IT Management & Cyber Security

VPC Network Address Translation When you associate an ENI with a public IP address, the ENI maintains its private IP address. Associating a public IP with an ENI doesn’t reconfigure the ENI with a new address. Instead, the Internet gateway maps the public IP address to the ENI’s private IP address using a process called network address translation (NAT). When an instance with a public IP connects to a host on the Internet, the host sees the traffic as originating from the instance’s public IP. For example, assume an instance with a private IP address of 172.31.7.10 is associated with the EIP 35.168.241.48. When the instance attempts to send a packet to the Internet host 198.51.100.11, it will send the following packet to the Internet gateway: The Internet gateway will translate this packet to change the source IP address to the instance’s public IP address. The translated packet, which the Internet gateway forwards to the host, looks like this: Likewise, when a host o...

Overview of an Amazon Virtual Private Cloud Virtual service provides the networking layer of EC2. A VPC is a virtual network that can contain EC2 instances as well as  network   resources for other AWS services. By default, every VPC is isolated from all other networks. You can, however, connect your VPC to other networks, including the Internet and other VPCs. In addition to EC2, VPCs are foundational to many  AWS services , so understanding how they work is fundamental to your success on the exam and as an AWS architect. Don’t assume you can ignore VPCs just because you’re not using EC2. A VPC can exist only within an AWS region. When you create a VPC in a region, it won’t show up in any other regions. You can have multiple VPCs in your account and create multiple VPCs in a single region. To keep things simple, I’ll start by assuming only one VPC in one region. Later, I’ll cover considerations for multiple VPCs. If you’re familiar with the components of a traditi...