Top 50 CCNA Interview Questions & Answers

After qualifying for the test and getting that CCNA certification, you will also need to pass the CCNA interview process for jobs to join your dream company. To prepare for the interview you can check out our CCNA interview questions and answers.

Here we have researched and compiled the 50 most frequently asked CCNA interview questions. Big IT giants Cisco Systems, AWS, Microsoft, AT&T, etc. ask CCNA concepts in interviews. We have provided the CCNA interview questions with answers for optimal preparation.

Many interview questions for CCNA are already covered in our Cisco Training courses, but if you have not studied our online courses, you can check these CCNA interview questions for beginners and experienced candidates.

CCNA Interview Topics for Freshers and Experienced

In preparation for CCNA interviews, candidates should familiarize themselves with common technical questions related to the OSI model, TCP/IP protocols, subnetting, and VLANs.

Interviewers often assess both technical knowledge and practical experience, so candidates should be ready to provide real-world examples of how they have applied their skills.

Based on your experience, the questions asked can be different. There are 2 levels of CCNA interviews i.e. freshers and experienced.

CCNA interview questions for beginners may include questions related to:

1. Routing

2. OSI Model Layers

3. Hub vs. Switch

4. Subnetting

5. IP Addressing

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CCNA Interview Questions for Experienced may include questions related to: 

1. OSPF (Open Shortest Path First)

2. VLANs (Virtual Local Area Networks)

3. Spanning Tree Protocol (STP)

4. NAT (Network Address Translation)

5. Network Troubleshooting Techniques 

Top 50 CCNA Interview Questions with Answers

Here are all the CCNA interview questions for beginners and experienced professionals. 

Q1) What is the IPX access list? 

Answer:  IPX (Internetwork Packet Exchange) access lists are used to control the flow of IPX packets in a network. They are like ACLs (Access Control Lists) used in IP networks but are specifically designed for IPX traffic. There are two primary types of IPX access lists: 

1. Standard IPX Access List: Filters packets based on the IPX network number. 

2. Extended IPX Access List: Provides more granular control by filtering packets based on source and destination IPX network numbers, as well as other attributes such as packet type. 

Q2) How do hold-downs work? 

Answer:  Hold-downs are a mechanism used in routing protocols to stabilize routing tables and prevent routing loops. When a routing protocol detects a route has become invalid (e.g., due to a link failure), it triggers a hold-down timer. During this time, the router will not accept any new updates about that route, even if they are better. This helps to avoid situations where regular update messages might erroneously reinstate a previously failed route. The hold-down period ensures that the network stabilizes and reduces the risk of routing loops. 

Q3) Expand DLCI? 

Answer: DLCI stands for Data Link Connection Identifier. It is a unique identifier used in Frame Relay networks to differentiate between multiple logical connections on the same physical link. Each DLCI is associated with a specific virtual circuit, enabling multiple virtual connections to share the same physical interface. 

Q4) What are the types of passwords used in Cisco routers? 

Answer: Cisco routers support various types of passwords for different access levels and services: 

1. Enable Secret Password: Encrypts the password and is used to access privileged EXEC mode. 

2. Enable Password: Unencrypted password used for the same purpose as Enable Secret, but less secure. 

3. Virtual Terminal (VTY) Password: Used for remote access via Telnet or SSH. 

4. Console Password: Protects console access to the router. 

5. Auxiliary Password: Protects access to the auxiliary (AUX) port for dial-in connections. 

Q5) Mention the clock rate? 

Answer: The clock rate refers to the speed at which data is transmitted over a serial link. It is specifically needed on the DCE (Data Communications Equipment) side of a serial link to synchronize the transmission of data. The clock rate is set on serial interfaces to ensure proper timing of data frames. 

Q6) How many types of RIP messages? 

Answer: RIP (Routing Information Protocol) uses two types of messages for communication: 

1. Request Message: Sent by a router to request routing information from other routers. 

2. Response Message: Sent by a router to respond to a request message and provide routing information. 

Q7) Expand BGP? 

Answer: BGP stands for Border Gateway Protocol. It is a path vector protocol used to exchange routing information between different autonomous systems (ASes) on the internet. BGP is crucial for inter-domain routing and helps in determining the best paths for data to travel across multiple networks. 

Q8) What is the difference between STP and RSTP? 

Answer: Diference between STP and RSTP is:

- STP (Spanning Tree Protocol): Designed to prevent network loops in Ethernet networks by creating a loop-free logical topology. It can be slow to converge (i.e., adapt to changes) when network changes occur. 

- RSTP (Rapid Spanning Tree Protocol): An enhancement of STP that provides faster convergence by improving the speed of transition between different states of the network topology. RSTP reduces the time required to recover from network changes, leading to quicker network stabilization. 

Q9) The Cisco IOS firewall feature acts as a stateful or stateless packet filter? 

Answer: The Cisco IOS firewall feature acts as a stateful packet filter. This means it tracks the state of active connections and makes decisions based on the state and context of the traffic, rather than simply examining each packet in isolation. Stateful filtering provides more comprehensive security by understanding the state of traffic flows. 

Q10) What are the two key features of URL filtering? 

  Answer: The two key features of URL filtering are: 

1. Predefined URL Categories: Allows administrators to categorize and filter URLs based on predefined categories such as social media, gambling, or news. This helps in controlling access to specific types of web content. 

2. Malware Protection: Blocks access to websites that are known to host malware or malicious content, providing an additional layer of security against potential threats. 

Q11) Define DMZ? 

Answer: A DMZ (Demilitarized Zone) is a network segment that sits between an internal network and an external network (such as the internet). It is used to host public-facing services (like web servers, email servers, and DNS servers) while providing an additional layer of security. The DMZ is protected by firewalls to ensure that even if these public-facing services are compromised, the internal network remains secure. 

Q12) What type of port is in the STP? 

Answer: In STP (Spanning Tree Protocol), there are three types of ports: 

1. Root Port: The port on a switch that has the shortest path to the root bridge. 

2. Designated Port: The port on a network segment that has the best path to the root bridge for that segment. 

3. Blocking Port: Ports that are disabled to prevent loops and ensure a loop-free topology. They do not forward traffic. 

Q13) Expand the term MTU. 

Answer: MTU stands for Maximum Transmission Unit. It represents the largest size of a packet or frame that can be sent over a network interface. MTU size affects network performance and can influence the fragmentation of packets. 

Q14) What are the different types of memories in Cisco Routers? 

Answer: Cisco routers use several types of memory: 

1. NVRAM (Non-Volatile Random Access Memory): Stores the startup configuration file, which persists across reboots. 

2. DRAM (Dynamic Random Access Memory): Holds the running configuration and operational data while the router is running. It is volatile memory and loses its content when power is lost. 

3. Flash Memory: Stores the IOS (Internetwork Operating System) image and other permanent files. Flash memory retains its data even when the router is powered off. 

Q15) Expand the term EIGRP. 

Answer: EIGRP stands for Enhanced Interior Gateway Routing Protocol. It is a Cisco proprietary routing protocol that combines the advantages of both distance vector and link-state protocols. EIGRP is used for routing within an autonomous system and provides fast convergence and efficient route calculation. 

Q16) What Is Administrative Distance? 

Answer: Administrative Distance (AD) is a metric used by routers to determine the reliability or trustworthiness of different routing protocols. It is a value assigned to each routing protocol, and the lower the AD, the more preferred the routing protocol is when multiple protocols provide routes to the same destination. For example, an AD of 90 is used for EIGRP, while OSPF has an AD of 110. 

Q17) Which router command enables IPv6? 

Answer: The command used to enable IPv6 routing on a router is: ipv6 unicast-routing

This command allows the router to participate in IPv6 routing protocols and handle IPv6 traffic. 

Q18) What are the major states in a switch? 

Answer: The major states in a switch port for STP (Spanning Tree Protocol) are: 

1. Disabled: The port is administratively shut down and does not participate in STP. 

2. Blocking: The port does not forward traffic and listens to BPDUs to ensure no loops occur. 

3. Listening: The port listens to BPDUs to determine the network topology but does not forward traffic. 

4. Learning: The port begins to learn MAC addresses from incoming frames but still does not forward traffic. 

5. Forwarding: The port forwards traffic and continues to learn MAC addresses. 

Q19) What are the major functions of SNMPv3? 

Answer: SNMPv3 (Simple Network Management Protocol version 3) provides several key functions for network management: 

1. Authentication: Verifies the identity of the users and devices interacting with the SNMP agent. 

2. Encryption: Ensures that the data transmitted between the SNMP manager and agent is secure and confidential. 

3. Message Integrity: Ensures that SNMP messages have not been tampered with during transit. 

Q20) Write the expanded form of NTP. 

Answer: NTP stands for Network Time Protocol. It is used to synchronize the clocks of computers and other network devices over a network, ensuring consistent timekeeping across systems. 

Q21) Write the command used for displaying the NVRAM contents. 

Answer: The command used to display the contents of NVRAM (Non-Volatile Random Access Memory) on a Cisco router is: show startup-config

This command shows the configuration stored in NVRAM that will be loaded upon reboot. 

Q22) What do you mean by the term SYSLOG? 

Answer: SYSLOG is a protocol used for sending log and event messages from network devices and servers to a centralized logging server. SYSLOG allows administrators to collect, monitor, and analyze logs from various network devices for troubleshooting and auditing purposes. 

Q23 What are the types of ACL? 

Answer: Access Control Lists (ACLs) in Cisco networking come in several types: 

1. Standard ACL: Filters traffic based only on the source IP address. 

2. Extended ACL: Filters traffic based on both source and destination IP addresses, as well as other parameters like protocol type and port numbers. 

3. Named ACL: Provides a way to name an ACL instead of using number-based identifiers, which can make ACLs easier to manage and understand. 

Q24) What are the types of VTP? 

Answer: VTP (VLAN Trunking Protocol) modes are: 

1. Server Mode: Allows the creation, modification, and deletion of VLANs and propagates VLAN information to other switches. 

2. Client Mode: Receives VLAN information from VTP servers but cannot create, modify, or delete VLANs. 

3. Transparent Mode: Does not participate in VTP but forwards VTP advertisements through trunk links. VLANs can be created or deleted locally on a switch in this mode. 

Q25) Name the two ports of Switches? 

Answer: The two main types of switch ports are: 

1. Access Port: A port that belongs to a single VLAN and is used to connect end devices (such as computers and printers) to the switch. 

2. Trunk Port: A port that can carry traffic for multiple VLANs and is used to connect switches to each other or to other networking devices that support VLAN tagging. 

Q26) What is the administrative distance of OSPF? 

Answer: The Administrative Distance (AD) of OSPF (Open Shortest Path First) is 110. This value helps determine the preference of OSPF routes compared to routes learned from other routing protocols. 

Q27) What do you mean by Distance Vector? 

Answer: Distance Vector is a type of routing protocol that calculates the best path to a destination based on distance (usually in hops) and the direction (vector) to the destination. Distance vector protocols periodically send out routing updates to all neighboring routers, which include the router's distance and the path to various destinations. 

Q28) What are the two types of cables? 

Answer: The two main types of network cables are: 

1. Straight-Through Cable: Used to connect different types of devices, such as a computer to a switch or a router to a switch. It maintains the same pin configuration on both ends. 

2. Cross-Over Cable: Used to connect similar devices directly, such as two switches or two computers. It swaps the transmit and receive pairs of wires between the ends of the cable. 

Q29) Enlist the major functions of the Transport Layer. 

Answer: The major functions of the Transport Layer (Layer 4 of the OSI model) include: 

1. Segmentation and Reassembly: Divides larger data from the application layer into smaller segments for transmission and reassembles them at the destination. 

2. Flow Control: Manages the rate of data transmission between sender and receiver to prevent congestion and ensure smooth data transfer. 

3. Error Detection and Correction: Ensures that data is transmitted accurately by detecting and correcting errors that may occur during transmission. 

4. Connection Establishment and Termination: Manages the setup, maintenance, and teardown of connections between applications on different devices. 

Q30) State the two types of addresses available. 

Answer: The two types of IP addresses are: 

1. IPv4 (Internet Protocol Version 4): Uses a 32-bit address scheme allowing for approximately 4.3 billion unique addresses. IPv4 addresses are typically represented in dotted-decimal format (e.g., 192.168.1.1). 

2. IPv6 (Internet Protocol Version 6): Uses a 128-bit address scheme allowing for a vastly larger number of unique addresses (approximately 340 undecillion addresses). IPv6 addresses are represented in hexadecimal format (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). 

Q31) What is AAA? 

Answer: AAA stands for Authentication, Authorization, and Accounting. It is a framework for managing network access and security: 

1. Authentication: Verifies the identity of users or devices attempting to access the network. 

2. Authorization: Determines what resources or actions authenticated users or devices are permitted to access or perform. 

3. Accounting: Tracks and records the activities of users or devices for auditing and billing purposes. 

Q32) What are the different load balancing methods for VRRP? 

Answer: The different load balancing methods for VRRP (Virtual Router Redundancy Protocol) include: 

1. Round-Robin: Distributes the load evenly among all available routers in the VRRP group by rotating the assignment of the virtual IP address. 

2. Host-Dependent: Distributes the load based on the source IP address of the traffic, ensuring that traffic from the same host is consistently directed to the same router. 

3. Weighted: Assigns different weights to routers based on their capacity or desired load distribution, with routers receiving more traffic based on their weight. 

Q33) Are HSRPv1 and v2 compatible? 

Answer: No, HSRP (Hot Standby Router Protocol) version 1 (v1) and version 2 (v2) are not compatible with each other. HSRP v2 introduced several improvements, including support for additional virtual IP addresses and enhanced security features, but it is not backward compatible with HSRP v1.  

Q34) What is the Cisco proprietary protocol for link aggregation? 

Answer: The Cisco proprietary protocol for link aggregation is PAgP (Port Aggregation Protocol). PAgP is used to automatically configure and manage link aggregation groups, allowing multiple physical links to be combined into a single logical link to increase bandwidth and provide redundancy. 

Q35) What is the Aging timer of the MAC address table? 

Answer: The Aging timer of the MAC address table on a Cisco switch is typically set to 300 seconds. This timer determines how long a MAC address remains in the MAC address table before it is removed if no traffic is observed from that address. 

Q36) How many seconds is the blocking period of a switch port? 

Answer: The blocking period of a switch port in STP (Spanning Tree Protocol) is typically 20 seconds. During this time, the port is in the blocking state and does not forward traffic while it listens for BPDUs (Bridge Protocol Data Units) to prevent loops. 

Q37) STP elects the root bridge on a basis of what? 

Answer: STP elects the root bridge based on the following criteria: 

1. Lowest Bridge Priority: The switch with the lowest bridge priority value is preferred. 

2. Lowest MAC Address: If multiple switches have the same priority, the switch with the lowest MAC address is selected as the root bridge. 

3. Lowest Port Number: If there is still a tie, the switch with the lowest port number is chosen. 

Q38) Does VTP version 2 support Private VLANs? 

Answer: No, VTP (VLAN Trunking Protocol) version 2 does not support Private VLANs. Private VLANs are a feature introduced in later versions of VTP and are not available in VTP v2. 

Q39) What is the native VLAN ID by default on a Cisco switch? 

Answer: The default native VLAN ID on a Cisco switch is VLAN 1. The native VLAN is used for untagged traffic on trunk links. 

Q40) Where is the VLAN configuration stored on a Cisco switch? 

Answer: The VLAN configuration on a Cisco switch is stored in the VLAN.DAT file, which is located in the switch's flash memory. This file contains information about VLANs and their configurations. 

Q41) What is the default Local Preference value of a BGP router? 

Answer: The default Local Preference value in BGP (Border Gateway Protocol) is 100. Local Preference is used to influence the outbound routing decisions within an autonomous system. 

Q42) What is BGP’s loop prevention mechanism? 

Answer: BGP uses the AS Path attribute as its loop prevention mechanism. When a BGP router receives a route update, it checks the AS Path attribute to ensure that its own AS number is not present. If the AS number is found in the AS Path, the route is discarded to prevent routing loops. 

Q43) What is the External AD value for EIGRP? 

Answer: The External Administrative Distance (AD) value for EIGRP (Enhanced Interior Gateway Routing Protocol) is 170. This value is used to evaluate the reliability of external routes learned from other autonomous systems. 

Q44) What is a Router ID with respect to OSPF? 

Answer: The Router ID in OSPF (Open Shortest Path First) is a unique identifier assigned to each router within an OSPF autonomous system. It is used to distinguish routers in OSPF routing tables and link-state advertisements. The Router ID is typically chosen based on the highest IP address on an active interface or manually configured. 

Q45) Which router generates LSA type 7 in OSPF? 

Q46) What is AS? 

Answer: AS (Autonomous System) refers to a collection of IP networks and routers under the control of a single organization that presents a common routing policy to the internet. Each AS is assigned a unique AS number and is responsible for its own internal routing and the exchange of routing information with other ASes. 

Q47) What are the types of Network? 

Answer: The types of networks are: 

1. Point-to-Point: A direct connection between two devices or nodes. Examples include serial links and direct Ethernet connections. 

2. Broadcast: A network where all devices on the network segment receive broadcast messages. Ethernet LANs are a common example. 

3. Non-broadcast: A network that does not support broadcasting. Examples include Frame Relay and ATM networks, where devices must be explicitly addressed. 

Q48) What is PREEMPT in HSRP? 

Answer: PREEMPT is a feature in HSRP (Hot Standby Router Protocol) that allows a backup router to take over as the active router if it has a higher priority value than the current active router. When a router with a higher priority comes back online after a failure, PREEMPT ensures it becomes the active router, assuming it is still operational and configured to do so. 

Q49) What is native VLAN? 

Answer: The native VLAN is a VLAN that carries untagged traffic on a trunk link. By default, this is VLAN 1 on Cisco switches. It ensures that traffic not explicitly tagged with a VLAN ID is assigned to the native VLAN. 

Q50) What is BPDU Guard? 

Answer: BPDU Guard is a feature in spanning tree protocols that protects against unauthorized BPDU (Bridge Protocol Data Unit) packets. If a switch port with BPDU Guard enabled receives a BPDU, it will put the port into an error-disabled state, effectively shutting it down to prevent potential network loops or other issues. 

Q51) How to elect Root Bridge in the switch? 

Answer: To elect the Root Bridge in STP (Spanning Tree Protocol), the following criteria are used: 

1. Lowest Bridge Priority: Switches with the lowest bridge priority value are preferred. 

2. Lowest MAC Address: If multiple switches have the same priority, the switch with the lowest MAC address is selected. 

3. Lowest Port Number: In case of a tie in priority and MAC address, the switch with the lowest port number is chosen. 

Q52) What is VLAN? 

Answer: VLAN (Virtual Local Area Network) is a network configuration that logically segments a physical network into multiple broadcast domains. VLANs allow administrators to group devices into the same network segment regardless of their physical location, providing isolation and control over broadcast traffic within the network. 

Q53) To which layer does the NetBIOS protocol belong to in the OSI model? 

Answer: NetBIOS (Network Basic Input/Output System) belongs to the Session Layer (Layer 5) of the OSI model. It provides session management and communication services for applications, enabling them to establish and maintain sessions across a network. 

Tips to Answer CCNA Interview Questions

1. Master the fundamentals: Ensure you have a strong grasp of core networking concepts like the OSI model, TCP/IP, routing protocols, switching, and security. Solid fundamentals will help you answer questions confidently.

2. Use real-world examples: Illustrate your answers with relevant examples from your own experience. Discussing how you applied CCNA concepts in practical situations will make your responses more compelling and memorable.

3. Be specific and concise: When answering technical questions, provide precise and to-the-point responses. Avoid rambling or going off on tangents. Stick to the key points the interviewer is looking for.

4. Practice, practice, practice: Prepare for a wide range of CCNA interview questions using online resources, books, and mock interviews. The more you practice, the more comfortable and confident you'll be during the actual interview.

5. Highlight your skills: When answering behavioral questions, emphasize the skills and experience that make you a strong candidate. Discuss how your CCNA knowledge and hands-on work have prepared you for the role you're interviewing for.