I had a call last night from a client who is implementing Active Directory (AD) in his organisation and was trying to resolve some replication issues. Like so many problems in AD the issue was related to the DNS configuration and once I had made a few configuration changes on the DNS servers to build a forwarding hierarchy from the remote sites to the head office and then on to the ISP, everything started to work.

Whilst I was looking over his domain I also noticed that there was only a single global catalog (GC) server – the first domain controller that he’d installed (the same DC that was holding all the operations master roles, although in his single domain forest the co-hosting of the infrastructure master and GC roles will not cause problems with phantom indexes as described in Microsoft knowledge base article 248047).

Microsoft knowledge base article 825036 describes best practices for DNS client settings in Windows 2000 Server and in Windows Server 2003 whilst Microsoft knowledge base article 223346 discusses the placement and optimisation of operations master roles.