LDAP authentication: Difference between revisions
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==Active Directory Troubleshooting Help== | ==Active Directory Troubleshooting Help== | ||
[[Active Directory]] is Microsoft's [[Directory service|directory service]]. It is included in Windows 2000 Server and later versions of their operating system. | |||
===Warning: The PHP LDAP module does not seem to be present. Please ensure it is installed and enabled.=== | ===Warning: The PHP LDAP module does not seem to be present. Please ensure it is installed and enabled.=== | ||
Revision as of 12:22, 15 December 2008
Template:Moodle 1.9 Location: Settings link in Administration > Users > Authentication > LDAP Server
This document describes how to set up Lightweight Directory Access Protocol (LDAP) authentication in Moodle. We cover the basic, advanced and some trouble shooting sections to assist the user in the installation and administrating LDAP in Moodle.
Basic Scenario
The simple and straightforward approach for most installations.
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 >> Manage authentication. In the table that appears, enable the "LDAP Server" authentication option (click on the closed eye to make it open) and then click on the associated 'Settings' link. You will get a page similar to this one:
Now, you just have to fill in the values. Let's go step by step.
LDAP Server Settings
| Field name | Value to fill in |
|---|---|
| Host URL | As the IP of your LDAP server is 192.168.1.100, type "ldap://192.168.1.100" (without the quotes), or just "192.168.1.100" (some people have trouble connecting with the first syntax, specially on MS Windows servers). |
| Version | Unless you are using a really old LDAP server, version 3 is the one you should choose. |
| LDAP Encoding | Specify encoding used by LDAP server. Most probably utf-8. |
Bind settings
| Field name | Value to fill in |
|---|---|
| Hide passwords | As you don't want to store the users's password in Moodle's database, choose Yes here. |
| Distinguisned Name | 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). |
| Password | This is the bind user password defined above. Type "hardtoguesspassword" (without the quotes). |
User lookup settings
| Field name | Value to fill in |
|---|---|
| User type | Choose:
|
| 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. |
| Search subcontexts | 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. |
| Dereference aliases | 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. |
| User attribute | The attribute used to name/search users in your LDAP tree. This option takes a default value based on the 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. |
| Member attribute | The attribute used to list the members of a given group. This option takes a default value based on the 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 values are member and memberUid. |
| Member attribute uses dn | Whether the member attribute contains distinguished names (1) or not (0).This option takes a default value based on the User type value you choosed above. So unless you need something special, you don't need to fill this in. |
| Object class | The type of LDAP object used to search for users. This option takes a default value based on the 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:
If you get an error about a problem with updating the ldap server (even if you have specified not to write changes back to the ldap server) try setting the ldap object class to * - see http://moodle.org/mod/forum/discuss.php?d=70566 for a discussion on this problem |
Force change password
| Field name | Value to fill in |
|---|---|
| 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 |
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 and Active Directory is almost not tested, so this may or may not work for other LDAP servers. |
| Password Format | Specify how the new password is encrypted before sending it to the LDAP server: Plain text, MD5 hash or SHA-1 hash. MS-AD uses plain text, for example. |
| Password change URL | Here you can specify a location at which your users can recover or change their username/password if they've forgotten it. This will be provided to users as a button on the login page and their user page. if you leave this blank the button will not be printed. |
LDAP password expiration settings
| Field name | Value to fill in |
|---|---|
| Expiration |
Current code only deals with Novell eDirectory LDAP server and MS-AD. So unless you have Novell eDirectory server or MS-AD, choose No here. |
| Expiration warning | This value sets how many days in advance of password expiration the user is warned that her password is about to expire. |
| Expiration attribute. | The LDAP user attribute used to check password expiration. This option takes a default value based on the User type value you choosed above. So unless you need something special, you don't need to fill this in. |
| Grace logins | 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. |
| Grace login attribute | This setting is currently not used in the code (and is specific to Novell eDirectory).
So you don't need to fill this in. |
Enable user creation
| Field name | Value to fill in |
|---|---|
| Create users externally | New (anonymous) users can self-create user accounts on the external LDAP server and confirm them via email. If you enable this, remember to also configure module-specific options for user creation and to fill in some instructions in auth_instructions field in Administration >> Users >> Authentication >> Manage authentication. Otherwise the new users won't be able to self-create new accounts.
As of now, only Novell eDirectory and MS-AD can create users externally. |
| Context for new users | Specify the context where users are created. This context should be different from other users' contexts to prevent security issues. |
Course creation
| Field name | Value to fill in |
|---|---|
| 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. |
Cron synchronization script
| Field name | Value to fill in |
|---|---|
| Removed ext user | Specify what to do with internal user account during mass synchronization when user was removed from external source. Only suspended users are automatically revived if they reappear in ext source. |
NTLM SSO
| Field name | Value to fill in |
|---|---|
| Enable | If you want to use NTLM SSO (see details at NTLM_authentication, choose Yes here. Otherwise, choose No. |
| Subnet | Specify the subnets of the clients that will use NTLM SSO (see details at NTLM_authentication). |
Data Mapping
| Field name | Value to fill in |
|---|---|
| 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 |
| 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 |
| Language | preferredLanguage
This setting is optional |
| Description | description
This setting is optional |
| Webpage | This setting is optional |
| ID Number |
This setting is optional |
| Institution |
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 |
| 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 |
| 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 |
Setting up regular automatic synchronisation using cron
There is a script located at /auth/ldap/auth_ldap_sync_users.php which will create or suspend/delete (see the setting above) all LDAP accounts automatically. Ideally, this is called from the command line once a day during a quiet time using exactly the same procedure as the standard cron job (so you will end up with two cron entries). It is important, however, to make sure that all of the above LDAP settings are working properly before you try this, as well as backing up your database and moodledata folders. Poor LDAP configuration could lead to users being wrongly deleted.
If you find that the script is not running through all of your users properly and you have MS Active Directory + over 1000 users, this is because by default, MS AD only sends back 1000 users at a time. Follow the instructions here to set the MaxPageSize setting to a number higher than your total number of users (both now and in future) to fix it.
Active Directory Troubleshooting Help
Active Directory is Microsoft's directory service. It is included in Windows 2000 Server and later versions of their operating system.
Warning: The PHP LDAP module does not seem to be present. Please ensure it is installed and enabled.
This usually means that the main ldap dll or one of the supporting dlls are missing. Let's start with the main one itself. Browse to http://(moodleserver)/admin/phpinfo.php and examine the "Configuration File (php.ini) Path" field to determine which php.ini is being used and open it with an editor. Find the line 'extension=php_ldap.dll' and take out the semi-colon if it is there. That semi-colon will stop it loading the module all together! While you have that file open, search for 'extension_dir' and note which folder it is set to. Open that folder and ensure the php_ldap.dll file is in there. If it isn't then put it in there. If that still hasn't fixed it you are missing a supporting dll, but you don't get told that. To see what dlls are missing open the Command Prompt and navigate to the php directory and execute the following line 'php -m'. You should get some error messages now. Ugly, but at least they give you information! Find the dlls listed and copy them to the php directory. You may now need to restart the apache/httpd service. Run 'php -m' again and you should be error free and the message in Moodle should be gone now.
LDAP-module cannot connect any LDAP servers : Server: 'ldap://my.ldap.server/' Connection: 'Resource id #26' Bind result:
Getting this message when you are trying to log in is a result of incorrect details for the Bind user, or the user account having insufficient permissions in Active Directory. The best way to test and resolve this is use ldp.exe to test binding until it suceeds. There are instructions on installing ldp.exe below. Open the program and Connect to AD, giving the server name, then from the Connection menu choose Bind. Enter the details you think are correct and you will probably find that an error is returned. Try adjusting the accounts priveleges or another account until you are returned an "Authenticated as" message. Once you are sure your account can be used to bind to AD, check that the DN of that users name is correct. Expand the tree on the left until you find the user you used to bind. Right click on that item and choose Copy DN. Go to the User Authentication page in Moodle and paste the value into the ldap_bind_dn field. Add the password and you can now feel safe your user is binding sucessfully.
Getting correct CNs for Contexts and Creators
For those not familiar with AD this could be very confusing, and not that easy for some who are familiar with it. Again, ldp.exe is your friend. There are instructions on installing ldp.exe below. Open it up and expand the tree on the left until you find the group or user you want to use and right click on it and select Copy DN. Go back to the Moodle User Authentication page and paste that value into either ldap_contexts or ldap_creators.
Getting the right user_attribute
By default, Moodle uses an accounts cn (full name) to verify against, but most networks don't use a full given name for logon as it's too easy to guess and you can easily have two people with the same name. If this is the case for you too you need to tell Moodle to look at another field for the logon id. In ldp.exe navigate the tree on the left to find a user account, preferably your own. Double-click the item in the tree and full-details will be loaded into the screen on the right. Look down the details until you find your logon id and note the item listed against it. For me, and a lot of people, it is sAMAccountName. Copy this name and paste it into the ldap_user_attribute on the Moodle User Authentication page. There are instructions on installing ldp.exe below.
Installing ldp.exe Server Tool
ldp.exe comes as part of the Server Tools on most versions of Windows Server. Find your Windows Server installation disc and find a folder on it called Support\Tools. In there will be a SupTools.msi which will install the server tools if run. You should now have a folder under Program Files called Support Tools, in which will be ldp.exe. ldp.exe is also available in the Windows XP Support Tools, which you can download from Microsoft here. Alternatively, a single download of ldp.exe is available here.
Example Active Directory Configuration
Below is an example configuration for Active Directory. As detailed above, the values may vary based on your local Active Directory configuration, but should provide a good starting point for most cases.
ldap_host_url = ldap://ads.example.com ldap_version = 3 ldap_preventpassindb = yes ldap_bind_dn = bind-user@example.com ldap_bind_pw = bind-password ldap_user_type = MS ActiveDirectory ldap_contexts = ou=moodleusers,dc=example,dc=com ldap_user_attribute = sAMAccountName
Note that the ldap_bind_dn value should work in either the CN=bin-user,CN=Users,DC=example,DC=com format as shown in the main instructions or the bind-user@example.com format shown in this example.
Advanced Scenarios - Multiple servers or locations
For larger installations with multiple LDAP servers, or multiple locations (contexts) in a LDAP tree.
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)
MS Active Directory + SSL
If the Certificate Authority is not installed you'll have to install it first as follows:
- Click Start -> Control Panel -> Add or Remove programs.
- Click Add/Remove Windows Components and select Certificate Services.
- Follow the procedure provided to install the Certificate Authority. Enterprise level is a good choice.
Verify that SSL has been enabled on the server by installing suptools.msi from Windows installation cd's \Support\tools directory. After support tools installation:
- Select Start -> Run, write ldp in the Open field.
- From the ldp window select Connection -> Connect and supply valid hostname and port number 636. Also select the SSL check box.
If successful, you should get information about the connection.
Next step is to tell PHP's OpenLDAP extension to disable SSL certificate checking. On Windows servers you're most likely using pre-compiled PHP version, where you must create a path C:\OpenLDAP\sysconf. In this path create a file called "ldap.conf" with content:
TLS_REQCERT never.
Now you should be able to use ldaps:// when connecting to MS-AD.
Appendices
Child Domains and the Global Catalog in MS Active Directory
Moodle currently only has limited support for multiple domain controllers; specifically it expects each of the LDAP servers listed to contain identical sets of information. If you have users in multiple domains this presents an issue. One solution when working with MS-AD is to use the Global Catalog. The Global Catalog is designed to be a read-only, partial representation of an entire MS-AD forest, designed for searching the entire directory when the domain of the required object is not known.
For example your organisation has a main domain example.org, staff and students are contained in two child domains staff.example.org and students.example.org. The 3 domains (example.org, staff.example.org and students.example.org) each have a domain controller (dc01, dc02 and dc03 respectively.) Each domain controller contains a full, writable, representation of only the objects that belong to its domain. However, assuming that the Global Catalog has been enabled (see below) on one of the domain controllers (for example dc01) a query to the Global Catalog would reveal matching objects from all three domains. The Global Catalog is automatically maintained through replication across the active directory forest, it can also be enabled on multiple servers (if, for example, you need redundancy / load balancing.)
To make use of this in Moodle to allow logins from multiple domains is simple. The Global Catalog runs on port 3268 as opposed to 389 for standard LDAP queries. As a result, still assuming the Global Catalog is running on dc01, the 'ldap_host_url' would be ldap://dc01.example.org:3268. The rest of the settings are the same as for other MS-AS Auth setups.
You should use the 'ldap_contexts' setting to indicate the locations of individuals you wish to grant access. To extend the example above a little: In the example.org domain users are all in the 'Users' OU, in the staff.example.org domain users are in two OUs at the root of the domain, 'Support Staff' and 'Teaching Staff' , and in the students.example.org domain students are in an OU indicating the year that they enrolled, all of which are under the 'Students' OU. As a result our 'ldap_contexts' setting may look a little like this: 'OU=Users,DC=example,DC=org; OU=Support Staff,DC=staff,DC=example,DC=org; OU=Teaching Staff,DC=staff,DC=example,DC=org; OU=Students,DC=students,DC=example,DC=org.' The 'ldap_search_sub' option should be set to 'Yes' to allow moodle to search within the child OUs.
Its worth noting that the Global Catalog only contains a partial representation of the attributes of each object, as defined in the Partial Attribute Set supplied by Microsoft. However common information likely to be of use to a general Moodle installation (Forename, Surname, Email Address, sAMAccountName etc) is included in the set. For specific needs the schema can be altered to remove or add various attributes.
In most cases the Global Catalog is read-only, update queries must be made over the standard LDAP ports to the domain controller that holds the object in question (in our example, updating a student's details would require an LDAP query to the students.example.org domain controller - dc03, it would not be possible to update details by querying the Global Catalog.) The exception to this would be in an environment where there is only a single domain in the active directory forest; in this case the Global Catalog holds a writable full set of attributes for each object in the domain. However, for the purposes of Moodle authorisation, there would be no need to use the Global Catalog in this case.
Enabling the Global Catalog
The Global Catalog is available on Windows 2000 and Windows 2003 Active Directory servers. To enable, open the ‘Active Directory Sites and Services’ MMC (Microsoft Management Console) snap-in. Extend ‘Sites’ and then the name of the Site containing the active directory forest you wish to use. Expand the server you wish to enable the Global Catalog on, right click ‘NTDS settings’ and select the ‘Properties’ tab. To enable, simply click the ‘Global Catalog’ checkbox. Under a Windows 2000 server it is necessary to restart the server (although it won’t prompt you to); under Windows 2003 server it is not necessary to restart the server. In either case you will generally have to wait for the AD forest to replicate before the Global Catalog offers a representation of the entire AD forest. Changes made in Active Directory will also be subject to a short delay due to the latency involved with replication. If your AD servers are firewalled port 3268 will need to be opened for Global Catalog servers. If your organisation uses Microsoft Exchange then it its highly likely that at least one Domain Controller will already have Global Catalog enabled – Exchange 2000 and 2003 rely on the Global Catalog for address information, users also access the Global Catalog when using the GAL (Global Address List)
ldap auth_user_create() only suports Novell
After configuring user authentication with ldap I realized ldap only support edir (Novell) when combining ldap an email user confirmation. For example in my case (I use openldap) I have the following error after filling the user form:
auth: ldap auth_user_create() does not support selected usertype:"rfc2307" (..yet)
Template:Moodle 1.9 The previous comment only applies to Moodle 1.8 and below. Moodle 1.9 adds support for MS Active Directory too.
Active Directory with Moodle 1.8
There is an issue with the PHP ldap options that are required for Active Directory access in version 1.8 of Moodle.
Using moodle on a LAMP platform with authentication to Active Directory may give some errors.
Check this bug [https://tracker.moodle.org/browse/MDL-10921 MDL-10921] or this post http://moodle.org/mod/forum/discuss.php?d=78316 for further information.
See also
- Using Moodle: User authentication forum
- Using Moodle PHP LDAP module does not seem to be present forum discussion
- NTLM_authentication
- LDAP enrolment
