In this tech talk, we will show how we deploy, operate and automate a highly available and geo redundant DNS Service for Swisscom's 5G mobile network using a Cloud Native tech stack. We will provide an in-depth insight into our multi-cluster architecture that leverages ExternalDNS, PowerDNS and CoreDNS to build a modern and reliable DNS setup. In addition we will deep dive into the automation and demonstrate the interplay between ExternalDNS and Kubernetes resources such as Ingresses, Services, Istio Gateways, Contour HTTPProxies and ExternalDNS DNSEndpoints. Our talk will be interesting for highly demanding DNS users – for instance applications that require the use of rather rare DNS Resource Records like NAPTR – as well as engineers and architects tasked with building a DNS service with cloud native tools that are – for compliance, governance or availability concerns – not allowed to use a publicly available DNS-as-a-service offering.