AWS networking is one of the most challenging topics for certification candidates. It's also one of the most heavily tested. Here's how to master it.
Why Networking Is Hard
Networking concepts are challenging because:
- Abstract concepts - Hard to visualize without hands-on experience
- Many components - VPCs, subnets, route tables, gateways, security groups, NACLs...
- Interconnections - Understanding how pieces work together
- Edge cases - Knowing when to use what
But with the right approach, you can master it.
The Core Networking Services
VPC (Virtual Private Cloud)
The foundation of AWS networking. You must understand:
Subnets
- Public vs private subnets
- CIDR blocks and IP addressing
- Availability Zone placement
Gateways
- Internet Gateway (public access)
- NAT Gateway (private subnet outbound)
- Virtual Private Gateway (VPN connections)
- Transit Gateway (connecting VPCs)
Route Tables
- How routes are evaluated
- Main vs custom route tables
- Route priority
Security
- Security Groups (stateful, instance-level)
- Network ACLs (stateless, subnet-level)
- When to use each
Route 53
AWS DNS service with routing policies:
- Simple routing - Single resource
- Weighted routing - Percentage-based distribution
- Latency routing - Lowest latency region
- Failover routing - Active-passive failover
- Geolocation routing - By user location
- Geoproximity routing - By distance with bias
- Multivalue answer - Multiple healthy resources
Know the differences! This is heavily tested.
CloudFront
Content delivery network (CDN):
- Edge locations vs regional edge caches
- Origin types (S3, ALB, custom)
- Cache behaviors
- Signed URLs vs signed cookies
- Origin Access Identity (OAI)
Other Networking Services
- Elastic Load Balancing (ALB, NLB, CLB differences)
- Direct Connect (dedicated network connection)
- AWS PrivateLink (private connectivity to services)
- VPC Peering (connecting VPCs)
Study Strategy for Networking
Step 1: Visual Learning
Networking is visual. Use diagrams.
Draw these scenarios:
- Basic VPC with public and private subnets
- Multi-AZ deployment with load balancer
- VPN connection to on-premises
- Multi-VPC architecture with Transit Gateway
Free tools:
- draw.io
- Lucidchart (free tier)
- AWS Architecture Icons
Step 2: Hands-On Labs
You cannot learn networking from reading alone.
Essential labs:
- Create a VPC from scratch (not the wizard)
- Set up public and private subnets
- Configure NAT Gateway
- Create security groups with specific rules
- Test connectivity between subnets
Use AWS Free Tier - Most networking components are free
Step 3: Focus on Common Scenarios
Exams test scenario-based questions:
Scenario 1: "Application needs to access S3 from private subnet"
- Answer: VPC Endpoint (Gateway type for S3)
Scenario 2: "Users in Asia experiencing slow load times"
- Answer: CloudFront with regional edge caches
Scenario 3: "Need to connect to on-premises with low latency"
- Answer: Direct Connect (or VPN for lower cost)
Scenario 4: "Instances can reach internet but internet can't reach them"
- Answer: NAT Gateway in public subnet
Step 4: Master Security Groups vs NACLs
This is tested on every AWS exam:
| Feature | Security Groups | NACLs |
|---|---|---|
| Level | Instance | Subnet |
| State | Stateful | Stateless |
| Rules | Allow only | Allow and Deny |
| Evaluation | All rules | Order matters |
| Default | Deny all inbound | Allow all |
Step 5: Route 53 Deep Dive
Create flashcards for each routing policy:
- Simple: Single resource, no health checks
- Weighted: A/B testing, gradual migration
- Latency: Global users, best performance
- Failover: DR scenarios, health checks required
- Geolocation: Compliance, localized content
- Geoproximity: Fine-tuned location control
- Multivalue: Simple load balancing with health checks
Common Exam Questions
VPC Questions
"A company needs instances in a private subnet to download software updates from the internet. What's the most cost-effective solution?"
- Answer: NAT Gateway (or NAT Instance for lower cost)
"How do you allow an EC2 instance to resolve DNS hostnames?"
- Answer: Enable DNS hostnames and DNS resolution in VPC
Route 53 Questions
"A company wants to route 70% of traffic to us-east-1 and 30% to eu-west-1. Which policy?"
- Answer: Weighted routing
"Users should be directed to the nearest healthy region. Which policy?"
- Answer: Latency routing with health checks
CloudFront Questions
"How do you restrict S3 bucket access to only CloudFront?"
- Answer: Origin Access Identity (OAI) or Origin Access Control (OAC)
"How do you serve different content based on device type?"
- Answer: CloudFront cache behaviors with device detection
Hands-On Lab Checklist
Complete these before your exam:
- Create VPC with public and private subnets
- Set up Internet Gateway and route tables
- Configure NAT Gateway
- Create security groups with specific rules
- Set up VPC endpoints for S3
- Create an ALB distributing traffic
- Configure Route 53 with health checks
- Set up CloudFront distribution
Quick Reference Cheat Sheet
CIDR Blocks
- /16 = 65,536 IPs (largest VPC)
- /24 = 256 IPs (common subnet)
- /28 = 16 IPs (smallest subnet)
Port Numbers
- 22 = SSH
- 80 = HTTP
- 443 = HTTPS
- 3306 = MySQL
- 5432 = PostgreSQL
Gateway Types
- Internet Gateway = Public access
- NAT Gateway = Private outbound
- VPN Gateway = On-premises VPN
- Transit Gateway = VPC hub
Identify Your Networking Gaps
Networking is the #1 area where learners waste time - either studying concepts they already know or missing critical gaps they didn't realize they had.
StudyTech's AI identifies your exact networking gaps:
- Know which VPC concepts you've mastered and which need work
- Get personalized practice questions on your specific weak spots
- Track your readiness with a real-time score
- Smart flashcards for Route 53 routing policies (the most-missed topic)
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