concept conditional forwarder in category active directory

This is an excerpt from Manning's book Learn Active Directory Management in a Month of Lunches. Login to get full access to this book.

Conditional forwarders are created to enable your DNS servers to forward requests to a specific domain. A normal forwarder will forward all requests to one or more DNS servers; a conditional forwarder will only forward requests for the one domain. Figure 15.4 illustrates this concept.

Figure 15.4. General and conditional forwarders. The general forwarder leads to the internet (top branch), while the conditional forwarder (bottom branch) leads to a specific website.

Imagine, for a moment, that you’ve created a conditional forwarder to morelunches.com. If a request to resolve www.morelunches.com is received by your internal DNS server, it’ll forward it to the DNS server indicated by the conditional forwarder. Any other request, such as www.microsoft.com, will be forwarded through your general forwarder for resolution by the internet DNS servers.

General forwarders are normally created in your perimeter network (also referred to as a DMZ, or demilitarized zone, though only the abbreviation is used) and usually remain unchanging. You can create conditional forwarders on your internal DNS server.