DNS plays a crucial role in service discovery, which enables different resources on the network to find out about each other. This is particularly important in large-scale environments where manually keeping track of IP addresses becomes impractical. Kubernetes, being a cloud-native environment with dozens or even thousands of entities, relies heavily on DNS for service discovery and management. The default DNS server used by Kubernetes is CoreDNS, which provides internal DNS services within the cluster. Additionally, ExternalDNS can be used to resolve external domains. To troubleshoot issues with kube-dns, administrators need to ensure its health, monitor performance, and configure separate DNS zones for each environment. By leveraging kube-dns, administrators can simplify their lives and ensure smooth communication between resources in a Kubernetes cluster.