ANS-C01 Network Design Practice Question

A company has a VPC with a CIDR of 10.0.0.0/16 and needs to connect to another VPC with CIDR 10.0.0.0/16 via VPC Peering. They encounter an error because of overlapping CIDRs. Which TWO actions can resolve this issue?

⚠ Common exam trap

Test-takers frequently think they can modify a VPC's CIDR after creation or use subnet-level peering, but AWS does not support either, and they may overlook Transit Gateway as a valid solution for overlapping CIDRs.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Create a new VPC with a non-overlapping CIDR and peer with that

Creating a new VPC with a non-overlapping CIDR and establishing a VPC peering connection resolves the conflict. VPC peering requires that the CIDR blocks of the two VPCs do not overlap, as overlapping ranges prevent proper route table entries and cause routing ambiguity. By using a non-overlapping CIDR, you enable direct connectivity between the VPCs without IP address conflicts.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Use a subnet-level peering connection
Why it's wrong here
VPC Peering is at VPC level, not subnet.
✓
Create a new VPC with a non-overlapping CIDR and peer with that
Why this is correct
New VPC can be peered.
✗
Modify the CIDR of one VPC to a non-overlapping range
Why it's wrong here
Cannot modify VPC CIDR after creation.
✓
Use AWS Transit Gateway with separate route tables
Why this is correct
Allows connecting overlapping VPCs with segmentation.
✗
Use a NAT Gateway to translate IPs
Why it's wrong here
NAT does not solve peering overlap.

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ANS-C01 Network Design Practice Question

Why each option matters

Option-by-option breakdown

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