Ndes-scep-windows-test-tool !new! -

The is an indispensable utility for anyone managing Windows-based PKI with SCEP enrollment. It reduces hours of manual wget , certreq , and Event Log spelunking into a structured, repeatable, and automatable process. By simulating a SCEP client faithfully, it exposes misconfigurations in IIS, NDES registry, CA templates, and network paths long before production devices fail. Whether you are onboarding thousands of IoT sensors or just troubleshooting a single router’s certificate renewal, this tool brings clarity and confidence to NDES operations.

: https:// /certsrv/mscep/mscep.dll

NDESScepTestTool.exe --server https://ndes.corp.local/certsrv/mscep/mscep.dll --challenge "secret123" ndes-scep-windows-test-tool

A successful run of the ndes-scep-windows-test-tool will produce:

The NDES SCEP Windows Test Tool fits into a broader PKI toolchain: The is an indispensable utility for anyone managing

If your tests fail, these are the key locations to check for clues: How to test a Windows NDES SCEP server

NDESScepTestTool.exe --server https://ndes.corp.local/mscep/mscep.dll --challenge env:CHALLENGE_PWD --key-type ECDSA_P256 --subject "CN=testdevice.corp.local" --san dns:testdevice.corp.local --install --verbose --log scep_test.log Whether you are onboarding thousands of IoT sensors

Open PowerShell as Administrator on the NDES server.

| Symptom | Tool’s Diagnostic | |---------|--------------------| | HTTP 403 Forbidden | Tests anonymous vs. Windows auth; suggests checking IIS authentication settings. | | “Invalid challenge password” | Compares provided hash vs. NDES registry ValidationFailures ; reveals mismatch in hashing algorithm (SHA1 vs SHA256). | | Timeout during polling | Shows NDES never created a transaction ID; points to CA permission or template mismatch. | | Certificate not trusted | After retrieval, attempts chain build; identifies missing CA or intermediate. | | “Bad recipient nonce” | Detects MS-SCEP anti-replay nonce mismatch; prompts to retry fresh enrollment. | | Event ID 30, 31, 33 in NDES log | Tool correlates local failure with remote event IDs via optional remote event log query. |

For IT administrators and security engineers, this tool is the difference between hours of guesswork and a five-minute diagnosis. In this article, we will dissect the ndes-scep-windows-test-tool , exploring what it is, how it works, and exactly how to use it to validate your SCEP infrastructure.

You can find this script in the official Microsoft Graph PowerShell Intune samples repository .