Amazon EKS provides two ways to implement network policy. You choose a network policy option when you create an EKS cluster. The policy option can’t be changed after the cluster is created: Calico Network Policies, an open-source network and network security solution founded by Tigera. Both implementations use Linux IPTables to enforce the specified policies. Policies are translated into sets of allowed and disallowed IP pairs. These pairs are then programmed as IPTable filter rules.