Real interview questions from top companies for Network engineer. Includes theoretical concepts and coding problems.
What is the difference between a hub and a switch?
A hub is a simple network device that broadcasts incoming data to all connected devices, while a switch is an intelligent device that forwards data to the intended recipient based on their MAC address.
What is the purpose of the Spanning Tree Protocol (STP)?
The Spanning Tree Protocol (STP) is used to prevent network loops and ensure a single path for data to travel between devices on a network.
What is the difference between a router and a firewall?
A router connects multiple networks together and routes traffic between them, while a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.
What is the purpose of the Domain Name System (DNS)?
The Domain Name System (DNS) is used to translate human-readable domain names into IP addresses that computers can understand.
What is the difference between HTTP and HTTPS?
HTTP (Hypertext Transfer Protocol) is a protocol used for transferring data over the internet, while HTTPS (Hypertext Transfer Protocol Secure) is a secure version of HTTP that uses encryption to protect data in transit.
What is the purpose of the Transport Layer Security (TLS) protocol?
The Transport Layer Security (TLS) protocol is used to provide secure communication between a web browser and a web server by encrypting data in transit.
What is the difference between a LAN and a WAN?
A LAN (Local Area Network) is a network that spans a small geographic area, such as a home or office building, while a WAN (Wide Area Network) is a network that spans a larger geographic area, such as a city or country.
What is the purpose of the Internet Protocol (IP)?
The Internet Protocol (IP) is used to provide logical addressing and routing for data packets on a network.
What is the difference between IPv4 and IPv6?
IPv4 (Internet Protocol version 4) is an older version of the Internet Protocol that uses 32-bit addresses, while IPv6 (Internet Protocol version 6) is a newer version that uses 128-bit addresses and provides improved security and scalability.
What is the purpose of the Address Resolution Protocol (ARP)?
The Address Resolution Protocol (ARP) is used to resolve IP addresses to MAC addresses on a network.
What is the difference between a subnet mask and a CIDR notation?
A subnet mask is a 32-bit number that determines the scope of a subnet, while CIDR (Classless Inter-Domain Routing) notation is a way of representing IP addresses and subnet masks using a prefix length.
What is the purpose of the Internet Control Message Protocol (ICMP)?
The Internet Control Message Protocol (ICMP) is used to send error messages and operational information between devices on a network.
What is the difference between a network interface card (NIC) and a network interface controller (NIC)?
A network interface card (NIC) is a hardware component that connects a computer to a network, while a network interface controller (NIC) is a chip or circuit that controls the flow of data between the computer and the network.
What is the purpose of the Simple Network Management Protocol (SNMP)?
The Simple Network Management Protocol (SNMP) is used to manage and monitor network devices, such as routers and switches.
What is the difference between a managed switch and an unmanaged switch?
A managed switch is a switch that can be configured and managed using a network management protocol, such as SNMP, while an unmanaged switch is a switch that cannot be configured or managed.
What is the purpose of the Dynamic Host Configuration Protocol (DHCP)?
The Dynamic Host Configuration Protocol (DHCP) is used to assign IP addresses and other network settings to devices on a network automatically.
What is the difference between a virtual private network (VPN) and a virtual local area network (VLAN)?
A virtual private network (VPN) is a network that uses encryption and tunneling to create a secure and private connection between devices over the internet, while a virtual local area network (VLAN) is a network that uses switches and routers to create a logical separation between devices on a network.
What is the purpose of the Network Time Protocol (NTP)?
The Network Time Protocol (NTP) is used to synchronize the clocks of devices on a network to a single time source.
Write a Python function to calculate the subnet mask of a given IP address and prefix length.
Write a Java function to determine if a given IP address is valid.
publicbooleanisValidIP(String ip) {
String[] parts = ip.split(".");
if (parts.length != 4) {
returnfalse;
}
for (String part : parts) {
intnum= Integer.parseInt(part);
if (num < 0 || num > 255) {
returnfalse;
}
}
returntrue;
}
Write a C++ function to calculate the checksum of a given packet.
unsignedshortcalculate_checksum(unsignedshort* packet, int length){
unsignedlong sum = 0;
for (int i = 0;
i < length;
i += 2) {
sum += packet[i];
}
while (sum > 0xffff) {
sum = (sum >> 16) + (sum & 0xffff);
}
return ~sum & 0xffff;
}
Write a Python function to simulate a simple router that forwards packets between two networks.
