First of all I would like to explain that I am taking my first steps in networking in general and in GCP in particular.That's why I apologize if the question makes no sense.
I'm facing a challenge with routing traffic from a subnet in Europe through a VPN tunnel based in the United States.
Here are the specifics:
- Subnet details: located in europe-west1, containing 2 instances
- VPN tunnel: Set up in the US, with the Cloud VPN gateway in us-west
- Issue: Cannot add the europe-west1 subnet to the tunnel due to regional differences
Current limitations:
- Unable to modify the other side of the tunnel
- Cannot relocate the Gateway to europe-west1 as it would result in losing the IP configured on the other side of the tunnel
- Unable to select a different range of local IPs for the tunnel.
- Cannot move the instances from europe-west1 to another region
Attempted solutions:
- Verified routing tables
- Tried creating a Cloud NAT between the two subnets, but this approach doesn't work as both subnets must be in the same region
- Attempted VPC peering, which yielded the same result
Core question: Is there a method to route traffic from instances in one region (europe-west1) through a VPN tunnel configured in a different region (us-west)?
The only thing I can think of is to create another instance in a subnet in the US that acts as a proxy between the instances in Europe and the tunnel but it seems a very inefficient solution and I would like to know if there is an alternative that escapes me.
After further investigation, I found that the issue could be resolved by changing dynamic routing mode in VPC settings from regional to global.
This approach resolved the issue without requiring changes to the other side of the VPN tunnel or relocating resources.