Configure your LDAP client with the local IP address of your server, port number 389, and the server root parameter as dc=yourdomain,dc=com (or,net, org, edu, etc.)
For Outlook 2000: 
1)Tools->Accounts->Directory-Services(Tab)->
  [Add]->Directory-Service
    Internet directory (LDAP) server: __some-name__
    Logon is *NOT* required
  [Next]
    Check Email Addresses: __your-choice-Yes-or-No__
  [Next]->[Finish]
  Click the [Properties] button
  General Tab
    
     Fill-in the server name (or IP address)
  Advance Tab
    
     Server Port Number: __389__
     Search Base: __dc=yourdomain,dc=com___
  Click [OK], then [Close]