IT Consultant Everyday Notes

Just some problems/solutions storage

SCCM: MP is not reachable via CMG (PKI scenario)

One of my Customers asked me to help with a CMG deployment. The idea is to get Internet-based machines managed and patched.

They do not have Hybrid AAD joined environment yet, so I need to use old good PKI.

I decided to get it in my Lab first. I do have CA on my pfsense router to get it even more interesting (the certs do not CRL link).

I issued required certificates for my SCCM, CMG and Clients and flipped my Primary site to PKI. On all Certificate settings I checked “No CRL verification” box (sice I do not have one.

Internally everything worked fine, but when I flipped a Client to “Internet” subnet I found it can connect for a short period of time only. After that connection to MP via CMG is lost, client goes grey and I see:

[CCMHTTP] ERROR INFO: StatusCode=403 StatusText=CMGConnector_Clientcertificaterequired

in LocationServices.log on the Client.

It turned out to be a known issue (KB4503442) or better by design behaviour for a scenario when Azure AD tokens are not in use.

So, I added a Client cert with the name of my MP as Subject Name and in SAN. Restarted Cloud Connector on my SCCM.

Still no go.

Checked the SMS_Cloud_ProxyConnector.log  and found:

Chain build failed cert: 77…………………………………………1

Chain 0 status: RevocationStatusUnknown

ok… So it looks like even though I unchecked Revocation List check in properties of CMG the connector is still trying to check it Smile. In troubleshooting guide (  Microsoft says the best way is to publish CRL properly (sure, I know that). and do not provide information how to disable the check.

But if we take a look in the registry HKLM\SOFTWARE\Microsoft\SMS\SMS_CLOUD_PROXYCONNECTOR  we can find a key: ClientCertSelectionNoCRLCheck set to 0 by default.

I switched it to 1 and restarted the connector.

After that the Internet Client successfully connected to the MP.

Note: I completely agree with the Vendor – the proper approach is to have your PKI properly configured and CRL published with public access; but in my case it is a Lab, so the workaround is acceptable.

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