aws vpc and subnet cidr blocks–ip address blocks

Right now, there are 3 subnets . I propose 5 subnets in all – Public (Palo Alto), Web, App, Data and an AD subnet.

This is a sample breakup of the addresses blocks.

Parent VPC – 172.30.0.0/20 –  VPC  CIDR block

Subnets

172.30.0.0/28  – Palo Alto – does not exist yet

172.30.3.0/24  – Web – already exists

172.30.2.0/24  – App  – already exists 

172.30.1.0/24  – Data  – already exists – Being used to host Cohesity’s Control VM?

172.30.0.0/28  – AD Subnet  – does not exist yet.

Next Steps –

1. If you / your networking team approves the address blocks above, I will go ahead and use the following  AD DC (2016) to install on a new EC2 in the AD subnet. Who would be a good Point of Contact for AD specific questions?  
2. Which subnets are currently being replicated to? I only saw one active EC2 instance – and that was Control VM. We need to maybe have a quick chat around the current status of Cohesity’s backups/replications.