FusionDirectory provides a solution to daily management of data stored in an LDAP directory.
Go in Configuration and in Login and Session panel. Set:
HTTP Header authentication: Activate
Header name: Auth-User
See also https://fusiondirectory-user-manual.readthedocs.io/en/latest/fusiondirectory/configuration/configuration.html
Just set the Auth-User header with the attribute that carries the user login, for example $uid.
Auth-User
$uid