Software Engineer

Which protocol is used to map IP addresses to MAC addresses?
A. DNS
B. ARP
C. DHCP
D. ICMP

What is the default administrative distance of OSPF?
A. 90
B. 100
C. 110
D. 120

Which layer of the OSI model does a switch operate on?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4

What is the purpose of VLANs?
A. Increase bandwidth
B. Segment broadcast domains
C. Encrypt traffic
D. Assign IP addresses

Which protocol is used for dynamic IP assignment?
A. FTP
B. DHCP
C. SNMP
D. Telnet

A router receives a packet with TTL = 1. What will happen?
A. Packet is forwarded
B. Packet is dropped
C. TTL is increased
D. Packet is encrypted

Which routing protocol uses Dijkstra’s algorithm?
A. RIP
B. OSPF
C. BGP
D. EIGRP

What is the default port for HTTPS?
A. 80
B. 21
C. 443
D. 25

Which command is used to view routing table in Cisco devices?
A. show ip route
B. show running-config
C. show interfaces
D. show version

What does NAT primarily do?
A. Encrypt data
B. Translate private IP to public IP
C. Assign MAC addresses
D. Monitor traffic

Which protocol is connectionless?
A. TCP
B. UDP
C. FTP
D. SSH

What is the main function of a default gateway?
A. Assign IP
B. Route traffic outside network
C. Encrypt packets
D. Filter traffic

Which cable type is used to connect two switches directly (traditional)?
A. Straight-through
B. Rollover
C. Crossover
D. Fiber

What is subnet mask for /24?
A. 255.255.0.0
B. 255.255.255.0
C. 255.0.0.0
D. 255.255.255.255

Which protocol is used to securely access remote devices?
A. Telnet
B. FTP
C. SSH
D. HTTP

What is the purpose of ICMP?
A. File transfer
B. Error reporting & diagnostics
C. Email sending
D. Routing

Which device operates at Layer 3?
A. Hub
B. Switch
C. Router
D. Repeater

What is the broadcast address of 192.168.1.0/24?
A. 192.168.1.1
B. 192.168.1.254
C. 192.168.1.255
D. 192.168.0.255

Which protocol is used for email sending?
A. POP3
B. SMTP
C. IMAP
D. SNMP

What happens in a broadcast storm?
A. Network slows due to excessive broadcasts
B. Packets are encrypted
C. IP conflicts occur
D. Routing stops

Which protocol uses port 23?
A. SSH
B. Telnet
C. FTP
D. SMTP

What is the main purpose of STP (Spanning Tree Protocol)?
A. Increase bandwidth
B. Prevent loops
C. Assign IPs
D. Encrypt traffic

Which routing protocol is distance-vector?
A. OSPF
B. BGP
C. RIP
D. IS-IS

What does a Layer 2 switch use to forward frames?
A. IP address
B. MAC address
C. Port number
D. Subnet mask

Which command shows interface status?
A. show ip route
B. show interfaces
C. show vlan
D. show version

What is the purpose of DNS?
A. Assign IP
B. Resolve names to IP
C. Route packets
D. Encrypt data

Which IP is private?
A. 8.8.8.8
B. 172.16.5.4
C. 1.1.1.1
D. 200.1.1.1

What is the range of Class C IP addresses?
A. 1–126
B. 128–191
C. 192–223
D. 224–239

Which protocol ensures reliable delivery?
A. UDP
B. TCP
C. ICMP
D. ARP

Which command saves configuration in Cisco devices?
A. write memory
B. show run
C. reload
D. erase startup-config

Which VLAN is default?
A. VLAN 0
B. VLAN 1
C. VLAN 10
D. VLAN 100

Which device filters traffic using ACLs?
A. Hub
B. Switch
C. Router
D. Repeater

What is the purpose of subnetting?
A. Increase broadcast traffic
B. Divide network into smaller parts
C. Encrypt packets
D. Assign MAC addresses

Which protocol is used for network monitoring?
A. SNMP
B. FTP
C. SMTP
D. HTTP

Which command displays MAC address table?
A. show mac address-table
B. show ip route
C. show vlan
D. show interfaces

Which port is used by FTP?
A. 20/21
B. 22
C. 80
D. 443

What is a trunk port?
A. Connects end devices
B. Carries multiple VLANs
C. Assigns IPs
D. Blocks traffic

Which routing protocol is used on the internet?
A. RIP
B. OSPF
C. BGP
D. EIGRP

What is loopback address?
A. 192.168.1.1
B. 127.0.0.1
C. 10.0.0.1
D. 0.0.0.0

Which device broadcasts traffic to all ports?
A. Switch
B. Router
C. Hub
D. Firewall

A user reports they cannot open www.example.com, but they can successfully ping its IP address. What is the most likely issue?
A. DNS server misconfiguration
B. Routing table error
C. Firewall blocking ICMP
D. Switch port failure

You need to securely transfer files between two servers over the network. Which protocol should you use?
A. FTP
B. TFTP
C. SFTP
D. HTTP

An organization wants to block unauthorized access from external networks while allowing internal users to browse the internet. Which device should be configured?
A. Switch
B. Router
C. Firewall
D. Hub

A network administrator wants to verify if a remote host is reachable. Which tool should they use first?
A. traceroute
B. ping
C. netstat
D. nslookup

A laptop fails to obtain an IP address from DHCP and assigns itself an address in the 169.254.x.x range. What is the issue?
A. DNS failure
B. DHCP server unreachable
C. Default gateway error
D. Subnet mismatch

A network engineer notices that domain names are not resolving, but users can access websites using IP addresses. Which service is failing?
A. DHCP
B. DNS
C. NAT
D. SNMP

A user can access local network resources but cannot access the internet. Which configuration is most likely missing?
A. Subnet mask
B. Default gateway
C. MAC address
D. VLAN ID

In a network where all devices connect to a central switch, which topology is being used?
A. Bus
B. Ring
C. Star
D. Mesh

An administrator wants to check which VLANs are configured on a switch. Which command should they use?
A. show ip route
B. show vlan brief
C. show interfaces
D. show version

A network device drops packets larger than a certain size. What configuration parameter is causing this?
A. TTL
B. MTU
C. Bandwidth
D. Latency

A new device is connected to the network and automatically receives an IP address. Which service provided this functionality?
A. DNS
B. DHCP
C. ARP
D. ICMP

Users complain of intermittent connectivity, and analysis shows collisions due to mismatched duplex settings. What is the likely problem?
A. Incorrect IP
B. Duplex mismatch
C. VLAN misconfiguration
D. DNS issue

An administrator wants to verify the mapping of IP addresses to MAC addresses on a router. Which command should be used?
A. show ip route
B. show arp
C. show vlan
D. show interfaces

A system administrator needs secure remote CLI access to a network device. Which protocol should be used?
A. Telnet
B. FTP
C. SSH
D. HTTP

A company wants to efficiently allocate IP address ranges and reduce wastage. Which technique should they use?
A. NAT
B. CIDR
C. VLAN
D. STP

Two different networks cannot communicate, and broadcast traffic is not passing between them. Which device is required to enable communication?
A. Hub
B. Switch
C. Router
D. Repeater

A user is able to send emails but cannot receive them. Which protocol is likely misconfigured?
A. SMTP
B. POP3
C. SNMP
D. HTTP

A company wants to prioritize voice traffic over regular data traffic to ensure call quality. Which feature should be implemented?
A. NAT
B. QoS
C. VLAN
D. DNS

A network engineer wants to discover directly connected Cisco devices automatically. Which protocol should be used?
A. CDP
B. FTP
C. HTTP
D. SMTP

Two devices on the same network are assigned the same IP address. What is the expected result?
A. Improved performance
B. IP conflict causing connectivity issues
C. Automatic correction by DHCP
D. Routing loop

You have been given an integer array/list (ARR) of size N. You have to return an array/list PRODUCT such that PRODUCT[i] is equal to the product of all the elements of ARR except ARR[i]

 Note :

Each product can cross the integer limits, so we should take modulo of the operation. 

Take MOD = 10^9 + 7 to always stay in the limits.

Follow up :

Can you try solving the problem in O(1) space?

You have been given a non-empty grid consisting of only 0s and 1s. You have to find the number of islands in the given grid.

An island is a group of 1s (representing land) connected horizontally, vertically or diagonally. You can assume that all four edges of the grid are surrounded by 0s (representing water).

You are given an Integer array ‘ARR’ and an Integer ‘K’.

Your task is to find the ‘K’ most frequent elements in ‘ARR’. Return the elements in any order.

For Example:

You are given ‘ARR’ = {1, 2, 2, 3, 3} and ‘K’ = 2. 

The answer will {2, 3} as 2 and 3 are the elements occurring most times.