Active Directory Monitor PRTG
Integrated & flexible Active Directory monitoring tool
Receive a prompt alert if performance levels drop
PRTG identifies logged-out users & group membership
PRTG monitors your
entire domain forest
PRTG Network Monitor: Active Directory monitoring software
A functional Active Directory is one of the core elements in a network’s organization.
Virtually every company with a Windows infrastructure uses Active Directory to manage network resources and regulate access rights within a domain and its domain forest. The Active Directory creates a directory service, which stores information relating to a network's resources and objects.
In addition, domain controllers – usually several within a single domain – are used to store data sets regarding objects.
A replication service ensures that all of a domain's directory information is always and fully available on all of its domain controllers.
This video explains Active Directory monitoring
PRTG network monitor offers integrated,
complete active directory monitoring in real time
PRTG solves typical Active Directory problems
How PRTG defines sensors
In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive. On average you need about 5-10 sensors per device or one sensor per switch port.
Preventing Replication Errors
The first problem involves so-called replication errors. The replication of directory data between various domain controllers can be prone to error. In turn, the resulting errors can cause problems with authentication and with access rights to resources.
A variety of factors play a role in the occurrence of these errors, including the number of consecutive synchronization failures, the time of the last synchronization attempt, and the number of pending replication operations.
The PRTG sensor Active Directory Replication Errors v2 monitors up to eight different parameters during the replication of directories and the synchronization of the various domain controllers, and intelligently sounds the alarm in the event of anomalies or errors.
Identifying logged-out and deactivated users
Another common problem associated with the use of an Active Directory involves logged-out or deactivated users. Maintaining an overview of such users is next to impossible with standard AD tools.
With PRTG, you’ll get a ready-to-use script for PRTG Network Monitor which searches the Active Directory for all logged-out and deactivated users, and then lists them in PRTG: https://kb.paessler.com/en/topic/57603-is-it-possible-to-monitor-active-directory-user-account-status
To use this script, PRTG requires the Active Directory PS module. A manual with information on how to install the module can be found here: Microsoft Manual.
With a Search-AD account, you can run the script with a number of different queries. For the switches, see Microsoft’s TechNet platform: TechNet Platform
Monitor AD Group Membership
Using a PRTG script, you can enumerate how many people are in a group and then set up channel limits to put the sensor into an error status when the number of members exceeds the intended amount.
If you want to know if someone joins an AD group like Domain Admins and get a notification when this happens: https://kb.paessler.com/en/topic/62616-can-i-use-prtg-to-monitor-ad-group-membership
PRTG immediately recognizes replication errors and
logged-out users and sends intelligent alerts.
Overview: Active Directory Replication Errors v2 Sensor
Active Directory (AD) is a directory service created by Microsoft for use in a Windows Server environment. It provides authentication and authorization functions, as well as providing a framework for other such services. The directory itself is an LDAP database that contains networked objects.
Read more
PRTG uses the Windows credentials of the parent device to check the domain controller for replication errors.
The Active Directory Replication Errors v2 sensor displays the following in PRTG:
- Number of consecutive synchronization errors
- If the source was deleted
- If the scheduled synchronization was disabled
- Time of the last synchronization attempt
- Result of the last synchronization
- The last time a synchronization was successful
- Number of aligned synchronization sequences
- Number of pending replication operations
The PRTG Active Directory Replication Errors v2 Sensor in action

TIP: Monitor your Active Directory ports (53, 88, 389, 445, 464) with the PRTG Port Range sensor.
Your Active Directory in the cloud: Keep an eye on Microsoft Entra ID

If you use Microsoft Entra ID (formerly Azure AD) and want to keep an eye on what’s happening there, we’ve got you covered as well.
Set up, for example, a Microsoft Azure Subscription Cost sensor to keep your subscription costs in check. Or create a custom PRTG sensor for monitoring activities that might pose a risk:
- Be informed about risky sign-ins, for example, from an unusual or suspicious country
- Get alerts about impossible travel activities, for example, if an account logs in from Germany and two minutes later from Hongkong
- Check for AD accounts that Microsoft believes are exposed to a risk
- Keep an eye on new devices that are registered for Multi-Factor Authentication
By the way, did you know that you can use Entra ID (formerly Azure AD) single sign-on to log in to PRTG? For more information, read our blog article.
PRTG makes your job easier
Our monitoring software frees you to focus on other tasks by promptly notifying you of potential issues.
Save effort
PRTG gives you one central monitoring tool for your servers and entire network. Enjoy a quick overview of your whole infrastructure via our dashboard and app.
Save time
Getting started with PRTG is a breeze. Setting up or switching from another network monitoring tool is easy thanks to the auto-discovery and pre-configured device templates.
Save money
80% of our customers report substantial cost savings with network monitoring. Your costs of licenses will likely pay for themselves within weeks.

Also interesting:
VPN Monitoring: PRTG monitors VPN connections and measures traffic, load, and the number of users. Identify connection problems and suspicious traffic.
Ping Monitoring: PRTG uses ping to check the availability of all your network devices. If the ping fails, you will be notified immediately.
VoIP Monitoring: PRTG monitors the quality of your VoIP-connections. By preventing malfunctions and verifying service level agreements, you’ll save time and money.
SSL Monitoring: PRTG determines the extent to which your connections are protected. You can therefore learn if your connections are strong, weak, or not protected at all.
Trusted by 500,000 users and recognized
by industry analysts as a leader
“Fantastic network and infrastructure monitoring solution that is easy to deploy and easier still to use. Simply the best available.”
“Software is absolutely perfect, Support is superior. Meets all needs and requirements, this is a must have solution if you are needing any form of monitoring.”
“The tool excels at its primary focus of being a unified infrastructure management and network monitoring service.”
Notification system:
Be alerted quickly
Flexible
PRTG features a variety of alert types: E-mail, SMS, Pager, Apps, running an external application, etc. You can specify when and how each person is to be informed about network issues. To do so, you can add contacts and edit, delete, or pause your notifications at any time.
Integrated
The notification system is built into the monitoring software and is available at no extra charge. Because of its integrated quality, configuring the alert feature is done in just a few clicks.
Proactive
PRTG won't wait to let you know if your "house is on fire." You define your own thresholds. If these are crossed, you'll receive a corresponding notification. This means you can intervene promptly before clients or coworkers are aware of any problems.
“Easy to implement and configure with good technical support.”
R. v. S., ICT Manager at Heinen & Hopman Eng BV
Steffen Ille, Bauhaus-University of Weimar, Germany
“The greatest advantage of PRTG? You get to rest easy.“
PRTG: The multi-tool for sysadmins
Adapt PRTG individually and dynamically to your needs and rely on a strong API:- HTTP API: Access monitoring data and manipulate monitoring objects via HTTP requests
- Custom sensors: Create your own PRTG sensors for customized monitoring
- Custom notifications: Create your own notifications and send action triggers to external systems
- REST Custom sensor: Monitor almost everything that provides data in XML or JSON format
Still not convinced?
More than 500,000 sysadmins love PRTG
Paessler PRTG is used by companies of all sizes. Sysadmins love PRTG because it makes their job a whole lot easier.
Still not convinced?
Monitor your entire IT infrastructure
Bandwidth, servers, virtual environments, websites, VoIP services – PRTG keeps an eye on your entire network.
Try Paessler PRTG for free
Everyone has different monitoring needs. That’s why we let you try PRTG for free. Start now with your trial.
PRTG |
Network Monitoring Software - Version 23.3.88.1421 (October 2nd, 2023) |
Hosting |
Download for Windows and cloud-based version PRTG Hosted Monitor available |
Languages |
English, German, Spanish, French, Portuguese, Dutch, Russian, Japanese, and Simplified Chinese |
Pricing |
Up to 100 sensors for free (Price List) |
Unified Monitoring |
Network devices, bandwidth, servers, applications, virtual environments, remote systems, IoT, and more |
Supported Vendors & Applications |
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