Top 100 Networking Interview Questions and answers You Need to Know in 2023

41. What is a Network Bridge?

A network bridge connects two or more network segments at the Data Link layer, forwarding data packets based on MAC addresses and enabling communication between devices on separate LANs.

42. Explain the difference between Telnet and SSH

Telnet is an older protocol used for remote command-line access to a network device, transmitting data in plain text without encryption. SSH (Secure Shell) is a more secure alternative that provides encrypted communication for remote access, ensuring data confidentiality and integrity.

43. What is MPLS?

Multiprotocol Label Switching (MPLS) is a routing technique employed in high-performance networks to direct the traffic based on short labels instead of long IP addresses, streamlining packet forwarding and improving traffic engineering.

44. Define LACP

Link Aggregation Control Protocol (LACP) is part of the IEEE 802.3ad standard that facilitates bundling multiple physical links into a single logical link to increase bandwidth, provide load balancing, and improve redundancy.

45. What are the primary functions of Wi-Fi access points?

Wi-Fi access points serve as wireless hubs for connecting client devices to wired networks, allowing users to join local or internet-based networks through Wi-Fi connections.

46. Describe CSMA/CD

Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is an Ethernet protocol that coordinates media access control in shared-media networks by detecting collisions and implementing back-off algorithms to reattempt transmissions after random time intervals.

47. What are SFP Transceivers?

Small Form-factor Pluggable (SFP) transceivers are compact, hot-swappable modules used in switches and routers to convert electrical signals into optical signals for transmission over fiber-optic cables or vice versa.

48. Explain Caching and its role in networking

Caching is the temporary storage and retrieval of frequently accessed data or content to reduce latency and improve performance. In networking, caching can be implemented through web proxies, Content Delivery Networks (CDNs), or DNS caching to expedite data delivery.

49. What are Autonomous Systems in networking?

An Autonomous System (AS) is a collection of IP networks and routers under the control of a single organization, sharing a common routing policy. ASes are identified by unique numbers assigned by the Internet Assigned Numbers Authority (IANA), facilitating large-scale internet routing through protocols like Border Gateway Protocol (BGP).

50. Describe Jumbo Frames

Jumbo frames are Ethernet frames with an MTU larger than the standard 1500 bytes, typically between 9000-9216 bytes. By using jumbo frames, networks can achieve higher throughput and improved efficiency by sending larger amounts of data within each frame and reducing overhead.

51. What is Power over Ethernet (PoE)?

Power over Ethernet (PoE) is a technology that enables the transmission of both data and electrical power over Ethernet cables, providing a single cable solution for supplying power to devices like IP cameras, VoIP phones, and wireless access points.

52. Explain N_Port ID Virtualization (NPIV)

N_Port ID Virtualization (NPIV) is a technique used in Fibre Channel SANs that allows multiple virtual N_Ports to share a single physical N_Port on an HBA. This enables multiple virtual machines or applications to have independent access to storage resources without requiring additional hardware.

53. Describe Anycast addressing

Anycast addressing is a network addressing method in which one IP address is assigned to multiple devices inside a network. When data are sent to this anycast address, they are delivered only to the nearest device based on routing metrics, providing load balancing and redundancy.

54. What is Network Tapping?

Network tapping involves creating a passive connection point within a network segment that allows the monitoring of traffic without disrupting normal communication between devices. Taps can be physical or virtual and are commonly used for troubleshooting, security analysis, or performance monitoring purposes.

55. Explain FCoE

Fibre Channel over Ethernet (FCoE) encapsulates Fibre Channel frames within Ethernet packets to enable the concurrent transmission of LAN and SAN traffic over the same network infrastructure while maintaining their respective characteristics.

56. What are Sockets in networking?

Sockets provide an endpoint for inter-process communication between applications running on different devices across networks. They act as an interface between the Transport Layer protocols such as TCP or UDP and the application layer protocols, allowing programs to send and receive frames.

57. Define Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP) cables

Unshielded Twisted Pair (UTP) cables consist of multiple pairs of color-coded wires twisted together without an additional protective shielding. They are the most common type of Ethernet cabling due to their low cost and ease of installation. Shielded Twisted Pair (STP) cables include a metallic shield surrounding the wire pairs, providing protection against electromagnetic interference and improving signal quality in noisy environments or over longer distances.

58. What is Congestion Control in networking?

Congestion Control refers to techniques used to manage network traffic load by monitoring and controlling congestion levels within networks, ensuring that resources are efficiently utilized and preventing the collapse of network performance due to excessive traffic demands.

59. Explain Flood Guard

Flood Guard is a security mechanism employed in firewalls or intrusion prevention systems that detects and prevents network flooding attacks, such as SYN flood or ICMP flood. It monitors incoming traffic patterns for signs of abnormal activity, limiting or blocking packets when thresholds are exceeded.

60. Describe Failover Clustering

Failover clustering involves configuring two or more servers with shared resources, such as storage devices or applications, to provide high availability and fault tolerance. If one server fails, its workload automatically transfers to another server within the cluster, minimizing downtime and ensuring continuous service availability.

61. What is a Demilitarized Zone (DMZ) in networking?

A Demilitarized Zone (DMZ) is a subnetwork that acts as a buffer between an organization’s internal network and the external, untrusted networks like the internet. DMZ hosts public-facing services such as web servers, email servers, and DNS servers while maintaining security for the private internal network.

62. Explain Network Addressing Modes

Network addressing modes determine how data are transmitted within networks:

• Unicast: One-to-one communication between sender and recipient.
• Multicast: One-to-many or many-to-many communication with multiple recipients.
• Broadcast: Communication with all devices inside a network segment.
• Anycast: Communication with the nearest device sharing an anycast address.

63. What is BGP?

Border Gateway Protocol (BGP) is an exterior gateway protocol used to exchange routing information between routers in different autonomous systems on the internet. BGP ensures optimal path selection and prevents switching loops by utilizing path vector routing algorithms.

64. Describe HSRP

Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol that provides high availability for IP networks by establishing a virtual router consisting of two or more physical routers. If the active router fails, the standby router takes over its role to maintain uninterrupted service.

65. What is Network Segmentation?

Network segmentation involves dividing a larger network into smaller, isolated segments to improve security, manageability, and performance. Segmentation can be achieved through VLANs, firewalls, or other access control methods.

66. Explain EtherChannel

EtherChannel is a technology developed by Cisco that combines multiple physical Ethernet links into a single logical link to increase bandwidth capacity and provide redundancy in case of link failures.

67. Describe Connection-Oriented vs Connectionless Protocols

Connection-oriented protocols establish a dedicated communication session between sender and recipient before transferring data, ensuring reliable and ordered delivery (e.g., TCP). In contrast, connectionless protocols transmit data without prior setup, prioritizing speed over reliability (e.g., UDP).

68. What is Network Function Virtualization (NFV)?

Network Function Virtualization (NFV) decouples network functions from dedicated hardware appliances by implementing them as software applications running on virtualized infrastructure. NFV increases scalability, flexibility, and resource utilization while reducing costs and deployment times.

69. Define VRRP

Virtual Router Redundancy Protocol (VRRP) is an open-standard protocol that enables automatic failover between routers to ensure high availability for IP networks. It creates a virtual router group consisting of master and backup routers that share a common IP address. When the master router fails, the backup router assumes its role to maintain continuous service.

70. Describe Virtual Networking in Cloud Computing

Virtual networking in cloud computing involves creating logical network constructs independent of underlying physical infrastructure to allow secure communication between virtual machines or resources within public or private cloud environments.

71. What is a Network Topology?

It refers to the physical or logical arrangement of devices, nodes, and connections inside a network. It defines how devices are interconnected and communicate with each other.

72. What is a Content Delivery Network (CDN)?

A Content Delivery Network (CDN) is a distributed network of servers that store and deliver cached copies of web content to users based on their geographical location, reducing latency and improving the performance of websites and applications.

73. Explain Three-way Handshake in TCP

The three-way handshake in TCP establishes a connection between two systems by synchronizing sequence numbers before data transmission. The process involves three steps:

1. SYN: Client sends a SYN packet with an initial sequence number.
2. SYN-ACK: Server replies with a SYN-ACK packet containing its own sequence number and the incremented client’s sequence number as an acknowledgment.
3. ACK: Client sends an ACK packet with the incremented server’s sequence number as an acknowledgment.

74. What is NIC Teaming?

NIC Teaming, also known as Link Aggregation or Port Trunking, combines multiple network interface cards (NICs) into one logical unit to improve bandwidth capacity, load balancing, and fault tolerance in case of hardware failures.

75. Describe Data Encapsulation in networking

Data encapsulation is the process by which data from higher layers of the OSI model is wrapped with protocol information from lower layers during transmission through a network. Each layer adds headers or trailers to the data before passing it down to the next layer until it reaches the Physical Layer for actual transmission.

76. Explain IGMP

Internet Group Management Protocol (IGMP) is used by IP hosts to report their multicast group memberships to neighboring multicast routers, allowing routers to learn which hosts belong to specific groups and efficiently forward multicast traffic to interested recipients.

77. What is a Network Loop and how to prevent it?

A network loop occurs when data frames circulate endlessly within a network segment due to redundant paths, causing congestion and disrupting network communication. Spanning Tree Protocol (STP) can be used to detect and prevent network loops by identifying and blocking redundant links.

78. Describe the difference between Static Routing and Dynamic Routing

Static routing involves manually configuring routes in a router’s routing table, providing fixed paths for data frame transmission. Dynamic routing employs routing protocols like RIP or OSPF to automatically update routing tables based on network topology changes, offering more adaptability and fault tolerance.

79. What is RADIUS?

Remote Authentication Dial-In User Service (RADIUS) is a protocol that provides centralized authentication, authorization, and accounting management for users connecting to a network service such as VPNs or Wi-Fi access points.

80. Explain Tunneling in networking

Tunneling encapsulates one type of data packet within another protocol’s frame for transmission over an incompatible network or infrastructure. This technique enables the creation of secure connections (e.g., VPNs) by hiding original packet information during transit through untrusted networks.

81. What is the role of a Network Analyzer?

A network analyzer, also known as a sniffer, is a tool used to capture and analyze traffic. It helps monitor and troubleshoot network issues, improve performance, detect security vulnerabilities, and verify protocol compliance.

82. Explain Dynamic DNS

Dynamic DNS (DDNS) is a service that automatically updates DNS records when an IP address changes in real-time. It is particularly useful for devices with frequently changing IP addresses assigned by DHCP, enabling consistent access to services hosted on those devices.

83. What are the different types of Cables used in networking?

There are several types of cables used in networking:

• Twisted Pair: Copper wires twisted together; available as Unshielded Twisted Pair (UTP) or Shielded Twisted Pair (STP).
• Coaxial Cable: Consists of a central copper conductor surrounded by an insulating material, braided metal shield, and outer plastic cover.
• Fiber Optic Cable: Transmits data using light signals through thin strands of glass or plastic fibers.

84. Describe the difference between Inbound and Outbound Traffic

Inbound traffic refers to incoming data from external sources entering a network or device, while outbound traffic consists of data frames sent from within the network or device to external destinations.

85. Explain Network Monitoring

Network monitoring involves continuously observing network performance, availability, and security through various tools and techniques such as SNMP, ping tests, traceroute, log analysis, packet capture analysis, and intrusion detection systems.

86. What is Asymmetric Encryption?

Asymmetric encryption uses two different keys – a public key for encryption and a private key for decryption – ensuring secure communication between sender and recipient without sharing secret information beforehand. A popular example is Public Key Infrastructure (PKI).

87. Describe Link State Routing Protocols

Link state routing protocols are a type of dynamic routing protocol that maintains the complete network in each router’s link-state database. They use the Shortest Path First (SPF) algorithm to calculate the best path between nodes. Examples include OSPF and IS-IS.

88. What is an Intrusion Detection System (IDS)?

An Intrusion Detection System (IDS) monitors network traffic for malicious activities, such as attacks or policy violations, by analyzing data frames and comparing them against known signatures or anomaly-based detection mechanisms.

89. Explain Network Time Protocol (NTP)

Network Time Protocol (NTP) is used to synchronize the time of devices inside a network to a precise reference time source, ensuring consistent timestamps across systems for accurate log analysis, event correlation, and network management.

90. What is URL Filtering?

URL Filtering is a security technique that blocks access to specific websites or webpages based on predefined criteria, such as keywords or categories. It can be implemented through firewalls, proxy servers, or dedicated security appliances to enforce internet usage policies and protect users from harmful content.

91. Explain Traffic Shaping

Traffic shaping, also known as packet shaping or bandwidth management, is a technique used to regulate traffic by controlling the rate at which data are transmitted. This helps ensure fair usage of available bandwidth, prevent network congestion, and prioritize specific applications or services.

92. What is Network Address Translation – Port Mapping Protocol (NAT-PMP)?

Network Address Translation – Port Mapping Protocol (NAT-PMP) is a protocol that enables devices within a private network to communicate with the NAT gateway to automatically open ports and establish connections with external networks. It simplifies the process of port forwarding and provides better security and functionality compared to manual configuration.

93. Describe TACACS+

Terminal Access Controller Access-Control System Plus (TACACS+) is a Cisco proprietary AAA (Authentication, Authorization, Accounting) protocol used for centralized management of user access control in large networks. It encrypts all communication between client devices and server, ensuring secure transmission of sensitive information.

94. What is Multihoming?

Multihoming refers to connecting a network device or an autonomous system (AS) to multiple internet service providers (ISPs) or upstream networks simultaneously. Multihoming improves redundancy, reliability, and performance by providing multiple paths for data traffic in case one connection fails or becomes congested.

95. Explain Network Virtualization

Network virtualization involves creating abstract representations of physical network components such as switches, routers, firewalls, and links on top of shared hardware resources. This allows multiple virtual networks to operate independently while sharing the same underlying infrastructure for better resource utilization and simplified management.

96. What is a Node in a computer network?

A node in a computer network refers to any active electronic device connected to the network that can send, receive, or process data. Nodes include computers, servers, switches, routers, and other networking devices.

97. Explain the purpose of a Subnet Mask

A subnet mask is a 32-bit number used in combination with an IP address to define the range of IP addresses within a subnetwork (subnet). The subnet mask helps identify which part of an IP address represents the network prefix and which part represents the host identifier. This allows efficient routing of data frames within networks and between multiple subnets.

98. What is a MAC Address?

A Media Access Control (MAC) address is a unique 48-bit hardware device identifier assigned to each network interface card (NIC) by its manufacturer. It functions at the Data Link layer of the OSI model and is responsible for facilitating communication between devices on local area networks (LANs) through Ethernet or Wi-Fi technologies.

99. Describe Virtual Private Networks and their role in computer networks

Virtual Private Networks (VPNs) establish secure connections between remote systems or networks over unsecured public networks such as the internet using encryption and tunneling protocols. VPNs enable private communication channels for sensitive data transmission while maintaining confidentiality and integrity against potential eavesdropping or tampering attempts.

100. What is a Reverse Proxy?

A reverse proxy is an intermediary server that receives client requests for resources hosted on backend servers or applications. The reverse proxy processes the requests on behalf of these servers before returning the response to the client. This provides load balancing, network security improvements, and caching mechanisms for better performance.

In conclusion, mastering these top 100 networking interview questions will undeniably give you a competitive edge in your quest for landing that coveted network administrator job. As the field of networking continues to evolve, it’s essential to stay updated with the latest trends and technologies, including network operating systems. Use this comprehensive list as a solid foundation, but don’t forget to explore beyond these questions and expand your knowledge in every aspect of networking.

To make your interview preparation even more effective, consider practicing with the Huru app – an AI-powered interview prep app specifically designed to help you ace those challenging networking questions. By simulating real-life interviews and providing instant feedback, Huru assists in refining your responses and boosting your confidence before the big day.

Remember, practice makes perfect – so invest time in understanding the concepts, rehearsing your answers, and gaining hands-on experience whenever possible. With determination, thorough preparation using helpful tools like Huru, and staying abreast of industry developments, you’ll be well on your way to acing your next networking interview in pursuit of becoming a successful network administrator! Good luck!