AWS Security Groups - EC2 to RDS

Question

I wanted to ask about connecting EC2 to RDP in AWS.

I have added my EC2 Security Group (that contains the EC2 instances) into the Default RDP Group and Data is flowi

Answer 1

You do not need to worry about additional ports being opened up on RDS server.

The EC2 security groups are just treated like an access control list when used in RDS DB security policies.

Basically what you are saying is that you want to let any instances which belong to specific EC2 security group have access to the RDS instances using that DB security groups policy.

The specific rules defined in the EC2 security groups do not matter.

This behavior basically just gives you a convenient way to easily allow access from a cluster of servers with some common association (their security group).