Your company has just acquired another company, and you have been asked to integrate their existing Google Cloud environment into your company's data center. Upon investigation, you discover that some of the RFC 1918 IP ranges being used in the new company's Virtual Private Cloud (VPC) overlap with your data center IP space. What should you do to enable connectivity and make sure that there are no routing conflicts when connectivity is established?
To enable connectivity and prevent routing conflicts when establishing connectivity between the new company's VPC and your data center, it is essential to manage overlapping IP ranges appropriately. The best approach is to create a Cloud VPN connection from the new VPC to the data center, set up a Cloud Router to manage route advertisements, and apply a custom route advertisement to block the overlapping IP space. This method ensures that there are no routing conflicts and maintains the integrity of the network without the need for reconfiguring IP addresses, which can be a complex and potentially disruptive process.
Correct Answer: A - IP Should not overlap so applying new IP address is the solution
A is not correct. "What should you do to enable connectivity and make sure that there are no routing conflicts when connectivity is established?" if you apply VPN con BGP, the actual IP address will be propagated to on prem environment with overlapping RFC1918 as result. B is correct with custom route
Answer is C. https://cloud.google.com/network-connectivity/docs/router/how-to/advertising-custom-ip
ANS is B https://cloud.google.com/architecture/best-practices-vpc-design
B is NOT correct. Cloud NAT is specifically used for translating the IP address of the outbound packets destined to the Internet. But this question is about using VPN communication between two private IP address spaces (RFC1918). Cloud NAT cannot achieve the purpose here, you can't use Cloud NAT to translate from one private IP to another private ip. I would vote for C.
Thanks for the clarification, just one question, without a solution like NAT or reip, the service on the devices with overlapping IP subnet will be unavailable for on-premise devices, not sure if the question also about this
You can use private or hybrid NAT https://cloud.google.com/nat/docs/overview#private-nat
You can't use Cloud NAT according to this documentation: https://cloud.google.com/nat/docs/troubleshooting#overlapping-ip-addresses "Can I use Cloud NAT to connect a VPC network to another network to work around overlapping IP addresses? No, Cloud NAT cannot apply to any custom route whose next hop is not the default internet gateway. For example, Cloud NAT cannot apply to traffic sent to a next hop Cloud VPN tunnel, even if the destination is a publicly routable IP address."
It will be a NAT Router instance, which will route the traffic. I have practically applied the configuration.
The Q states to establish connectivity. This would merely prevent that. Ans is A
I would also agree with C. Still, this part is confusing: "C. Create a Cloud VPN connection from the new VPC to the data center, create a Cloud Router, and apply a custom route advertisement to *block* the overlapping IP space." To *block*? Not to block. just to alias with advertised IP addresses.
I think now the answer should change since Private NAT is publicly available: https://cloud.google.com/nat/docs/private-nat
I was absolutely sure that B was obviously wrong until I found that https://cloud.google.com/nat/docs/overview#private-nat So it seems like the answer is B...
B. THIS should be the accepted answer, the link you provide is 100% certain. It's a Private Hybrid NAT: " ...private-to-private translations... traffic between VPC networks and on-premises networks..." "...IP addresses overlap with the IP addresses of your VPC network. In this scenario, you create a Private NAT gateway..." B, 100%
Could not be B, as Cloud NAT only apply on route targeting default gateway. Could not be C : if you block route advertisement, then you will have no route to your datacenter, and you will be unable to connect your datacenter Could not be D : blocking using firewall the overlapping IP space will not provide connectivity to these ressource So answer could only be A : user should update its IP space so it does not overlap
A. Create a Cloud VPN connection from the new VPC to the data center, create a Cloud Router, and apply new IP addresses so there is no overlapping IP space. In a situation where RFC 1918 IP ranges overlap between the new company's VPC and your data center IP space, it is important to reconfigure the IP addresses to avoid any conflicts. To enable connectivity, first create a Cloud VPN connection between the new VPC and the data center. Then, set up a Cloud Router to manage routing between the environments. Finally, apply new IP addresses to the new company's VPC to ensure there is no overlapping IP space with your data center. This will prevent routing conflicts when connectivity is established.
I believe answer is C: https://cloud.google.com/network-connectivity/docs/router/how-to/advertising-subnets
Create a Cloud VPN connection from the new VPC to the data center, create a Cloud Router, and apply new IP addresses so there is no overlapping IP space.When there is overlapping IP space between two networks that need to be connected, it is necessary to re-address one of the networks to eliminate the conflict.
All answers are incorrect. Overall, it is a NAT question, but cloud NAT can't nat private IP space. No idea how route can solve the overlapping issue. There is a third party NAT option: https://www.linkedin.com/pulse/resolving-overlapping-ip-issue-when-connecting-tofrom-bayu-wibowo
Apply new IP addresses? You do not apply new IP, you replace them. Either poorly written or deceiving. To enable connectivity and avoid routing conflicts, C is perfect. Long term of course we need to replace IP, but not to enable connectivity. C.
with C option we would not able to connect to VM with those overlapping IP. we need to add a middle VPC between them. it will be more complicated. we have not choice here except reassigning IP adresses so i choose option A
The challenge with Option A is that changing IP addresses can be complex and might impact existing applications, configurations, and dependencies within the new company's VPC. It might introduce additional complexity and potential risks during the integration process. Option C, on the other hand, allows you to maintain the existing IP addressing in the new company's VPC while selectively blocking the overlapping IP space during the routing process. This can be a more flexible and less disruptive approach, especially in scenarios where readdressing is not practical. In summary, both options might have their use cases, but Option C provides a solution that doesn't require changing IP addresses and can help avoid potential disruptions caused by such changes.
https://cloud.google.com/nat/docs/overview#private-nat Assume that the resources in your VPC network need to communicate with the resources in a VPC network or an on-premises or other cloud provider network that is owned by a different business entity. However, the VPC network of that business entity contains subnets whose IP addresses overlap with the IP addresses of your VPC network. In this scenario, you create a Private NAT gateway that routes traffic between the subnets in your VPC network to the non-overlapping subnets of that business entity.
Ans is B
Using Cloud NAT to translate overlapping IP addresses is the most effective solution to ensure seamless connectivity between the new company's VPC and your company's data center without routing conflicts. This approach avoids the complexity of reconfiguring IP addresses and ensures that both networks can communicate effectively. https://cloud.google.com/nat/docs/overview#private-nat
It is not NAT, we are not going out to internet. We need cloud router
The answer is B. Cloud VPN and Cloud NAT help you get around this problem easily without all the work of creating a new subnet and reassigning IPs to everything. Cloud NAT: Network Address Translation (NAT) allows you to translate IP addresses in your VPC to a different IP range, avoiding conflicts with overlapping IP ranges in your data center. This ensures that traffic can flow between the environments without routing conflicts. Cloud VPN: Establishing a Cloud VPN connection provides secure connectivity between the new VPC and your data center. By combining this with Cloud NAT, you can effectively manage and resolve the IP address overlap.
Cloud NAT does not directly resolve IP address conflicts due to overlapping ranges. Cloud NAT is typically used for instances without external IP addresses to access the internet while preserving their internal IPs for internal communications.
would go for B