So I'm building a lab to learn AD and networking best practices and I've setup an AD domain on an internal network. Doing some reading, I've come upon an idea of using a caching DNS server to resolve external (internet) domain names, in an internal network. Now that I've got this setup I'm wondering, why would I actually want to resolve external domain names in a sandboxed internal network? What is the benefit if I can't reach the network anyway? The only theory is maybe for proxy servers?
Initially I thought I would have clients connecting from a public network through a VPN perhaps, so I set this up, but the client would have 2 NIC's and each their own DNS servers specified. What am I missing here from the big picture...?
Thanks, Paul