Section Five - Use of the Directory

20.	Overview

This section describes the uses to which the MHS may put the Directory if it is present. If the Directory is unavailable to the MHS, how, if at all, the MHS performs these same tasks is a local matter.

This section covers the following topics:

a)	Authentication

b)	Name resolution

c)	DL expansion

d)	Capability assessment

21.	Authentication

A functional object may accomplish authentication using information stored in the Directory.

22.	Name Resolution

A functional object may accomplish name resolution using the Directory.

To obtain the O/R address(es) of a user or DL whose Directory name it possesses, an object presents that name to the Directory and requests from the object's Directory entry the following attributes:

a)	MHS O/R Addresses

b)	MHS Preferred Delivery Methods

To do this successfully, the object must first authenticate itself to the Directory and have access rights to the information requested.

23.	DL Expansion

A functional object may accomplish DL expansion using the Directory, first verifying that the necessary submit permissions exist.

To obtain the members of a DL whose Directory name it possesses, the object presents that name to the Directory and requests from the object's Directory entry the following attributes:

a)	MHS DL Members

b)	MHS DL Submit Permissions

c)	MHS Preferred Delivery Methods

To do this successfully, the MTA must first authenticate itself to the Directory and have access rights to the information requested.

24.	Capability Assessment

A functional object may assess the capabilities of a user or MS using the Directory.

The following Directory attributes represent user capabilities of possible significance in Message Handling:

a)	MHS Deliverable Content Length

b)	MHS Deliverable Content Types

c)	MHS Deliverable EITs

d)	MHS Preferred Delivery Methods

The following Directory attributes represent MS capabilities of possible significance in Message Handling:

a)	MHS Supported Automatic Actions

b)	MHS Supported Content Types

c)	MHS Supported Optional Attributes

To assess a particular capability of a user or MS whose Directory name it possesses, the object presents that name to the Directory and requests from the object's Directory entry the attribute associated with that capability.

To do this successfully, the MTA must first authenticate itself to the Directory and have access rights to the information requested.