Recap day. Testing everything from Day 0 through Day 7 with quick single-line answers, plus a hands-on nslookup practical to try yourself.
Cloud Computing & Service/Deployment Models
Q: What is Cloud Computing?
A: Accessing computing resources remotely over the internet instead of managing infrastructure on-premises.
Q: What does NIST define cloud computing as?
A: A model for on-demand network access to a shared pool of configurable computing resources.
Q: What are the three main service models?
A: IaaS, PaaS, SaaS.
Q: In IaaS, who manages the OS and runtime?
A: You do — the vendor only provides the infrastructure.
Q: In PaaS, who manages the OS and runtime?
A: The vendor does — you only manage your application and data.
Q: In SaaS, what do you manage?
A: Nothing — you just use the finished application.
Q: What are the four deployment models?
A: Public, Private, Hybrid, Community.
Q: Which deployment model is dedicated to one organization?
A: Private Cloud.
Q: Which deployment model mixes public and private?
A: Hybrid Cloud.
Q: Which deployment model serves a group of organizations with shared concerns?
A: Community Cloud.
Client-Server Architecture
Q: What is a client?
A: A device or application that requests services from a server.
Q: What is a server?
A: A system that provides services or resources to clients.
Q: What defines 1-tier architecture?
A: Everything — UI, logic, database — lives on a single machine.
Q: What defines 2-tier architecture?
A: The client talks directly to the database server.
Q: What defines 3-tier architecture?
A: The client talks to an app server, which talks to the database — no direct client-to-database access.
Q: Why is 3-tier architecture more secure than 2-tier?
A: The client never has direct access to the database.
Data Centers, Virtualization & Hypervisors
Q: What is a classic data center made up of?
A: Compute, storage, network, application, and DBMS.
Q: What is virtualization?
A: Abstracting physical resources so they function as logical/virtual resources.
Q: What problem does virtualization solve?
A: Underutilization and complex management caused by dedicating resources per business unit.
Q: What is a hypervisor?
A: The software layer that creates and manages virtual machines.
Q: What's the difference between Type 1 and Type 2 hypervisors?
A: Type 1 runs directly on hardware; Type 2 runs on top of an existing OS.
Q: What is a virtual machine?
A: A software-based emulation of a physical computer, sharing hardware but running its own OS.
OSI Model
Q: How many layers does the OSI model have?
A: 7.
Q: What's a mnemonic to remember the OSI layers?
A: "All People Seem To Need Data Processing."
Q: Which OSI layer handles encryption and data formatting?
A: Presentation layer.
Q: Which OSI layer manages sessions between devices?
A: Session layer.
Q: Which OSI layer handles MAC addressing?
A: Data Link layer.
Q: Which OSI layer is the actual physical medium (cables, Wi-Fi)?
A: Physical layer.
DNS, Load Balancers, Firewalls & Protocols
Q: What does DNS stand for?
A: Domain Name Server.
Q: Where is Local DNS stored on a machine?
A: In /etc/host.
Q: What does the Root Name Server identify?
A: The TLD (Top Level Domain).
Q: What is an SOA record?
A: Start of Authority — the record holding the actual IP for a domain.
Q: What does a Firewall do?
A: Stops unauthorized access by allowing or denying traffic based on rules.
Q: What does a Load Balancer do?
A: Distributes incoming traffic across multiple servers.
Q: What is the Round Robin method?
A: Equally distributing traffic across servers in rotation.
Q: What port does HTTP use by default?
A: Port 80.
Q: What port does HTTPS use by default?
A: Port 443.
Q: What port does SSH use?
A: Port 22.
Q: What port does RDP use?
A: Port 3389.
Q: Why is HTTP not secure?
A: It sends data in plain text, readable by anyone intercepting it.
Q: What does TCP do?
A: Establishes a reliable, tracked connection between two hosts.
Q: How is UDP different from TCP?
A: Faster, but connectionless and not reliable.
Q: What status code means success?
A: 200.
Q: What status code means "page not found"?
A: 404.
Q: What status code means "internal server error"?
A: 500.
nslookup Command Practical
nslookup is a command-line tool that resolves a domain name to its IP address — a hands-on way to see DNS resolution actually happen.
Try it yourself:
- Open Command Prompt
- Type
nslookup - Enter any domain (e.g., facebook.com, google.com) to see its resolved IP
- Try entering an IP address directly to see the reverse — it'll return the hostname behind that IP
(Screenshot of my own nslookup practical run attached below as proof.)
Where to read & follow
- GitHub: https://github.com/sr-palatasingh/AWS-DevOps-Blog/tree/main/posts
- Hashnode: https://sr-palatasingh.hashnode.dev/series/aws-devops-blog
- LinkedIn: https://www.linkedin.com/in/soumyaranjan-palatasingh/
Coming up next: Moving into AWS.
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