AWS Solutions Architect · Module 3 · Day 9
Operating Systems & a Windows EC2 Instance
Today you use everything from Day 8 to launch a real Windows server and log in to it. First, a quick look at operating systems; then a step-by-step lab with RDP; then the fixes for the problems everyone hits the first time.
In this session
- What an operating system is
- GUI vs CLI, client vs server OS
- Windows vs Linux on EC2
- Lab: launch a Windows instance
- Lab: get the password and connect with RDP
- Troubleshooting and safer access
01What is an operating system?
Operating System (OS): the interface between the user and the hardware.
| Type | Meaning | Examples |
|---|---|---|
| GUI | windows, icons, mouse | Windows, macOS |
| CLI | typing commands | Linux on servers |
| Client OS | for laptops and desktops | Windows 10, Windows 11 |
| Server OS | for hosting websites, databases, Active Directory | Windows Server 2025, 2022 |
| Windows | Linux | |
|---|---|---|
| Super-user | Administrator | root (on EC2 you log in as ec2-user/ubuntu, then use sudo) |
02Windows vs Linux on EC2
| Linux | Windows | |
|---|---|---|
| Login method | SSH | RDP |
| Port | 22 | 3389 |
| Username | ec2-user / ubuntu | Administrator |
| Key pair is used to… | log in directly | decrypt the password |
| Screen | terminal (text) | full desktop |
| Cost | lower | higher (Windows licence included in the price) |
03Lab: launch a Windows instance
Demo · Do it yourself
04Lab: connect with RDP
Demo · Get the password and connect
Note: Windows Server allows two admin RDP sessions at the same time by default (desktop Windows allows one). More users need Remote Desktop Services licences.
05Troubleshooting and safer access
| Problem | Likely cause | Fix |
|---|---|---|
| RDP times out | security group doesn’t allow 3389 from your IP | add inbound rule RDP, TCP 3389, source My IP |
| Worked yesterday, not today | your home/office public IP changed | update the rule with your new IP |
| Wrong address after restart | public IP changed on stop/start | use the new IP or an Elastic IP |
| “Password not available yet” | Windows still setting up | wait 4–5 minutes |
| Can’t decrypt password | wrong .pem, or not RSA | use the key chosen at launch; RSA for Windows |
| Very slow desktop | t3.micro has 1 GiB RAM | fine for practice; use t3.medium+ for real work |
- Never leave RDP (3389) open to
0.0.0.0/0: it is one of the most attacked ports. - Best: Systems Manager Fleet Manager (RDP in the browser) needs no open port and no public IP, and every session is logged.
- Windows AMIs are License Included; bringing your own licence (BYOL) usually needs Dedicated Hosts.
🎯 Exam corner
- Windows → RDP, 3389; Linux → SSH, 22.
- Windows admin password → decrypt with the key pair’s private key.
- Access without open ports or bastion hosts → Systems Manager (Session/Fleet Manager).
06Summary
- OS = interface between user and hardware; GUI vs CLI; client vs server OS.
- Windows EC2: RDP, port 3389, Administrator, RSA key pair decrypts the password.
- Connect with
mstsc(or MobaXterm) using the public IP. - Restrict 3389 to My IP or use Fleet Manager; terminate after practice.
07Quick quiz
1. Which protocol and port connect to Windows EC2?
2. How do you get the Administrator password?
3. Key pair type for Windows?
4. RDP times out. First thing to check?
5. Why is Windows EC2 more expensive than Linux?
08References
Created by Ajeetkumar