AIA Option Numbers and %Variables – What do they mean? · Tech

What do these %Variables and option numbers mean? Not sure what I’m talking about? Take a look at the screenshot below:

The subordinate CA's AIA extension settings beside the registry value CACertPublicationURLs, where each URL starts with an option number

How are these values determined? Well for AIA’s, the values are based off the table below:

Option Number	Description
0	No Options Defined
1	Automatically Publish CA Certificate to this location
2	Include in the AIA extension of issued certificates
32	Include in the online certificate status protocol (OCSP) extension

From our screenshot above and combining the information from the table, we can work out how the values are calculated:

Value	Description
1	Automatically Publish CA Certificate to this location
2	Include in the AIA extension of issued certificates
3	Automatically Publish CA Certificate to this location Include in the AIA extension of issued certificates

What about the percentage values (variables) such as the ones in the screenshot below?

The AIA locations in the CA console beside CACertPublicationURLs in the registry, showing how variables like %1 map to <ServerDNSName>

Variable	Variable Display Name in CertSrv MMC	Description
%1	<ServerDNSName>	The DNS name of the certification authority server
%2	<ServerShortName>	The NetBIOS name of the certification authority server
%3	<CaName>	The name of the Certificate Authority
%4	<CertificateName>	The renewal extension of the certification authority
%6	<ConfigurationContainer>	The location of the Configuration container in Active Directory
%7	<CATruncatedName>	The “sanitized” name of the certification authority, truncated to 32 characters with a hash on the end
%11	<CAObjectClass>	The object class identifier for a certification authority, used when publishing to an LDAP URL