Mail-Enabling User Objects
Mail-enabled user or inetOrgPerson objects are objects that have an e-mail address, but they do not have a mailbox stored on the servers running Exchange in that forest. These objects are similar to a contact, which can also be mail-enabled, except that there are security rights associated with the user object that a contact object does not possess within the forest boundary. To mail-enable a user or inetOrgPerson object, the Exchange Administrator must have the Exchange delegated role, Exchange View-Only Administrator (or higher), on the target administrative group. In addition, the Exchange Administrator must have Read and Write access to the following user or inetOrgPerson Object attributes:
adminDisplayName
autoReplyMessage (ILS Settings)
displayName (Display Name)
dLMemDefault
homeMDB (Exchange Mailbox Store)
homeMTA
internetEncoding
legacyExchangeDN
mail (E-Mail Address)
mailNickname (Alias)
mAPIRecipient
msExchADCGlobalNames
msExchControllingZone
msExchFBURL
msExchHideFromAddressLists
msExchHomeServerName (Exchange Home Server)
msExchMailboxGuid
msExchMailboxSecurityDescriptor
msExchPoliciesExcluded
msExchPoliciesIncluded
msExchResourceGUID
proxyAddresses (Proxy Addresses)
showInAddressBook
targetAddress
textEncodedORAddress