Under normal circumstances, is the windows server 2008r2 firewall, running on an amazon ec2 instance even necessary? Can it safely be turned off? It appears that thru the security groups, amazon is providing a firewall for the machine, or am I missing something?
SnapOverflow
This is a matter of personal preference. If you're not using VPC I would say it's safe to turn it off. If you were using VPC, I would leave it on to act as another security blanket that protects your internal network from the perimeter if it's exploited. Since there's only one NIC attached to your instance and Security Groups are handling all the access control lists, I personally would turn it off.