I have a MS 2008 Domain with two servers that are domain controllers and Global Catalog servers. When the primary server (also an exchange server) goes down for maintenance, workstations that reboot during that time can log in however they cannot access network resources such as network shares. The primary server is also the DHCP server for the network and those rebooted workstations don't get a valid ip address upon reboot even though the lease time is set to two weeks.
I expected the 2nd server to step up and become the active directory server while the first one is down but that doesn't seem to be happening. I also thought the rebooted system should retain the leased ip address until the lease has expired but that doesn't seem to be true either. What am I missing or do I need to do to correct the issues?
I'm considering moving DHCP to the router to correct the DHCP issue since it's seldom if ever down.