Exam AWS-SysOps topic 1 question 905 discussion

A is answer - Assign Elastic IP address to NAT gateway when create You must also specify an Elastic IP address to associate with the NAT gateway when you create it. The Elastic IP address cannot be changed after you associate it with the NAT Gateway. After you've created a NAT gateway, you must update the route table associated with one or more of your private subnets to point internet-bound traffic to the NAT gateway. This enables instances in your private subnets to communicate with the internet. https://medium.com/@gboyegadada/aws-how-to-create-a-static-ip-address-using-a-nat-gateway-845c884aa4bd https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html

By moving all of the EC2 instances behind a NAT (Network Address Translation) gateway, all outgoing traffic from the instances will appear to come from the NAT gateway's public IP address. This effectively makes all build uploads originate from the same IP address, which aligns with the strict IP whitelisting requirement of the third-party service.

A is the answer

A is Correct. NAT gateway has an option to attach an EIP on creation and you can see it. Yes NAT hides the internal IP Addresses but it doesn't mean bidirectional communication is not possible, every known IP network uses NAT. The point of it is though that the internet sources cannot initiate a session, gateways are designed to be stateful therefore as long as the connection is initiated from inside your VPC, it will be bidirectional. | There is no way to attach an EIP to IGW, therefore making A the correct answer.

B - For me the answer is an IGW. NAT is for only outbound. IGW Ensure that instances in your subnet have a globally unique IP address (public IPv4 address, Elastic IP address, or IPv6 address). https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html

A is the answer, no need to use IGW.

Correct Answer: A The NAT GW's public IP Address would comply with this requirement

A is the answer use NAT IP as a whitelisted one

It should be B the IG Ip Address