Michael Waterman

Ramblings on IT and Security

Tag: WSTEP

Part 4: Using Certificate Enrollment Services in Practice

August 8, 2026 / / 0 Comments

In the previous parts of this series, I’ve looked at the architecture behind Microsoft Certificate Enrollment Services and built both the Certificate Enrollment Policy Web Service (CEP) and Certificate Enrollment Web Service (CES). At this point, all the server-side components are in place. But having a working CEP and CES infrastructure is only half the story. Ultimately, a client needs to know where to retrieve certificate enrollment policy, determine which certificate templates it is allowed to use, discover the appropriate enrollment service, and finally submit a certificate request. That’s what I will show you in this part.

I will configure Windows clients to use our CEP service in two different ways. First, I will use Group Policy, which is the obvious choice for centrally managed domain-joined systems. After that, I will configure the enrollment policy locally, which is useful for individual systems and becomes particularly interesting when working with devices that cannot rely on Active Directory Group Policy. I will then follow the complete process from policy discovery to certificate enrollment and look at what Windows is actually doing behind the scenes.

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Part 3: Installing the Certificate Enrollment Web Service (CES)

August 3, 2026 / / 0 Comments

In the previous article, we deployed the Certificate Enrollment Policy Web Service (CEP) and configured support for Kerberos, Username/Password, and Client Certificate authentication. Clients can now successfully retrieve certificate enrollment policies over HTTPS using the XCEP protocol. However, while the policy infrastructure is now in place, clients still have no way to request certificates.

In this article, I’ll complete the Microsoft Certificate Enrollment Services architecture by deploying the Certificate Enrollment Web Service (CES). I’ll prepare Active Directory, configure a dedicated Group Managed Service Account (gMSA), install IIS, deploy the CES role, configure the supported authentication methods, and validate the deployment using PowerShell. By the end of this article, you’ll have a fully operational Certificate Enrollment Web Service capable of securely processing certificate requests over HTTPS using the WSTEP protocol.

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Part 1: Understanding Microsoft Certificate Enrollment Services (CEP & CES)

August 2, 2026 / / 2 Comments

If you’ve ever worked with Microsoft Active Directory Certificate Services (AD CS), you’ve probably come across the Certificate Enrollment Policy Web Service (CEP) and the Certificate Enrollment Web Service (CES). While Microsoft provides documentation on both services, I often notice that the focus is on how to install them rather than why they exist and how they fit into the bigger picture.

When I started diving into CEP and CES myself, I quickly discovered that understanding the architecture is far more important than simply clicking through an installation wizard. Why are there two separate web services? What problem were they designed to solve? What are XCEP and WSTEP? And when should you actually consider deploying CEP and CES instead of relying on traditional certificate enrollment?

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