Mail server and address lookup by Sendmail using OpenLDAP.

[Kristina <kristina@fsas.fujitsu.co.jp>]

I am posting  to you all again about what I am trying to do with Sendmail an
d OpenLDAP.

My organization has thousands of users.  In an attempt to make management
of user accounts easier I have been assigned with creating an LDAP directory
service for our relay mail server(mail hub).

I want to register all user accouts on the LDAP server which the
relay mail server(mail hub) will look up for email routing to our three mail
servers. 
**That is, the mail hub will refer to LDAP to know to which
mail host(mail server) it should relay the mail for a particular user**  WHICH
AT THE SAME TIME PROVIDES A SECURITY FUNCTION AS MAIL SENT TO OR FROM A USER
NOT REGISTERED ON THE LDAP SERVER WILL NOT BE RELAYED THE MAIL BY THE
MAIL HUB** (Below is a basic diagram)

Upon reading the Man pages for mail500 I need to write a base array which
corresponds my LDAP.  HOWEVER, MY FIRST QUESTION IS
WHAT OBJECT CLASSES AND ATTRIBUTES DO I USE IN LDAP TO CONTAIN
THE EMAIL ADDRESS AND MAIL SERVER OF USERS?

At first, I thought I should use the "inetOrgPerson" objectclass as it has an 
optional "mail" attribute and I thought that putting users of server1 as one
ou, and users of server2 under another ou.  However, I am confused because the
example in the man page of mail500 does not use the mail attribute, it uses
"uid" and "cn".
Then again, there is the Sendmail with LDAP support method and the Stanford 
method of "rfc822mailbox" as described at
http://www.stanford.edu/group/networking/directory/doc/NotesOnDITDesign-22-O
ct-1998.txt.
 

Please advize me on the best method: Sendmail with LDAP support, mail500 or
the rfc822mailbox method and how to set up my LDAP objectclasses and attribu
tes.

Thanks so very much for all your replies ...........I look forward to many
more!!
See ya,
Kristina