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Certdog ADCS (Microsoft CA) Driver

This component is the interface to ADCS (Active Directory Certificate Services)

You have the option of installing this together with the other components but it can also be installed separately and/or on other machines

Multiple instances of the driver can be installed in the same and different domains


  • Windows Server 2019, 2022
  • .NET Framework 4.8 Runtime
  • A service account

The server hosting the driver must be in the same domain as the Microsoft CA you wish to obtain certificates from

You will normally require a service account with the required permissions to access your Microsoft CA. See the Service Account section below

If you are running multiple drivers or the driver is not installed on the same machine, ensure that port 27017 is open to wherever the database is hosted i.e. the server hosting the database must allow incoming connections on port 27017 from the machine hosting the ADCS Driver


  1. From the .\certdog\install directory, run: install-adcs-service.ps1

  2. The installer will attempt to locate the database URL but if prompted, you must enter this

  3. The full URL starts: mongodb://certmanuser...

  4. If you do not know what this value is, in the main installation, locate this file:

  5. .\certdog\config\ the database URL is referenced by the property e.g.

In this case the URL that must be entered is:


This URL contains sensitive information. Do not store unprotected. Once entered the ADCS driver will store this value encrypted

Monitor the system’s Event Log for entries in the Application log with Source: CertdogAdcsDriver

If you see entries such as the following:

Unable to connect to database at Details: Connection  to database is down. Check URL and connectivity - including any whitelists Will  try again in 30 seconds

This indicates that either the database URL was not set correctly or the TLS certificate is not trusted

If the UI is working OK then the most likely cause is that the TLS certificate is not trusted. If you are still using the default certificate bundled with the system, you can (temporarily) install this certificate:


Into the Local Machine Trusted Root Certification Authorities store. Then restart the ADCS service

If this does not resolve the issue, check that the main server’s 27017 port can be accessed from this location and the database URL entered is correct


  • Start Apps and Features. Locate the Certdog ADCS Driver and select Uninstall

  • As an Administrator, run the AdcsDriverInstaller.msifile from the \install\bin directory of the new version (e.g. c:\certdog\install\bin\AdcsDriverInstaller.msi)

    This will install the new version of the driver

If after the upgrade, the driver shows as unregistered in the Certdog UI (under the Agents menu), re-register following the steps in Registering the service below

Service Account

The Microsoft CA requires that the certificate requestor has the required permissions on the CA and certificate template in order to be issued with a certificate

See here for details around configuring permissions on the CA and templates

To configure these permissions on the ADCS Driver, you have the following options:

1. Configure a Credential from within Certdog

By default, the ADCS Driver runs as service (called Krestfield Adcs Driver) under the LOCAL SYSTEM account. As part of a certificate request, Certdog instructs the driver what account to use to request the certificate from the CA

This account to be used to request the certificates is specified in Certdog as a Credential and when creating the Certificate Issuer you select this Credential from the drop down

The account must be a service account (configured with the logon as a service and deny local logon rights) and must have the correct permissions on the CA and template in order to be able to obtain a certificate

2. Configure the ADCS Driver to run under a service account

Alternatively you may configure the ADCS Driver to run under a specific account and configure your Certificate Issuer within Certdog to not specify a credential - but to use the account the local agent (i.e. the ADCS Service) is running under

To configure the driver to run under another account, from the services snapin, locate the Krestfield Adcs Driver service and enter the details for the account on the Log On tab. You will need to enter the account’s username and password at this point

This account must still be a service account (configured with the logon as a service and deny local logon rights) and must have the correct permissions on the CA and template in order to be able to obtain a certificate

1. Run under the LOCAL SYSTEM (Computer) account

The final option does not require a specific service account but this will only work correctly if your CA and template are configured to allow the Computer Account (where this ADCS Driver is running) to obtain certificates

In this case the Krestfield Adcs Driver service remains running under LOCAL SYSTEM and your Certificate Issuer in Certdog is configured to use No Credential (use local agent account)

This means the ADCS Driver will make requests to the CA based on the account it is running under, which is the LOCAL SYSTEM (Computer) account

If you switch between these options (e.g. you decide to specify a credential within Certdog rather than run the service under a service account) the agent must be re-registered (see below)

Registering the Service

On initial install the ADCS Driver will be configured with the required settings (database URL) so there is nothing more to do

But, if the account the driver is running under changes, the agent will lose these details (as they are protected under the account the service runs under)

To reset, perform the following:

  • Open a PowerShell window as Administrator and navigate to the .\install directory e.g. c:\certdog\install and run the following command: .\configure-adcs-service.ps1

  • Next, from Certdog, select the Agents menu. The Agent entry may disappear then (when the page is refreshed after a minute or so) re-appear as un-approved. This is due to the agent going through the initialisation and key-exchange process with Certdog. Select the entry and click Approve

  • If you have existing Microsoft CA Certificate Issuers configured, for each one, click Edit and re-select the Permitted Agents (which in most cases will just be the one agent that was just approved)

Configuration in Certdog

Once the service has been successfully installed to enable it for use within Certdog it must be approved as follows:

Login to the UI and select Administration > Agents from the menu

You should see an entry for the agent. It will be named the FQDN of the machine it resides on

Click this entry and select Approve

The agent will now be able to process requests

Note that when configuring a Certificate Issuer for a Microsoft CA you must select the agent that you want to process requests for that CA

Additional File Logging

To enable more logging, set the following environment variable to true:



And restart the Krestfield Adcs Driver from the services snapin

The log file will be written to:

Environment.SpecialFolder.CommonApplicationData \Krestfield\AdcsAgent

Which is here in Windows Server 2019


Note: This log provides debug level, verbose output and may be useful for tracing issues but the log file will continue to grow. You should therefore, switch this level of logging off when not required


By default, the driver creates a number of threads (typically 5) to process certificate requests and this value should not be changed

In some high volume/performance scenarios you may want to change or experiment with this value

To change this value, set the following environment variable to the number of threads required:



Restart the Krestfield Adcs Driver from the services snapin