Samba 3.0.0 beta3 config option "domain controller = xxx"

[Joseph Phillips]

After upgrading to the latest Red Hat RPM packages for Samba 3.0.0 beta 3,
the default smb.conf file includes this option:

# Use only if you have an NT server on your network that has been
# configured at install time to be a primary domain controller.
   domain controller = xxx 

But, the official RPM packages from Samba.org do not contain this option.  I
am on the samba mailing list, and, according to John H Terpstra from
samba.org, this "domain controller" is not a parameter from samba.

Is this a parameter that Red Hat added?  If so, why did Red Hat add a
parameter that doesn't exist in the official build of samba?  What does this
parameter do?

Thanks.