Article ID: 200866 - View products that this article applies to.
This article was previously published under Q200866
This article discusses having a backup domain controller (BDC) in a Microsoft BackOffice Small Business Server domain model.
First, what is a BDC? According to page 3 of the "Concepts and Planning Guide" for Microsoft Windows NT 4.0, a BDC is defined as follows:
"A backup domain controller (BDC) maintains a copy of the directory database. This copy is synchronized periodically and automatically with the Primary Domain Controller (PDC). BDCs also authenticate user logons, and can be promoted to function as the PDC. Multiple BDCs can exist in a domain."Second, what do Small Business Server (SBS) standards say about this? Page 137 of the "Start Here Guide," which accompanies the installation software, states:
"You can only have one computer running Small Business Server on your network, but you can connect other server computers to your network. For example, you may want a dedicated computer to host a Web site, printer services, or a database. We recommend that these server computers run Windows NT Server as a backup domain controller or as a standalone server, a.k.a. member server. You may not install applications shipped with BackOffice Small Business Server on non-BackOffice Small Business Server servers. You must purchase the appropriate software licenses for each server and any of the applications you install on the server. Small Business Server does not support "trust" relationships with other Windows NT Server computers."
So, what does all of this mean for a Small Business Server domain? Here are a few key points to keep in mind: