Top Network Engineer Interview Questions & Answers

Network Engineer Interview  Q&A

Q1. What is a ‘link’?
Ans. A link refers to the connectivity between two devices. It includes the type of cables and protocols used in order for one device to be able to communicate with the other.

Q2. What are the types of LAN cables used?
Ans. There are two types of LAN cables used – ‘Cat 5’ and ‘Cat 6.’ Cat 5 can support 100Mbps of speed while Cat 6 can support 1Gbps of speed.

Q3. What is a ‘cross Cable’?
Ans. This is a type of connection between same types of devices without using a hub/switch so that they can communicate.

Q4. How many layers are there in the OSI reference model? Name them
Ans. There are 7 layers in an OSI (Open Systems Interconnection) reference model. They are:
Physical layer
Data link layer
Network layer
Transport layer
Session layer
Presentation layer
Application layer

Q5.What is DNS? Why is it used?
Ans.DNS - Domain Name System is a central part of the Internet, providing a way to match names of a website you’re seeking to numbers of the address for the website.

Q6. Differentiate between ‘forward lookup’ and ‘reverse lookup’ in DNS?
Ans. Converting names to IP addresses is called forward lookup.
Resolving IP addresses to names is called reverse lookup.

Q7. What is a LAN?
Ans. A LAN (Local Area Network) refers to the connection between computers and other network devices that are located within a small physical location.

Q8. What is a WAN?
Ans. A wide area network (WAN) is a telecommunications network or computer network that extends over a large geographical distance.

Q9. What is a router? What are its basic roles?
Ans. A router is a layer 3 network device used to establish communication between different networks. The roles of a router are –
- inter-network communication
- Best path selection
- Packet forwarding
- Packet filtering

Q10. What is a ‘backbone network’?
Ans. A backbone network is a centralised infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

Q11. What are the criteria for the best path selection of a router?
Ans. The following parameters define the path selection:
- Longest prefix match
- Minimum AD (administrative distance)
- Lowest metric value

Q12. What is the difference between ‘standard’ and ‘extended’ ACL?
Ans. Standard ACLs are source-based, whereas extended ACLs are source- and destination-based.

Q13. What is NIC?
Ans. NIC (Network Interface Card) is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

Q14. Define ‘anonymous FTP’.
Ans. Anonymous FTP is a way of granting a user access to files in public servers.

Q15. How many layers are there under TCP/IP?
Ans. There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

Q16. What is ‘network topology’?
Ans. Network topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

Q17. What is RAS?
Ans. RAS (Remote Access Services) refers to any combination of hardware and software to enable remote access to tools or information that typically reside on a network of IT devices.

Q18. What are ‘firewalls’?
Ans. A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules.

Q19. What is the AD of RIP, EIGRP & OSPF?
Ans. AD of RIP, EIGRP and OSPF are respectively 120, 90 and 110.

Q20. In BGP, what is the purpose of AS_PATH attribute?
Ans. If a route has more than one route to the same IP prefix, the best path is the one with the shortest AS_PATH.