Amazon Elastic Kubernetes Service (EKS) now allows you to restrict access to your Kubernetes cluster’s public endpoint by specifying allowed IPv4 address ranges in CIDR notation. This allows you to implement network-based access control to your public endpoint.

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/12/amazon-eks-enables-network-access-restrictions-to-kubernetes-cluster-public-endpoints/