Top 50 Networking Interview Questions 2023
CCNA (Cisco Certified Network Associate) is a widely recognized certification in the networking industry. It validates your knowledge and skills in the field of networking and is a great way to enhance your career prospects. CCNA Training in Pune is an entry-level certification offered by Cisco Systems, a leading provider of networking hardware and software. In this blog, you will find the top 50 networking interview questions 2023 which are asked in the interview exam frequently.
Top 50 Most Important Networking Interview Questions 2023
Q1. Explain the range of Class. B private IP?
ANS. 172.16.0.0 to 172.31.255.255
Q2. Explain NAT.
ANS. NAT translates Public IP to Private and Private to Public.
Q3. Command to check the route in the router.
ANS. Router# shows ip route
Q4. Command to check interface status.
ANS. Router# Show ip interface brief
Q5. What is the Administrative distance between OSPF and EIGRP?
ANS. OSPF 110 and EIGRP 90
Q6. What is Layer 3 in OSI?
ANS. Layer 3 is the network layer and the IP address work in Layer 3
Q7. In which layer switch work?
ANS Switch works in 2 layers
Layer 2 DATA link layer
Layer 3 Network Layer
Q8. User plan to connect two switches back to back. Which cable do you suggest?
ANS. Cross cable
Q9. What is a subnet mask of Class C IP?
Q10. Identify network id of 10.128.10.10/10
Q11. Is 184.108.40.206 public or private?
ANS public as a range of private is 172.16.0.0 to 172.31.255.255
Q12. What is the port number of HTTP, SMTP, and DNS?
ANS http=80, SMTP=25, DNS=53
Q13. Which protocol is responsible for Ip distribution?
Q14. What is the Default gateway?
ANS. The default gateway is the role of the router. And default router IP is ip of the router interface directly connected to the LAN.
Q15.What is Subnetting?
ANS. Subnetting is breaking the Network id to sub-network id as per the requirement of the number of hosts in network.
Q16.Which are 3 modes of cisco IOS?
ANS. User mode, Privileged mode, Global Configuration mode.
Q17. Command to clear NVRAM.
ANS. Router# erase startup-config
Q18. What do you mean by interior routing protocol?
ANS. Interior routing protocol makes communication/routing between routers with similar network IDs.
Q19. What is the difference between Static and dynamic routing?
ANS. In static routing, the route is defined by the administrator, and in dynamic routing router defines the best route with the help of routing protocols.
Q20. The administrator wants to break the switch broadcast domain, what is your suggestion?
ANS. I suggest the administrator configure VLAN on the Cisco switch.
Best Top 50 Networking Interview Questions 2023
Q21. Explain ACL.
ANS ACL is an access control List. Administrators configure ACL to restrict data between routers after enabling routing. ACL is configured to limit traffic flow and to optimize network bandwidth utilization.
Two ACL Standard and Extended.
Q22. How many bit is IPv6 in length?
ANS. IPv6 is the 128-bit hexadecimal address.
Q23. The administrator wants to provide redundancy and load balancing between cisco switches, what will you suggest?
ANS: I suggest the administrator configure Ether-channel rather than STP.
Q24.What are the different layers of the OSI model?
ANS: Basically, there are 7 layers of the OSI model. Each layer has its own functionality in the OSI model.
Layer 1 – Physical
Layer 2 – Data Link Layer
Layer 3 – Network
Layer 4 – Transport
Layer 5 – Session
Layer 6 – Presentation
Layer 7- Application
Q25.What are Routers?
ANS: Router is the Device that makes communication between a network with different network IDs, with the help of routing techniques like static, dynamic, or default.
Q26.What is the difference between Switch, Routers?
Switch: A Switch device that makes communication between a device with a similar net id. Forwarding decisions are made with the help of the MAC address. It supports a single broadcast domain and multiple collision domains.
Router: Routing is the Device that makes communication between different network IDs with the help of routing techniques like static, dynamic, or default.
Q27. What is Half-duplex and Full-duplex?
ANS: In half-duplex, the transmission of information or communication is from one direction. E.g. Walkie-talkie
In full-duplex, the transmission of information or communication is from both directions. e.g. Telephone
Q28.Define IP Address.
ANS: Internet Protocol (IP Address) is a 32-bits to 128-bit identifier for a device on TCP/IP protocol. The IP address of a device must be uniquely defined for communication.
It has 2 principal functions which include host and location address. And it has two versions which are IPv4 (32-bits) and IPv6 (128-bits).
Q29. Can the IP address be assigned to Layer 2?
ANS: No, IP addresses cannot be assigned to Layer 2 as it is a layer 3 protocol.
Q30. What are the different classes and ranges of IP addresses?
ANS: There are 5 different classes of IP addresses:
Class Range A 1-126 B 127-191 C 192-223 D 224-239 E 240-254
Q31. What are Private IP and Public IP?
Private IP: It is used within the local LAN. Those are free addresses from class A- 10.0.0.0 to 10.255.255.255
B-172.16.0.0 to 172.31.255.255
C- 192.168.0.0 to 192.168.255.255
Public IP: It is used across the Internet. Distributed by ISP. These are not free.
Q32.Define MAC Address.
ANS. MAC address is the Media Access Control address. It is stored in ROM and also called a Hardware address. Managed by IEEE. And represented in HEXA decimal and 48-bit in length.
Q33.Why is VLAN used?
ANS. It is a Virtual LAN network that is used to make a separate broadcast domain and to create Virtual LAN in a single switch.
Q34. What are the different types of passwords that you can use in Cisco routers?
ANS: Different types of passwords that are used in Cisco routers are Enabled passwords i.e. privileged mode passwords.
Enable secret password i.e. privileged mode password.
Auxiliary (AUX) i.e. user mode password.
Console password i.e. is user mode password.
Virtual terminal (VTY) i.e. is telnet password.
Q35. How many types of memories are used in the Cisco router?
ANS: Given below are the different types of memory that are used: Flash memory: It stores the IOS which is in .bin extension and Linux based.
RAM: Stores running configuration. It is volatile.
NVRAM: Store start-up configuration file and it is non-volatile. ROM: Read Only Memory. It saves the information if the router is shut down or restarted. It maintains the instructions for POST diagnostics. And MINI IOS for troubleshooting.
Q36. What are the different types of cables that are used in routing?
ANS: Three different types of cables that are used include:
Straight cable (switch-router):- different category device. Cross cable (PC-PC, switch-switch):- similar category device. Rollover cable (Console port to computer):- Console cable for configuration.
Q 37. Define the Autonomous System (AS).
ANS: AS numbers are unique numbers distributed by IANA for WAN networks. Interior routing protocols can make data communication between routers with similar AS number routers and exterior routing protocols make communication with routers with different AS numbers. e.g. BGP protocol.
Q38. Explain the DHCP scope.
ANS: Dynamic Host Configuration Protocol (DHCP) is used to automatically assign an IP host with its address to a client.
Q 39. What is the Domain Name System (DNS)?
ANS: DNS is an internet service that translates domain names FQDN into IP addresses.
Q40. What is DHCP?
ANS: DHCP is Dynamic Host Configuration Protocol. It is an application layer protocol used by hosts for obtaining network setup information. The DHCP is controlled by a DHCP server that dynamically distributes network configuration parameters such as IP addresses, subnet masks, and gateway addresses.
Q 41. What is APIPA in networking?
ANS: APIPA is automatically assigned an IP address. This address is self-assigned to the system if the system fails to get ip from the DHCP server.
Q 42. How many VTP modes are there and what are they?
ANS: VTP is VLAN trunking protocol. Three modes are VTP server (default), VTP client, and VTP transparent.
Q 43. What type of routing protocol is EIGRP?
ANS: EIGRP uses a Hybrid algorithm named DUAL
Q 44. What is the ether-channel protocol?
ANS: LACP (open stand) and PAgp (cisco prop)
Q45. How is the port cost of OSPF calculated?
ANS: Port cost is calculated with the formula
Cost= reference bandwidth/ actual bandwidth
Q46. What is BPDU?
ANS: Bridge protocol unit is used by STP for selection for ROOT Bridge and Non-root Bridge. It calculated bridge Id with help of priority number and base Mac address. Switch with lowest bridge id become Root Bridge.
Q47. Maximum hope count support by EIGRP?
AND: 224 and the default is 100
Q48. Explain Active Directory.
ANS: Active directory is the central database of all users and computers. It is stored in a server called a domain controller.
Q49.Explain the Administrative distance value.
ANS: Ad value is the rank given to each routing protocol and technique. It allows the admin to config multiple routing protocols and techniques on a single router. But routers use that tech or protocol with the smallest AD value.
Q50. Create 4 subnets of 10.0.0.0/8
10.0.0.0/10 valid-ip= 10.0.0.1 to 10.63.255.254 BC-id= 10.63.255.255 10.64.0.0/10 Valid-ip= 10.64.0.1 to 10.127.255.254 BC-id= 10.127.255.255 10.128.0.0/10 Valid-ip= 10.128.0.1 to 10.191.255.254 BC-id=10.191.255.255
10.192.0.0/10 Valid-ip= 10.192.0.1 to 10.255.255.254 BC-id= 10.255.255.255 Subnet mask 255.192.0.0
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