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Computer Networking Topics For Interviews
Includes a list of topics which are very important in computer networking.
Computer networking is a very important topic to learn if you want to make a career in the IT industry. You will find computer networking questions being asked in many of the technical roles like SDE, SRE, DevOps, Cloud engineer, System admin, Support engineer etc. The level of questions being asked will vary depending on the requirements of the company. SDE interviews may focus on understanding the basics of networking whereas SRE/DevOps/Cloud/System engineering roles may test in depth understanding of networking.
Below is a list of topics that are important in computer networking. I have also provided references at the end which can help you in preparing for the computer networking interview.
TCP/IP protocol and OSI model
Layers in TCP/IP and OSI model
Function of each layers
Examples of protocols in each layer
Encapsulation and decapsulation in TCP/IP protocol - Explain the flow of a packet through different layers
Application layer protocols
For each protocol, you should be able to explain the following:
What is the use of the protocol ?
How does the protocol work ?
Which port numbers are used by the protocol ?
Does the protocol use TCP or UDP and why ?
List of important application layer protocols
Understand request and response cycle
HTTP status codes
HTTP 1 vs HTTP 2 vs HTTP3
Working of TLS handshake
Symmetric vs asymmetric encryption
Public and private key
HTTP vs HTTPS
How does DNS work ? (Understand both iterative and recursive working of DNS)
Different types of DNS servers
DNS records - A, NS, MX, CNAME
Understand how DHCP works
DORA process in DHCP
Mail access protocols
What does SMTP do ?
How does the SMTP protocol help in delivering email ?
IMAP vs POP3 vs SMTP protocol
Understand why we use SSH
How does SSH work ?
Understand about ssh public and private keys and how they help in a secure connection
Transport layer protocols
What is socket programming ?
Difference in TCP vs UDP socket program
Understand important headers in TCP and UDP packet
Difference between TCP and UDP. When will you prefer UDP over TCP ?
TCP 3-way handshake
TCP 4-way connection termination process
Different states in TCP connection
Network layer protocols
Understand important headers in each network layer protocol
IPv4 vs IPv6 addresses
Subnetting - CIDR vs classless routing, subnet mask, broadcast address, network address
Why do we use the ICMP protocol ?
How does the ping command work ?
How does the traceroute command work ?
BGP, OSPF, RIP
Understand what is NAT and how it works
What is a router ? How does the router work ?
What is a gateway ?
Data link layer protocols
Understand what it does and how it works
What is a switch ? Difference between switch and router ?
LAN vs MAN vs WAN
Linux networking commands
Application layer - telnet, curl, wget, ssh, sftp, scp, dig, nslookup
Transport layer - nc, tcpdump, netstat(ss)
Network layer - ping, traceroute, route, ip addr, iptables, nmap
Data link layer - arp
What happens when you enter www.google.com on your browser and press enter ?
Difference between switch, router and hub
Unicast vs multicast vs anycast vs broadcast messaging
What is a firewall ? Examples
What is VPN? How does it work ?
What is DDos attack ?
TCP SYN flooding
Computer networking tutorial by letusdevops(my channel) - Videos in this playlist contain in depth discussion about computer networking topics.
PowerCert Animated Videos has done a wonderful job in explaining computer networking topics through some powerful visualization.
Videos by Ben Eater helps in understanding the low level basics of computer networking from cables to important networking protocols.
Eli The Computer Guy tutorial is another great series explaining bits and pieces of the networking infrastructure.