Django authentication using LDAP

This authentication backend enables a Django project to authenticate against any LDAP server. To use it, add django_auth_ldap.backend.LDAPBackend to AUTHENTICATION_BACKENDS. It is not necessary to add django_auth_ldap to INSTALLED_APPLICATIONS unless you would like to run the unit tests. LDAP configuration can be as simple as a single distinguished name template, but there are many rich options for working with User objects, groups, and permissions. This backend depends on the python-ldap module.


LDAPBackend does not inherit from ModelBackend. It is possible to use LDAPBackend exclusively by configuring it to draw group membership from the LDAP server. However, if you would like to assign permissions to individual users or add users to groups within Django, you’ll need to have both backends installed:


Configuring basic authentication

If your LDAP server isn’t running locally on the default port, you’ll want to start by setting AUTH_LDAP_SERVER_URI to point to your server.


That done, the first step is to authenticate a username and password against the LDAP service. There are two ways to do this, called search/bind and simply bind. The first one involves connecting to the LDAP server either anonymously or with a fixed account and searching for the distinguished name of the authenticating user. Then we can attempt to bind again with the user’s password. The second method is to derive the user’s DN from his username and attempt to bind as the user directly.

Because LDAP searches appear elsewhere in the configuration, the LDAPSearch class is provided to encapsulate search information. In this case, the filter parameter should contain the placeholder %(user)s. A simple configuration for the search/bind approach looks like this (some defaults included for completeness):

import ldap
from django_auth_ldap.config import LDAPSearch

AUTH_LDAP_USER_SEARCH = LDAPSearch("ou=users,dc=example,dc=com",
    ldap.SCOPE_SUBTREE, "(uid=%(user)s)")

This will perform an anonymous bind, search under "ou=users,dc=example,dc=com" for an object with a uid matching the user’s name, and try to bind using that DN and the user’s password. The search must return exactly one result or authentication will fail. If you can’t search anonymously, you can set AUTH_LDAP_BIND_DN to the distinguished name of an authorized user and AUTH_LDAP_BIND_PASSWORD to the password.

To skip the search phase, set AUTH_LDAP_USER_DN_TEMPLATE to a template that will produce the authenticating user’s DN directly. This template should have one placeholder, %(user)s. If the previous example had used ldap.SCOPE_ONELEVEL, the following would be a more straightforward (and efficient) equivalent:

AUTH_LDAP_USER_DN_TEMPLATE = "uid=%(user)s,ou=users,dc=example,dc=com"

LDAP is fairly flexible when it comes to matching DNs. LDAPBackend make an effort to accommodate this by forcing usernames to lower case when creating Django users and trimming whitespace when authenticating.

By default, all LDAP operations are performed with the AUTH_LDAP_BIND_DN and AUTH_LDAP_BIND_PASSWORD credentials, not with the user’s. Otherwise, the LDAP connection would be bound as the authenticating user during login requests and as the default credentials during other requests, so you would see inconsistent LDAP attributes depending on the nature of the Django view. If you’re willing to accept the inconsistency in order to retrieve attributes while bound as the authenticating user. see AUTH_LDAP_BIND_AS_AUTHENTICATING_USER.

By default, LDAP connections are unencrypted and make no attempt to protect sensitive information, such as passwords. When communicating with an LDAP server on localhost or on a local network, this might be fine. If you need a secure connection to the LDAP server, you can either use an ldaps:// URL or enable the StartTLS extension. The latter is generally the preferred mechanism. To enable StartTLS, set AUTH_LDAP_START_TLS to True:


Working with groups

Working with groups in LDAP can be a tricky business, mostly because there are so many different kinds. This module includes an extensible API for working with any kind of group and includes implementations for the most common ones. LDAPGroupType is a base class whose concrete subclasses can determine group membership for particular grouping mechanisms. Three built-in subclasses cover most grouping mechanisms:

posixGroup objects are somewhat specialized, so they get their own class. The other two cover mechanisms whereby a group object stores a list of its members as distinguished names. This includes groupOfNames, groupOfUniqueNames, and Active Directory groups, among others. The nested variant allows groups to contain other groups, to as many levels as you like. For convenience and readability, several trivial subclasses of the above are provided:

To get started, you’ll need to provide some basic information about your LDAP groups. AUTH_LDAP_GROUP_SEARCH is an LDAPSearch object that identifies the set of relevant group objects. That is, all groups that users might belong to as well as any others that we might need to know about (in the case of nested groups, for example). AUTH_LDAP_GROUP_TYPE is an instance of the class corresponding to the type of group that will be returned by AUTH_LDAP_GROUP_SEARCH. All groups referenced elsewhere in the configuration must be of this type and part of the search results.

import ldap
from django_auth_ldap.config import LDAPSearch, GroupOfNamesType

AUTH_LDAP_GROUP_SEARCH = LDAPSearch("ou=groups,dc=example,dc=com",
    ldap.SCOPE_SUBTREE, "(objectClass=groupOfNames)"

The simplest use of groups is to limit the users who are allowed to log in. If AUTH_LDAP_REQUIRE_GROUP is set, then only users who are members of that group will successfully authenticate. AUTH_LDAP_DENY_GROUP is the reverse: if given, members of this group will be rejected.

AUTH_LDAP_REQUIRE_GROUP = "cn=enabled,ou=groups,dc=example,dc=com"
AUTH_LDAP_DENY_GROUP = "cn=disabled,ou=groups,dc=example,dc=com"

More advanced uses of groups are covered in the next two sections.

User objects

Authenticating against an external source is swell, but Django’s auth module is tightly bound to the django.contrib.auth.models.User model. Thus, when a user logs in, we have to create a User object to represent him in the database. Because the LDAP search is case-insenstive, the default implementation also searches for existing Django users with an iexact query and new users are created with lowercase usernames. See get_or_create_user() if you’d like to override this behavior.

The only required field for a user is the username, which we obviously have. The User model is picky about the characters allowed in usernames, so LDAPBackend includes a pair of hooks, ldap_to_django_username() and django_to_ldap_username(), to translate between LDAP usernames and Django usernames. You’ll need this, for example, if your LDAP names have periods in them. You can subclass LDAPBackend to implement these hooks; by default the username is not modified. User objects that are authenticated by LDAPBackend will have an ldap_username attribute with the original (LDAP) username. username will, of course, be the Django username.

LDAP directories tend to contain much more information about users that you may wish to propagate. A pair of settings, AUTH_LDAP_USER_ATTR_MAP and AUTH_LDAP_PROFILE_ATTR_MAP, serve to copy directory information into User and profile objects. These are dictionaries that map user and profile model keys, respectively, to (case-insensitive) LDAP attribute names:

AUTH_LDAP_USER_ATTR_MAP = {"first_name": "givenName", "last_name": "sn"}
AUTH_LDAP_PROFILE_ATTR_MAP = {"home_directory": "homeDirectory"}

Only string fields can be mapped to attributes. Boolean fields can be defined by group membership:

    "is_active": "cn=active,ou=groups,dc=example,dc=com",
    "is_staff": "cn=staff,ou=groups,dc=example,dc=com",
    "is_superuser": "cn=superuser,ou=groups,dc=example,dc=com"

    "is_awesome": "cn=awesome,ou=django,ou=groups,dc=example,dc=com"

By default, all mapped user fields will be updated each time the user logs in. To disable this, set AUTH_LDAP_ALWAYS_UPDATE_USER to False. If you need to populate a user outside of the authentication process—for example, to create associated model objects before the user logs in for the first time—you can call django_auth_ldap.backend.LDAPBackend.populate_user(). You’ll need an instance of LDAPBackend, which you should feel free to create yourself. populate_user() returns the new User or None if the user could not be found in LDAP.

If you need to access multi-value attributes or there is some other reason that the above is inadequate, you can also access the user’s raw LDAP attributes. user.ldap_user is an object with four public properties. The group properties are, of course, only valid if groups are configured.

  • dn: The user’s distinguished name.
  • attrs: The user’s LDAP attributes as a dictionary of lists of string values. The dictionaries are modified to use case-insensitive keys.
  • group_dns: The set of groups that this user belongs to, as DNs.
  • group_names: The set of groups that this user belongs to, as simple names. These are the names that will be used if AUTH_LDAP_MIRROR_GROUPS is used.

Python-ldap returns all attribute values as utf8-encoded strings. For convenience, this module will try to decode all values into Unicode strings. Any string that can not be successfully decoded will be left as-is; this may apply to binary values such as Active Directory’s objectSid.

If you would like to perform any additional population of user or profile objects, django_auth_ldap exposes two custom signals to help: populate_user and populate_user_profile. These are sent after the backend has finished populating the respective objects and before they are saved to the database. You can use this to propagate additional information from the LDAP directory to the user and profile objects any way you like.


Users created by LDAPBackend will have an unusable password set. This will only happen when the user is created, so if you set a valid password in Django, the user will be able to log in through ModelBackend (if configured) even if he is rejected by LDAP. This is not generally recommended, but could be useful as a fail-safe for selected users in case the LDAP server is unavailable.


Groups are useful for more than just populating the user’s is_* fields. LDAPBackend would not be complete without some way to turn a user’s LDAP group memberships into Django model permissions. In fact, there are two ways to do this.

Ultimately, both mechanisms need some way to map LDAP groups to Django groups. Implementations of LDAPGroupType will have an algorithm for deriving the Django group name from the LDAP group. Clients that need to modify this behavior can subclass the LDAPGroupType class. All of the built-in implementations take a name_attr argument to __init__, which specifies the LDAP attribute from which to take the Django group name. By default, the cn attribute is used.

The least invasive way to map group permissions is to set AUTH_LDAP_FIND_GROUP_PERMS to True. LDAPBackend will then find all of the LDAP groups that a user belongs to, map them to Django groups, and load the permissions for those groups. You will need to create the Django groups yourself, generally through the admin interface.

To minimize traffic to the LDAP server, LDAPBackend can make use of Django’s cache framework to keep a copy of a user’s LDAP group memberships. To enable this feature, set AUTH_LDAP_CACHE_GROUPS to True. You can also set AUTH_LDAP_GROUP_CACHE_TIMEOUT to override the timeout of cache entries (in seconds).


The second way to turn LDAP group memberships into permissions is to mirror the groups themselves. If AUTH_LDAP_MIRROR_GROUPS is True, then every time a user logs in, LDAPBackend will update the database with the user’s LDAP groups. Any group that doesn’t exist will be created and the user’s Django group membership will be updated to exactly match his LDAP group membership. Note that if the LDAP server has nested groups, the Django database will end up with a flattened representation.

This approach has two main differences from AUTH_LDAP_FIND_GROUP_PERMS. First, AUTH_LDAP_FIND_GROUP_PERMS will query for LDAP group membership either for every request or according to the cache timeout. With group mirroring, membership will be updated when the user authenticates. This may not be appropriate for sites with long session timeouts. The second difference is that with AUTH_LDAP_FIND_GROUP_PERMS, there is no way for clients to determine a user’s group memberships, only their permissions. If you want to make decisions based directly on group membership, you’ll have to mirror the groups.

LDAPBackend has one more feature pertaining to permissions, which is the ability to handle authorization for users that it did not authenticate. For example, you might be using Django’s RemoteUserBackend to map externally authenticated users to Django users. By setting AUTH_LDAP_AUTHORIZE_ALL_USERS, LDAPBackend will map these users to LDAP users in the normal way in order to provide authorization information. Note that this does not work with AUTH_LDAP_MIRROR_GROUPS; group mirroring is a feature of authentication, not authorization.


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')

More options

Miscellaneous settings for LDAPBackend:


LDAPBackend is carefully designed not to require a connection to the LDAP service for every request. Of course, this depends heavily on how it is configured. If LDAP traffic or latency is a concern for your deployment, this section has a few tips on minimizing it, in decreasing order of impact.

  1. Cache groups. If AUTH_LDAP_FIND_GROUP_PERMS is True, the default behavior is to reload a user’s group memberships on every request. This is the safest behavior, as any membership change takes effect immediately, but it is expensive. If possible, set AUTH_LDAP_CACHE_GROUPS to True to remove most of this traffic. Alternatively, you might consider using AUTH_LDAP_MIRROR_GROUPS and relying on ModelBackend to supply group permissions.
  2. Don’t access user.ldap_user.*. These properties are only cached on a per-request basis. If you can propagate LDAP attributes to a User or profile object, they will only be updated at login. user.ldap_user.attrs triggers an LDAP connection for every request in which it’s accessed. If you’re not using AUTH_LDAP_USER_DN_TEMPLATE, then accessing user.ldap_user.dn will also trigger an LDAP connection.
  3. Use simpler group types. Some grouping mechanisms are more expensive than others. This will often be outside your control, but it’s important to note that the extra functionality of more complex group types like NestedGroupOfNamesType is not free and will generally require a greater number and complexity of LDAP queries.
  4. Use direct binding. Binding with AUTH_LDAP_USER_DN_TEMPLATE is a little bit more efficient than relying on AUTH_LDAP_USER_SEARCH. Specifically, it saves two LDAP operations (one bind and one search) per login.

Example configuration

Here is a complete example configuration from that exercises nearly all of the features. In this example, we’re authenticating against a global pool of users in the directory, but we have a special area set aside for Django groups (ou=django,ou=groups,dc=example,dc=com). Remember that most of this is optional if you just need simple authentication. Some default settings and arguments are included for completeness.

import ldap
from django_auth_ldap.config import LDAPSearch, GroupOfNamesType

# Baseline configuration.

AUTH_LDAP_BIND_DN = "cn=django-agent,dc=example,dc=com"
AUTH_LDAP_USER_SEARCH = LDAPSearch("ou=users,dc=example,dc=com",
    ldap.SCOPE_SUBTREE, "(uid=%(user)s)")
# or perhaps:
# AUTH_LDAP_USER_DN_TEMPLATE = "uid=%(user)s,ou=users,dc=example,dc=com"

# Set up the basic group parameters.
AUTH_LDAP_GROUP_SEARCH = LDAPSearch("ou=django,ou=groups,dc=example,dc=com",
    ldap.SCOPE_SUBTREE, "(objectClass=groupOfNames)"
AUTH_LDAP_GROUP_TYPE = GroupOfNamesType(name_attr="cn")

# Simple group restrictions
AUTH_LDAP_REQUIRE_GROUP = "cn=enabled,ou=django,ou=groups,dc=example,dc=com"
AUTH_LDAP_DENY_GROUP = "cn=disabled,ou=django,ou=groups,dc=example,dc=com"

# Populate the Django user from the LDAP directory.
    "first_name": "givenName",
    "last_name": "sn",
    "email": "mail"

    "employee_number": "employeeNumber"

    "is_active": "cn=active,ou=django,ou=groups,dc=example,dc=com",
    "is_staff": "cn=staff,ou=django,ou=groups,dc=example,dc=com",
    "is_superuser": "cn=superuser,ou=django,ou=groups,dc=example,dc=com"

    "is_awesome": "cn=awesome,ou=django,ou=groups,dc=example,dc=com",

# This is the default, but I like to be explicit.

# Use LDAP group membership to calculate group permissions.

# Cache group memberships for an hour to minimize LDAP traffic

# Keep ModelBackend around for per-user permissions and maybe a local
# superuser.




Default: True

If True, the fields of a User object will be updated with the latest values from the LDAP directory every time the user logs in. Otherwise the User object will only be populated when it is automatically created.


Default: False

If True, LDAPBackend will be able furnish permissions for any Django user, regardless of which backend authenticated it.


Default: False

If True, authentication will leave the LDAP connection bound as the authenticating user, rather than forcing it to re-bind with the default credentials after authentication succeeds. This may be desirable if you do not have global credentials that are able to access the user’s attributes. django-auth-ldap never stores the user’s password, so this only applies to requests where the user is authenticated. Thus, the downside to this setting is that LDAP results may vary based on whether the user was authenticated earlier in the Django view, which could be surprising to code not directly concerned with authentication.


Default: '' (Empty string)

The distinguished name to use when binding to the LDAP server (with AUTH_LDAP_BIND_PASSWORD). Use the empty string (the default) for an anonymous bind. To authenticate a user, we will bind with that user’s DN and password, but for all other LDAP operations, we will be bound as the DN in this setting. For example, if AUTH_LDAP_USER_DN_TEMPLATE is not set, we’ll use this to search for the user. If AUTH_LDAP_FIND_GROUP_PERMS is True, we’ll also use it to determine group membership.


Default: '' (Empty string)

The password to use with AUTH_LDAP_BIND_DN.


Default: False

If True, LDAP group membership will be cached using Django’s cache framework. The cache timeout can be customized with AUTH_LDAP_GROUP_CACHE_TIMEOUT.


Default: {}

A dictionary of options to pass to each connection to the LDAP server via LDAPObject.set_option(). Keys are ldap.OPT_* constants.


Default: None

The distinguished name of a group; authentication will fail for any user that belongs to this group.


Default: False

If True, LDAPBackend will furnish group permissions based on the LDAP groups the authenticated user belongs to. AUTH_LDAP_GROUP_SEARCH and AUTH_LDAP_GROUP_TYPE must also be set.


Default: {}

A dictionary of options to pass to ldap.set_option(). Keys are ldap.OPT_* constants.


Default: None

If AUTH_LDAP_CACHE_GROUPS is True, this is the cache timeout for group memberships. If None, the global cache timeout will be used.


Default: None

An LDAPGroupType instance describing the type of group returned by AUTH_LDAP_GROUP_SEARCH.


Default: False

If True, LDAPBackend will mirror a user’s LDAP group membership in the Django database. Any time a user authenticates, we will create all of his LDAP groups as Django groups and update his Django group membership to exactly match his LDAP group membership. If the LDAP server has nested groups, the Django database will end up with a flattened representation.


Default: {}

A mapping from user profile field names to LDAP attribute names. A user’s profile will be populated from his LDAP attributes at login.


Default: {}

A mapping from boolean profile field names to distinguished names of LDAP groups. The corresponding field in a user’s profile is set to True or False according to whether the user is a member of the group.


Default: None

The distinguished name of a group; authentication will fail for any user that does not belong to this group.


Default: ldap://localhost

The URI of the LDAP server. This can be any URI that is supported by your underlying LDAP libraries.


Default: False

If True, each connection to the LDAP server will call start_tls to enable TLS encryption over the standard LDAP port. There are a number of configuration options that can be given to AUTH_LDAP_GLOBAL_OPTIONS that affect the TLS connection. For example, ldap.OPT_X_TLS_REQUIRE_CERT can be set to ldap.OPT_X_TLS_NEVER to disable certificate verification, perhaps to allow self-signed certificates.


Default: {}

A mapping from User field names to LDAP attribute names. A users’s User object will be populated from his LDAP attributes at login.


Default: None

A string template that describes any user’s distinguished name based on the username. This must contain the placeholder %(user)s.


Default: {}

A mapping from boolean User field names to distinguished names of LDAP groups. The corresponding field is set to True or False according to whether the user is a member of the group.

Module Properties


The library’s current version number as a 3-tuple.


The library’s current version number as a string.


class django_auth_ldap.config.LDAPSearch
__init__(base_dn, scope, filterstr='(objectClass=*)')
  • base_dn: The distinguished name of the search base.
  • scope: One of ldap.SCOPE_*.
  • filterstr: An optional filter string (e.g. ‘(objectClass=person)’). In order to be valid, filterstr must be enclosed in parentheses.
class django_auth_ldap.config.LDAPGroupType

The base class for objects that will determine group membership for various LDAP grouping mechanisms. Implementations are provided for common group types or you can write your own. See the source code for subclassing notes.


By default, LDAP groups will be mapped to Django groups by taking the first value of the cn attribute. You can specify a different attribute with name_attr.

class django_auth_ldap.config.PosixGroupType

A concrete subclass of LDAPGroupType that handles the posixGroup object class. This checks for both primary group and group membership.

class django_auth_ldap.config.MemberDNGroupType

A concrete subclass of LDAPGroupType that handles grouping mechanisms wherein the group object contains a list of its member DNs.

__init__(member_attr, name_attr='cn')
  • member_attr: The attribute on the group object that contains a list of member DNs. ‘member’ and ‘uniqueMember’ are common examples.
class django_auth_ldap.config.NestedMemberDNGroupType

Similar to MemberDNGroupType, except this allows groups to contain other groups as members. Group hierarchies will be traversed to determine membership.

__init__(member_attr, name_attr='cn')

As above.

class django_auth_ldap.config.GroupOfNamesType

A concrete subclass of MemberDNGroupType that handles the groupOfNames object class. Equivalent to MemberDNGroupType('member').

class django_auth_ldap.config.NestedGroupOfNamesType

A concrete subclass of NestedMemberDNGroupType that handles the groupOfNames object class. Equivalent to NestedMemberDNGroupType('member').

class django_auth_ldap.config.GroupOfUniqueNamesType

A concrete subclass of MemberDNGroupType that handles the groupOfUniqueNames object class. Equivalent to MemberDNGroupType('uniqueMember').

class django_auth_ldap.config.NestedGroupOfUniqueNamesType

A concrete subclass of NestedMemberDNGroupType that handles the groupOfUniqueNames object class. Equivalent to NestedMemberDNGroupType('uniqueMember').

class django_auth_ldap.config.ActiveDirectoryGroupType

A concrete subclass of MemberDNGroupType that handles Active Directory groups. Equivalent to MemberDNGroupType('member').

class django_auth_ldap.config.NestedActiveDirectoryGroupType

A concrete subclass of NestedMemberDNGroupType that handles Active Directory groups. Equivalent to NestedMemberDNGroupType('member').




This is a Django signal that is sent when clients should perform additional customization of a User object. It is sent after a user has been authenticated and the backend has finished populating it, and just before it is saved. The client may take this opportunity to populate additional model fields, perhaps based on ldap_user.attrs. This signal has two keyword arguments: user is the User object and ldap_user is the same as user.ldap_user. The sender is the LDAPBackend class.


Like populate_user, but sent for the user profile object. This will only be sent if the user has an existing profile. As with populate_user, it is sent after the backend has finished setting properties and before the object is saved. This signal has two keyword arguments: profile is the user profile object and ldap_user is the same as user.ldap_user. The sender is the LDAPBackend class.

class django_auth_ldap.backend.LDAPBackend

LDAPBackend has one method that may be called directly and several that may be overridden in subclasses.


Populates the Django user for the given LDAP username. This connects to the LDAP directory with the default credentials and attempts to populate the indicated Django user as if they had just logged in. AUTH_LDAP_ALWAYS_UPDATE_USER is ignored (assumed True).

get_or_create_user(self, username, ldap_user)

Given a username and an LDAP user object, this must return the associated Django User object. The username argument has already been passed through ldap_to_django_username(). You can get information about the LDAP user via ldap_user.dn and ldap_user.attrs. The return value must be the same as User.objects.get_or_create(): a (User, created) two-tuple.

The default implementation calls User.objects.get_or_create(), using a case-insensitive query and creating new users with lowercase usernames. Subclasses are welcome to associate LDAP users to Django users any way they like.


Returns a valid Django username based on the given LDAP username (which is what the user enters). By default, username is returned unchanged. This can be overriden by subclasses.


The inverse of ldap_to_django_username(). If this is not symmetrical to ldap_to_django_username(), the behavior is undefined.


Copyright (c) 2009, Peter Sagerson All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
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