Jul 14, 2025

Jul 14, 2025

Setup VPC Peering using Rebase in minutes

This comprehensive tutorial demonstrates how Rebase AI eliminates the complexity of setting up VPC peering in AWS. The post walks through a complete end-to-end scenario: creating two VPCs with non-overlapping CIDR blocks, deploying EC2 instances, configuring SSM access, and establishing VPC peering connections - all through natural language commands.

Mubbashir Mustafa

Mubbashir Mustafa

Co-founder

Mubbashir Mustafa

Mubbashir Mustafa

If you work with multiple VPCs in AWS, sooner or later you’ll want them to talk to each other. Sometimes you split workloads into different VPCs to keep things separate, or your team is working across different AWS accounts. AWS lets you connect those VPCs with something called VPC peering. That way, the traffic stays private, never hitting the public internet. But if you’ve ever tried to set this up by hand, you know it can be a hassle. You have to make sure the CIDR blocks do not overlap, the route tables are right, and both sides accept the connection. Missing one step means your setup just doesn’t work.

With Rebase, you can do all of this just by telling the agent what you want. Here’s how it works from start to finish.

We’ll start by spinning up two VPCs, both with private subnets and non-overlapping CIDR blocks. This is important, because VPC peering won’t work if the address ranges clash.

![This screenshot shows two separate VPCs with their own private subnets and unique CIDR blocks. The network diagrams are side by side

The AI agent will put together a plan and show you exactly what it’s about to do. If it needs more info, it’ll ask before moving ahead.

Here, the agent prompts for any extra details it needs to finish building the plan, like subnet ranges or region.

Once you answer, the agent finalizes the plan for you.

The agent asks for a quick confirmation to make sure everything looks right.

The agent asks for a quick confirmation to make sure everything looks right.

The agent displays a confirmation message, waiting for your approval

After you confirm, the agent goes ahead and provisions everything.

The UI shows that resources are being created and progress updates as it moves through the steps

When it’s done, you’ll get a summary of everything it created. You can see all the details here.

Summary screen with the new VPC IDs, subnets, and other details

Now grab those VPC and subnet IDs. Let’s try connecting to an EC2 instance in one of these VPCs using AWS SSM (Session Manager).

When you tell the agent you want to access EC2 via SSM, it will ask for confirmation and take care of the setup.

The UI confirms that it’s about to set up the IAM permissions and any prerequisites needed for SSM

After it’s done, it will let you know that everything is set up and ready.

Screenshot shows SSM access has been configured successfully

You’ll see the exact commands you need to connect through AWS SSM.

Screen with copy-paste ready commands to connect to your EC2 instances using SSM

If you hit any errors, just tell the agent and it will troubleshoot and fix things for you.

Screenshot shows the agent working through and resolving a user-reported problem

It’ll walk you through any follow-up steps if you need more help.

Agent is showing additional instructions or info on the screenAnother example of the agent breaking things down for you

Now, grab the private IPs of both instances in each VPC. You’ll need them for the next step.

The EC2 dashboard displays private IP addresses for each running instance

If you’re not sure how to test the setup, just ask the agent and it’ll help out.

Screen displays suggested ways to check connectivity, like ping commands

When you log in with SSM and try to ping the other instance from the first one, it won’t work yet. That’s because VPC peering isn’t enabled.

Screenshot shows a ping command timing out, showing the two VPCs are not connected yet.

Now, let the agent know you want to enable VPC peering. It will handle everything needed for that.

Screen shows the agent starting the VPC peering setup

The agent figures out all the steps, including updating route tables, so traffic can flow between the VPCs.

Here, it shows the agent updating routes and confirming peering is enabled

If there’s anything else needed, the agent will suggest it and ask for your go-ahead.

Screenshot with a confirmation prompt for additional changes

When it’s all done, you’ll get a summary of what was changed.

Screen shows a summary of the peering connection and updated route tables

If you want to double-check, you can confirm everything from the AWS console.

Here’s the VPCs:

Screenshot shows the AWS VPC dashboard with both VPCs and the peering connection

And here’s the EC2 instances:

EC2 dashboard with both instances running in separate VPCs

Now, if you try pinging from one EC2 instance to the other over their private IPs, it works. You’re all set.

Screenshot shows a successful ping from one instance to the other after peering is complete

That’s it. VPC peering, start to finish, without having to mess with the AWS console or memorize all the steps.