Transit gateway route table and check for the result

For Transit Gateway Attachment to work, we need to create a route table for them. In this section, you will create a route table and check if the systems are connected to each other or not.

1. Access Transit Gateway route table
2. Select Transit Gateway and Create Transit Gateway route table.
3. Select route table which just created -> Associatons -> Create Associations
4. Select Attachment -> Create Associations

• Do the same with other attachments

5. Continue with that route table -> Propagations -> Create Propagations
6. Select Attachment -> Create Propagations

• Do the same with other attachments

Next, we going to config route table to add route from transit gateway

1. Access route table -> select route table -> routes -> edit routes
2. With Public route table, we add route and config it

• Fill IP address 172.12.0.0
• Select Transit Gateway.
• Select Transit Gateway which is created.
• Save changes

3. With Private route table, we add route and config it.

• Fill IP address 0.0.0.0/0
• Select Transit Gateway.
• Select Transit Gateway which is created.
• Save changes
• Do the same with other private route table

Test the connection between VPCs

• We will SSH from EC2 public to EC2 private to test the connection between private EC2

ssh -i "file-name" ec2-user@<private ec2 ip>

• After accessed into EC2 private 1 we ping to EC2 private 2 and 3

Congratulations. The EC2 Instances in your VPCs were able to connect through the Transit Gateway. For monitor transit gateways, you can reference this article CloudWatch metrics