OSUser's LDAP integration (ie. JIRA's current LDAP integration) offers delegated authentication to LDAP and does not automatically create the user in locally on successful auth.

The current Crowd Delegated Authentication Directory does perform the auto create on successful auth.

We could provide a flag to option to disable auto creation of users upon successful auth - this makes migration from JIRA's user management system easier as JIRA's LDAP config does not store the necessary data (such as user attribute mapping, eg. firstname, lastname, email, etc) to generate the user object for auto-creation.

If auto-create is disabled, then authentication should fail immediately if the user with the supplied username does not exist locally.