RPC Error When requesting Requesting new User Cert WIN32: 1722

Question

Hi have spent 3 days trying to resolve this RPC error when trying to request a new user certificate. Have checked pretty much everything !! DCOM , , Certificate Security groups DCOM security groups, followed most articles on google. but still struggling.

The weird thing is it works on the latest build of windows 10. but doesn't work on win build 1809 ???

Anyone any ideas?

Cheers
Mark

Answer 1

Hello markgreen-2670,

Thank you for posting in our Q&A forum.

The issue may caused by port mostly, please check if all ports that AD CS needed is open on client and CA server, including AD DS ports.

Certificate Services relies on RPC and DCOM to communicate with clients by using random TCP ports that are higher than port 1024.

RPC TCP 135
SMB TCP 445, 139
Randomly allocated high TCP ports
TCP random port number between 1024 - 65535
random port number between 49152 - 65535

For more information about AD CD ports, please read the links below.

https://learn.microsoft.com/zh-tw/archive/blogs/pki/firewall-rules-for-active-directory-certificate-services

https://learn.microsoft.com/en-US/troubleshoot/windows-server/networking/service-overview-and-network-port-requirements

Best Regards,
Daisy Zhou

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