What is the best practice for using IPTABLES with an Amazon Linux server?

Question

Amazon has their own port security and IPTABLES is not running by default. Do I need to configure and enable IPTABLES?

Answer 1

Only Whitelists

Amazon effectively only gives you whitelisting ability.

Their documentation points this out directly:

Security group rules are always permissive; you can't create rules that deny access.

If you want fine-grained control over blacklists or you want to set up port forwarding, using iptables is one way to go.

Examples

Perhaps you want to drop packets from a bot scanning your box

$ iptables -I INPUT -s 174.132.223.252 -j DROP

You also might want to run an application as a non-root user on an unprivileged port and forward to port 80.

$ iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080