An internal DNS name facilitates seamless VM-to-VM communication within a Virtual Private Cloud (VPC). It allows virtual machines (VMs) in the same network to access each other using easily resolvable internal DNS names instead of relying on changing IP addresses.
When used in the forwarding rule of a load balancer, an internal DNS name simplifies both configuration and maintenance. Rather than depending on IP addresses which may change over time due to scaling, failover, or maintenance the DNS name remains consistent, ensuring stable connections.
Additionally, using an internal DNS name enhances security by restricting access to trusted internal services only. It prevents external clients from reaching the load balancer through a public IP or DNS, thus ensuring that the load balancer is isolated within the internal network and is only accessible by authorized services.