Is there an easy way to configure AWS RDS security groups so that specific users can access the RDS instance?

Question

I have an Oracle instance set up in Amazon Web Services' RDS, and I want to give three users access to the database. The issue that I'm having is that the way security groups work, it seems that I can only approve specific IP's (or ranges) to have access. This instance is set up for a group project at my University, so we are not likely to have the same IP every time we connect. Is it possible to set up specific users' access to the instance, regardless of the IP they are connecting with?

The only solution I could think of was to set up an EC2 instance, and have everyone tunnel their traffic through that so that it looks like we are always coming from the same system. Since we are using the free tier of AWS, we are likely to go over if everyone is tunneling their traffic through the EC2 instance.

Answer 1

we are likely to go over if everyone is tunneling their traffic through the EC2 instance

Why?

It's the same amount of traffic between AWS and you (plus the overhead for the tunnel encapsulation) if you go through an EC2 instance or if you connect directly to RDS from the Internet.

Data transferred between Amazon RDS and Amazon EC2 Instances in the same Availability Zone is free.

^{— http://aws.amazon.com/rds/pricing/oracle/}

If you configure the EC2 instance on the same AWS account and in the same availability zone then you'll be billed (or be using your free tier allocation) for data transfer from EC2 to the Internet instead of being billed for data transfer from RDS to the Internet. The free tier bandwidth allocation is for all services combined, not per-service, so I don't see a significant difference in your potential cost.