ANS-C01 Network Implementation Practice Question

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?

⚠ Common exam trap

Watch out — candidates often 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.

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

✓

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.

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.
✗
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.

Go deeper

ANS-C01 Network Implementation Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

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