During the Active Directory Domain Services Installation Wizard, when you're first deploying a RODC, DCPROMO recommends that you install a DNS server locally on the RODC. That server is fed zones from the AD DS infrastructure, and the process will add the RODC's local IP address to the RODC's local DNS client properties, so queries will be directed automatically to the AD-integrated zone on the machine itself.

However, for maximum fault tolerance, if there is only one DNS server and RODC (for instance, if the two services are running on the same machine) at a branch office, Microsoft recommends using the options in your DHCP scope—assuming you are using dynamic IP addresses at your branch office—to include not only the local RODC-based DNS server, but also a DNS server at the main office, where your other AD servers are centrally located. Make sure the local RODC-based DNS server is first on the list, so that only queries that fail to get a response from your local server are directed over the wire to your hub site.

If you have a larger branch office contingent, and you have multiple RODCs deployed at one branch office, you can install a DNS server instance on each RODC. Remember that since RODCs are indeed read-only, any dynamic update requests from your clients have to go directly to a writeable domain controller at your central office. The DNS server instances on RODCs will not attempt to replicate with one another; rather, they will receive all updates directly from the central AD DS infrastructure, so there may indeed be certain times wherein one local RODC has received an updated DNS entry for a client, but another has not. This issue resolves itself (no pun intended) within a replication cycle, but to avoid it, make sure the clients themselves have identical DNS server lists—use DHCP options to assist with this—and only install one DNS server instance per site.

Comment an article   Name   E-mail    Title Available characters: 4000  Notify me of follow-up comments Enter what you see:

No comment posted