Introduction to LDAP
LDAP (Lightweight Directory Access Protocol) is a network protocol that can be used to share databases of Unix users, groups and other information between multiple systems.
Typically, a single LDAP Server will store a database of users, which is then queried by multiple LDAP Clients. If these clients also mount home directories via NFS, users will be able to login to any one of those systems with the same username and password. In many ways, LDAP is used similarly to NIS for synchronizing user information across multiple systems in a network, as a database can store additional attributes for each user in addition to the standard Unix username, shell and so on.
Naturally, an LDAP server must be running on your system or on some host on your network for this module to be used. In addition, one or more hosts must be configured to use LDAP for user and/or group authentication. Neither of these tasks can be done from within the module - they must be done manually, or with other Webmin modules for the purpose.
If you have Samba Windows File Sharing configured to use an LDAP server as well, LDAP server module can also create and manage the necessary password attributes for each LDAP user to be able to login to the Samba server as well. For this feature to work, your LDAP server must be configured to support the additional Samba attributes and object class for each user in its schema. Only when the Samba login? option is set to Yes will the Samba attributes be created.
Cyrus IMAP server
The module can also create users on a Cyrus IMAP server, if it is set up to authenticate against the same LDAP database. It will create mailboxes for each new user, subscribe the user to his mailboxes and grant admin access to them. If an LDAP user is deleted, his IMAP mailbox will be as well. Currently this feature only works with the Cyrus IMAP server - it has not been tested and is probably not even necessary for other servers, which use users' home directories for mail storage.