Securely implementing Active Directory on Windows Server 2019

August 18, 2023  |  Thomas Jung

The content of this post is solely the responsibility of the author.  AT&T does not adopt or endorse any of the views, positions, or information provided by the author in this article. 

The installation of Active Directory (AD) on Windows Server 2019 calls for a thorough understanding of technical nuances and a steadfast dedication to security best practices. This guide will walk you through the process of securely implementing Active Directory, ensuring the highest level of protection for the information and resources within your company.

Planning and design

Start by carefully planning and designing. Analyze your organization's requirements, network topology, and security requirements in great detail. Establish the necessary number of organizational units (OUs), domains, and user and group structures. Make a thorough design plan that complies with your organization's compliance standards and security guidelines.

Installing Windows Server 2019

Install Windows Server 2019 on a dedicated system that satisfies the system minimums. Use the most recent Windows Server 2019 ISO and adhere to recommended procedures for a secure installation. Set a strong password for the Administrator account and enable Secure Boot if it is supported in the BIOS/UEFI settings for hardware security.

Choose the right deployment type

Select the domain controller (DC) installation as the Active Directory deployment type. By doing this, you can be confident that your server is a dedicated domain controller overseeing your domain's directory services, authentication, and security policies.

Install Active Directory Domain Services (AD DS) role

Add the Active Directory Domain Services (AD DS) role to Windows Server 2019. For the installation, use Server Manager or PowerShell. Select the appropriate forest and domain functional levels during the procedure and specify the server as a domain controller.

Choose an appropriate Forest Functional Level (FFL)

Select the highest Forest Functional Level (FFL) compatible with your domain controllers. This enables access to the most recent AD features and security upgrades. Examine the FFL specifications and confirm that every domain controller currently in use can support the selected level.

Secure DNS configuration

AD heavily relies on DNS for name resolution and service location. Ensure that DNS is configured securely by:

a. Using Active Directory Integrated Zones for DNS storage, enabling secure updates and zone replication through AD.

b. Implementing DNSSEC to protect against DNS data tampering and for secure zone signing.

c. Restricting zone transfers to authorized servers only, preventing unauthorized access to DNS data.

d. Implementing DNS monitoring and logging for suspicious activities using tools like DNS auditing and query logging.

Use strong authentication protocols

Configure Active Directory to use strong authentication protocols such as Kerberos. To stop credential-based attacks, disable older, less secure protocols like NTLM and LM hashes. Ensure domain controllers are set up to favor robust authentication techniques over weak ones when performing authentication.

Securing administrative accounts

Safeguard administrative accounts by:

a. Creating complicated, one-of-a-kind passwords for each administrative account, following the password policy guidelines, and rotating passwords frequently.

b. Adding multi-factor authentication (MFA) to all administrative accounts to improve login security and reduce the risk of credential theft.

c. Enforcing the principle of least privilege, role-based access control (RBAC), and limiting the use of administrative accounts to authorized personnel only.

d. To reduce the attack surface and potential insider threats, administrative account privileges should be regularly reviewed, and extra access rights should be removed.

Applying group policies

Leverage Group Policy Objects (GPOs) to enforce security settings and standards across your Active Directory domain. Implement password policies, account lockout policies, and other security-related configurations to improve the overall security posture.

Protecting domain controllers

Domain controllers are the backbone of Active Directory. Safeguard them by:

a. Isolating domain controllers in a separate network segment or VLAN to minimize the attack surface and prevent lateral movement.

b. Enabling BitLocker Drive Encryption on the system volume of the domain controller to safeguard critical data from physical theft or unauthorized access.

c. Setting up Windows Firewall rules to restrict inbound traffic to critical AD services and thwart potential dangers.

d. Performing regular domain controller backups and securely storing those backups to protect data integrity and speed up disaster recovery. Create system state backups using the Windows Server Backup feature, and for redundancy, think about using off-site storage.

Monitor and audit

Implement a robust monitoring and auditing system to detect potential security breaches and unauthorized access. Employ Security Information and Event Management (SIEM) solutions for thorough threat monitoring, set up real-time alerts for crucial security events, and use Windows Event Forwarding to centralize log data for analysis.

Perform regular backups

Create regular system state backups of Active Directory to ensure data integrity and quick recovery in case of data loss or disaster. Periodically test the restoration procedure to confirm its efficacy and guarantee that backups are safely kept off-site.


By following this technical guide, you can confidently and securely implement Active Directory on Windows Server 2019, ensuring your organization has a robust, dependable, highly secure Active Directory environment that safeguards valuable assets and sensitive data from the constantly changing threat landscape. Always remember that security is a continuous process, and maintaining a resilient AD infrastructure requires staying current with the latest security measures.

Share this with others

Featured resources


Insights Report

2023 AT&T Cybersecurity Insights Report: Edge Ecosystem



2023 AT&T Cybersecurity Insights Report: Edge Ecosystem

Get price Free trial