# Integrating Microsoft AD CS server with MDM

Last updated: August 13, 2026

This page guides IT admins through integrating Microsoft Active Directory Certificate Services (AD CS) with Mobile Device Manager Plus using SCEP. It covers prerequisites including NDES installation, configuring and mapping certificate templates in Windows Server, preventing challenge password expiry, and setting up the CA server and certificate templates in MDM. The integration enables organizations to dynamically create user-specific certificates, distribute them at scale, and automate certificate renewal on managed devices to ensure data security and compliance.

Microsoft Active Directory Certificate Services (AD CS) provides digital certificates that can be used to encrypt, digitally sign and authenticate users and devices on a network. By integrating Microsoft AD CS with Mobile Device Manager Plus, IT admins can leverage AD and Groups Policy for certificate registration and assignments. It allows organizations to dynamically create user-specific certificates, distribute certificates at large scale and automatically renew the certificates on devices, thereby ensuring data security and compliance to organizational standards.

## Pre-requisites

[NDES must be installed in a Windows Server machine](https://learn.microsoft.com/en-us/windows-server/identity/ad-cs/network-device-enrollment-service-overview)

### Steps to increase the password cache limit

1. Open the Registry Editor in NDES machine and navigate to **HKEY_LOCAL_MACHINE - > SOFTWARE -> Microsoft -> Cryptography -> MSCEP -> UseSinglePassword**

   ![](https://www.manageengine.com/mobile-device-management/help/images/scep_pwd1.PNG)

2. Set the value for **UseSinglePassword** to **0**. By configuring this, every time we hit the NDES admin URL, it will generate a unique challenge password. Admin URL: **https://<ndes_fqdn>/certsrv/mscep_admin/mscep.dll**
3. Restart the IIS server.

   ![](https://www.manageengine.com/mobile-device-management/help/images/scep_pwd2.PNG)

4. As shown in the above screenshot, when we navigate to the Admin URL, we will get a challenge password, and upon refreshing the page, we will get another challenge password.
5. A problem with this configuration is that NDES will only generate 5 passwords each hour.

   ![](https://www.manageengine.com/mobile-device-management/help/images/scep_pwd3.PNG)

6. We can resolve this, by increasing the Password cache limit of the NDES. To do this, in the registry editor, navigate to **HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MSCEP**
7. Create a new key and provide the name as **PasswordMax**
8. Right click on the **PasswordMax** key, and select **New -> DWORD (32-bit) Value**, provide the name as **PasswordMax** and provide a value according to your organization needs.

   ![](https://www.manageengine.com/mobile-device-management/help/images/scep_pwd4.PNG)

9. Restart the IIS.

### Configuring SCEP in MDM

1. The value for Subject should be in LDAP DN format as explained [here](https://msdn.microsoft.com/en-us/library/aa366101(v=vs.85).aspx).

Follow the steps given below to configure SCEP in MDM:

- On the console, navigate to **Device Mgmt -> Certificates**
- Click on the **CA Servers** tab and click on **Add CA server**
- Provide the following details:

| Profile Specification | Description |
|---|---|
| Server Type | Specify server type as Microsoft AD CS. |
| Certificate Authority Name | Specify the name of the Certificate Authority issuing certificates. |
| Server URL | The URL to be specified in the device to obtain certificate. Provide HTTP Server URL, if the SCEP server is within the organization network and not exposed to external networks. The certificate is requested through this URL. |
| Add CA Certificate | Upload the Certificate Authority's certificate |

## Creating templates for the CA servers

For creating user-specific certificates, a template needs to be configured based on which all the certificates will be issued by the CA.

Follow the steps given below to configure the template on MDM:

- On the console, navigate to **Device Mgmt -> Certificates**.
- Click on **Templates** tab and click on **Add Templates**
- Select the server to which the template belongs
- Provide the following details:

| Profile Specification | Description |
|---|---|
| Certificate Template Name | Specify the certificate template name. |
| Subject | Specify the Subject DN that needs to be present in the certificate. You can use dynamic keys such as %username%, %email%, %firstname% to fetch the the corresponding details mapped to the device. For instance, you can specify C=US,O=Zylker,OU=Zylker,CN=%firstname%. |
| Subject Alternative Name Type | Specify one of the following values None, RFC 822 Name, DNS Name or Uniform Resource Identifier for the subject alternative name type |
| Subject Alternative Name Value **(Can be configured only if Subject Alternative Name Type is configured)** | Specify a value for subject alternative name value. The values to be entered can include DNS name, URI or email. For instance, you can use the dynamic key **%email%** for the subject alternative name value, email. |
| NT Principal Name | Specify the NT Principal Name used in the organization. |
| Maximum Number of Failed Attempts | Maximum number of failed validation attempts allowed to obtain the certificate from the CA. Once the maximum limit is exceeded, users will be temporarily restrcted from attempting to vaildate the user account. |
| Time interval between attempts | Time to wait before subsequent attempts to obtain the certificate |
| Challenge Type | A pre-shared secret key provided by the CA, which adds additional layer of security. If **Static** is chosen, the challenge password will be submitted to the SCEP server for authentication and all the devices will use the same password for authentication. If **Dynamic** is chosen, each device will use a unique challenge password for authentication. If **None** is chosen, no authentication is requested by the SCEP server and any device can receive the certificate by accessing the SCEP URL. |
| Enrollment Challenge Password **(Can be configured only if Static challenge type is selected)** | Provide the challenge password to be used for authentication. |
| Challenge URL **(Configurable only if challenge type is set as Dynamic)** | Specify the AD CS MSCEP admin endpoint URL. |
| Challenge Username **(Configurable only if challenge type is set as Dynamic)** | Specify the AD CS MSCEP admin username to be used. |
| Challenge Password **(Configurable only if challenge type is set as Dynamic)** | Specify the AD CS MSCEP admin password to be used. |
| Key Size | Specify whether the key is 1024 or 2048 bits |
| Use as Digital Signature | Enabling this option ensures the certificate can be used for Digital Signature |
| Use for Key Encipherment | Enabling this option ensures the certificate can be used for Key Encipherment |
| Certificate Auto Renewal | Enabling this option ensures the certificates are renewed automatically before it expires. |
| Certificate Automatic Renewal Before | Specify the number of days before which the the certificate must be auto-renewed. |

## Creating a SCEP profile

To distribute certificates to managed devices, a SCEP profile need to associated with these devices. Follow the steps given below to create and associate the SCEP profile to devices:

1. Navigate to **Device Mgmt -> Profiles** and create either an Apple, Android or Windows profile.
2. Select **SCEP** from the left pane.
3. Select the created Certificate template.
4. Click on **Save** and publish the profile.

It is recommended to distribute the [profile to a device](https://www.manageengine.com/mobile-device-management/help/profile_management/mdm_associating_profiles_to_devices.html) for testing before distributing it to your production environment. Once testing is complete, you can distribute the profile to your production environment using [Groups](https://www.manageengine.com/mobile-device-management/help/profile_management/mdm_associating_profiles_to_groups.html).

## Frequently Asked Questions

### 1. Why shouldn't I grant Enroll permissions to broad groups like Domain Users on the certificate template?

Granting Enroll permissions to broad or widely scoped groups such as Domain Users can lead to unintended enrollments, unauthorized certificate requests, and potential impersonation risks. Only the dedicated NDES service account should be granted Read and Enroll permissions.

### 2. Why do I need NDES installed before integrating AD CS?

NDES (Network Device Enrollment Service) must be installed on a Windows Server machine because it lets ADCS proxy certificate requests from MDM-enrolled devices using SCEP.

### 3. How do I prevent the SCEP challenge password from expiring?

Set the UseSinglePassword registry value under HKEY_LOCAL_MACHINE -> SOFTWARE -> Microsoft -> Cryptography -> MSCEP to 1, then restart the NDES server. This is recommended if you're using a Challenge password.

### 4. What's the difference between the Static and Dynamic challenge types?

With Static, all devices submit the same pre-shared challenge password for authentication. With Dynamic, each device uses a unique challenge password generated per request, and requires the AD CS MSCEP admin endpoint URL, username, and password to be configured.

### 5. NDES only generates 5 challenge passwords per hour. How can I fix this?

Create a new DWORD (32-bit) value named PasswordMax under HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MSCEP in the registry editor, set it to a value suited to your organization's needs, and restart IIS.