This ANS-C01 practice question tests your understanding of network implementation. 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.
Exhibit
Refer to the exhibit. The following is an AWS CLI output:
{
"RouteTables": [
{
"RouteTableId": "rtb-12345678",
"Routes": [
{
"DestinationCidrBlock": "10.0.0.0/16",
"GatewayId": "local",
"State": "active"
},
{
"DestinationCidrBlock": "0.0.0.0/0",
"GatewayId": "igw-12345678",
"State": "active"
},
{
"DestinationCidrBlock": "10.0.0.0/8",
"GatewayId": "vpce-12345678",
"State": "blackhole"
}
]
}
]
}
A network engineer is troubleshooting connectivity issues. The route table shows a blackhole route for 10.0.0.0/8 pointing to a VPC endpoint (vpce-12345678). What is the most likely cause of the blackhole state?
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.
Exhibit
Refer to the exhibit. The following is an AWS CLI output:
{
"RouteTables": [
{
"RouteTableId": "rtb-12345678",
"Routes": [
{
"DestinationCidrBlock": "10.0.0.0/16",
"GatewayId": "local",
"State": "active"
},
{
"DestinationCidrBlock": "0.0.0.0/0",
"GatewayId": "igw-12345678",
"State": "active"
},
{
"DestinationCidrBlock": "10.0.0.0/8",
"GatewayId": "vpce-12345678",
"State": "blackhole"
}
]
}
]
}
A
The VPC endpoint (vpce-12345678) has been deleted.
A deleted endpoint results in a blackhole route.
B
The VPC CIDR 10.0.0.0/16 is overlapping with the endpoint route.
Why wrong: Overlap doesn't cause blackhole; the local route takes precedence.
C
The route table does not have a route to the internet.
Why wrong: There is a route to IGW.
D
The internet gateway is not attached to the VPC.
Why wrong: IGW is active and not related to endpoint route.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VPC endpoint (vpce-12345678) has been deleted.
A blackhole route in a VPC route table indicates that the target for the route (in this case, a VPC endpoint) is not in a valid state. When a VPC endpoint (vpce-12345678) is deleted, all routes pointing to it become blackhole routes because the target no longer exists. This causes traffic destined for 10.0.0.0/8 to be dropped silently.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 VPC endpoint (vpce-12345678) has been deleted.
Why this is correct
A deleted endpoint results in a blackhole route.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The VPC CIDR 10.0.0.0/16 is overlapping with the endpoint route.
Why it's wrong here
Overlap doesn't cause blackhole; the local route takes precedence.
✗
The route table does not have a route to the internet.
Why it's wrong here
There is a route to IGW.
✗
The internet gateway is not attached to the VPC.
Why it's wrong here
IGW is active and not related to endpoint route.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think a blackhole route is caused by routing conflicts or missing internet connectivity, rather than recognizing that it specifically indicates the target resource (like a VPC endpoint) has been deleted or is in an invalid state.
Detailed technical explanation
How to think about this question
Under the hood, AWS VPC route tables maintain a 'target' field that references the resource ID (e.g., vpce-12345678). When the resource is deleted, the route table entry is not automatically removed; instead, it transitions to a 'blackhole' state to indicate the target is unreachable. This behavior is similar to how a static route with a next-hop that goes down is treated in traditional routing, but AWS explicitly marks it as blackhole rather than removing it, which can cause silent packet drops if not noticed.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network Implementation — This question tests Network Implementation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The VPC endpoint (vpce-12345678) has been deleted. — A blackhole route in a VPC route table indicates that the target for the route (in this case, a VPC endpoint) is not in a valid state. When a VPC endpoint (vpce-12345678) is deleted, all routes pointing to it become blackhole routes because the target no longer exists. This causes traffic destined for 10.0.0.0/8 to be dropped silently.
What should I do if I get this ANS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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?
Read the scenario before looking for a memorised answer.
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Question Discussion
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