为具有公共和私有子网的VPC选择一个好的网络掩码

Question

I am trying out AWS free tier and choose to set up a VPC with Public and Private Subnets.
The IP CIDR Block is defaulted to: 10.0.0.0/16 which is 65531 ip addresses. Both public and private subnets are set to 10.0.0.0/24.

Isn't the less the number of ip addresses that will fit my need the better for security? So for example, if I intend to run 2 EC2 then all I need is just 2 ip addresses?
I need to deploy a Meteor web application to be used by the public. Could some one please explain if I need to have the most number of ip address to server the hieghtest number of connection to my app? I am confused.

Answer 1

In VPC number of IP address does not matter as per the security goes. For better security it depends how you are exposing the application and the resources in your VPC to open world.

65531 IP address means your VPC can have 65531 EC2 instances into it. So if your application is going to have more than 65531 EC2 instances then you need to create a new VPC. And if you need less IP address for your VPC you can any time create another VPC with less IP address by tweaking the CIDR block as per your requirement.

As per the security goes you need to follow the AWS best practices when you are creating the infrastructure in a AWS VPC.

This is a good read

https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Security.html

http://harish11g.blogspot.com/2014/01/Amazon-Virtual-Private-Cloud-VPC-best-practices-tips-for-architecture-migration.html