AWS Virtual Private Cloud (Amazon VPC)学习笔记

Amazon VPC is the networking layer for Amazon Elastic Compute Cloud (Amazon EC2), and it allows you to build your own virtual network within AWS.

An Amazon VPC address range may be as large as /16 (65,536 available addresses) or as small as /28 (16 available addresses)

An Amazon VPC consists of the following components:
Subnets
Route tables
Dynamic Host Configuration Protocol (DHCP) option sets
Security groups
Network Access Control Lists (ACLs)

An Amazon VPC has the following optional components:
Internet Gateways (IGWs)
Elastic IP (EIP) addresses
Elastic Network Interfaces (ENIs)
Endpoints
Peering
Network Address Translation (NATs) instances and NAT gateways
Virtual Private Gateway (VPG), Customer Gateways (CGWs), and Virtual Private Networks (VPNs)

Subnets

subnet is a segment of an Amazon VPC’s IP address range where you can launch Amazon EC2 instances。.
The smallest subnet that you can create is a /28 (16 IP addresses).
AWS reserves the first four IP addresses and the last IP address of every subnet for internal networking purposes. //考点
Subnets reside within one Availability Zone and cannot span zones.so remember that one subnet equals one Availability Zone.
Subnets can be classified as public, private, or VPN-only.
Default Amazon VPCs contain one public subnet in every Availability Zone within the region,with a netmask of /20.

Route Tables

A route table is a logical construct within an Amazon VPC that contains a set of rules (called routes) that are applied to the subnet and used to determine where network traffic is directed.

Each route table contains a default route called the local route, which enables
communication within the Amazon VPC,and this route cannot be modified or removed.

Internet Gateways