This is a step by step guide to install Root CA and Sub-Ordinate CA installation. Install Certificate Server – ROOT CA and Sub-Ordinate CA. This Installation is an Offline method for non-trusted domains.
This helps to install CA Servers for SCCM PKI/Internet clients, creating Certificate templates and How to Configure GPO for Certificate auto-enrollment.
Related Post – Learn The Basic Concepts of PKI – Intune PKI Made Easy With Joy Part-1
TL;DR
Installation Root CA
Perquisites
To Install Certificate Authority roles that Server should be member server of the ROOT domain.
Pre-Configuration
Only Domain Admin can install CA Server, your account needs to be add in Domain Admins group before starting CA installaiton.
Installation of Root CA
Go to the CA Server and Install role “Active Directory Certificate Services” to install ROOT CA
Select “Certificate Authority” and Click Next
If you are the member server of the domain, you can install Enterprises CA or else you can install Standalone CA
Select the “ROOTCA” and click next for continue
Select “Create a new Private key” and Click next
Enter the ROOTCA name as you preferred, and click next
After Installation completed you need to completed post Configuration by Open “Certificate Authority” Console
Validation
Sub Ordinate CA Installation
In order to install Sub Ordinate CA on Non-Trusted domain we have follow some manual export, Import and Certificate generation steps to complete
Note! – Non-Trusted Domain Sub-Ordinate CA will not get auto enroll for new Sub-Ordinate CA, you need to complete create new Req file from Sub-Ordinate CA and generate new certificate from ROOT CA then Import and start services for Sub-Ordinate CA.
Perquisites
TCP/IP 80, 443 ports should allowed between ROOT CA and Sub-Ordinate CA servers
Copy below given 2 files from ROOT CA to Sub-Ordinate CA Server (Where you want to install Sub Ordinate CA)
C:\Windows\System32\certsrv\CertEnroll
- .crt (Security Certificate file)
- .crl (Certificate Revocation file)
Pre–Configuration
Connect Sub Ordinate CA (Non-Trusted Domain Server) and open PowerShell or CMD as Administrator go to the certificate folder (where you copied certs from ROOT CA)
And execute below commands to
"certutil –dspublish –f “CRTfilename.crt” RootCA"
Note! – This command places the root CA public certificate into the Configuration container of Active Directory. Doing so allows domain client computers to automatically trust the root CA certificate and there is no additional need to distribute that certificate in Group Policy.
"certutil –addstore –f root “'CRTfilename'.crt”"
"certutil –addstore –f root “'CRLfilename.crl”"
Note! – This 2 commands place the root CA certificate and CRL into the local store of the SUBCA. This provides SUBCA immediate trust of root CA public certificate and knowledge of the root CA CRL. SUBCA could obtain the certificate from Group Policy and the CRL from the CDP location, but publishing these two items to the local store on SUBCA is helpful to speed the configuration of SUBCA as a subordinate CA.
Validation
Using the mmc command open the “Certificate snap-in” dialog box, select “Computer account“, and then click Next. In the “Select Computer” dialog box, ensure that “Local computer: (the computer this console is running on)” is selected, and then click Finish. In the console, expand “Trusted Root Certificate Authorities“, expand “Certificate Revocation List” verify ROOT CA and also expand “Certificates” validate ROOT CA
Install Sub Ordinate CA
Click Add Roles and Features and Select “Active Directory Certificates Services“
Select “Certificate Authority“
Select “Install” to continue the CA role installation
CA Role installation in in-progress
Once installation complete close the windows and open open “Active Directory Certificate Services to configure CA on the server.
Select “Certificate Authority” and click next
Select “Enterprises CA” click next
Select “Sub Ordinate CA” and Click Next
Select “Create a new private key” click next
Select Required cryptographic and algorithm for signing certificates options as per your org requirements
Provide your CA Name which will update as CA certificate issuer.
Save the request file from Sub-Ordinate CA with this request file we need to generate New Sub-Ordinate CA certificate from ROOT CA server
Click “Configure” to complete Sub-Ordinate CA Installation
Successfully configured Certificate Server with some warring errors, due to unable to communicate ROOT CA from non-trusted domain.
We need to executive some manual steps to generate New Sub-Ordinate CA to start services and enroll certificates to Non-Trusted domain clients
Connect “ROOTCA” and copy the file Certificate request file from SubOrdinate CA to ROOTCA Server.
Open PowerShell with RunAsAdministrator and execute below command to create Sub Ordinate Certificate
"certreq -submit requestfile.req"
It will popup all your ROOT CA servers, select the correct ROOT CA and click OK to generate certificate
Save the Certificate file
Run below command to create CRT file for Sub Ordinate CA
"certreq -retrieve "RequestId" c:\filename.crt" to save CRT file
Connect Sub Ordinate CA Server, copy sub-ordinate CA crl and crt files from ROOT CA
Open “Certificate Authority” Console on Sub Ordinate CA
Right Click on Server Name – All Tasks – Install CA Certificate
Browse and select CRT file which is got generated from ROOT CA
Once Certificate install you can start service
Once Service started you can see GREEN symbol for CA servers as it indicates CA services is running.
Configure Certificate Templet’s
Create “ConfigMgr Client Certificate” templet
Right Click on Certificate Templates and Click Manage to open Certificate Management Console
To create SCCM Client Authentication Certificate – right click on “Workstation Authentication” and click Duplicate Template
Give the name of Template “ConfigMgr Client Certificate”
Provide allow permissions to “Read, Enroll and Autoenroll” for domain Computers
Click OK for Save “ConfigMgr Client Certificate” Templet.
To create Web Server Authentication Certificate – Right click on “Web Server” Templet and Click Duplicate Template
Give the name of Web Server Template “ConfigMgr Web Server Certificate”
Go to “Request Handling” tab and select “Allow Private Key to be exported”
Go to the “Subject Name” Tab and Select “Supply in the Request”
Go to “Security” Tab and give allow permission to only our SCCM Server, As this certificate required for SCCM DP Server only.
Close Certificate manage window
To add newly created template in Certificate Template’s page by running below cmd.
certutil -SetCAtemplates +ConfigMgrClientCertificate
certutil -SetCAtemplates +ConfigMgrWebServerCertificate
Once Templates add in Certificate Templates page it available for enroll to client machines.
Configure Group Policy for Auto Enrolment of Certificates
On the domain controller, launch the “Group Policy Management“. Navigate to your domain, right-click the domain, and then select Create a GPO in this domain, and Link it here. In the “New GPO” dialog box, enter a name for the new Group Policy, such as “Autoenroll Certificates“, and click “OK“
In the results pane, on the “Linked Group Policy Objects” tab, right-click the new Group Policy, and then click Edit. In the “Group Policy Management Editor“, expand Policies under “Computer Configuration“, and then navigate to Windows Settings > Security Settings > Public Key Policies. Right-click the object type named “Certificate Services Client – Auto-enrollment“, and then click “Properties“
From the “Configuration Model” drop-down list, select “Enabled“, select “Renew expired certificates, update pending certificates, and remove revoked certificates“, select “Update certificates that use certificate templates“, and then click “OK”. Close the GPMC.
Verifying Certificate Installation on Computers
In the above steps we have configured auto enrollment of the workstation authentication template by using group policy. This procedure installs the client certificate on computers and verifies the installation. Restart the workstation computer, and wait a few minutes before logging on.
- Using the mmc command open the “Certificate snap-in” dialog box
- select “Computer account“, and then click Next.
- In the “Select Computer” dialog box, ensure that “Local computer: (the computer this console is running on)” is selected, and then click Finish.
- In the console, expand “Certificates (Local Computer)“, expand “Personal“, and then click “Certificates“.
- In the results pane, confirm that a certificate is displayed that has “Client Authentication” displayed in the “Intended Purpose” column, and that “SCCM Client Certificate” is displayed in the “Certificate Template” column.
- Close the console.
