14-19Lesson 2 Important Active Directory ConceptsDistinguished name (DN)Relative distinguished name (RDN)
Domain_name / Users / Sales / Managers / Jane DoeDomain_nameUsers OUSales OUManagers OU• DN must be unique
Jane Doe in the Directory.• RDN must be unique in an OU.
eF14us09
Figure 14-9 DNs must be unique to a directory, whereas RDNs are unique within an OU.
Globally Unique Identifier
A globally unique identifier (GUID) is a 128-bit number that is guaranteed to be
unique. GUIDs are assigned to objects when they are created. The GUID never
changes, even if you move or rename the object. Applications can store the GUID of
an object and use it to retrieve that object regardless of its current DN.
User Principal Name
User accounts have a “friendly” name, the user principal name (UPN). The UPN is
composed of a “shorthand” name for the user account and the DNS name of the tree
in which the user account object resides. For example, user Firstname Lastname (sub-
stitute the first and last names of an actual user) in the microsoft.com tree might have
a UPN of [email protected] (using the full first name and the first letter of the
last name).
Lesson Review
Use the following questions to help determine whether you have learned enough to
move on to the next lesson. If you have difficulty answering these questions, review
the material in this lesson before beginning the next lesson. You can find answers to
these questions in the “Questions and Answers” section at the end of this chapter.