User Authentication with LDAP¶
ownCloud ships an LDAP backend, which allows full use of ownCloud for user logging in with LDAP credentials including:
- LDAP group support
- File sharing with users and groups
- Access via WebDAV and of course ownCloud Desktop Client
- Versioning, external Storages and all other ownCloud Goodies
To connect to an LDAP server the configuration needs to be set up properly. Once the LDAP backend is activated (Settings→Apps, choose LDAP user and group backend, click on Enable) the configuration can be found on Settings→Admin. Read on for a detailed description of the configuration fields.
The basic settings are all you need. However, if you have a larger directory, custom requirements or need to connect to Active Directory (AD) you want to have a look on the advanced settings afterwards. The basic part allows you to set up a working connection to your LDAP server and use it with ownCloud.
Note that a hint will be shown on the right hand side, when hovering with the mouse over an input field. This gives you more context information while filling out the settings.
- Server configuration:
ownCloud can be configured to connect to multiple LDAP servers. Using this control you can pick a configuration you want to edit or add a new one. The button Delete Configuration deletes the current configuration.
- Example: 1. Server
The host name of the LDAP server. It can also be a ldaps:// URI, for instance.
- Example: directory.my-company.com
- Base DN:
The base DN of LDAP, from where all users and groups can be reached. Separated Base DNs for users and groups can be set in the Advanced tab. Nevertheless, this field is mandatory.
- Example: dc=my-company,dc=com
- User DN:
The name as DN of a user who is able to do searches in the LDAP directory. Let it empty for anonymous access. It is recommended to have a special system user for ownCloud.
- Example: uid=owncloudsystemuser,cn=sysusers,dc=my-company,dc=com
- The password for the user given above. Empty for anonymous access.
- User Login Filter:
The filter to use when a users tries to login. Use %uid as placeholder for the user name. Note, that login applies this filter only, but not User List Filter. This may change in future.
- Example (allows login with user name and email address): (|(uid=%uid)(email=$uid))
- User List Filter:
The filter to use when a search for users will be executed.
- Example: objectClass=posixAccount
- Group Filter:
The filter to use when a search for groups will be executed. In case you do not want to use LDAP groups in ownCloud, leave it empty.
- Example: objectClass=posixGroup
In the LDAP Advanced settings section you can define options, that are less common to set. They are not needed for a working connection, unless you use a non-standard Port, e.g. It can also have a positive effect on the performance to specify distinguished bases for user and group searches.
The Advanced Settings are structured into three parts: * Connection Settings * Directory Settings * Special Attributes
- Configuration Active:
Enables or Disables the current configuration. Disabled configuration will not connect to the LDAP server.
- Example: [X]
The port on which to connect to the LDAP server.
- Example: 389
- Backup (Replica) Host:
A backup server can be defined here. ownCloud tries to connect to the backup server automatically, when the main host (as specified in basic settings) cannot be reached. It is import that the backup server is a replica of the main server, because the object UUIDs must match.
- Example: directory2.my-company.com
- Backup (Replica) Port:
The port on which to connect to the backup LDAP server. If no port is given, but a host, then the main port (as specified above) will be used.
- Example: 389
- Disable Main Server:
You can manually override the main server and make ownCloud only connect to the backup server. It may be handy for planned downtimes.
- Example: [ ]
- Use TLS:
Whether to use TLS encrypted connection to the LDAP server. This will be ignored when “ldaps://” protocol is specified in the host entries.
- Example: [ ]
- Case insensitive LDAP server (Windows):
Whether the LDAP server is running on a Windows Host
- Example: [ ]
- Turn off SSL certificate validation:
Turns of check of valid SSL certificates. Use it – if needed – for testing, only!
- Example: [ ]
- Cache Time-To-Live:
A cache is introduced to avoid unnecessary LDAP traffic, for example lookups check whether the users exists on every page request or WebDAV interaction. It is also supposed to speed up the Admin → User page or list of users to share with, once it is populated. Saving the configuration empties the cache (changes are not necessary). The time is given in seconds.
Note that almost every PHP request would require to build up a new connection to the LDAP server. If you require a most up-to-dateness it is recommended not to totally switch off the cache, but define a minimum life time of 15s.
- Example (10 min): 600
- User Display Name Field:
The attribute that should be used as display name in ownCloud. Prior to ownCloud 5 it was used as internal user name. This is not the case anymore. It also means that display names are not permanent in ownCloud, i.e. if the attribute’s value changes in LDAP, it changes in ownCloud too. Display names to not need to be unique, but you rather want to specify a more or less unique attribute here to avoid confusion.
- Example: displayName
- Base User Tree:
The base DN of LDAP, from where all users can be reached. It needs to be given completely despite to the Base DN from the Basic settings. You can specifiy multiple base trees, one in each line.
- User Search Attributes:
These attributes are used when a search for users with a search string is done. This happens, for instance, in the share dialogue. By default the user display name attribute as specified above is being used. Multiple attributes can be given, one in each line.
- Group Display Name Field:
The attribute that should be used as ownCloud group name. ownCloud allows a limited set of characters (a-zA-Z0-9.-_@), every other character will be replaced in ownCloud. Once a group name is assigned, it will not be changed, i.e. changing this value will only have effect to new LDAP groups.
- Example: cn
- Base Group Tree:
The base DN of LDAP, from where all groups can be reached. It needs to be given completely despite to the Base DN from the Basic settings. You can specifiy multiple base trees, one in each line.
- Group Search Attributes:
These attributes are used when a search for groups with a search string is done. This happens, for instance, in the share dialogue. By default the group display name attribute as specified above is being used. Multiple attributes can be given, one in each line.
- Group Member association:
The attribute that is used to indicate group memberships, i.e. the attribute used by LDAP groups to refer to their users.
- Example: uniquemember
- Quota Field:
ownCloud can read an LDAP attribute and set the user quota according to its value. Specify the attribute here, otherwise keep it empty. The attribute shall return human readable values, e.g. “2 GB”.
- Example: ownCloudQuota
- Quota Default:
Override ownCloud default quota for LDAP users who do not have a quota set in the attribute given above.
- Example: 15 GB
- Email Field:
ownCloud can read an LDAP attribute and set the user email there from. Specify the attribute here, otherwise keep it empty.
- Example: mail
- User Home Folder Naming Rule:
By default, the ownCloud creates the user directory, where all files and meta data are kept, according to the ownCloud user name. You may want to override this setting and name it after an attribute’s value. The attribute given can also return an absolute path, e.g. /mnt/storage43/alice. Leave it empty for default behavior.
- Example: cn
Expert Settings (>= ownCloud 5.0.7)¶
In the Expert Settings fundamental behavior can be adjusted to your needs. The configuration should be done before starting production use or when testing the installation.
- Internal Username:
The internal username is the identifier in ownCloud for LDAP users. By default it will be created from the UUID attribute. By using the UUID attribute it is made sure that the username is unique and characters do not need to be converted. The internal username has the restriction that only these characters are allowed: [a-zA-Z0-9_.@-]. Other characters are replaced with their ASCII correspondence or are simply omitted.
The LDAP backend ensures that there are no duplicate internal usernames in ownCloud, i.e. that it is checking all other activated user backends (including local ownCloud users). On collisions a random number (between 1000 and 9999) will be attached to the retrieved value. For example, if “alice” exists, the next username may be “alice_1337”.
The internal username is also the default name for the user home folder in ownCloud. It is also a part of remote URLs, for instance for all *DAV services. With this setting the default behaviour can be overriden. To achieve a similar behaviour as before ownCloud 5 enter the user display name attribute in the following field.
Leave it empty for default behaviour. Changes will have effect only on newly mapped (added) LDAP users.
- Example: uid
- Override UUID detection
By default, ownCloud autodetects the UUID attribute. The UUID attribute is used to doubtlessly identify LDAP users and groups. Also, the internal username will be created based on the UUID, if not specified otherwise above.
You can override the setting and pass an attribute of your choice. You must make sure that the attribute of your choice can be fetched for both users and groups and it is unique. Leave it empty for default behaviour. Changes will have effect only on newly mapped (added) LDAP users and groups. It also will have effect when a user’s or group’s DN changes and an old UUID was cached: It will result in a new user. Because of this, the setting should be applied before putting ownCloud in production use and cleaning the bindings (see below).
The default behaviour does not differ from ownCloud 4.5. You do not want to change this after upgrading from ownCloud 4.5 unless you update the mapping tables yourself.
- Example: cn
- Username-LDAP User Mapping
ownCloud uses the usernames as key to store and assign data. In order to precisely identify and recognize users, each LDAP user will have a internal username in ownCloud. This requires a mapping from ownCloud username to LDAP user. The created username is mapped to the UUID of the LDAP user. Additionally the DN is cached as well to reduce LDAP interaction, but it is not used for identification. If the DN changes, the change will be detected by ownCloud by checking the UUID value.
The same is valid for groups.
The internal ownCloud name is used all over in ownCloud. Clearing the Mappings will have leftovers everywhere. Do never clear the mappings in a production environment. Only clear mappings in a testing or experimental stage.
Clearing the Mappings is not configuration sensitive, it affects all LDAP configurations!
Testing the configuration¶
In this version we introduced the Test Configuration button on the bottom of the LDAP settings section. It will always check the values as currently given in the input fields. You do not need to save before testing. By clicking on the button, ownCloud will try to bind to the ownCloud server with the settings currently given in the input fields. The response will look like this:
In case the configuration fails, you can see details in ownCloud’s log, which is in the data directory and called owncloud.log or on the bottom the Settings → Admin page. Unfortunately it requires a reload – sorry for the inconvenience.
In this case, Save the settings. You can check if the users and groups are fetched correctly on the Settings → Users page.
Troubleshooting, Tips and Tricks¶
SSL Certificate Verification (LDAPS, TLS)¶
A common mistake with SSL certificates is that they may not be known to PHP. If you have trouble with certificate validation make sure that
- you have the certificate of the server installed on the ownCloud server
- the certificate is announced in the system’s LDAP configuration file (usually /etc/ldap/ldap.conf on Linux, C:\openldap\sysconf\ldap.conf or C:\ldap.conf on Windows) using a TLS_CACERT /path/to/cert line.
- Using LDAPS, also make sure that the port is correctly configured (by default 686)
Microsoft Active Directory¶
In case you want to connect to a Windows AD, you must change some values in the Advanced tab.
- The default login filter will not work with AD. Use “samaccountname=%uid” instead.
- The default in User Display Name Field will not work with Active Directory.
- The Group Member association must be set to “member (AD)”
- Check Case insensitive LDAP server (Windows)
Duplicating Server Configurations¶
In case you have a working configuration and want to create a similar one or “snapshot” configurations before modifying them you can do the following:
- Go to the LDAP Basic tab
- On Server Configuration choose Add Server Configuration
- Answer the question Take over settings from recent server configuration? with yes.
- (optional) Switch to Advanced tab and uncheck Configuration Active in the Connection Settings, so the new configuration is not used on Save
- Click on Save
Now you can modify the configuration and enable it if you wish.
ownCloud LDAP Internals¶
Some parts of how the LDAP backend works are described here. May it be helpful.
User and Group Mapping¶
In ownCloud the user or group name is used to have all relevant information in the database assigned. To work reliably a permanent internal user name and group name is created and mapped to the LDAP DN and UUID. If the DN changes in LDAP it will be detected, there will be no conflicts.
Those mappings are done in the database table ldap_user_mapping and ldap_group_mapping. The user name is also used for the user’s folder (except something else is specified in User Home Folder Naming Rule), which contains files and meta data.
As of ownCloud 5 internal user name and a visible display name are separated. This is not the case for group names, yet, i.e. group cannot be altered.
That means that your LDAP configuration should be good and ready before putting it into production. The mapping tables are filled early, but as long as you are testing, you can empty the tables any time. Do not do this in production. If you want to rename a group, be very careful. Do not rename the user’s internal name.
For performance reasons a cache has been introduced to ownCloud. He we store all users and groups, group memberships or internal userExists-requests. Since ownCloud is written in PHP and each and every page request (also done by Ajax) loads ownCloud and would execute one or more LDAP queries again, you do want to have some of those queries cached and save those requests and traffic. It is highly recommended to have the cache filled for a small amount of time, which comes also very handy when using the sync client, as it is yet another request for PHP.
Handling with Backup Server¶
When ownCloud is not able to contact the main server, he will be treated as offline and no connection attempts will be done for the time specified in Cache Time-To-Live. If a backup server is configured, it will be connected instead. If you plan a maintained downtime, check Disable Main Server for the time being to avoid unnecessary connection attempts every now and then.