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In Windows, a domain can have:

  • forest name (e.g.
  • dns name (e.g.
  • NetBios name (e.g. AVATOPIA)

What is the differene between a forest name and a dns name?

i how how a NetBIOS name differs from the other two: It is a legacy Windows NT 4 name, only around for compatibility with non-ActiveDirectory domains.


  • what is a forest verses a dns name?
  • when would one be different from the other?
  • which one is the "name of my domain"?
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up vote 6 down vote accepted

A forest is a collection of domains. When you create a new domain, you choose whether to make it the root domain of a new forest, or to make it part of an existing forest.

The forest name is the DNS name of the root domain of the forest, i.e., the first domain that was created in the forest.

So the forest name and the DNS name will be the same if and only if the domain is the forest root domain.

In answer to your third question: The DNS name is the name of your domain. (The forest name is, of course, the name of your forest!)

Update: If you're looking for the name of your domain:

  • forest name (e.g. <--- this is not the name of your domain, do not use
  • dns name (e.g. <-- this is the name of your domain, use this one
  • NetBios name (e.g. AVATOPIA) <-- this is a legacy domain name
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Oh my god you've hurt my brain. So a forest is a collection of domains, but one domain is special? – Ian Boyd Mar 24 '12 at 20:34
@IanBoyd: yes, that's right; the first domain in a forest is the root domain and has certain special characteristics. For example, IIRC, any schema changes have to come from the root domain. – Harry Johnston Mar 25 '12 at 1:26

According to TechNet, your forest name should not be the same as any existing domain name, so that there won't be any conflicts that require you to modify your existing DNS infrastructure. The convention suggested is choosing a suffix from an existing DNS name and adding a unique prefix to it to create a unique namespace.

To understand what a forest name is, you need to understand what forests, trees, and domains are in Active Directory. The Wikipedia page has a pretty good overview.

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Those links don't quite seem to make sense. They imply that a forest name cannot be the same as a domain name. – Ian Boyd Mar 22 '12 at 1:30
The name of a newly created AD forest must not be the same as the name of any already existing AD domain, and should not be the same as that of any already existing DNS domain. But the name of the newly created root domain will always be the same as the forest name, by definition. – Harry Johnston Mar 22 '12 at 1:35

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