Hi there!

Unfortunately, DOKS NodePort services only bind to the nodes public interface at this time. One option to control access is to use and ingress controller such as nginx(https://github.com/kubernetes/ingress-nginx) , and then configure ingress rules using ingress objects(https://kubernetes.io/docs/concepts/services-networking/ingress/).

By using this you can setup a whitelist on the ingress controller and whitelist your external droplet’s IP: https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/#whitelist-source-range

This would allow you to expose that service publicly but only allow one IP to actually contact your service.

Regards,

John Kwiatkoski
Senior Developer Support Engineer