Prior to migrating from Server 2003 to Server 2012 R2, you’ll need to figure out which servers in your organization are functioning as DNS servers. You’ll also have to figure out which DNS zones are hosted on your DNS servers and the nature of those zones.
An Active Directory Integrated zone is stored within Active Directory. A standard primary or secondary zone is stored in a file. Stub zones, which just host name server records, can also either be stored in Active Directory or within a file.
Windows Server 2003 DNS deployments generally take two forms, domain controllers as DNS server or stand alone DNS servers. Stand alone DNS servers will be configured to host either the standard primary or standard secondary version of a zone. While domain controllers can also host standard primary and standard secondary versions of a zone.
You can determine whether a zone is stored within Active Directory or as a file by using the following command on a DNS server:
You can also do it by checking the zones in the DNS Manager console. The advantage of using dnscmd is that you can use it to remotely query DNS servers.
You should also determine if any DNS forwarders are configured and if any Advanced options, such as round robin or netmask ordering, are configured in a way that differs from the defaults. In general, most organizations don’t change the defaults, but it’s a good idea to do a check during the assessment phase rather than figuring out that you missed an important bit of configuration information half way through your migration.