I am preparing for the AWS Certified Security – Specialty (SCS-C02) exam and today is about two topics – Identity Federation and AWS Directory Services. These two play a key role in enabling seamless and secure access for users—whether they’re employees in a corporate office or app users signing in from mobile devices.

Let’s break them down using real-world analogies and then link them back to how they’re tested on the exam.

---

Part 1: Identity Federation – Granting Access Without Managing Credentials

Imagine the AWS environment is like a secure office building, and you need to decide how people can enter without giving everyone their own permanent key.

🎫 The 4 Types of Identity Federation Are Like Different Visitor Pass Systems

1. SAML 2.0 Federation – Work Badge from a Trusted Company

SAML is like letting employees from a trusted company (e.g., Azure AD, Okta, ADFS) enter your office by scanning their corporate badge. You don’t manage them directly, but you trust their employer.

📌 Use this when:

• Your organization uses ADFS/Okta/Azure AD
• You want SSO to the AWS Console and CLI
• You need role-based access via SAML assertions

📝 SCS Exam Tip: Expect a question where an enterprise user needs to use corporate credentials to log in to AWS—SAML is the correct solution.

---

2. Custom Identity Broker – You Build Your Own Reception Desk

You’re running a club and want to accept people with unique ID cards from various places. You verify their identity yourself and hand them a temporary access badge.

📌 Use this when:

• You have a custom login system
• You want to issue temporary credentials manually using STS
• You don’t want to use Cognito

📝 SCS Exam Tip: Know that this requires you to handle token validation and STS AssumeRole logic.

---

3. Web Identity Federation – Login via Google/Facebook

Visitors use their Google or Facebook login to get a temporary visitor badge at the front desk. With or without Cognito, you verify their identity and issue a short-term pass.

📌 Use this when:

• You’re building a web/mobile app
• Users sign in with Google, Facebook, Apple, etc.
• You want to allow access to AWS (e.g., S3, DynamoDB) using their identity

📝 SCS Exam Tip: Questions may show an app using social login needing temporary access to S3—this points to Web Identity Federation or Cognito Identity Pool.

---

4. AWS SSO (now IAM Identity Center) – Master Access System

This is like having a unified badge system across multiple office buildings (AWS Accounts). You assign users centralized access with specific permissions to each floor.

📌 Use this when:

• You have multiple AWS accounts or apps
• You want to manage access from one place
• You’re using an identity source like Azure AD or Okta

📝 SCS Exam Tip: Watch for multi-account access management scenarios; IAM Identity Center is the go-to solution.

---

Part 2: AWS Directory Services – Microsoft AD in the Cloud

Now let’s shift focus to AWS Directory Services, which is like setting up and managing Active Directory in the cloud. Think of this as managing your own campus library (user database) and deciding who can read, borrow, or manage the books (access resources).

---

📘 1. AWS Managed Microsoft AD – Full-Service Professional Library

You rent a full-service library in the cloud, fully staffed by AWS. It’s a complete, managed Microsoft AD environment—backups, patches, and monitoring are handled by AWS.

📌 Use this when:

• You need Group Policy, Kerberos, Trust relationships
• You want Active Directory-integrated apps
• You need to join EC2 to a domain

📝 SCS Exam Tip: If a question asks about trusts with on-prem AD, or Windows-based authentication, this is your choice.

---

📗 2. AD Connector – Forwarding Requests to On-Prem AD

You don’t want a new library; instead, you set up a forwarding desk that asks your campus’ main library to verify users. No data stored, no duplication.

📌 Use this when:

• You have an existing on-premises AD
• You need AWS services (e.g., Workspaces, RDS) to authenticate using your AD
• You don’t want to sync users to the cloud

📝 SCS Exam Tip: If you see a scenario with “reuse on-prem credentials” or “no data replication”, think AD Connector.

---

📙 3. Simple AD – A Small DIY Library

You build a small library yourself using basic tools (Samba). It’s lightweight and doesn’t support advanced features like trusts or schema extensions.

📌 Use this when:

• You have a small team
• You want basic directory needs
• It’s for testing, dev environments

📝 SCS Exam Tip: Pick this when the use case mentions cost-efficiency, small user base, and basic LDAP needs.

---

🎯 Final Exam-Focused Tips

Feature / Use Case	SAML	Custom Broker	Web Identity	IAM Identity Center	Managed AD	AD Connector	Simple AD
Use for AWS Console/CLI login	✅	✅	❌	✅	✅	✅	✅
Social login support	❌	✅	✅	✅ (via IdP)	❌	❌	❌
Trust with on-prem AD	❌	✅	❌	✅	✅	✅	❌
Microsoft AD full features	❌	❌	❌	❌	✅	❌	❌
Lightweight & cost-effective	❌	✅	✅	❌	❌	✅	✅

The analogies helped me clearly see when to use each type of Identity Federation and Directory Service in AWS, especially for exam scenarios.

Created By Yao Zhang Using Midjourney And ChatGPT