Top 50 Networking Interview Questions and Answers

1) What is a Network?

A Network refers to the connectivity between two or more computers linked. The computers on Network linked through cables,telephone lines and satellites etc…

2) What are routers?

The router is a network device that connects two or more data lines from different IP networks. It is used transfer information from the source to destination.Most routers are placed at gateways where the networks are connected.

3) What is OSI model and how many layers?

Open Systems Interconnection (OSI) model describes seven layers. OSI was introduced in 1983 by representatives of the major computer and telecom companies, and was adopted by ISO as an international standard in 1984.There are 7 OSI layers: 1) Physical Layer, 2) Data Link Layer, 3) Network Layer, 4) Transport Layer, 5) Session Layer, 6) Presentation Layer, and 7) Application Layer.

4) What is HTTP and what port no is use?

HTTP (HyperText Transfer Protocol) is responsible for web content. HTTP use webpages transmit the web content and allow the navigation and display of HyperText. HTTP port used here is TCP port 80.

5) What is HTTPs and what port no is use?

HTTPs is Secure than HTTP. HTTPs is used for secure computer network. HTTPs provides authentication of websites that prevents unwanted attacks. HTTP port used here is TCP port 443.

6) Different Between Hub,Router and Switch

Hub 

• Connects Two Or More Devices
• No perform filtering
• Physical Layer

Router

• Connects Two Or More LAN Devices
• Filter Packets before forwording
• Network Layer

Switch

• Connects Two Or More LAN AND WAN Devices
• Highly configured to filter and send packets
• Data Link Layer

7) What is a Firewall?

Firewall is used to protect computer networks from unauthorized access. Firewalls serve protect an internal network from external attacks. It prevents malicious access from outside to the computer network. A firewall can grant limited access to outside users network.The firewall two types available hardware and software program configuration. The Firewall also helps to prevent worms, viruses, etc.

8) What is DNS?

Domain Name Server (DNS) public IP addresses and hostnames are stored in the DNS and it translates into a corresponding IP address.it is work for Domain to IP Adress convert.

 9) What is a MAC address?

MAC (Media Access Control) address is the unique 48-bit .The MAC address is assign to a network card or device. Each MAC address is unique. It is also known as a physical address represented by hexadecimal digits.

 10) What is an IP address?

IP address (Internet Protocol address) is a numerical label assigned to each device (e.g., computer,router, printer) participating in a computer network that use Internet Protocol for communication.

 11) What is a point to point link?

It is use direct connection between two computers on a network. A point to point connection is use one office to another corporate office connected.

12) What is a VPN?

VPN (Virtual Private Network) is built on the Internet as a private wide area network. Internet-based VPNs are connected from anywhere in the world and less expensive. VPNs are used for secure data transferred between multiple offices and remotely connected.

13) What is DoS?

DoS (Denial-of-Service attack) is an attempt to prevent users from being able to access the Internet or any other network services. DoS attack is characterized by using a single computer to launch the attack.

14) What is ASCII?

ASCII(American Standard Code for Information Interchange). ASCII uses numeric codes to represent characters.

15) What is DHCP and describe how it works?

DHCP (Dynamic Host Configuration Protocol). DHCP is used to assign IP addresses automatically to the devices over the network. DHCP through IP management became very easy.

16) What is Network Topology?

The physical layout of network is called  Network Topology.

Network Topology Types :-

• Bus Topology - All the devices share a common communication line.
• Star Topology - All nodes are connected to a central hub device.
• Ring Topology - Each node connects to exactly two other nodes.
• Mesh Topology - Each node is connected to one or more nodes.
• Tree Topology - Similar to star topology and inherits the bus topology.
• Hybrid Topology - Nodes are connected in more than one topology styles.

17) What is a UTP cable and how much length allowed for a UTP cable?

A UTP cable is a 100 ohms cable made up of copper. The length allowed for a UTP cable is 100m. 

18) What is a Ping?

A ping is a used to test the reachability of a host and check it can accept requests on an IP network. It can be used for troubleshooting.

19) What is ipconfig and ifconfig?

• Ipconfig - Ipconfig is used configure the network interface. It display all TCP/IP network summary information.
• Ifconfig - Ifconfig Interface Configuration and is used on Linux, Mac, and UNIX operating systems.

20) What is difference between Domain and Workgroup?

The main difference between workgroups and domains is Computers on home networks are part of a workgroup, and computers on workplace networks are part of a domain.

21) What is 127.0.0.1 and localhost?

Localhost is hostname given to the machine, and it represented by the IP address 127.0.0.1.localhost and 127.0.0.1 is same.

22) What is a Gateway?

A gateway is a connected to two or more networks. It may be connected router, firewall, server etc. and is capable of regulating traffic in a network.

23) What is the classes of internet addresses?

Five types of classes internet address

• Class A : 0.0.0.0 – 127.255.255.255
• Class B : 128.0.0.0 – 191.255.255.255
• Class C : 192.0.0.0 – 223.255.255.255
• Class D : 224.0.0.0 – 239.255.255.255
• Class E : 240.0.0.0 – 247.255.255.255

24) Explain NAT in networking.

Network Address Translation (NAT) is a protocol used to convert the IP address of the computer network into local network to IP address to internet. NAT is used computer, router, firewall in a local network.

25) What is RAS?

RAS (Remote Access Services) information that typically outside network acess easily.remote acess through anywhere location file and folder acess easily.

26) What is ICMP?

ICMP (Internet Control Message Protocol) is a network layer protocol. TCP/IP suite used by gateways and hosts to send notification of datagram problems back to the sender.

27) What is tracert?

Tracert use to trace the route taken by data from the router to the destination network. It also shows the number transmission route.

28) What are the maximum networks and hosts in class A, B, and C network?

• class A – There are 126 possible networks and 16,777,214 hosts
• class B – There are 16,384 possible networks and 65,534 hosts
• class C - There are 2,097,152 possible networks and 254 hosts

29) What is the standard color sequence of lan cable straight-through cable?

Orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.

30) What is IPV4 and IPV6?

• IPv4 is 32-Bit and  IPv6 is a 128-Bit IP address.
• IPv4 adress is decimal and IPv6 adress is hexadecimal.
• IPv4 checksumfield is available and IPv6 checksumfield is not available

31) What is Proxy Server?

Proxy Server is gateway between you and the internet.Proxy servers act as a web filter and firewall provide sharing network connections.proxies won't encrypt your traffic and they won't hide your IP address. Proxy server prevents the external users unauthorized to access the network.

32) What is POP3 and IMAP?

POP3(Post Office Protocol)  - Emails are stored on a single device. If you want to keep messages on the server,make sure setting " Keep email on server " is enabled or all messages are deleted from the server once downloaded to the app or software.

POP3 protocol works on two ports:

•   Port 110 – Default POP3 non-encrypted port
•   Port 995 – This port you need to use if you want to connect using POP3                            securely

IMAP (Internet Messaging Access Protocol) - Emails are stored on the server. Messages is synced and accessed across multiple devices.

IMAP protocol works on two ports:

•   Port 143 – Default IMAP non-encrypted port;
•   Port 993 – This port you need to use if you want to connect using IMAP                              securely.

33) How many layers TCP/IP?

There are four layers: (1) Transport (2) Internet (3) Application (4) Network Interface

34) What is ARP?

ARP (Address Resolution Protocol) main task is recognized ip address to mac address layer

35) What is VLAN?

VLAN(Virtual LAN) is a group of devices on one or more LANs that are configured and  communicate same wire. VLAN  advantage of reducing network traffic,security ,collisions and  cost effective.  VLAN divided  department wise and easier to prevent a compromised computer from infecting the entire network.

36) what is tunnel mode?

Tunnel mode is used to encrypt IP packet including headers and payload. It is basically used in a Site-to-Site VPN to secure communications between security firewalls, gateways,router etc.

37) What is bandwidth?

Bandwidth use range of limit of network between its upper and lower frequency is called bandwidth.

38) What is RAID?

RAID is use for provide Fault Tolerance by using multiple Hard Disc Drives.

39) What is FTP and which port no is use?

FTP(file transfer protocol) is use for one file transfer to another computer and use for lan and wan network in file transfer. FTP in port number 20 and 21 used.

40) What is peer-peer process.

The processes of each machine that communicate at a given layer are called peer-peer process.

41) What is backbone network?

A backbone network is centralized infrastructure that is designed to distribute different data and routes to various networks. It also handles management of bandwidth and channels.

42) What is Telnet?

Network convention that enables a client on one PC to sign into another PC .it tcp Port number is 23.

43) What is Routing?

Routing is path to reach source to destination. It give entire view packet travel from source to detination.

44) What is 10Base-T mean?

The 10 means data transfer rate, in this case is 10Mbps. The Base means refers to base band as oppose to broad band. T means twisted pair.

45) What is port forwarding?

Port forwarding is sometimes called port mapping and it allows computers services in private networks to connect over the internet with other private or public computers services.

46) what is virtualize systems?

Virtualization is software-based,single hardware in such as virtual applications, servers, networks and storage use. It is use Reduced operating costs and Increased IT productivity, efficiency and Simplified data center management.

47) what is Windows Server and what is use?

Window server is a series of server operating system developed by Microsoft Corporation. Multiple users data storage, applications and corporate networks connects and provide extensive administrative control.

48) what is Active Directory?

Active Directory (AD) is a Microsoft technology used to manage devices and computers and network. Active Directory to maintain proper order in arranging that is file servers, users, computers, and many more.

49) what is the difference between 2012 & 2016 server?

Huper-v and Vm Size Increased

50) What is netstat?

Netstat is a command-line utility program and it provides useful information about the current IP/TCP settings of a connection.