Some external application and devices (such as external E-mail filters) use the LDAP protocol to verify if the E-mail recipient should be accepted on behalf of the "main" mail server. These applications check a object@domain E-mail address using one of the following requests:
To support these application and devices, the CommuniGate Pro LDAP module implements a virtual dc=cgprouter Directory subtree. If a 'record retrieval' (scope=base) request DN is mail=object@domain,dc=cgprouter, or a 'record search' (scope=one) request DN is dc=cgprouter, and the search filter is mail=object@domain, the LDAP module does not consult the Directory. Instead, it tries to process the specified object@domain E-mail address using the Router component.
If the specified E-mail address is successfully routed to a local Account, or to the "Black Hole", or it is routed to an external host, but relaying to that host is allowed, the LDAP module returns a fictitious Directory record, informing an application that the supplied E-mail address is a valid one, and E-mail sent to that address can be accepted.
If the address can not be routed (or relaying is not allowed) and the request was the 'record search' one, the result is empty. If the request was the 'record retrieval' one, the result delivers routing error.