Chapter 13. Domain Name System (DNS)
The Domain Name System (DNS) is one of the most critical services on your network. When DNS isn't working, users are unable to browse the web, send or receive email, and, in the case of Active Directory, log on to a domain. Both clients and domain controllers use DNS to locate domain controllers in a particular site or that serve a particular function. Fortunately, the Microsoft DNS Server has steadily improved over the years to the point where it is robust and reliable.
DNS has been around since the early 1980s, so it is a mature protocol. Rarely does DNS change in a significant way. However, Active Directory introduced an innovative change to how DNS data is stored. Instead of using the antiquated primary and secondary zone transfer method to replicate zone data between servers, Active Directory-integrated zones store zone data in Active Directory and take advantage of the same replication process domain controllers use to replicate data. This adds multimaster capabilities to DNS that current standards do not allow for. The one catch with Active Directory-integrated zones is that the DNS Server must run on a domain controller. Overloading DNS Server responsibilities on your domain controllers may not be something you want to do if you plan on supporting a large volume of DNS requests, but it is definitely something to consider for medium to small sites.
For more on the Microsoft DNS Server beyond what this chapter covers, I recommend ...