Active Directory Interview Questions and Answers

Q1. Mention what is Active Directory?
An active directory is a directory structure used on Micro-soft Windows based servers and computers to store data and information about networks and domains.

Q2. What is Native Mode?
When all the domain controllers in a given domain are running Windows 2000 Server. This mode allows organizations to take advantage of new Active Directory features such as Universal groups, nested group membership, and inter-domain group membership.

Q3. What is Organizational Units ?
The Organizational Unit (OU)is a critical design factor impacting security, policy, efficiency, and the cost of administration. Organizational Units are a type of LDAP (X.500) container. It can be thought of as a sub-domain element with similar properties to domains. They are components internal to domains. OUs are part of the LDAP name space and not the DNS namespace.

Q4. Do we use clustering in Active Directory? Why?
No one installs Active Directory in a cluster. There is no need of clustering a domain controller. Because Active Directory provides total redundancy with two or more servers

Q5. What is sites ? What are they used for ?
One or more well-connected (highly reliable and fast) TCP/IP subnets.
A site allows administrators to configure Active Directory access and replication topology to take advantage of the physical network.
A Site object in Active Directory represents a physical geographic location that hosts networks. Sites contain objects called Subnets.
Sites can be used to Assign Group Policy Objects, facilitate the discovery of resources, manage active directory replication, and manage network link traffic.
Sites can be linked to other Sites. Site-linked objects may be assigned a cost value that represents the speed, reliability, availability, or other real property of a physical resource. Site Links may also be assigned a schedule.

Q6. What is Domains in Active Directory?
In Windows 2000, a domain defines both an administrative boundary and a security boundary for a collection of objects that are relevant to a specific group of users on a network. A domain is an administrative boundary because administrative privileges do not extend to other domains. It is a security boundary because each domain has a security policy that extends to all security accounts within the domain. Active Directory stores information about objects in one or more domains.
Domains can be organized into parent-child relationships to form a hierarchy. A parent domain is the domain directly superior in the hierarchy to one or more subordinate, or child, domains. A child domain also can be the parent of one or more child domains, as shown below.

Q7. Explain what is SYSVOL?
The SysVOL folder keeps the server’s copy of the domain’s public files. The contents such as users, group policy, etc. of the sysvol folders are replicated to all domain controllers in the domain.

Q8. Tell me about Infrastructure master?
The Infrastructure Master is used to maintain references to objects in other domains, known as phantoms.The Infrastructure Master is responsible for fixing up stale references from objects in its domain to objects in other domains. The Infrastructure Master FSMO role owner is used to continually maintain the phantoms whenever the objects they refer to are changed or moved in the object’s domain.

Q9. What is Active Directory Recycle Bin?
Active Directory Recycle bin is a feature of Windows Server 2008 AD. It helps to restore accidentally deleted Active Directory objects without using a backedup AD database, rebooting domain controller or restarting any services

Q10. Trying to look at the Schema, how can I do that ?
register schmmgmt.dll using this command
c:\windows\system32>regsvr32 schmmgmt.dll
Open mmc –> add snapin –> add Active directory schema
name it as schema.msc
Open administrative tool –> schema.msc

Q11. Mention which is the default protocol used in directory services?
The default protocol used in directory services is LDAP (Lightweight Directory Access Protocol).

Q12. What is LDAP?
LDAP is the directory service protocol that is used to query and update AD. LDAP naming
paths are used to access AD objects and include the following:

• Distinguished names
• Relative Distinguished names 

Q13. What is the purpose of replication in AD ?
The purpose of replication is to distribute the data stored within the directory throughout the organization for increased availability, performance, and data protection. Systems administrators can tune replication to occur based on their physical network infrastructure and other constraints.

Q14. What is RODC? Why do we configure RODC?
Read only domain controller (RODC) is a feature of Windows Server 2008 Operating System. RODC is a read only copy of Active Directory database and it can be deployed in a remote branch office where physical security cannot be guaranteed. RODC provides more improved security and faster log on time for the branch office

Q15. What is the port no of Kerbrose ?
88

Q16. What is Mixed Mode?
Allows domain controllers running both Windows 2000 and earlier versions of Windows NT to co-exist in the domain. In mixed mode, the domain features from previous versions of Windows NT Server are still enabled, while some Windows 2000 features are disabled. Windows 2000 Server domains are installed in mixed mode by default. In mixed mode the domain may have Windows NT 4.0 backup domain controllers present. Nested groups are not supported in mixed mode.

Q17. Mention what is Kerberos?
Kerberos is an authentication protocol for network. It is built to offer strong authentication for server/client applications by using secret-key cryptography.

Q18. What is stale ?
Stale means references to objects that have been moved or renamed so that the local copy of the remote object’s name is out of date .

Q19. How do you check currently forest and domain functional levels? Say both GUI and Command line.
To find out forest and domain functional levels in GUI mode, open ADUC, right click on the domain name and take properties. Both domain and forest functional levels will be listed there. TO find out forest and domain functional levels, you can use DSQUERY command.

Q20. What is the port no of Global catalog ? 
3268

Q21. Explain the term FOREST in AD?
Forest is used to define an assembly of AD domains that share a single schema for the AD. All DC’s in the forest share this schema and is replicated in a hierarchical fashion among them.

Q22. Minimum Requirement for Installing AD?

• Windows Server, Advanced Server, Datacenter Server
• Minimum Disk space of 200MB for AD and 50MB for log files
• NTFS partition
• TCP/IP Installed and Configured to use DNS
• Administrative privilege for creating a domain in existing network

Q23. What is SID ?
Security Identifier (SID) is a unique, variable-length identifier used to identify a trustee or security principal.

Q24. Explain Knowledge Consistency Checker (KCC)
KCC can be expanded as Knowledge Consistency Checker. It is a protocol process running on all domain controllers, and it generates and maintains the replication topology for replication within sites and between sites.

Q25. What is the port no of LDAP ?
389

Q26. What are the tools used to check and troubleshoot replication of Active Directory?
We can use command line tools such as repadmin and dcdiag. GUI toolREPLMON can also be used for replication monitoring and troubleshooting.

Q27. Explain Active Directory Schema ? 
Windows 2000 and Windows Server 2003 Active Directory uses a database set of rules called “Schema”. The Schema is defines as the formal definition of all object classes, and the attributes that make up those object classes, that can be stored in the directory. As mentioned earlier, the Active Directory database includes a default Schema, which defines many object classes, such as users, groups, computers, domains, organizational units, and so on.
These objects are also known as “Classes”. The Active Directory Schema can be dynamically extensible, meaning that you can modify the schema by defining new object types and their attributes and by defining new attributes for existing objects. You can do this either with the Schema Manager snap-in tool included with Windows 2000/2003 Server, or programmatically.