You have an environment that consists of a public subnet using Amazon VPC and 3 instances that are running
in this subnet. These three instances can successfully communicate with other hosts on the Internet. You
launch a fourth instance in the same subnet, using the same AMI and security group configuration you used for
the others, but find that this instance cannot be accessed from the internet. What should you do to enable
Internet access?
A.
Deploy a NAT instance into the public subnet.
B.
Assign an Elastic IP address to the fourth instance.
C.
Configure a publically routable IP Address in the host OS of the fourth instance.
D.
Modify the routing table for the public subnet.
B
B
I agree with the answer. C
How exactly would even go about configuring a public IP via the host OS that would be allowed to communicate through AWS network?
C is wrong, when you assign a public IP / EIP, you do not configure it in the host OS, instead you configure it in AWS console
IP address is the property of network interface not the OS and hence C is incorrect
B
B
Answer is B.
A. Public subnet does not use NAT to access internet: wrong
C. when you assign a public IP / EIP, you don’t configure it in the host OS but you configure it in AWS console (or using API)
D. Routing table is not the root cause of the issue becouse “You launch a fourth instance in the same subnet, using the same AMI and security group configuration you used for the others”
B
you launched your instance into a public subnet — a subnet that has a route to an Internet gateway. However, the instance in your subnet also needs a public IP address to be able to communicate with the Internet. By default, an instance in a nondefault VPC is not assigned a public IP address. In this step, you’ll allocate an Elastic IP address to your account, and then associate it with your instance.
was looking for the “WHY” on this one. thanks for giving the context. much appreciated.
C is right. All that the answer says is, instance needs a public IP. Not necessarily an Elastic IP
C is wrong because you cannot do anything on the host OS, you only have control over guest OS.
Right answer is B.
B is not wrong either. I would say, this should have been a question to select all that is right
B
B. Assign an Elastic IP address to the fourth instance.
Answer is B