Internet gateway quiz · Level 0 · Todo.io Learns AWS

Question 1A teammate says a subnet is public because the instances in it have public IP addresses. What actually makes a subnet public?

Its route table sends traffic for 0.0.0.0/0 to an internet gateway.Correct. That route is the only thing that makes a subnet public. Without it, even an instance with a public IP has no path to the internet.The instances in it have public IP addresses.Not this one. A public IP is needed to be reached from the internet, but it doesn't make the subnet public. With no route to an internet gateway, the address leads nowhere.Its security group allows inbound traffic from 0.0.0.0/0.Not this one. Security groups filter traffic at a network card. They don't create a path to the internet, and they belong to network interfaces, not to subnets.It was created with the "public" subnet type.Not this one. There is no such setting. "Public" and "private" are names for what the route table does.

Learn it: Subnet · Internet gateway

Question 2How many internet gateways can be attached to one VPC?

One.Correct. A VPC has at most one internet gateway. AWS runs it and scales it for you, so one is enough.One per subnet.Not this one. Subnets share the VPC's gateway; their route tables decide whether they use it.One per Availability Zone.Not this one. The internet gateway isn't tied to an AZ.As many as you need for bandwidth.Not this one. It scales by itself, so you never add more.

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Question 3Todo.io's app on EC2, in a public subnet, calls DynamoDB. Which way does the request travel?

Out through the internet gateway to DynamoDB's public AWS endpoint.Correct. DynamoDB isn't inside your VPC. A gateway endpoint (Level 1) can keep this traffic off the internet.Straight to the table inside the VPC.Not this one. Tables don't live in your VPC.Through the RDS database.Not this one. RDS and DynamoDB are unrelated.Through an SQS queue.Not this one. Queues pass messages between your own components.

Learn it: VPC (Virtual Private Cloud) · DynamoDB · Internet gateway

Question 4What does "Internet gateway" mean?

The VPC's door to the public internet.Correct. Think of it as: The estate's front gate.A slice of a VPC's addresses that lives in one Availability Zone.Not this one. That describes Subnet.An address the whole internet can reach.Not this one. That describes Public IP address.Your own private network inside an AWS Region.Not this one. That describes VPC (Virtual Private Cloud).

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Question 5Which term is this? "The VPC's door to the public internet."

Internet gatewayCorrect. Yes. Think of it as: The estate's front gate.SubnetNot this one. Subnet is: A slice of a VPC's addresses that lives in one Availability Zone.Public IP addressNot this one. Public IP address is: An address the whole internet can reach.VPC (Virtual Private Cloud)Not this one. VPC (Virtual Private Cloud) is: Your own private network inside an AWS Region.

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Question 6Which AWS term is described by this analogy? "The estate's front gate."

Internet gatewayCorrect. Yes: The VPC's door to the public internet.SubnetNot this one. Subnet is: A slice of a VPC's addresses that lives in one Availability Zone. Its analogy: One street on the estate.Public IP addressNot this one. Public IP address is: An address the whole internet can reach. Its analogy: A street address printed on the outside of the building.VPC (Virtual Private Cloud)Not this one. VPC (Virtual Private Cloud) is: Your own private network inside an AWS Region. Its analogy: A fenced-off private estate inside the city.

Learn it: Internet gateway

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