ANS-C01 Question 173
Single answerYour company has acquired a new subsidiary, and both organizations use AWS for their workloads. Upon merging their network infrastructure, you discover overlapping CIDR ranges (192.168.1.0/24) are being used in both accounts. You need to establish network connectivity between these two accounts without reassigning IP addresses in either environment. Which solution should you implement?
- A
Use AWS Transit Gateway and configure route tables to prevent IP conflicts.
- B
Implement VPC Peering and use NAT gateways to handle overlapping CIDR ranges.
- C
Deploy a VPN connection between the VPCs and configure IP address translation using AWS NAT Gateway.
- D
Use AWS Transit Gateway with a third-party network appliance for IP address translation.
Show answer and explanation
Correct answer: D
Explanation
Overlapping CIDR ranges prevent direct communication between VPCs using methods such as VPC Peering or Transit Gateway alone. AWS does not natively support IP address translation for overlapping CIDRs. By leveraging AWS Transit Gateway with a third-party network appliance capable of IP address translation, you can enable connectivity between the VPCs while avoiding conflicts caused by overlapping IP ranges.
- A. Incorrect.
AWS Transit Gateway alone does not resolve overlapping CIDR ranges. Route tables allow traffic control but cannot translate overlapping IP addresses.
- B. Incorrect.
VPC Peering does not support overlapping CIDR ranges, even with NAT gateways. Overlapping IPs will cause routing conflicts.
- C. Incorrect.
While VPN connections can be used, AWS NAT Gateway does not natively support IP address translation for overlapping CIDRs in this scenario.
- D. Correct.
AWS Transit Gateway combined with a third-party network appliance can perform IP address translation, which resolves overlapping CIDR conflicts between the two VPCs.