I would like to join a new windows server 2012 member server to our domain which is at 2003 functional level and domain level. I am being told that an AD Schema update is required to do this.
Can anyone explain what is involved in this schema update and why it is necessary? Can it join the domain without this schema update?
I don't know where you're getting your information, but I admin a 2003 FL Forest and Domain, and joined a Server 2012 server to it a couple weeks ago without any schema update. I'm in the process of standing up another Server 2012 server onto it at this very moment, as well.
There's no schema update required to add a Server 2012 member server to a 2003 forest and/or domain. It's no different than joining a 2008 or 2008R2 server to a 2003 FL domain, in fact. Build server, join to domain, reboot and done.
There might have been some misunderstandings / misinterpretations of your initial supporter.
Simply joining a machine never required so far any schema change. The schema defines what can be stored how in AD and has not too much to do with the domain join process. Having said that, depending on the functional level / DC OS level certain new security features like encryption mechanism have been introduced.
If you simply join the 2012 server you don't need the latest schema.
But certain features you may want to use require new schema or adding a 2012 DC or even updating the functional level. Claims based access control would require new schema and a 2012 DC
