Login to Server
It seems if you get to the server stage you should test remote access to it, unless that is not allowed. If you can access the server remotely, then I would login using ssh (if supported) then see if there is, indeed, a problem with DNS/DHCP. I also use servers that have the lights out management (LOM) interface so I can also do a remote boot of the server if necessary. It's a good selling point to clients if you can convince them that having some type of remote access to servers and switches/routers will make it faster and easier for someone to correct their problems.
I know that I am bringing up things that may not be what a small client setup has as a configuration, but in the future (if not now) many servers have LOM and many switches/routers can be accessed remotely if configured to do so.
