Configuring Amazon VPC IP Address Manager (IPAM)

In many enterprise environments a common challenge is to how to handle the allocation of IP CIDR blocks be that to Data Centers, Offices, Subnets so as to ensure that resources don’t end up with IP addresses that have already been assigned to resources on the Network. Duplicate IP Addresses on the Network can cause numerous issues and AWS have previously written the following blog that discusses several solutions to this challenge such as the use of NAT Gateways and AWS PrivateLink or a couple of more manual approaches to workaround the issue.

Field Notes: Using Amazon VPC Prefixes with Security Groups

Recently during a Customer engagement I encountered what seemed to be a fairly straightforward issues with a Security Group that was running into a service quota isssue with the number of Inbound or outbound rules per security group.

Background to the Issue

To give a little bit of context, this particulary security group was associated with a couple of Amazon EC2 Instances that were running Microsoft Windows Server 2019 and performing the function of Active Directory Domain Controllers that were being self-managed by the Customer.