Let’s start with the basic networking interview questions. This section covers networking interview questions for freshers.
What is a network?
A network consists of two or more separate devices linked together such that they can communicate. Networks can be classified according to different criteria such as scope, type of connection, functional relationship, topology, or function, among others.
What are the different types of networks?
Considering the size or span of a network, we can classify them as follows:
- PAN (Personal Area Network) – PAN is made up of devices used by a single person. It has a range of a few meters.
- WPAN (Wireless Personal Area Network) – It is a PAN network that uses wireless technologies as a medium.
- LAN (Local Area Network) – LAN is a network whose range is limited to a relatively small area, such as a room, a building, an airplane, etc.
- WLAN (Wireless Local Area Network) – WLAN is a LAN network that uses wireless means of communication. It is a widely used configuration due to its scalability and because it does not require the installation of cables.
- CAN (Campus Area Network) – A network of high-speed devices that connects LANs in a limited geographical area, such as a university campus, a military base, etc.
- MAN (Metropolitan Area Network) or metropolitan area network – It is a high-speed (broadband) network providing coverage in a larger geographic area than a campus, but still limited.
- WAN (Wide Area Network) – WAN extends over a large geographical area using unusual means of communication, such as satellites, interoceanic cables, fiber optics, etc. Use public media.
- VLAN – It is a type of logical or virtual LAN, mounted on a physical network, in order to increase security and performance. In special cases, thanks to the 802.11Q protocol (also called QinQ), it is possible to mount virtual networks on WAN networks. It is important not to confuse this implementation with VPN technology.
What is BIOS?
• It means Basic Input Output System.
• It is Firmware.
• It acts as an intermediary between computer hardware and its Operating System.
Related Post: Operating System-related Interview Questions
What is difference between MBR & GPT?
| MBR (Master Boot Record) | GPT (Guid Partition Table) |
|---|---|
| MBR used legacy OS standard BIOS partition table. | GPT creates multiple partitions & 128 primary partitions. |
| MBR supports up to 2 TB Hard Disk. | GPT also supports more than 2 TB Hard Disk. |
| In MBR disk the boot data is store in one place, so sometimes data is corrupted, it is difficult to recover. | GPT is more secure because of primary GPT store data at beginning and secondary GPT store data at ending. |
Classification of IPv4 or range of the IPv4 address?
IANA has divided the IPv4 address into 5 classes on the basis of the first Octet value.
| Range | Class | Usage |
|---|---|---|
| 0 to 127 | ‘A’ | It is used for Networking. |
| 128 to 191 | ‘B’ | It is used for Multicasting. |
| 192 to 223 | ‘C’ | It is used for Multicasting. |
| 224 to 239 | D’ | It is used for Multicasting. |
| 240 to 255 | ‘E’ | It is used for Research & Development. |
What is a Physical Address?
This is also called a MAC (Media Access Control) address.
a) This is a permanent address.
b) This is hard-coated on NIC at the time of manufacturing.
c) MAC address is 48 bits.
d) MAC consists of 12 Hexadecimal digits.
e) MAC address consists are two parts 24 bits & 24 bits.
f) 24 bits are manufacturer ID given by IEEE and 24 bits are serial no. of given by manufacturer at the time of manufacturing.
What is a Logical address or IP address?
IP (Internet Protocol) is a logical address used to identify any device in a network uniquely and the network itself.
a) IP version is of 2 types – IPv4 & IPv6.
b) IPv4 is 32 bits & IPv6 is 128 bits.
c) IANA has managed the IPv4 address.
d) ICANN has managed IPv6 address.
e) Every IPv4 address consists of 4 Octet.
f) Every IPv4 address is denoted by 4 decimal numbers separated by dots.
What is the difference between IPv4 & IPv6?
| IPv4 | IPv6 |
|---|---|
| It is a 32 bits address. | It is a 128 bits address. |
| 32 bits are divided into 4 equal parts, each part is having 8 bits called as an Octet. | 128 bits are divided into 8 groups, each group is having 16 bits and called a Block. |
| Octets are separated by .(dot). | Blocks are separated by :(Colon). |
| IPv4 is written in decimal format. | IPv4 is written in Hexadecimal format. |
| It uses subnet mask to determine network and host bits. | It uses prefix to determine network and host bits. |
| It is divided into 5 different classes. | No classification. |
What is a MAC address?
Ans. A MAC (Media Access Control) address is the unique 48-bit hardware address of a LAN card, usually stored in the ROM of the network adapter card.
The MAC address is a unique identifier that manufacturers assign to a network card or device. It is also known as a physical address represented by hexadecimal digits. Each MAC address is unique worldwide and, in theory, they are fixed for each device.
What is the difference between IP address & MAC address?
| IP address | MAC address |
|---|---|
| IP is a Logical address. | MAC is a Physical address. |
| It is helps to identify the connection of a device on the internet. | It is help to uniquely identify the device. |
| It is assigned by ISP. | It is assigned by IEEE. |
| Its can be change. | It cannot be change. |
| It is 2 type, Ipv4 – 32 bits & Ipv6 – 128 bits. | It is 48 bits. |
| It is works on Network layer of OSI model. | It is work on Data Link layer of OSI model. |
What is a ‘subnet’?
A ‘subnet’ is a generic term for a section of an extensive network, usually separated by a bridge or a router. It also works for the network’s broadcast domains, manages traffic flow, and helps increasing network performance. Uses of the subnet in networking include:
- Relieving network congestion
- Reallocating IP addresses
- Improving network security
What are the type of Subnetting?
There are 2 types of Subnetting –
1) FLSM (Fixed Length Subnet Mask)
2) VLSM (Variable Length Subnet Mask)
What is FLSM?
The process of subnetting through we get subnets of all equal length is called as FLSM.
What is VLSM?
The process of subnetting through which we can get required no. of hosts per subnet is called as VLSM.
What is “PING”?
The PING (Packet Internet Groper) command is the simplest tool and its used to test connectivity. It sends ICMP (Internet Control Message Protocol) echo packets to a host and listens for an echo reply in order to verify connection status.
What is mean by “Destination Host Unreachable”?
This message indicates either the local system has no route to the desired destination, or a remote router reports that it has no route to the destination.
Related Post: Basic Computer Interview Questions
What is mean by “Request Timed Out”?
This message indicates that the server did not receive a complete request from the client computer within a specific period of time tracked by the server.
What is use of “Traceroute” command?
Traceroute command can show you the path of packet from your computer to the Destination. It will list all the routers it passes through until it reaches it destination.
Give a short description of ICANN?
Its full from Internet Corporation for Assigned Names and Numbers.
It is a private corporation and its main role is to keep the Internet stable, secure and interconnected.
Give a short description of IANA?
Its full from Internet Assigned Numbers Authority.
It is a standards organization and its main role Domain Name Service, Numbers Resources and Protocol Assignments.
What is DNS?
The Domain Name System (DNS) is a central part of the internet, providing a way to match names (a website you’re seeking) to numbers (the address for the website). Anything connected to the internet – laptops, tablets, mobile phones, and websites – has an Internet Protocol (IP) address made up of numbers.
Differentiate between ‘forward lookup’ and ‘reverse lookup’ in DNS?
Following are the major differences between a forward lookup and reverse lookup in DNS:
| Forward DNS lookup | Reverse DNS lookup |
| Converts a human input or a domain name to an IP address | Converts an IP address into a domain name |
| Has a mapping between hostnames and IP addresses | Has a mapping that relates IP addresses to hostnames |
| Used for a website or other server access | Used for network troubleshooting |
| Utilizes different servers with different IP addresses | Resolves reverse lookup queries where a client requests a hostname by providing an IP address |
| Uses A Records (basic) to identify any IP address for a particular hostname | Uses DNS pointer record to identify a hostname for a given IP address |
What is DHCP?
It is a protocol for assigning dynamic IP addresses to a device on a network.
• Its stands for Dynamic Host Configuration Protocol.
• DHCP is an application layer protocol of the OSI model.
• It uses the port of no. 67 (Server) & 68 (Client).
• It is a UDP base service.
• It is providing IP address to the client computer automatically.
What is Network Topology?
Ans. This is among the important networking interview questions. Network topology is the physical or logical arrangement in which the devices or nodes of a network (e.g. computers, printers, servers, hubs, switches, routers, etc.) are interconnected with each other over a communication medium. It consists of two parts – the physical topology, which is the actual arrangement of the cables (the media), and the logical topology, which defines how the hosts access the media.
Types of network topologies –
- Bus topology
- Ring topology
- Star topology
- Mesh topology
- Tree topology
What are routers?
Routers connect two or more network segments. These intelligent network devices store information in their routing tables such as paths, hops, and bottlenecks. They determine the most accurate data transfer paths and operate in Open Systems Interconnection (OSI) Network Layer.
The roles of a router include:
- Inter-network communication
- Best path selection
- Packet forwarding
- Packet filtering
What is Routing?
Routing is the process of finding a path on which data can pass from source to destination. Routing is done by a device called routers, which are network layer devices.
What is routing on a network?
This might seem like a basic question, but the interviewer might ask it just to see if you know the basics. Routing is done by routers. Routers have a routing table that send network traffic from one location to another location or segment on the network. Routers reduce network traffic compared to regular hubs. When a user sends network traffic across the network, a hub broadcasts to all segments of the network. With a router, the device analyzes the TCP/IP packet, sees the destination location, and then uses its lookup table to route the packet to the right network segment and destination. Switches also route traffic in a similar fashion.
What is 100BaseFX?
This is Ethernet that makes use of fiber optic cable as the main transmission medium. The 100 stands for 100Mbps, which is the data speed.
What is Loopback address?
A loopback address is a type of IP address that is used to check the communication on the local network card and testing for the network application.
Its range 127.0.0.0 to 127.255.255.255
What is Host?
Any node having IP address is called a Host.
Related Post: Linux Interview Questions
What is Hostname?
The name of any Node/Device is called as Host Name.
What is Node?
Any device in a network is called as Node.
What is Private IP address?
The IP address which is used to communicate in a private network (Intranet) is called a Private IP address.
What is Public IP address?
The IP address which is assigned by an ISP and is used to communicate in a public network (Internet) is called Public IP address.
What is the range of the Private IP address?
| Class | Range | Total Host |
|---|---|---|
| Class ‘A’ | 10.0.0.0 to 10.255.255.255 | 16777216 |
| Class ‘B’ | 172.16.0.0 to 172.31.255.255 | 1048576 |
| Class ‘C’ | 192.168.0.0 to 192.168.255.255 | 65536 |
What is range of Public IP address?
| Class | Range |
|---|---|
| Class ‘A’ | 1.0.0.0 to 9.255.255.255 11.0.0.0 to 126.255.255.255 |
| Class ‘B’ | 128.0.0.0 to 172.15.255.255 172.32.0.0 to 191.255.255.255 |
| Class ‘C’ | 192.0.0.0 to 192.167.255.255 192.169.0.0 to 223.255.255.255 |
What are ‘client’ and ‘server’ in a network?
Clients and servers are separate logical entities that work together over a network to accomplish a task. A client application is the element of communication that requests or requests a network service, for example, accessing a web page, or downloading a file, or sending an email. A server application is the element of communication that responds to customer requests, providing the required service, that is, sending the web page or the requested file or email.
What is ‘bandwidth’?
Ans. The limited range of frequencies of signals that a line can carry is called the bandwidth. Bandwidth is often confused with Internet speed when it is actually the volume of information that can be sent over a connection in a measured amount of time, calculated in megabits per second (Mbps).
What are ‘firewalls’?
Ans. A firewall is a network security system, responsible to manage network traffic. It uses a set of security rules to prevent remote access and content filtering. Firewalls are used to protect the systems or networks from viruses, worms, malware, etc. Firewalls are usually of two types –
- Physical – A physical firewall or hardware firewall is a physical device, sits between the external network and the server. They analyze incoming traffic and filter out any threats to the device. Widely used in institutions and large companies.
- Logical – A logical or software firewall can exist anywhere on the subnet and protects hosts anywhere on the subnet without rewiring. They only protect the computer on which they are installed, and in many cases, they are integrated into the operating system itself.
Details of most important protocol, services, port no. & their function?
| Protocol | TCP/ UDP | Port No. | Function |
|---|---|---|---|
| FTP | TCP | 20 (Data) & 21 (Control) | (File Transfer Protocol) File Upload / Download service. |
| SSH | TCP | 22 | (Secure Shell) It provides remote login and secure file access. |
| Telnet | TCP | 23 | You can configure remote device such as Routers, Switches. |
| SMTP | TCP | 25 | (Simple Mail Transfer Protocol) For sending mail. |
| DNS | TCP/ UDP | 53 | (Domain Naming Service) Name resolution service |
| DHCP | UDP | 67 (Server) & 68 (Client) | (Dynamic Host Configuration Protocol) It helps automatically assign an IP address to a computer. |
| TFTP | UDP | 69 | (Trivial File Transfer Protocol) File Upload/ Download service. |
| HTTP | TCP | 80 | (Hyper Text Transfer Protocol) For Web service. |
| POP3 | TCP | 110 | (Post Office Protocol version 3) For receiving mail. |
| NNTP | TCP | 119 | (Network News Transmission Protocol) For News group service. |
| IMAP | TCP | 143 | (Internet Mailing Application Protocol) For receiving mail. |
| SNMP | UDP | 161 | (Secure Network Management Protocol) For network management. |
| HTTPS | TCP | 443 | (Secure Hyper Text Transfer Protocol) Web service in secure way. |
What is different between HTTP & HTTPS?
| HTTP (Hyper Text Transfer Protocol) | HTTPS (Hyper Text Transfer Protocol Secure) |
|---|---|
| HTTP is an unsecured protocol. | HTTPS is a secured protocol. |
| It uses port no. 80. | It uses port no 443. |
| Here no data encryption. | Here data is encrypted. |
| No SSL certificates are required for HTTP. | HTTPS is required SSL certificate. |
What is difference between POP3 & IMAP?
| POP3 (Post Office Protocol version 3) | IMAP (Internet Message Access Protocol) |
|---|---|
| Its port no. 110 & SSL port no. 995. | Its port no. 143 & SSL port no. 993. |
| It is a simple protocol that only allows downloading messages from your Inbox to your local computer. | IMAP is much more advanced and allows you the user to see all the folders on the mail server. |
| In POP3 the mail can only be accessed from a single device at a time. | Messages can be accessed across multiple devices at a time. |
| After download, the message exists in the local system if the local system crashes message is lost. | Multiple copies store in mail server, in case of loss of message of a local server, the mail can still be retrieved. |
What is ISO/OSI Model?
OSI model system defines and use to understand how data is transferred from one system to another system. It is developed by ISO (International Standard Organization). It’s full from the International organization of Standardization/ Open System Interconnection.
It has 7 layers –
- Physical Layer.
- Data Link Layer.
- Network Layer.
- Transport Layer.
- Session Layer.
- Presentation Layer.
- Application Layer.
What is TCP/ IP model?
Transmission Control Protocol/ Internet Protocol are two separate computer network protocols that define a set of rules to govern connection among all devices connected to the internet.
It is developed by DoD (Department of Defense).
There are 4 layers –
- Application Layer.
- Transport Layer.
- Internet Layer.
- Network Interface Layer.
What is MTU?
The biggest bundle that can be sent through an information connection layer is called as the Maximum Transmission Unit.
What is the difference between OSI & TCP/IP reference model?
| OSI model | TCP/ IP model |
|---|---|
| Its stands for Open System Interconnection. | Its stands for Transmission Control Protocol/ Internet Protocol. |
| OSI has 7 layers. | TCP/IP has 4 layers. |
| OSI has less reliable. | TCP/IP has more reliable. |
| OSI model developed by ISO. | TCP/IP model developed by DoD. |
| OSI model follows a vertical approach. | TCP/IP model follows a horizontal approach. |
Different between TCP & UDP?
| TCP (Transmission Control Protocol) | UDP (User Datagram Protocol) |
|---|---|
| It provides Acknowledgement. | It never provides Acknowledgement. |
| It is a Reliable protocol. | It is an Unreliable protocol. |
| It guarantees the delivery of packets. | It’s never guarantees of delivery of the packet. |
| It is Slow. | It is very Fast. |
| It’s port no. – 6. | It’s port no. – 17. |
What is different between Switch & Router?
| Switch | Router |
|---|---|
| It is a LAN device. | It is a WAN device. |
| It is a Networking device. | It is an Inter-networking device. |
| It works on the Data Link layer. | It works on the network layer. |
| The switch has one broadcast domain. | In a router, every port has its own broadcast domain. |
| It is uses the MAC address. | It uses IP address. |
| It transmits Frame. | It transmits Packet. |
| It is maintaining CAM table (Content Accessible memory). | It is maintaining the Routing table. |
| Its manufacturers are Cisco, D-Link, Juniper. | Its manufacturers are Cisco, Netgear, Asus, D-Link, TP-Link. |
What is Gateway?
A Gateway is a network node that connects two networks in a different protocol.
Example – A router can act as a gateway to reach another network.
What is different between UEFI & Legacy Boot?
| UEFI | Legacy Boot |
|---|---|
| It is used GUID partition table (GPT). | It is used MBR (Master Boot Record) table. |
| It is more user-friendly. | It is less user-friendly. |
| It has additional security features and is more efficient. | Not as efficient as UEFI. |
| UEFI boot is the boot process used by UEFI firmware. | Legacy Boot is the boot process used by BIOS firmware. |
What is Bandwidth?
Bandwidth is the maximum transfer rate of data from a network device. It is measured by bits per second.
What is Frequency?
Frequency refers to the number of cycles in a particular unit of time.
What is Throughput?
Throughput refers to how much data can be transferred from one location to another in a given amount of time.
What is the difference between Bandwidth, Throughput & Speed?
Bandwidth often refers to the maximum amount of data transfer per second. Throughput is an actual amount of data passing through media or a connection. Speed often refers to how much data can be downloaded or uploaded per second.
What is NIC?
NIC stands for Network Interface Card. It is also known as Network Adapter or Ethernet Card. It is in the form of an add-in card and is installed on a computer so that the computer can be connected to a network.
Each NIC has a MAC address which helps in identifying the computer on a network.
Pingback: Apache Tomcat Interview Questions And Answers - Youngster Company