Why would I want to resolve external domain names in an internal testlab network? [closed]

Solution 1:

You're correct about there not being any inherent value to this. Labs tend to work best when they're as self-contained as possible. Having an internal DNS domain dedicated to your lab helps to ensure that the changes that you made in the production environment don't impact your lab, and more importantly, that changes made to support your lab can't somehow impact the production environment.