Methods and practices for managing a network that has no internet connection

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http://superuser.com – Long story short, I am setting up a network with 32 servers of varying specs that will be used for testing and development. The small cluster will be on an isolated network with no internet. I can use external harddrives and discs to transfer anything from external sources into machines on the network, so this isn't a locked down secure network, it just won't have a direct connection to the outside world. I've worked on such setups before, but always long after they were setup. So I'm reaching out to see what everyone knows as far as how groups have handled initial setup and maintenance of (HowTos)