# django-auth-ldap / docs / source / authentication.rst

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# Authentication

## Server Config

If your LDAP server isn't running locally on the default port, you'll want to start by setting :setting:AUTH_LDAP_SERVER_URI to point to your server. The value of this setting can be anything that your LDAP library supports. For instance, openldap may allow you to give a comma- or space-separated list of URIs to try in sequence.

AUTH_LDAP_SERVER_URI = "ldap://ldap.example.com"


If you need to configure any python-ldap options, you can set :setting:AUTH_LDAP_GLOBAL_OPTIONS and/or :setting:AUTH_LDAP_CONNECTION_OPTIONS. For example, disabling referrals is not uncommon:

import ldap

AUTH_LDAP_CONNECTION_OPTIONS = {
ldap.OPT_REFERRALS: 0
}


## Search/Bind

Now that you can talk to your LDAP server, the next step is to authenticate a username and password. There are two ways to do this, called search/bind and direct 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 :class:~django_auth_ldap.config.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_BIND_DN = ""
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 :setting:AUTH_LDAP_BIND_DN to the distinguished name of an authorized user and :setting:AUTH_LDAP_BIND_PASSWORD to the password.

(New in 1.1) If you need to search in more than one place for a user, you can use :class:~django_auth_ldap.config.LDAPSearchUnion. This takes multiple LDAPSearch objects and returns the union of the results. The precedence of the underlying searches is unspecified.

import ldap
from django_auth_ldap.config import LDAPSearch, LDAPSearchUnion

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


## Direct Bind

To skip the search phase, set :setting: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 first 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"


## Notes

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

Some LDAP servers are configured to allow users to bind without a password. As a precaution against false positives, :class:~django_auth_ldap.backend.LDAPBackend will summarily reject any authentication attempt with an empty password. You can disable this behavior by setting :setting:AUTH_LDAP_PERMIT_EMPTY_PASSWORD to True.

By default, all LDAP operations are performed with the :setting:AUTH_LDAP_BIND_DN and :setting: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 might 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 :setting: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 :setting:AUTH_LDAP_START_TLS to True:

AUTH_LDAP_START_TLS = True