AWS CSA
  • Introduction
  • 1. AWS Overview
    • 1.1 AWS global Infrastructure
    • 1.2 Networking and Content Delivery
    • 1.3 Computing
    • 1.4 Storage
    • 1.5 Databases
    • 1.6 Migration Services
    • 1.7 Analytics
    • 1.8 Security and Identity
    • 1.9 Management Tools
    • 1.10 Application Services
    • 1.11 Developer Tools
    • 1.12 Mobile Services
    • 1.13 Desktop and App Streaming
    • 1.14 Artificial Intelligence
    • 1.15 Messaging
  • 2. IAM - Identity Access Management
    • 2.1 IAM Introduction
    • 2.2 IAM Labs
    • 2.3 Create a billing alart
    • 2.4 IAM Conclusion
  • 3. S3 - Simple Storage Service
    • 3.1 S3 Introduction
    • 3.2 S3 Labs
    • 3.3 Version Control Labs
    • 3.4 Cross Region Replication
    • 3.5 Life Cycle Management
    • 3.6 CloudFront
    • 3.7 CloudFront Labs
    • 3.8 S3 Security and Encryption
    • 3.9 Storage Gateway
    • 3.10 Snowball
    • 3.11 Snowball Labs
    • 3.12 S3 Transfer Acceleration
    • 3.13 Create a static web page using S3
    • 3.14 Storage Summary
  • 4. EC2 - Elastic Compute Cloud
    • 4.1 EC2 Introduction I
    • 4.2 EC2 Introduction II
    • 4.3 EC2 Lab 1
    • 4.4 EC2 Lab 2
    • 4.5 Security Groups Lab
    • 4.6 Upgrade EBS Volume Types - Lab1
    • 4.7 Upgrade EBS Volume Types - Lab2
    • 4.8 RAID, Volumes & Snapshots
    • 4.9 Create An AMI - Lab
    • 4.10 AMI's EBS Root Volumes vs. Instance Store
    • 4.11 Elastic Load Balancer & Health Check - Lab
    • 4.12 CloudWatch EC2 - Lab
    • 4.13 The AWS Command Line & EC2
    • 4.14 Using IAM Roles with EC2
    • 4.15 S3 CLI & Regions
    • 4.16 Using Bootstrap Scripts
    • 4.17 EC2 Instance Metadata
    • 4.18 Launch Configurations & Auto Scaling Groups
    • 4.19 EC2 Placement Groups - Exam Must Know
    • 4.20 Elastic File System (EFS) Lab
    • 4.21 Lambda Concepts
    • 4.22 Build A Serverless Webpage Using API Gateway & Lambda
    • 4.23 Use Polly to Pass Your Exam - Lab of a Serverless Application
    • 4.24 Use Polly to Pass Your Exam - Lab of a Serverless Application
    • 4.25 EC2 - Summary & Exam Tips
  • 5. Route53
    • 5.1 DNS 101
    • 5.2 Route53 - Register A Domain Name - Lab
    • 5.3 Setup Our EC2 Instances - Lab
    • 5.4 Routing Policies - Lab
  • 6. Databases on AWS
    • 6.1 Databases 101
    • 6.2 Launching an RDS Instance - Lab
    • 6.3 RDS - Backups, Multi-AZ & Read Replicas
    • 6.4 DynamoDB
    • 6.5 Redshift
    • 6.6 ElastiCache
    • 6.7 Aurora
    • 6.8 Database Summary
  • 7. VPC
    • 7.1 VPC Overview
    • 7.2 VPC Lab - Part 1
    • 7.3 VPC Lab - Part 2
    • 7.4 NAT Instances & NAT Gateways
    • 7.5 Network Access Control Lists vs. Security Groups
    • 7.6 Load Balancers & Custom VPCs
    • 7.7 VPC Flow Logs
    • 7.8 NATs vs. Bastions
    • 7.9 VPC End Points
    • 7.10 VPC Clean Up
    • 7.11 VPC Summary
  • 8. Application Services
    • 8.1 SQS - Simple Queue Service
    • 8.2 SWF - Simple Workflow Service
    • 8.3 SNS - Simple Notification Service
    • 8.4 Elastic Transcoder
    • 8.5 API Gateway
    • 8.6 Kinesis 101
    • 8.7 Kinesis Streams Lab
    • 8.8 Application Services Summary
  • 9. White Paper Reviews
    • 9.1 Overview of AWS
    • 9.2 Overview of Security Processes - Part 1
    • 9.3 Overview of Security Processes - Part 2
    • 9.4 Risk & Compliance Whitepaper
    • 9.5 Storage Options in the Cloud Whitepaper
    • 9.6 Architecting For The Cloud Best Practices Whitepaper
  • 10. Well Architected Framework
    • 10.1 Introduction of Well Architected Framework
    • 10.2 Pillar One - Security
    • 10.3 Pillar Two - Reliability
    • 10.4 Pillar Three - Performance
    • 10.5 Pillar Four - Cost Optimization
    • 10.6 Pillar Five - Operational Excellence
    • 10.7 Well Architected Framework - Summary
  • 11. Additional Exam Tips
    • 11.1 Exam Tips Based On Student Feedback
    • 11.2 Consolidated Billing
    • 11.3 AWS Organizations - Lab
    • 11.4 Cross Accounts Access
    • 11.5 Resource Groups & Tagging
    • 11.6 VPC Peering & ClassicLink
    • 11.7 Direct Connect
    • 11.8 Security Token Service
    • 11.9 Active Directory Integration
    • 11.10 Workspaces
    • 11.11 ECS - Part 1 - What is Docker
    • 11.12 ECS - Part 2 - What is ECS
    • 11.13 CloudFormation - A Brief Introduction
    • 11.14 Step Functions - A Brief Introduction
  • 12. Practice Tests Questions Summary
    • 12.1 Whizlabs - Free Test
    • 12.2 Whizlabs - Diagnosis Test
    • 12.3 Whizlabs - Practice Test I
    • 12.4 Whizlabs - Practice Test II
    • 12.5 Whizlabs - Practice Test III
    • 12.6 Whizlabs - Practice Test IV
    • 12.7 Whizlabs - Practice Test V
    • 12.8 Whizlabs - Practice Test VI
    • 12.9 Whizlabs - Practice Test VII
    • 12.10 Whizlabs - Section Tests - Part 1
    • 12.11 Whizlabs - Section Tests - Part 2
    • 12.12 Udemy - Final Quiz
  • 13. The Real World - Creating a fault tolerant Word Press Site
    • 13.1 Getting Setup
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  • VPC Peering
  • ClassicLink

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  1. 11. Additional Exam Tips

11.6 VPC Peering & ClassicLink

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Last updated 4 years ago

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VPC Peering

VPC Peering is simply a connection between two VPCs that enables you to route traffic between them using private IP addresses. Instances in either VPC can communicate with each other as if they are within the same network. Instances in different VPCs can communicate with each other use internal IP addresses spaces without having to go out through the Internet. You can create a VPC peering connection between your own VPCs, or with a VPC in another AWS account. The VPCs can be in different regions (also known as an inter-region VPC peering connection).

AWS uses the existing infrastructure of a VPC to create a VPC peering connection. It is neither a gateway nor a VPN connection, and doesn't rely on a separate piece of physical hardware. There is no single point of failure for communication or a bandwidth bottleneck.

A VPC peering example:

However, if we change the IP address range of VPC B,

Transitive Peering is NOT supported. Instances in VPC A cannot communicate with the instances in VPC C directly. You have to peer VPC A with VPC C. You've always got to have a one to one peering connection.

VPC Peering Limitations:

  • You can NOT create a VPC peering connection between VPCs that have matching or overlapping CIDR blocks.

  • VPC peering does NOT support transitive peering relationships.

ClassicLink

Up until now, you learnt how to got a Virtual Private Cloud (VPC) which has lots of benefits and advantages, but the EC2 instances that were not running within a VPC (commonly known as EC2-Classic) had to use public IP addresses or tunneling to communicate with AWS resources in a VPC. They could not take advantage of the higher throughput and lower latency connectivity available for inter-instance communication. This model also resulted in additional bandwidth charges and has some undesirable security implications.

ClassicLink allows you to link your EC2-Classic instance to a VPC in your account, within the same region. This allows you to associate the VPC security groups with the EC2-Classic instance, enabling communication between your EC2-Classic instance and instances in your VPC using private IPv4 addresses. ClassicLink removes the need to make use of public IPv4 addresses or Elastic IP addresses to enable communication between instances in these platforms.

ClassicLink is available to all users with accounts that support the EC2-Classic platform, and can be used with any EC2-Classic instance. There is no additional charge for using ClassicLink. Standard charges for data transfer and instance usage apply. Go to VPC, select a VPC and right click, choose Enable ClassicLink.

It is not going to work because A, B got the same internal address range, so they share overlapping CIDR block. VPC A and VPC B are not able to peer, so they are not able to communicate with each other.