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Quick-Revision Summary (All Chapters)

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Friends, use this one-page revision before an exam or interview. The must-remember points of every chapter are here – if a point isn't clear, read that chapter again.

Chapter Must-remember points
1 Networking IP = host, port = service; 22/80/443/3306/27017/3000/5000/8080; IPv4 32-bit, CIDR 2^(32−n), AWS reserves 5/subnet; IPv6 128-bit, :: once; RFC 1918 private ranges; NAT; auto public IP vs Elastic IP
2 OSI 7 layers (Physical → Application), PDUs bit/frame/packet/segment/data; TCP/IP 4 layers; TCP vs UDP; DNS → TCP → TLS → HTTP
3 Linux basics ls cd cp mv rm mkdir cat less tail; chmod 755/​644/​400, chown; useradd, usermod -aG; apt vs yum; ps top kill; nano/vim
4 Linux advanced grep find awk sed; pipes/redirection/tee; tar; service (+ systemctl enable)/journalctl; ip ss curl dig; df du lsblk mount fstab; cron; env vars; ssh scp rsync; bash scripts
5 EC2 AMI + type + key pair + SG + EBS; pricing models; SSH users; chmod 400; PuTTY/.ppk, MobaXterm, OpenSSH; stop vs terminate; best practices
6 Web servers Nginx (event-driven, proxy) vs Apache (modules, .htaccess); httpd vs apache2; web roots; nginx -t; firewalld/SELinux on CentOS
7 Static hosting Files → /var/www/mysite → 755/644 → server block / vhost → test → reload; restorecon; 403/404 troubleshooting
8 Configuring web servers Port → site (Host header) → folder → file; conf.d vs sites-available; default_server / first vhost wins; change root + <Directory>; semanage fcontext/port; redirects, server_​tokens off; backup → test → reload → curl
9 Domains & DNS Registrar ≠ name servers ≠ web host; resolver → root → TLD → authoritative, TTL; A, CNAME (not apex), MX, TXT, NS; Elastic IP first; GoDaddy A @ → EIP, CNAME www; Route 53 hosted zone + NS; subdomain = record + vhost; dig/nslookup; certbot -d for each name
10 Dynamic hosting MariaDB/MySQL install & secure; app user; PHP-FPM; Flask + Gunicorn + systemd; Express + pm2; reverse proxy; 502 fixes
11 Apps WordPress full install; Flask with Gunicorn + Nginx; Express with pm2 cluster + Nginx
12 Stacks LAMP, LEMP, MEAN, MERN; MongoDB official repo; SPA build served by Nginx + /api proxy
13 EBS gp3/gp2/io2/st1/sc1; snapshots; NVMe names; grow: modify → growpart → xfs_growfs/resize2fs; add: attach → mkfs → mount → fstab UUID nofail; detach safely
14 EC2 operations Elastic IP: allocate → associate → re-associate → release (5/region, charged even idle); AMI = snapshots + block device mapping + permissions, create/launch/copy/share, deregister + delete snapshots, golden AMI; snapshot restore (ro,nouuid), DLM; change instance type: stop → change → start, verify nproc/free -h/lscpu

Got it? From networking to EC2 operations – the whole journey is together here. Now redo every lab on your own.

A Last Word from Ravindra

Shabbas, mitranno — you have reached the end of the handbook! Now the real learning starts: rebuild every lab on your own, without looking at the book, until it feels natural. Break things, fix them, and write down what you learnt. Keep practising, keep asking "why", and all the best for your projects and interviews. Chala, bhetuya pudhchya session madhe (let's meet in the next session)!

— Ravindra Bagale, Cloud Trainer · linkedin.com/in/ravindra-bagale

Practice Tasks

About this scenario

Shivneri Schools is a education business in Junnar. Kavita Shinde looks after its IT and cloud work. They count money in INR and run their AWS resources in the ap-south-1 Region. In the tasks below you do real jobs for them using what this lesson teaches. All names, account IDs, IP addresses and numbers are made up for practice.

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Easy List your EC2 instances

Why: Before changing anything, see what is running and in which state.

What to do: Show details of all EC2 instances of Shivneri Schools in ap-south-1.

How:
  1. Read the task and decide which AWS service it is about.
  2. Write aws, then the service name, then the operation (the action word).
  3. Add each needed flag (--name) followed by its value from the task.
  4. Flags can be in any order. Click Check answer.

Easy List files in a bucket folder

Why: Check that the upload worked and see file sizes.

What to do: List the objects under s3://shivnerischool-invoices-2026/reports/.

How:
  1. Read the task and decide which AWS service it is about.
  2. Write aws, then the service name, then the operation (the action word).
  3. Add each needed flag (--name) followed by its value from the task.
  4. Flags can be in any order. Click Check answer.

Easy Create a bucket

Why: A bucket is the top-level container for your files in S3.

What to do: Create the bucket shivnerischool-invoices-2026 in ap-south-1.

How:
  1. Read the task and decide which AWS service it is about.
  2. Write aws, then the service name, then the operation (the action word).
  3. Add each needed flag (--name) followed by its value from the task.
  4. Flags can be in any order. Click Check answer.

Easy How many addresses in a /16?

Why: Picking a VPC size needs this count.

What to do: Shivneri Schools plans the VPC 10.64.0.0/16. How many IP addresses does it hold in total?

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Medium First usable IP for a server

Why: The first 4 addresses are reserved by AWS.

What to do: What is the first IP address a server can get in 10.64.20.0/24 on AWS?

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Medium Do these VPCs overlap?

Why: Peering fails when ranges overlap.

What to do: Can VPC 10.64.0.0/16 peer with VPC 10.64.128.0/17? Answer yes or no.

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Medium Find the VPC router address

Why: AWS reserves base+1 for the router.

What to do: Which address does AWS reserve for the VPC router in subnet 10.64.4.0/24?

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Medium Usable IPs in an AWS /24 subnet

Why: AWS keeps 5 addresses in every subnet.

What to do: How many addresses can Shivneri Schools use for servers in subnet 10.64.1.0/24 on AWS?

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Medium Usable IPs in a /28

Why: /28 is the smallest AWS subnet.

What to do: Subnet 10.64.9.0/28 on AWS. How many usable IPs?

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Hard Pick the smallest prefix

Why: Right-sizing saves address space.

What to do: A subnet must hold 100 servers on AWS. What is the largest prefix number (smallest subnet) that fits? Answer like /25.

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Hard Range of a /26

Why: Knowing the range stops subnets from overlapping.

What to do: Write the first and last address of 10.64.3.64/26 (like a.b.c.d - e.f.g.h).

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

Hard Split a /24 into two

Why: Public and private subnets often split one block.

What to do: Split 10.64.8.0/24 into two equal subnets. Write both CIDRs separated by a comma.

How:
  1. Write down the numbers the task gives you.
  2. Work it out step by step on paper.
  3. Type only the final answer in the box.
  4. Click Check answer.

See all practice tasks in the Task Hub →