Split-brain DNS

In all of our lab configurations, screenshots, and examples you will notice that domains we create on the internal network always end with .local. This is purposeful and is best practice. Public DNS zones, as you well know, can end in a myriad of ways. Websites or services that live on the internet may end with .com, .org, .edu, .biz, .info, .tech, .construction—the list goes on and on. These are known as top-level domains, and the creative use of such DNS suffixes should remain on the internet and away from our internal DNS zones.

Now, many of you may already work in corporate environments where your internal DNS is configured as something other than a .local, and so you already realize that internal domains can certainly be configured as one of these other suffixes. For example, Microsoft.com is obviously one of the public domains that Microsoft owns, and they could very well also have used Microsoft.com as an internal DNS zone too. In fact, it could even...