Two main DNS server implementations
DNS has a large and complex infrastructure on the internet (which we'll touch on in this section). This is made up of 13 root name servers (which are each a reliable cluster of servers), a group of commonly used name servers (for instance, the servers we use at Google or Cloudflare), and a series of registrars who will, for a fee, register a DNS domain name for you—for instance, your organization's domain name.
However, for the most part, most administrators are working with the needs of their organization—working with their internal DNS name servers that face their internal folks, or with their external DNS name servers that face the internet. It is these two use cases that we'll be focusing on in this chapter. You will see as we build these examples out how the Google or Cloudflare DNS infrastructure, or even the root DNS servers, are not all that different.
