Amazon AWS/EC2 - How to put to servers on same “private network”

Question

I'm new at Amazon AWS/EC2. Basically, I have two EC2 instances set up and running - 2x t2.medium, Windows 2012 servers, etc.

Each server has it's own public and private ip addresses from different subnets:

Server 1: 53.171.139.195/171.30.51.181
Server 2: 53.164.26.68/171.30.59.198

I simply need these servers to be able to communicate with one another on the same private network.

I see things like elastic ip's, vpc's. Still researching, but I'm not sure what I need. Can this be done and what do I need to configure?

Update: Based on @Bram's response below, I looked at VPC's. Apparently, a default VPC was created when I started my instances.

171.30.0.0/16

So... Are the on the same subnet by default???

Answer 1

You need a Virtual Private Cloud, a VPC. In a VPC you can create private and public subnets and your instances can be added to those subnets as you like.