Round 4: Technical Interview 3: (1.5 hours) Part 1: Networking - What exactly are the requirements to make two computers communicate (they are close to each other, connected to same network) (here, also highlight the fact that how one computer will uniquely identify the other computer) - Different layers of the OSI model, protocols involved at each layer and name of data units at each layer. - Hardware devices involved in network, DLL and physical layer - Why the TCP/IP model used over OSI model - MSS and MTU - command to track and print the path traversed between different routers - Components of TCP header (Flags, window size, etc.) - Broadcast domain - ARP (indirect question based on it) and ICMP - How DHCP server is uniquely identified by the client , DHCP DORA process (and why each step of DORA process, such as request and acknowledgment are important) - router functions - Port number of HTTP, https, FTP, DHCP - How TCP/ IP connection is established (via 3-way handshake) and terminated - Different flag codes in TCP header - How remote connection is established through SSH - Subnetting? Numerical based on subnetting where I had to create 5 subnets and 32 hosts. - Concept of public and private IPs? Can two systems connected to same network have the same public IPs? How conflict is resolved in that case? - NAT? Mapping of public and private IPs, MAC address - Flow control and error control related questions - Difference between TCP/ UDP - When amazon.com is searched for, how the entire process works - Will I able to access amazon.com if I'm using private IP (say, if I'm a part of an organization). Or will I need a public IP as well to connect with it? - Concept of Proxy and firewall? Stateless and stateful firewalls? - If one person is able to access amazon.com website, while the other person is not, what can be the possible valid reasons for the 2nd person, provided the amazon.com website is working fine. Why clearing cookies also helps in reaching to a website? Part 2: Operating Systems - Virtual Memory - how I'm able to run a 7GB game with my 4 GB RAM? Why the game gets slow in such cases - which OS I primarily work on and why? - OS Boot process - Difference between buffer and cache - explain chmod command - remotely managing a system - if I have to run a management script in my system at a particular time each day, how will I proceed? What exactly goes inside cron jobs scripts - Difference between processes and threads, pages and fragments Part 3: Troubleshooting - If I'm unable to copy a file from my system and paste it, what can be the possible reasons and how will I troubleshoot (is it memory scarcity, storage scarcity or are there any other reasons as well?) P.S.: Some more interesting questions were also there that I do not remember The interviewer was very friendly and was ready to give some hints/ make you feel comfortable if you were stuck somewhere, although its always better if you drive the conversation on your own and are confident about your answer.
