100 Days of Cloud (AWS) : Day 29

rau83 · June 24, 2026, 7:00am

Hi Team,

Could someone please recheck my VPC Peering task?

I have completed the following:

Created the VPC peering connection nautilus-vpc-peering and it is in Active state.
Added route from the Default VPC (172.31.0.0/16) to the Private VPC (10.1.0.0/16) through the peering connection.
Added route from the Private VPC (10.1.0.0/16) to the Default VPC (172.31.0.0/16) through the peering connection.
Verified subnet associations for both route tables.
Updated the security group to allow ICMP traffic.
Added the required public key to the public EC2 instance.
Successfully SSH’d into the public EC2 and verified that I can ping the private EC2 instance.

The environment appears to be working correctly, but the validator still reports: “Route from private VPC to default VPC is missing.”

Could someone please review the task or let me know if there is any validator-specific requirement I might be missing?

Thank you.

raymond.baoly · June 24, 2026, 7:02am

Hi @rau83

Please refer to the solution here and try again:

github.com

Srikanth0824/kodekloud-engineer/blob/main/100_Days_of_Cloud-AWS/Day29.md

## Task: Establishing Secure Communication Between Public and Private VPCs via VPC Peering
The Nautilus DevOps team has been tasked with demonstrating the use of VPC Peering to enable communication between two VPCs. One VPC will be a private VPC that contains a private EC2 instance, while the other will be the default public VPC containing a publicly accessible EC2 instance.

1. There is already an existing **EC2 instance** in the public vpc/subnet:
    - Name: `nautilus-public-ec2`
2. There is already an existing Private VPC:
    - Name: `nautilus-private-vpc`
    - CIDR: `10.1.0.0/16`
3. There is already an existing **Subnet** in `nautilus-private-vpc`:
    - Name: `nautilus-private-subnet`
    - CIDR: `10.1.1.0/24`
4. There is already an existing **EC2 instance** in the private subnet:
    - Name: `nautilus-private-ec2`
5. **Create a Peering Connection** between the Default VPC and the Private VPC:
    - VPC Peering Connection Name: `nautilus-vpc-peering`
6. **Configure Route Tables** to enable communication between the two VPCs.
    - Ensure the private EC2 instance is accessible from the public EC2 instance.
7. **Test the Connection**:
    - Add `/root/.ssh/id_rsa.pub` public key to the public EC2 instance's `ec2-user`'s `authorized_keys` to make sure we are able to ssh into this instance from AWS client host. You may also need to update the security group of the private EC2 instance to allow ICMP traffic from the public/default VPC CIDR. This will enable you to ping the private instance from the public instance.
    - SSH into the public EC2 instance and ensure that you can ping the private EC2 instance.

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Please let me know if you still cannot pass the task.

rau83 · June 24, 2026, 8:17am

Hi Srikanth,

Thank you for your response. I have already verified the route table entries and subnet associations on both sides. The VPC peering connection is active, the routes are configured correctly, and I am able to successfully ping the private EC2 instance from the public EC2 instance.

Since the connectivity is working as expected, It seems the validation is still reporting “Route from private VPC to default VPC is missing” even though the route is present and communication between the instances is successful.

Thank you.

Please find attached snap for the same .