LDAPBackend uses the standard logging module to log debug and warning messages to the logger named 'django_auth_ldap'. If you need debug messages to help with configuration issues, you should add a handler to this logger. Note that this logger is initialized with a level of NOTSET, so you may need to change the level of the logger in order to get debug messages.

import logging

logger = logging.getLogger('django_auth_ldap')