Block IP on EC2. Firewall or other options?

Question

My EC2 (Fedora AMI) based service is being heavily hit by a rogue misconfigured client. What options do I have to block the IP of this rogue client?

Answer 1

Iptables seems to be an easy/quick option:

$ iptables -I INPUT -s 1.2.3.4 -j DROP

Answer 2

You could also use the EC2 security groups to control access, although that's more appropriate if you want to restrict access to a specific IP range rather than blocking a particular address or range.