Tag Archives: Policy CA

Post Installation Script (Post_Install.bat) Template for Windows Server 2008 R2 Policy CA

While implementing PKI at my current employer, I used the Microsoft Press books extensively to develop our implementation strategy.  While doing so, I noticed that some of the scripts in the book had errors in them, so I ended up revising them to correct the errors and implement PKI with the policies we felt worked best in our environment.

The Post Installation Script below is specifically for a Policy CA in a three tier hierarchy.  With this policy, your Policy CA will issue a certificate to your Issuing CA lasting 5 years and you will only need to update your CRL once a year, allowing you to keep the Policy CA offline all but a few minutes a year.  We did that in the CAPolicy.inf file as well, but this makes doubly sure that those settings were set.

Additionally, we are using this batch file to set publication points in Active Directory as well as on two web servers.  Those web servers will be listed on the Root CA Certificate, but you will manually need to copy the CRL’s and CRT’s there from %SystemRoot%\System32\CertSrv\CertEnroll.  As your Policy CA should not be a member of the domain, you will also need to import the certificates into Active Directory.


::Policy CA Post Installation Script
::Declare Configuration NC
certutil -setreg CA\DSConfigDN CN=Configuration, DC=DOMAIN,DC=TLD

::Define CRL Publication Intervals
certutil -setreg CA\CRLPeriodUnits 52
certutil -setreg CA\CRLPeriod "Weeks"
certutil -setreg CA\CRLOverlapUnits 2
certutil -setreg CA\CRLOverlapPeriod "Weeks"
certutil -setreg CA\CRLDeltaPeriodUnits 0
certutil -setreg CA\CRLDeltaPeriod "Days"

::Apply the required CDP Extension URLs
certutil -setreg CA\CRLPublicationURLs "1:%windir%\system32\CertSrv\CertEnroll\%%3%%8%%9.crl\n10:ldap:///CN=%%7%%8,CN=%%2,CN=CDP,CN=Public Key Services,CN=Services,%%6%%10\n2:http://WEBSERVER1/Certdata/%%3%%8%%9.crl\n2:http://WEBSERVER2/Certdata/%%3%%8%%9.crl"

::Apply the required AIA Extension URLs
certutil -setreg CA\CACertPublicationURLs  "1:%windir%\system32\CertSrv\CertEnroll\%%1_%%3%%4.crt\n2:ldap:///CN=%%7,CN=AIA,CN=Public Key Services,CN=Services,%%6%%11\n2:http://WEBSERVER1/CertData/%%1_%%3%%4.crt\n2:http://WEBSERVER2/CertData/%%1_%%3%%4.crt"

::Enable all auditing events for the [CompanyName] Policy CA
certutil -setreg CA\AuditFilter 127

::Set Validity Period for Issued Certificates
certutil -setreg CA\ValidityPeriodUnits 5
certutil -setreg CA\ValidityPeriod "Years"

:: Enable discrete signatures in subordinate CA certificates
Certutil -setreg CA\csp\DiscreteSignatureAlgorithm 1

::Restart Certificate Services
net stop certsvc & net start certsvc

Copy the text below into a file named Post_Install.bat and run it on your Policy CA immediately after Active Directory Certificate Services role installation.

Install Policy (CAPolicy.inf) Template for Windows Server 2008 R2 Policy CA

While implementing PKI at my current employer, I used the Microsoft Press books extensively to develop our implementation strategy.  While doing so, I noticed that some of the scripts in the book had errors in them, so I ended up revising them to correct the errors and implement PKI with the policies we felt worked best in our environment.

The Install Policy below is specifically for a Policy CA in a three tier hierarchy.  With this policy, your Policy CA certificate will last 10 years and you will only need to update your CRL once a year, allowing you to keep the Policy CA offline all but a few minutes a year.

Since this is a Policy CA, we also include a link to the Certificate Practice Statement in the configuration.

Save the text below into a file named “CAPolicy.inf” (changing the items in bold to fit your environment) and place it in C:\Windows prior to adding the Active Directory Certificate Services role on your Policy CA.


[Version Intermediate CAPolicy]
Signature="$Windows NT$"

[PolicyStatementExtension]
Policies=[CompanyName]CPS

[[CompanyNameCPS]]
OID=1.3.6.1.4.1.311.509.3.1
NOTICE=[CompanyName]  Certificate Practice Statement
URL=http://WEBSERVER/Policies-Checklists-Procedures/

[certsrv_server]
RenewalKeyLength=2048
RenewalValidityPeriodUnits=10
RenewalValidityPeriod=years

CRLPeriod=weeks
CRLPeriodUnits=52
CRLOverlapPeriod=weeks
CRLOverlapUnits=2
CRLDeltaPeriodUnits=0
CRLDeltaPeriod=days

AlternativeSignatureAlgorithm=1

How to Install Root CA Certificates on Policy CA

Prior to installing the Policy CA certificate that is issued by the Root CA, you will need to install the Root CA Certificates on the Policy CA so that it knows it can trust the CA that issued its certificate.

To do this, copy the Root CA certs from “%SystemRoot%\System32\CertSrv\CertEnroll” on the Root CA to a directory on the Policy CA (I used c:\RootCA as an example below), and then run this script (modify paths & filenames) to add them to the local certificate store.


certutil -addstore -f Root "C:\RootCA\ROOTCA.crt"
certutil -addstore -f Root "C:\RootCA\ROOTCA.crl"