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.