What is actually VPC peering?

A virtual private cloud (VPC) is a virtual network dedicated to your AWS account. It is logically isolated from other virtual networks in the AWS Cloud. You can launch AWS resources, such as Amazon EC2 instances, into your VPC.

A VPC peering connection is a networking connection between two VPCs that enables you to route traffic between them using private IPv4 addresses or IPv6 addresses. Instances in either VPC can communicate as if they are within the same network. You can create a VPC peering connection between your VPCs or a VPC in another AWS account. The VPCs can be in different Regions (also known as an inter-Region VPC peering connection).

Pricing for a VPC peering connection

There is no charge to create a VPC peering connection. All data transfer over a VPC Peering connection within an Availability Zone (AZ) is free. Charges apply for data transfer over VPC Peering connections that cross Availability Zones and Regions.

LAB: How to create VPC peering?

Note: In this lab session we are going to create two different instances and try to connect the private IP of one instance by using another instance.

Step 1: Create a First VPC

1. Goto Your VPCs and Create vpc1:

   • Resources to create VPC only

   • Name tag - optional eg. vpc1

   • IPv4 CIDR eg. 10.0.0.0/16

     Create VPC with all other default

2. Goto Subnets and create subnet for vpc1 as:

   • VPC ID select vpc1

   • Scroll down to Subnet settings

     • Subnet name vpc1subnet

     • Availability Zone anyone your choice eg. us-east-1a

     • IPv4 CIDR block: 10.0.0.0/24

       and Create subnet

3. Goto Internet gateways and Create internet gateway as:

   • In Internet gateway setting

     • Name tag: IGvpc1

     • Create internet gateway

   • Click on the popup Attach to VPC

     • Available VPCs -> select a VPC : vpc1

       Attach internet gateway

4. Goto Route tables and create a route table for vpc1

   • Route table settings

     • Name: route_vpc1

     • VPC: Select vpc1

       Create route table

Step 2: Similarly, Create a Second VPC

1. Goto Your VPCs and Create vpc2:

   • Resources to create VPC only

   • Name tag - optional eg. vpc2

   • IPv4 CIDR eg. 194.0.0.0/16

     Create VPC with all other default

2. Goto Subnets and create subnet for vpc2 as:

   • VPC ID select vpc2

   • Scroll down to Subnet settings

     • Subnet name vpc2subnet

     • Availability Zone anyone your choice eg. us-east-1b

     • IPv4 CIDR block: 194.0.0.0/24

       and Create subnet

3. Goto Internet gateways and Create internet gateway as:

   • In Internet gateway setting

     • Name tag: IGvpc2

     • Create internet gateway

   • Click on the popup Attach to VPC

     • Available VPCs -> Select a VPC : vpc2

       Attach internet gateway

4. Goto Route tables and create a route table for vpc2

   • Route table settings

     • Name: route_vpc2

     • VPC: Select vpc2

       Create route table

Step 3: Now, Create a peering connection:

• Goto Peering connections by scrolling down on the left side of the bar

• Click on Create peering connection

• Peering connection settings

  • Name: peerVPC

  • VPC ID (Requester): Select vpc1

  • VPC ID (Accepter): Select vpc2

    Create peering connection

• Select peerVPC -> Actions -> Accept request

Step 4: Last thing to do Modify a route table:

• Goto Route tables

• Select route_vpc1

  • Click on Subnet associations -> Edit subnet associations

    • Available subnets: Select vpc1subnet and Save associations

  • Click on Routes -> Edit routes -> Add route

    Destination: 0.0.0.0/0 Targe: Internet Gateway -> (IGvpc1)

    Destination: 194.0.0.0/16 Targe: Peering Connection -> (peerVPC)

• Similarly, Select route_vpc2

  • Click on Subnet associations -> Edit subnet associations

    • Available subnets: Select vpc2subnet and Save associations

  • Click on Routes -> Edit routes -> Add route

    Destination: 0.0.0.0/0 Targe: Internet Gateway -> (IGvpc2)

    Destination: 10.0.0.0/16 Targe: Peering Connection -> (peerVPC)

Step 4: Now, Smile all VPC work was done. Next goto EC2 -> instances

1. For First Instance

   • Launch instances

   • Name: server1

   • select the existing key or create new

   • Network settings -> Edit

     • VPC: Select vpc1

     • Subnet: vpc1subnet

     • Auto-assign public IP: enable

     • Leave Create a security group checked

     • Leave all default and Launch instance

2. For Second Instance

   • Launch instances

   • Name: server2

   • select the existing key or create new

   • Network settings -> Edit

     • VPC: Select vpc2

     • Subnet: vpc2subnet

     • Auto-assign public IP: desable

     • Leave Create a security group checked

     • Add security group rule

       • Type: All traffic

       • Source type: Anywhere

         [ Note: It is not good practice to set the type All traffic just for basic understanding ]

     • Leave all default and Launch instance

Step 4: Connect the EC2 instance

• After the Status check 2/2 checks passed

• Select the EC2 instance with private IP i.e. server2 and copy private IP

• Then, Select the EC2 instance with public IP i.e. server1

• And Click on Connect at the top, again Connect

• Now, you reached this window:

• Here, perform the following commands:

    sudo su
  

    ping <private-ip-you-copied>
  

  • You get the following output CTRL+C to exit

Don't forget to terminate all the services you started...

Thanks for your time