Azure MFA NPS extension 100% CPU usage

Matt 21 Reputation points
2020-01-20T02:15:19.96+00:00

I have an NPS server with the Azure MFA extension enabled. While the extension is working properly, after a few hours the dllhost.exe process starts consuming 100% of the CPU. I haven't been able to find any logs that indicate what's going on so I don't have a whole lot more info to present here.

All I can do to resolve the issue is to kill the process and then restart the NPS service. Of course, the problem repeats.

Microsoft Entra ID
Microsoft Entra ID
A Microsoft Entra identity service that provides identity management and access control capabilities. Replaces Azure Active Directory.
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  1. AmanpreetSingh-MSFT 56,466 Reputation points
    2020-01-20T08:32:51.307+00:00

    @Matt , Please capture a NetMon trace and filter the traffic for dllhost.exe process. I have seen this if there are frequent retries to perform RADIUS auth by RADIUS clients, such as VPN client.

    If that is not the case, kill the process, restart the NPS service and capture 2-3 samples of ProcDump while the CPU is spiking up and if you need assistance with dump analysis, please open a support case with Microsoft.

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    Please "Accept as answer" wherever the information provided helps you to help others in the community.

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  2. Gerald Lopez 1 Reputation point
    2021-04-19T13:18:18.563+00:00

    @Matt

    Did you ever come across a solution for this, I am having the same issue, only fix right now is restarting the NPS every 3 hours which I read as a temp solution. One persion mentioned if your using fortinets which I am, certain firmware versions do this where the root issue is that the Fortinet's can't handle text message MFA and send the NPS into a forever loop spiking dllhost (com surrogate) to 100%.

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