LDAP can be used to identify mail recipients by configuring the mail transport agent (MTA) to issue queries to a suitable service. Where necessary, the following definitions need to be incorporated into the example configuration files given below:
| Definition | Purpose |
| LDAP_SERVICE_BIND_DN | LDAP user identity to connect to the service |
| LDAP_SERVICE_PASSWORD | LDAP user password for connection |
| LDAP_HOST | The host providing the LDAP service |
| LDAP_PORT | The port number of the LDAP service |
| LDAP_BASE_DN | The section of the database to search |
Example configuration files for Exim are distributed in conf/exim/ldap:
File | Purpose |
010_exim4-config_ldap_people_outgoing | Defines recipients and outgoing mail routing |
020_exim4-config_ldap_people | |
020_exim4-config_ldap_resources | |
020_exim4-config_ldap_people_outgoing_recipients |
Where local SMTP routing is being performed and the recipients are local system users, the following file is also useful:
File | Purpose |
020_exim4-config_ldap_people_local_system | Defines routing for local recipients for delivery to local system mailboxes |
These files can be incorporated into the Exim configuration. On Debian systems, they can be copied into /etc/exim4/conf.d/router.
Example configuration files for Postfix are distributed in conf/postfix/ldap:
File | Purpose |
main.cf.example | Defines recipients and outgoing mail routing (for inclusion in main.cf) |
virtual_alias_maps_people.cf | Defines recipients and outgoing mail routing |
virtual_alias_maps_people_outgoing.cf | |
virtual_alias_maps_resources.cf |
The following files are common to LDAP and simple integration and are found in conf/postfix:
File | Purpose |
master.cf.items | Mail handler definitions for the imip-agent transports |
transport | Transport definitions for /etc/postfix/transport |
virtual | Outgoing message routing for /etc/postfix/virtual |
These files can be incorporated into the Postfix configuration. On Debian systems, master.cf.items can be merged into /etc/postfix/master.cf, whereas the other files can be merged into any existing files of the same names in /etc/postfix.
Relevant LDAP resources for structuring recipient information include the following:
RFC | Relevance |
Defines the posixAccount object class | |
Defines the calEntry object class supporting calFBURL | |
Defines the inetOrgPerson object class | |
Defines the mail attribute |
An additional draft RFC describes the mailRecipient object class:
Resource schemas for LDAP are not effectively standardised for the purposes of this software. A useful object class, inetResource, was defined for the iPlanet Calendar Server:
Although Kolab maintains notions of resources, they are tied up with the notion of a shared folder and the kolabSharedFolder object class, although the mailRecipient object class is employed by resources in Kolab.