisco router interface to prevent neighbor information disclosure?
The interface-level command 'no cdp enable' disables CDP on that specific interface without affecting other interfaces.
4. Which of the following protocols is a Distance Vector Protocol?
Distance Vector routing protocols determine the best path to a destination based on the 'distance' (e.g., hop count) and the 'direction' (vector) to reach it, typically relying on information from directly connected neighbors. RIP (Routing Information Protocol) is a classic example of a distance vector protocol, using hop count as its primary metric and periodically exchanging full routing tables with its neighbors.
5. Which AAA protocol encrypts only the password in the authentication packet, while the other encrypts the entire payload?
RADIUS encrypts only the user's password in the Access-Request packet, while TACACS+ encrypts the entire body of every packet for greater security.
6. A network engineer configures an EtherChannel but notices only some member ports are active. The switch shows flags 'I' on those ports. What does 'I' indicate?
The 'I' (independent) flag in 'show etherchannel summary' means the port is not bundled, typically because its speed, duplex, or VLAN settings differ from the other member ports.