The answer is that the route table for VPC A is missing a route to 192.168.0.0/16 via the peering connection. This is correct because for a VPC peering connection to work bidirectionally, each VPC’s route table must have an explicit route pointing to the other VPC’s CIDR block using the peering ID as the target. Without that route in VPC A, traffic destined for 192.168.0.0/16 has no path and is dropped, even though VPC B’s route table has the correct peering route and the connection status is active. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding that a peering connection alone is insufficient—you must configure routes in both directions, and the missing route trap often appears alongside distractors like security groups or NACLs, which are not shown in the exhibit. A common memory tip is “peer both ways, route both ways”—always verify that each VPC’s route table has the other VPC’s CIDR mapped to the peering ID.
SOA-C02 Networking and Content Delivery Practice Question
This SOA-C02 practice question tests your understanding of networking and content delivery. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Network Topology
Refer to the exhibit. A VPC peering connection exists between VPC A (CIDR 10.0.0.0/16) and VPC B (CIDR 192.168.0.0/16). The command output shows the route table for VPC A (rtb-11111111) and VPC B (rtb-33333333). An instance in VPC A (private IP 10.0.1.5) cannot ping an instance in VPC B (private IP 192.168.1.10). What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The route table for VPC A is missing a route to 192.168.0.0/16 via the peering connection.
The route table for VPC A does not have a route to VPC B's CIDR (192.168.0.0/16) via the peering connection (pcx-44444444). It only has routes for local and IGW. The route table for VPC B has the peering route. Therefore, traffic from VPC A to VPC B is not routed correctly. Option B is incorrect because the peering status is active. Option C is incorrect because security groups are not shown. Option D is incorrect because NACLs are not shown.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The route table for VPC A is missing a route to 192.168.0.0/16 via the peering connection.
Why this is correct
Without this route, traffic from VPC A to VPC B is dropped.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
The security group for the instance in VPC B blocks ICMP traffic.
Why it's wrong here
Security groups are not shown in the exhibit.
✗
The VPC peering connection status is not active.
Why it's wrong here
The status shows 'active'.
✗
The network ACL for the subnet in VPC A blocks outbound ICMP.
Why it's wrong here
NACLs are not shown in the exhibit.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Trap categories for this question
Command / output trap
Security groups are not shown in the exhibit.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SOA-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Networking and Content Delivery — This question tests Networking and Content Delivery — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: The route table for VPC A is missing a route to 192.168.0.0/16 via the peering connection. — The route table for VPC A does not have a route to VPC B's CIDR (192.168.0.0/16) via the peering connection (pcx-44444444). It only has routes for local and IGW. The route table for VPC B has the peering route. Therefore, traffic from VPC A to VPC B is not routed correctly. Option B is incorrect because the peering status is active. Option C is incorrect because security groups are not shown. Option D is incorrect because NACLs are not shown.
What should I do if I get this SOA-C02 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SOA-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An organization has a VPC peering connection between VPC A and VPC B. Instances in VPC A can reach instances in VPC B, but not vice versa. What is the most likely cause?
medium
✓ A.The route table in VPC B does not have a route to VPC A's CIDR.
B.DNS resolution is not enabled for the VPC peering connection.
C.Security groups in VPC B block inbound traffic from VPC A.
D.The VPC peering connection is in a 'pending-acceptance' state.
Why A: Option C is correct because VPC peering requires route table entries in both VPCs for bidirectional traffic. Option A is wrong because security groups are stateful but only affect inbound/outbound; the issue is routing. Option B is wrong because the peering connection is already established. Option D is wrong because DNS resolution settings don't affect basic connectivity.
Last reviewed: Jun 20, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.