What are CN, OU, DC in an LDAP search?

Question

I have a search query in LDAP like this. What exactly does this query mean?

("CN=Dev-India,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com");

Answer 1

What are CN, OU, DC?

From RFC2253 (UTF-8 String Representation of Distinguished Names):

String  X.500 AttributeType
------------------------------
CN      commonName
L       localityName
ST      stateOrProvinceName
O       organizationName
OU      organizationalUnitName
C       countryName
STREET  streetAddress
DC      domainComponent
UID     userid

What does the string from that query mean?

The string ("CN=Dev-India,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com") is a path from an hierarchical structure (DIT = Directory Information Tree) and should be read from right (root) to left (leaf).

It is a DN (Distinguished Name) (a series of comma-separated key/value pairs used to identify entries uniquely in the directory hierarchy). The DN is actually the entry's fully qualified name.

Here you can see an example where I added some more possible entries.
The actual path is represented using green.

The following paths represent DNs (and their value depends on what you want to get after the query is run):

• "DC=gp,DC=gl,DC=google,DC=com"
• "OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com"
• "OU=People,DC=gp,DC=gl,DC=google,DC=com"
• "OU=Groups,DC=gp,DC=gl,DC=google,DC=com"
• "CN=QA-USA,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com"
• "CN=Dev-India,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com"
• "CN=Ted Owen,OU=People,DC=gp,DC=gl,DC=google,DC=com"

Answer 2

• CN = Common Name
• OU = Organizational Unit
• DC = Domain Component

These are all parts of the X.500 Directory Specification, which defines nodes in a LDAP directory.

You can also read up on LDAP data Interchange Format (LDIF), which is an alternate format.

You read it from right to left, the right-most component is the root of the tree, and the left most component is the node (or leaf) you want to reach.

Each = pair is a search criteria.

With your example query

("CN=Dev-India,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com");

In effect the query is:

From the com Domain Component, find the google Domain Component, and then inside it the gl Domain Component and then inside it the gp Domain Component.

In the gp Domain Component, find the Organizational Unit called Distribution Groups and then find the the object that has a common name of Dev-India.