I have found an example if using Apache proxypass to proxy access to cups. We could put the ldap authentication there, but we need to pass that information along to cups.

Should you implement a custom user registry to help mitigate access to your various LDAP servers in order to simplify security tasks such as authentication and group association? The answer to that ...

For services that are unable to use CAS and SAML authentication and are hosted on a Purdue network, the Identity and Access Management Office (IAMO) offers an LDAP authentication service. This service ...