LDAP authentication

2006-07-19T15:10:43Z

Wirelessben: /* Assumptions */

This document describes how to set up LDAP authentication in Moodle. You can find a [[#Basic Scenario|Basic Scenario]], where everything is simple and straightforward, and that should be enough for most installations. If your installation is a little bigger and you are using multiple LDAP servers, or multiple locations (contexts) for your users in your LDAP tree, then have a look at the [[#Advanced Scenarios|Advanced Scenarios]].

==Basic Scenario==

===Assumptions===

# Your Moodle site is located at '''http://your.moodle.site/'''
# You have configured your PHP installation with the LDAP extension. It is loaded and activated, and it shows when you go to '''http://your.moodle.site/admin/phpinfo.php''' (logged in as user 'admin').
# Your LDAP server has '''192.168.1.100''' as its IP address.
# You are not using LDAP with SSL (also known as LDAPS) in your settings. This might prevent certain operations from working (e.g., you cannot update data if you are using MS Active Directory -- MS-AD from here on --), but should be OK if you just want to authenticate your users.
# You don't want your users to change their passwords the first time they log in into Moodle.
# You are using a single domain as the source of your authentication data in case you are using MS-AD (more on this in the Appendices).
# You are using a top level distinguished name (DN) of '''dc=my,dc=organization,dc=domain''' as the root of your LDAP tree.
# You have a non-privileged LDAP user account you will use to bind to the LDAP server. This is not necessary with certain LDAP servers, but MS-AD requires this and it won't hurt if you use it even if your LDAP server doesn't need it. Make sure '''this account and its password don't expire''', and make this password as strong as possible. Remember you only need to type this password once, when configuring Moodle, so don't be afraid of making it as hard to guess as possible. Let's say this user account has a DN of '''cn=ldap-user,dc=my,dc=organization,dc=domain''', and password '''hardtoguesspassword'''.
# All of your Moodle users are in an organizational unit (OU) called '''moodleusers''', which is right under your LDAP root. That OU has a DN of '''ou=moodleusers,dc=my,dc=organization,dc=domain'''.
# You '''don't''' want your LDAP users' passwords to be stored in Moodle at all.

===Configuring Moodle authentication===

Log in as an admin user and go to Administration >> Users >> Authentication. In the drop down listbox titled "Choose an authentication method" select "Use an LDAP Server". You will get a page similar to this one:

 
::: [[Image:auth_ldap_config_screenshot.jpg]]
 

Now, you just have to fill in the values. Let's go step by step.
 
 

{| border="1" cellspacing="0" cellpadding="5"
! Field name
! Value to fill in
|-
| ldap_host_url
| As the IP of your LDAP server is 192.168.1.100, type "'''ldap://192.168.1.100'''" (without the quotes).
|-
| ldap_version
| Unless you are using a really old LDAP server, '''version 3''' is the one you should choose.
|-
| ldap_preventpassindb
| As you '''don't''' want to store the users's password in Moodle's database, choose '''Yes''' here.
|-
| ldap_bind_dn
| This is the distinguished name of the bind user defined above. Just type "'''cn=ldap-user,dc=my,dc=organization,dc=domain'''" (without the quotes).
|-
| ldap_bind_pw
| This is the bind user password defined above. Type "'''hardtoguesspassword'''" (without the quotes).
|-
| ldap_user_type
| Choose:
* '''Novel Edirectory''' if your LDAP server is running Novell's eDdirectory.
* '''posixAccount (rfc2307)''' if your LDAP server is running a RFC-2307 compatible LDAP server (choose this is your server is running OpenLDAP).
* '''posixAccount (rfc2307bis)''' if your LDAP server is running a RFC-2307bis compatible LDAP server.
* '''sambaSamAccount (v.3.0.7)''' if your LDAP server is running with SAMBA's 3.x LDAP schema extension and you want to use it.
* '''MS ActiveDirectory''' if your LDAP server is running Microsoft's Active Directory (MS-AD)
|-
| ldap_contexts
| The DN of the context (container) where all of your Moodle users are found. Type '''ou=moodleusers,dc=my,dc=organization,dc=domain''' here.
|-
| ldap_search_sub
| If you have any sub organizational units (subcontexts) hanging from '''ou=moodleusers,dc=my,dc=organization,dc=domain''' and you want Moodle to search there too, set this to '''yes'''. Otherwise, set this to '''no'''.
|-
| ldap_opt_deref
| Sometimes your LDAP server will tell you that the real value you are searching for is in fact in another part of the LDAP tree (this is called an alias). If you want Moodle to 'dereference' the alias and fetch the real value from the original location, set this to '''yes'''. If you don't want Moodle to dereference it, set this to '''no'''. If you are using MS-AD, set this to '''no'''.
|-
| ldap_user_attribute
| The attribute used to name/search users in your LDAP tree. This option takes a default value based on the ''ldap_user_type'' value you choosed above. So unless you need something special, you don't need to fill this in.

By the way, it's usually '''cn''' (Novell eDirectory and MS-AD) or '''uid''' (RFC-2037, RFC-2037bis and SAMBA 3.x LDAP extension), but if you are using MS-AD you could use '''sAMAccountName''' (the pre-Windows 2000 logon account name) if you need too.
|-
| ldap_memberattribute
| The attribute used to list the members of a given group. This option takes a default value based on the ''ldap_user_type'' value you choosed above. So unless you need something special, you don't need to fill this in.

By the way, the usual value is '''member'''.
|-
| ldap_objectclass
| The type of LDAP object used to search for users. This option takes a default value based on the ''ldap_user_type'' value you choosed above. So unless you need something special, you don't need to fill this in.

Here are the default values for each of the ''ldap_user_type'' values:
* '''User''' for Novel eDirectory
* '''posixAccount''' for RFC-2037 and RFC-2037bis
* '''sambaSamAccount''' for SAMBA 3.0.x LDAP extension
* '''user''' for MS-AD
|-
| Force change password
| Set this to ''Yes'' if you want to force your users to change their password on the first login into Moodle. Otherwise, set this to ''no''. Bear in mind the password they are forced to change is the one stored in your LDAP server.

As you don't want your users to change their passwords in their first login, leave this set to ''No''
|-
| Use standard Change Password Page
|
* Setting this to ''Yes'' makes Moodle use it's own standard password change page, everytime users want to change their passwords.
* Setting this to ''No'' makes Moodle use the the page specified in the field called "Change password URL" (at the bottom of the configuration page).

Bear in mind that changing your LDAP passwords from Moodle might require a LDAPS connection (this is true at least for MS-AD).

Also, code for changing passwords from Moodle for anything but Novell eDirectory is almost not tested, so this may or may not work for other LDAP servers.
|-
| ldap_expiration
|
* Setting this to ''No'' will make Moodle not to check if the password of the user has expired or not.
* Setting this to ''LDAP'' will make Moodle check if the LDAP password of the user has expired or not, and warn her a number of days before the password expires.

Current code only deals with Novell eDirectory LDAP server, but there is a patch floating around to make it work with MS-AD too (search in the authentication forum).

So unless you have Novell eDirectory server (or use the patch), choose ''No'' here.
|-
| ldap_expiration_warning
| This value sets how many days in advance of password expiration the user is warned that her password is about to expire.
|-
| ldap_exprireattr
| The LDAP user attribute used to check password expiration. This option takes a default value based on the ''ldap_user_type'' value you choosed above. So unless you need something special, you don't need to fill this in.
|-
| ldap_gracelogins
| This setting is specific to Novell eDirectory. If set to ''Yes'', enable LDAP gracelogin support. After password has expired the user can login until gracelogin count is 0.

So unless you have Novell eDirectory server and want to allow gracelogin support, choose ''No'' here.
|-
| ldap_graceattr
| This setting is currently not used in the code (and is specific to Novell eDirectory).

So you don't need to fill this in.
|-
| ldap_create_context
|
|-
| ldap_creators
| The DN of the group that contains all of your Moodle creators. This is typically a posixGroup with a "memberUid" attribute for each user you want to be a creator. If your group is called ''creators'', type '''cn=creators,ou=moodleusers,dc=my,dc=organization,dc=domain''' here. Each memberUid attribute contains the CN of a user who is authorized to be a creator. Do not use the user's full DN (e.g., not '''memberUid: cn=JoeTeacher,ou=moodleusers,dc-my,dc=organizations,dc=domain''', but rather '''memberUid: JoeTeacher''').

In eDirectory, the objectClass for a group is (by default) not '''posixGroup''' but '''groupOfNames,''' whose member attribute is '''member,''' not '''memberUid,''' and whose value is the full DN of the user in question. Although you can probably modify Moodle's code to use this field, a better solution is just to add a new '''objectClass''' attribute of '''posixGroup''' to your creators group and put the CNs for each creator in a '''memberUid''' attribute.

In MS Active Directory, you will need to create a security group for your creators to be part of and then add them all. If your ldap context above is 'ou=staff,dc=my,dc=org' then your group should then be 'cn=creators,ou=staff,dc=my,dc=org'. If some of the users are from other contexts and have been added to the same security group, you'll have to add these as separate contexts after the first one using the same format.
|-
| First name
| The name of the attribute that holds the first name of your users in your LDAP server. This is usually '''givenName'''.

This setting is optional
|-
| Surname
| The name of the attribute that holds the surname of your users in your LDAP server. This is usually '''sn'''.

This setting is optional
|-
| Email address
| The name of the attribute that holds the email address of your users in your LDAP server. This is usually '''mail'''.

This setting is optional
|-
| Phone 1
| The name of the attribute that holds the telephone number of your users in your LDAP server. This is usually '''telephoneNumber'''.

This setting is optional
|-
| Phone 2
| The name of the attribute that holds an additional telephone number of your users in your LDAP server. This can be '''homePhone''', '''mobile''', '''pager''', '''facsimileTelephoneNumber''' or even others.

This setting is optional
|-
| Department
| The name of the attribute that holds the department name of your users in your LDAP server. This is usully '''departmentNumber''' (for posixAccount and maybe eDirectory) or '''department''' (for MS-AD).

This setting is optional
|-
| Address
| The name of the attribute that holds the street address of your users in your LDAP server. This is usully '''streetAddress''' or '''street'.

This setting is optional
|-
| City/town
| The name of the attribute that holds the city/town of your users in your LDAP server. This is usully '''l''' (lowercase L) or '''localityName''' (not valid in MS-AD).

This setting is optional
|-
| Country
| The name of the attribute that holds the couuntry of your users in your LDAP server. This is usully '''c''' or '''countryName''' (not valid in MS-AD).

This setting is optional
|-
| Description
| '''description'''

This setting is optional
|-
| ID Number
|

This setting is optional
|-
| Language
| '''preferredLanguage'''

This setting is optional
|-
| Instructions
|
|}

The rest of the fields are common to all authentication methods and will not be discussed here.

==Advanced Scenarios==

===Using multiple LDAP Servers===
Entering more than one name in the ldap_host_url field can provide some sort of resilience to your system. Simply use the syntax :
ldap://my.first.server ; ldap//my.second.server ; ...

Of course, this will only work if all the servers share the same directory information, using a replication or synchronization mecanism once introduced in eDirectory and now generalized to the main LDAP-compatible directories.

There is one drawback in Moodle 1.5 - 1.6 implementation of LDAP authentication : the auth_ldap_connect() function processes the servers sequentially, not in a round robin mode. Thus, if the primary server fails, you will have to wait for the connection to time out before switching to the following one.

===Using multiple user locations (contexts) in your LDAP tree===
There is no need to use multiple user locations if your directory tree is flat, i.e. if all user accounts reside in a '''ou=people,dc=my,dc=organization,dc=domain''' or '''ou=people,o=myorg''' container.

At the opposite, if you use the ACL mecanism to delegate user management, there are chances that your users will be stored in containers like '''ou=students,ou=dept1,o=myorg''' and '''ou=students,ou=dept2,o=myorg''' ...

Then there is an alternative :
* Look at the '''o=myorg''' level with the ldap_search_sub attribute set to '''yes'''.
* Set the ldap_context to '''ou=students,ou=dept1,o=myorg ; ou=students,ou=dept2,o=myorg'''.

Choosing between these two solutions supposes some sort of benchmarking, as the result depends heavily on the structure of your directory tree '''and''' on your LDAP software indexing capabilities. Simply note that there is a probability in such deep trees that two users share the same ''common name'' (cn), while having different ''distinguished names''. Then only the second solution will have a deterministic result (returning allways the same user).

===Using LDAPS (LDAP + SSL)===

==Appendices==

Talk about Global Catalog servers and MS Active Directory.

==See also==

*[http://moodle.org/mod/forum/view.php?id=42 Using Moodle: User authentication] forum
*Using Moodle [http://moodle.org/mod/forum/discuss.php?d=32168 PHP LDAP module does not seem to be present] forum discussion

[[Category:Administrator]]
[[Category:Authentication]]

MoodleDocs - User contributions [en]

LDAP authentication