Interview preparation for Network Engineer L1.

  DNS(DOMAIN NAME SYSTEM)   Table of Contents:- 1.  Introduction. 2. Name Space. 3. Why do we need DNS. 4. Working or Flow of DNS.  5. DNS Records.   6.     Interview  questions for Network Engineer L1 asked from DNS.   l   INTRODUCTION:-   - DNS resolves IP address into name. User puts the name of the website into the address bar and DNS resolves its IP address so that the user can access the website. - It uses client-server model. - It uses port 53 of TCP and UDP. I’ll explain this afterwards that in which condition it uses TCP-53 and in which condition it uses UDP-53. - It uses 3 messages- 1. Query - From client to server. à Its of 2 types- Recursive (Provides complete answer) and Iterative (Provides partial answer). 2. Reply - From server to client. 3. Update - From server to client.     l   NAME SPACE:-   A namespace in DNS (Domain Name System) refers to t...

  DHCP (DYNAMIC HOST CONFIGURATION PROTOCOL)     Table of Contents:-      1.    Introduction. 2.    Why do we need DHCP. 3.    What is DHCP. 4.    How does DHCP work. 5.    DHCP Relay Agent. 5.1.       Why do we need Relay Agent. 5.2.       How does Relay Agent work. 6.    Messages of DHCP. 7.    Questions asked from DHCP in the Network Engineer L1 Interview.         l INTRODUCTION:-   Dhcp is a protocol used to provide IPs to the host devices in a dynamic manner. In Dhcp we create a pool of IPs on the Dhcp server, the host devices reach out to the dhcp server to ask for a IP address to which dhcp server responds with providing an IP address to the host from the Dhcp pool. - Dhcp uses UDP protocol and port 67/68 (67 for server and 68 for client). - It works on Appli...