Week 4 Summary — April 20–24, 2026

AWS re/Start Cohort 3: Project CloudIgnite

What We Learned

Bash Scripting (Mon Apr 20)

Script basics: Shebang (#!/bin/bash), echo, read, variables, chmod +x, ./script.sh
Conditionals: if/elif/else/fi, comparison operators (-eq, -gt, -lt), file test operators (-f, -e, -d)
Loops: for (range/list), while, until, break, continue
Exit codes, command substitution ($(date)), printf
Lab: Backup script using tar -czvf with date-stamped filenames
Package management: yum (Amazon Linux), apt (Ubuntu/Debian)
AWS CLI installation: Download, unzip, install, configure with aws configure

Networking & VPC (Tue Apr 21 – Fri Apr 24)

OSI Model (7 layers): Application, Presentation, Session, Transport, Network, Data Link, Physical
Amazon VPC: Logically isolated virtual network; public vs private subnets; CIDR blocks; Internet Gateway; VPC Peering
Protocols: TCP (connection-oriented, 3-way handshake) vs UDP (connectionless, fast)
IP addressing: IPv4 (32-bit), IPv6 (128-bit), public vs private IP, DHCP, Elastic IP
Subnetting: CIDR notation, formula for host count
Port numbers: 22 (SSH), 80 (HTTP), 443 (HTTPS), 20/21 (FTP), 53 (DNS), 3389 (RDP)
NAT Gateway: Outbound-only internet for private subnets; requires Elastic IP
Security Groups: Instance-level, stateful, default deny all inbound, allow-only rules
NACLs: Subnet-level, stateless, both allow and deny rules
Labs 261–264: Elastic IP, VPC build, VPC troubleshooting, Security Groups & NACLs

Key CLF-C02 Connections

VPC, subnets (public/private), Security Groups, NACLs, Internet Gateway, NAT Gateway, Route Tables, CIDR blocks, Elastic IP, TCP vs UDP, key port numbers

Daily Notes

April 20 — Bash Scripting, Linux Software Management, AWS CLI Installation
April 21 — System Logs, Bash Challenge Lab, Intro to Networking & OSI Model
April 22 — Networking Fundamentals, VPC, TCP/UDP, IP Addressing, Ports
April 23 — IP Addressing, Elastic IP, VPC Fundamentals, CIDR Calculation
April 24 — NAT Gateway, Route Tables, Security Groups, NACLs, VPC Labs

What We Learned

Bash Scripting (Mon Apr 20)

Script basics: Shebang (#!/bin/bash), echo, read, variables, chmod +x, ./script.sh

Conditionals: if/elif/else/fi, comparison operators (-eq, -gt, -lt), file test operators (-f, -e, -d)

Loops: for (range/list), while, until, break, continue

Exit codes, command substitution ($(date)), printf

Lab: Backup script using tar -czvf with date-stamped filenames

Package management: yum (Amazon Linux), apt (Ubuntu/Debian)

AWS CLI installation: Download, unzip, install, configure with aws configure

Networking & VPC (Tue Apr 21 – Fri Apr 24)

OSI Model (7 layers): Application, Presentation, Session, Transport, Network, Data Link, Physical

Amazon VPC: Logically isolated virtual network; public vs private subnets; CIDR blocks; Internet Gateway; VPC Peering

Protocols: TCP (connection-oriented, 3-way handshake) vs UDP (connectionless, fast)

IP addressing: IPv4 (32-bit), IPv6 (128-bit), public vs private IP, DHCP, Elastic IP

Subnetting: CIDR notation, formula for host count

Port numbers: 22 (SSH), 80 (HTTP), 443 (HTTPS), 20/21 (FTP), 53 (DNS), 3389 (RDP)

NAT Gateway: Outbound-only internet for private subnets; requires Elastic IP

Security Groups: Instance-level, stateful, default deny all inbound, allow-only rules

NACLs: Subnet-level, stateless, both allow and deny rules

Labs 261–264: Elastic IP, VPC build, VPC troubleshooting, Security Groups & NACLs

Key CLF-C02 Connections

VPC, subnets (public/private), Security Groups, NACLs, Internet Gateway, NAT Gateway, Route Tables, CIDR blocks, Elastic IP, TCP vs UDP, key port numbers

Daily Notes

April 20 — Bash Scripting, Linux Software Management, AWS CLI Installation

April 21 — System Logs, Bash Challenge Lab, Intro to Networking & OSI Model

April 22 — Networking Fundamentals, VPC, TCP/UDP, IP Addressing, Ports

April 23 — IP Addressing, Elastic IP, VPC Fundamentals, CIDR Calculation

April 24 — NAT Gateway, Route Tables, Security Groups, NACLs, VPC Labs