CompTIA Network+ (N10-007) Interview Questions

The CompTIA Network+ exam is a vendor-neutral exam that assesses an IT professional’s knowledge of network infrastructure installation, configuration, and management. Obtaining a Network+ certification can lead to a variety of job opportunities, including:

• Manager of information technology and systems administration
• Administrator of a network
• Information technology specialist, network engineer
• Technician on the helpline

The following are some technical questions that you might be asked during an interview.

What is the OSI model and how does it relate to network communication?

The OSI model (Open Systems Interconnection model) is a reference model for networking that describes how data is transmitted between different devices in a network. Further, the OSI model defines seven layers, each of which is responsible for a different aspect of network communication:

1. Physical Layer (layer 1): The physical layer defines the electrical, mechanical, and functional specifications for transmitting and receiving data over a physical medium, such as a network cable.
2. Data Link Layer (layer 2): The data link layer provides error-free transmission of data frames over the physical layer. It is responsible for creating, transmitting, and receiving frames, which are units of data that contain both the payload and control information.
3. Network Layer (layer 3): The network layer is responsible for routing data between different networks. It provides the means to address and route data, as well as to control the flow of data to prevent network congestion.
4. Transport Layer (layer 4): The transport layer provides reliable data transmission between devices. It is responsible for segmenting data into smaller units, transmitting the units, and reassembling the data at the receiving end.
5. Session Layer (layer 5): The session layer establishes, maintains, and terminates communication sessions between applications. A session is a logical communication channel between two devices that provides a higher-level, application-level view of the data being transmitted.
6. Presentation Layer (layer 6): The presentation layer is responsible for converting data from the application layer into a format that can be transmitted across the network, and for converting the received data back into a format that can be used by the application layer.

What are the differences between a switch and a router?

A switch and a router are both networking devices, but they serve different purposes and operate at different layers of the OSI model.

1. Purpose: A switch is used to connect devices within a local network, while a router is used to connect multiple networks and route traffic between them.
2. Layer of Operation: A switch operates at the data link layer (layer 2) of the OSI model, while a router operates at the network layer (layer 3). This means that a switch is used to forward data between devices within a single network, while a router is used to forward data between different networks.
3. Network Segmentation: A switch can be used to segment a network into multiple broadcast domains, while a router is used to connect multiple broadcast domains. This allows a switch to improve network performance by reducing the size of broadcast domains, while a router is used to create multiple broadcast domains for security and scalability purposes.
4. IP Addressing: A switch does not perform IP addressing, while a router does. This means that a switch is not capable of routing IP packets between networks, while a router can route IP packets based on their destination IP addresses.
5. Network Address Translation (NAT): A router can perform NAT, which involves rewriting the source or destination IP address of a packet as it passes through the router. NAT can be used to hide the internal IP addresses of a network from the Internet and to provide a level of security by making it more difficult for external attackers to access internal network resources. A switch does not perform NAT.

In summary, a switch is used to connect devices within a single network and improve network performance, while a router is used to connect multiple networks and route traffic between them.

How does a firewall protect a network?

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It protects a network by performing the following functions:

1. Packet Filtering: A firewall examines each incoming and outgoing network packet and compares it against a set of rules to determine whether the packet should be allowed to pass through or blocked. This helps to prevent unauthorized access to the network and protects against malicious network traffic.
2. Stateful Inspection: A firewall performs stateful inspection of network traffic, which means it not only examines individual packets but also tracks the context of each connection, such as its origin, destination, and state. This allows the firewall to make more informed decisions about what traffic is allowed to pass through the network.
3. Application-Level Filtering: A firewall can inspect network traffic at the application level, which allows it to enforce security policies based on the type of application being used, such as email, web browsing, or file sharing.
4. Network Address Translation (NAT): A firewall can perform NAT, which involves rewriting the source or destination IP address of a packet as it passes through the firewall. NAT can be used to hide the internal IP addresses of a network from the Internet and to provide a level of security by making it more difficult for external attackers to access internal network resources.
5. VPN Support: A firewall can also be configured to support virtual private network (VPN) connections, which allow users to securely access the network from remote locations. The firewall can be configured to allow VPN traffic to pass through while blocking other types of traffic.

A firewall is a critical component of a secure network and helps to prevent unauthorized access, protect against malicious network traffic, and enforce security policies.

What is a VLAN and how is it used in networking?

A VLAN (Virtual LAN) is a logical subnetwork that can be used to segment a physical network into separate broadcast domains. The main purpose of VLANs is to increase network security, improve network performance, and increase network scalability.

Here’s how VLANs are used in networking:

1. Network Segmentation: VLANs allow a network administrator to divide a physical network into multiple virtual networks, each with its own broadcast domain. This can be used to separate different parts of a network for security reasons, to limit the size of broadcast domains, or to separate network traffic based on specific requirements.
2. Improved Network Security: By segmenting a network into separate VLANs, it becomes more difficult for unauthorized users to access sensitive information or interfere with network traffic. VLANs can also be used to enforce security policies on a network, such as allowing or denying access based on the source or destination of network traffic.
3. Improved Network Performance: VLANs can be used to separate network traffic and improve performance by reducing the amount of broadcast traffic on the network. This can help to reduce network congestion and increase the overall speed and efficiency of the network.
4. Increased Network Scalability: VLANs can be used to increase the scalability of a network by allowing new devices and services to be added to the network without affecting the rest of the network.

VLANs are created and managed through the use of VLAN tagging, which involves adding a VLAN identifier to each network packet to identify the VLAN to which it belongs. VLAN tagging is supported by most modern networking devices, including switches, routers, and firewalls.

What is the purpose of an IP address and how is it used in networking?

An IP address (Internet Protocol address) is a unique numerical label assigned to every device connected to a computer network that uses the Internet Protocol for communication.

The purpose of an IP address is to identify a device on a network and to locate it for the purpose of transmitting data.

Here’s how IP addresses are used in networking:

1. Identifying Devices: An IP address serves as a unique identifier for a device on a network, allowing other devices to send and receive data to and from that device.
2. Routing Data: IP addresses are used by routers to determine the best path for transmitting data between devices on a network. Routers use the destination IP address of a packet to determine which network the destination device is located on and how to forward the packet to that network.
3. Network Configuration: IP addresses are used to configure and manage devices on a network, including setting up DHCP servers to dynamically assign IP addresses to devices and resolving hostnames to IP addresses using the Domain Name System (DNS).
4. Network Security: IP addresses can be used to enforce security policies on a network, such as allowing or denying access based on the source IP address of incoming packets.

There are two versions of IP addresses in use today: IPv4 and IPv6. IPv4 addresses are 32-bits long and can support 4.3 billion unique addresses, while IPv6 addresses are 128-bits long and can support 340 undecillion unique addresses.

What is subnetting and how is it used in networking?

Subnetting is the process of dividing a larger network into smaller subnetworks, known as subnets. The main purpose of subnetting is to divide a single large network into smaller, more manageable subnets while conserving IP addresses.

Here’s how subnetting works:

1. A network administrator takes a large network and divides it into smaller subnets based on the needs of the network, such as the number of devices, geographic location, or network security requirements.
2. The administrator assigns a portion of the host bits in an IP address to represent the subnet, creating a unique subnet mask for each subnet.
3. Each subnet is assigned a unique range of IP addresses, with the subnet mask determining which portion of the IP address represents the subnet and which portion represents the host.

Subnetting provides the following benefits:

1. Increased network security, as subnets can be used to isolate different parts of a network for security reasons.
2. Improved network performance, as subnets can be used to limit the size of broadcast domains and reduce network congestion.
3. Increased network scalability, as subnets allow for the addition of new devices and services without affecting the rest of the network.

What is the difference between IPv4 and IPv6?

IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6) are two versions of the Internet Protocol (IP) that are used to identify and locate devices on the Internet.

The main difference between IPv4 and IPv6 is the length of their addresses:

1. IPv4 addresses are 32-bits long and can support 4.3 billion unique addresses.
2. IPv6 addresses are 128-bits long and can support 340 undecillion unique addresses.

Other differences include:

1. IPv6 has improved security features, such as built-in encryption, which are not present in IPv4.
2. IPv6 has a simpler header format, reducing the processing overhead for routers and allowing for more efficient routing of packets.
3. IPv6 supports more efficient multicast, allowing for the efficient transmission of data to multiple recipients.
4. IPv6 has improved support for autoconfiguration, allowing devices to automatically obtain an IP address and other network configuration information.

Due to the limited number of available IPv4 addresses, IPv6 is becoming increasingly important as the Internet continues to grow. Most networks today use a combination of both IPv4 and IPv6, with IPv4 used for legacy support and IPv6 for new devices and services.

What is the purpose of DHCP and how does it work?

The purpose of the Dynamic Host Configuration Protocol (DHCP) is to automate the process of assigning IP addresses to devices on a network. DHCP eliminates the need for manual configuration of IP addresses, reducing the possibility of IP address conflicts and making it easier to manage a network.

Here’s how DHCP works:

1. A device, such as a laptop or smartphone, connects to a network and sends a broadcast request for an IP address, known as a DHCP discover message.
2. A DHCP server receives the request and responds with an offer of an available IP address, subnet mask, default gateway, and other network configuration information, known as a DHCP offer message.
3. The device sends a request to the DHCP server to confirm the offer, known as a DHCP request message.
4. The DHCP server confirms the offer by sending a DHCP acknowledgement message, which includes the assigned IP address and other network configuration information.
5. The device configures itself with the IP address and other information received from the DHCP server.
6. The DHCP server tracks the assigned IP address and maintains a record of the mapping between the IP address and the device’s MAC address.

DHCP provides the following benefits:

1. Automated IP address assignment, reducing the chance of IP address conflicts.
2. Ease of network management, as DHCP automatically updates IP addresses and network configurations.
3. Support for mobile devices, as DHCP allows for easy assignment of IP addresses to devices that connect and disconnect from the network.

What is the purpose of DNS and how does it work?

The purpose of the Domain Name System (DNS) is to translate human-readable domain names into IP addresses, which are used to locate and communicate with devices on the Internet.

Here’s how DNS works:

1. A user types a domain name into a browser or application, such as www.example.com.
2. The user’s device sends a query to a DNS resolver, which is usually provided by the user’s internet service provider (ISP).
3. The DNS resolver performs a query to a DNS server, starting with a root name server, to determine the IP address associated with the domain name.
4. The DNS server responds with the IP address of the target domain name.
5. The DNS resolver caches the IP address for a set amount of time to speed up future queries for the same domain name.
6. The user’s device uses the IP address to establish a connection with the target device and send a request for the requested information.

DNS enables users to access websites and other Internet resources using easy-to-remember domain names, rather than IP addresses. It also allows for the distribution of traffic across multiple servers, improving the reliability and scalability of the Internet.

What is the purpose of a network topology and what are the common types of network topologies?

The purpose of a network topology is to define the physical and logical arrangement of devices on a network, such as computers, servers, and other devices. A network topology describes how devices are connected to each other and how data is transmitted between them.

The following are common types of network topologies:

1. Bus topology – a linear network structure where all devices are connected to a common backbone, called the bus.
2. Star topology – a central device, such as a switch or hub, connects to all other devices in the network.
3. Ring topology – devices are connected in a circular manner, with data transmitted in a single direction.
4. Mesh topology – a network where every device has a direct connection to every other device, providing multiple paths for data transmission.
5. Tree topology – a hierarchical structure where multiple star topologies are connected to a bus backbone.
6. Hybrid topology – a combination of two or more different topologies.

Each topology has its own strengths and weaknesses, and the choice of topology depends on the specific requirements and goals of the network.

1.What exactly is the Open System Interconnection (OSI) Model?

The International Organization for Standardization (ISO) created the open systems interconnection (OSI) model, which enables various communication systems to communicate using standard protocols. It consists of seven layers:

• Physical Layer
• Data Link Layer
• Network Layer
• Transport Layer
• Session Layer
• Presentation Layer
• Application Layer

2. Which protocol would be use to automatically assign IP addresses?

DHCP (Dynamic Host Configuration Protocol) is a network management protocol for allocating IP addresses to computers, servers, and printers. APIPA (Automatic Private IP Addressing) provides IP addresses for internal communication when our device cannot find a DHCP server.

3. What exactly is the Subnet Mask?

Subnet Mask divides an IP address into two parts: a network address and a host address. A 32-bit address is the subnet mask.

4. What exactly is a VPN?

When connecting to public networks, a VPN (Virtual Private Network) is use to create a secure network connection. A virtual private network (VPN) encrypts your network traffic and hides your true identity on the internet by routing it through a virtual tunnel. VPN makes it more difficult to track your online activity

5. What are the different methods for safeguarding a computer network?

This can be accomplished in a variety of ways. Install a trustworthy and up-to-date anti-virus application on all PCs. Ensure that firewalls are properly installed and configured. User authentication will also be extremely useful. When all of these factors are combine, the result is a network that is extremely secure.

6. What exactly is a MAC address?

MAC is an abbreviation for “Media Access Control.” A MAC address is a device’s unique address that aids in identifying the device in a network. It is also known as a machine’s physical address. It is assigned to each device’s Network Interface Card (NIC). The MAC address is 48 bits long. The first three octets are known as OUI (Organizational Unique Identifier), and the last three octets are known as EUI (Enterprise Unique Identifier) (Extended Unique identifier).

7. Explain what is network.

A network is a collection of computers, routers, cables, and other hardware that connects users so they can share files, email, and access the Internet. This is a basic question designed to assess your knowledge of networking fundamentals.

8. What exactly is a node?

Any desktop, server, or virtual machine on the network is referred to as a node. These devices are linked by a cable or wireless connection, but each device on the network is referred to as a node.

9. What do you understand by a router?

A router is a device that routes traffic from one section of a network to another. Routers differ from hubs in that they direct traffic rather than broadcasting signals throughout the network.

10. What exactly is a protocol?

A protocol is a set of instructions that govern network communication. The Internet employs the TCP/IP protocol, which is also widely use in private networks. The TCP/IP protocol is what allows devices to communicate using a specific “language,” or set of rules that allow each device to read and respond to network messages.

11. What can you do to test server connectivity if your users are unable to access a server?

To see if packets are returned, use the “ping” command. Ping will notify you that the server is operational and connected. You can also use a remote desktop connection to check if the computer is running slowly. Check for server resources with custom tools.

12. What is the OSI model’s network layer?

The network layer performs two types of functions: routing and address assignment. Routing is the process of assigning traffic to a different network segment. Addresses are assigned to each node on the network so that they can be found and communicated on the network.

13. What procedure is in place to protect the company from massive data loss and loss?

Disaster recovery is use to create backups, securely store data, and protect data from hackers. DR also ensures that users can continue to work even after a disaster.

14. What protocol can you use to assign IP addresses automatically?

The DHCP protocol assigns IP addresses to desktops, servers, and printers automatically. Your servers and printers, on the other hand, should have a static IP address. These addresses can still be assigned in the DHCP server settings.

15. Explain the TCP three-way handshake procedure.

Syn/Act – Ack – the client sends an SYN packet to the server. The server has an open port where new connections can be accepted. When an SYN is received, a confirmation SYN/ACK is sent. When the client receives the SYN/ACK, it responds with an acknowledgment ACK packet. Once completed, the client and server can freely communicate.

16. Can you name some routing protocols?

Border gateway protocol (BGP), external gateway protocol (EGP), routing information protocol (RIP), open shortest path first (OSPF), and enhanced Internet gateway routing protocol (EIGRP); Cisco no longer supports the Internet gateway routing protocol, which served as an alternative to RIP.

17. TCP/IP Internet Layer manages which protocol?

The TCP/IP internet layer is in charge of four protocols:

1. IGMP (Internet Group Message Protocol)
2. ICMP (Internet Group Management Protocol)
3. IP (Internet Protocol)
4. ARP (Address Resolution Protocol)

18. Define switch.

Switches function similarly to Hubs, but more efficiently. It establishes connections on the fly and only sends data to the port that requests it.A switch is a network device that forwards packets in a network.

19. What exactly is HTTP, and what port does it use?

HTTP stands for HyperText Transfer Protocol, and it is in charge of web content. Many web pages use HTTP to transmit web content and allow HyperText display and navigation. TCP port 80 is use here as the primary protocol.

20. Define DNS.

Domain Name Server (DNS), also known as the Internet’s phone book in layman’s terms. The DNS stores all public IP addresses and hostnames, which are then translated into corresponding IP addresses.

21. Explain the term firewall.

A firewall is a network security system that is use to prevent unauthorised access to computer networks. It guards against unauthorised access to the computer network. A firewall can also be built to allow outside users limited access.

The firewall is made up of a hardware device, a software programme, or a combination of the two. All messages that pass through the firewall are subjected to specific security criteria, and those that meet the criteria are allow to pass through the network; otherwise, those messages are blocked.

22. What do 127.0.0.1 and localhost mean?

The answer is that the IP address 127.0.0.1 is reserved for loopback or localhost connections. These networks are typically reserve for the largest customers or some of the Internet’s original members. The first step in determining a connection problem is to ping the server and see if it responds.

If the server does not respond, it could be due to a number of factors, such as a network outage, a faulty cable, or a network card that is no longer in good working order. 127.0.0.1 is a loopback connection on the Network Interface Card (NIC), and pinging this server successfully indicates that the hardware is in good working order.

23. What exactly is a Proxy Server, and how do they protect a computer network?

IP addresses are require for data transmission, and DNS uses IP addresses to route to the correct website. It means that identifying the physical location of the network is impossible without knowledge of correct and actual IP addresses. Proxy servers prevent unauthorised external users from accessing internal network IP addresses. It effectively renders the computer network invisible to outside users.

24. Define Data Encapsulation.

In a computer network, network devices send messages in the form of packets to enable data transmission from one computer to another. The OSI reference model layer then adds these packets to the IP header. Each packet is encapsulate in a frame by the Data Link Layer, which includes the hardware addresses of the source and destination computers. If the destination computer is on the remote network, the frames are route to the destination computer via a gateway or router.

25. What exactly is a VPN?

VPN stands for Virtual Private Network, and it is a private wide area network built on the Internet. VPNs are less expensive and can be access from any location on the planet. VPNs are use to connect offices remotely, and they are less expensive than WAN connections. Next, VPNs are use for secure transactions and the transfer of confidential data between offices. VPN protects company information from unauthorise access.

26. Could you please explain DHCP briefly?

DHCP stands for Dynamic Host Configuration Protocol, and it assigns IP addresses to network devices automatically. It eliminates the manual allocation of IP addresses and reduces the errors that result from it. This entire process is centralise, allowing TCP/IP configuration to be complete from a single location. DHCP maintains a “pool of IP addresses” from which it assigns IP addresses to network devices. If any device is manually configure and assigned the same IP address from the DHCP pool, DHCP will fail to recognise it.

27. Can you tell the difference between communication and transmission?

Data is transferred from source to destination via transmission (only one way). It is regards as the physical transfer of data. The process of sending and receiving data between two media is referred to as communication (data is transferred between source and destination in both ways.

28. What is the Round Trip Time?

The time it takes for a signal to travel to its destination and then back to the sender with an acknowledgment is referred to as the Round Trip Time (RTT). It is also known as Round Trip Delay (RTD).

29. What is Brouter?

Brouter or Bridge as an answer A router is a device that functions both as a bridge and as a router. It acts as a bridge, forwarding data between networks. It also acts as a router, routing data to specific systems within a network.

30. What exactly is piggybacking?

When transmitting data, if the sender sends a data frame to the receiver, the receiver must acknowledge the sender. The receiver temporarily delays (waits for the network layer to send the next data packet) the acknowledgment and attaches it to the next outgoing data frame; this is piggybanking.

Conclusion for CompTIA Network+ (N10-007) Interview Questions

If you are given an interview based on your Network+ certification, the interviewer will ask you numerous networking questions. Make sure you understand subnetting, how to configure firewalls, routers, switches, hubs, iptables, TCP, and UDP, and can recall the most commonly used network protocols and port numbers. Interviewers frequently inquire about FTP, DNS, Telnet, email protocols, HTTP, and/or HTTPS. Understand the OSI model, as well as the netstat command, tcpdump, ping, and telnet.