Assuming an environment with multiple domain controllers (assume that they all run DNS as well), in what order should the DNS servers be listed in the network adapters for each domain controller? Should 127.0.0.1 be used as the primary DNS server for each domain controller?
According to this link and the Windows Server 2008 R2 Best Practices Analyzer, the lookback address should be in the list, but never as the primary DNS server. In certain situations like a topology change, this could break replication and cause a server to be "on an island" as far as replication is concerned.
Say that you have two servers: DC01 (10.1.1.1) and DC02 (10.1.1.2) that are both domain controllers in the same domain and both hold copies of the ADI zones for that domain. They should be configured as follows:
Never, ever have a DC use itself as Primary DNS.
All sorts of havoc can (and Murphy dictates: will) happen if the AD services become online before the DNS service is live after a reboot. (Or DNS crashes, gets DOSsed, whatever.)
Always put 127.0.0.1 last. Also: Don't be tempted to use the real LAN ip-address of the server either.