Exchange 2010 Reciepient Types and AD attributes required for enabling

Recipient type	Description
Dynamic distribution group	A distribution group that uses recipient filters and conditions to derive its membership at the time messages are sent.
Equipment mailbox	A resource mailbox that's assigned to a resource that’s not location-specific, such as a portable computer, projector, microphone, or a company car. Equipment mailboxes can be included as resources in meeting requests, providing a simple and efficient way of using resources for your users.
Linked mailbox	A mailbox that's assigned to an individual user in a separate, trusted forest.
Mail contact	A mail-enabled Active Directory contact that contains information about people or organizations that exist outside the Exchange organization. Each mail contact has an external email address. All messages sent to the mail contact are routed to this external email address.
Mail forest contact	A mail contact that represents a recipient object from another forest. Mail forest contacts are typically created by Microsoft Identity Integration Server (MIIS) synchronization. Important: Mail forest contacts are read-only recipient objects that are updated only through MIIS or similar custom synchronization. You can't use the EAC or the Shell to remove or modify a mail forest contact.
Mail user	A mail-enabled Active Directory user that represents a user outside the Exchange organization. Each mail user has an external email address. All messages sent to the mail user are routed to this external email address. A mail user is similar to a mail contact, except that a mail user has Active Directory logon credentials and can access resources.
Mail-enabled non-universal group	A mail-enabled Active Directory global or local group object. Mail-enabled non-universal groups were discontinued in Exchange Server 2007 and can exist only if they were migrated from Exchange 2003 or earlier versions of Exchange. You can't use Exchange Server 2013 to create non-universal distribution groups.
Mail-enabled public folder	An Exchange public folder that's configured to receive messages.
Distribution groups	A distribution group is a mail-enabled Active Directory distribution group object that can be used only to distribute messages to a group of recipients.
Mail-enabled security group	A mail-enabled security group is an Active Directory universal security group object that can be used to assign access permissions to resources in Active Directory and can also be used to distribute messages.
Microsoft Exchange recipient	A special recipient object that provides a unified and well-known message sender that differentiates system-generated messages from other messages. It replaces the System Administrator sender used for system-generated messages in earlier versions of Exchange.
Room mailbox	A resource mailbox that's assigned to a meeting location, such as a conference room, auditorium, or training room. Room mailboxes can be included as resources in meeting requests, providing a simple and efficient way of organizing meetings for your users.
Shared mailbox	A mailbox that's not primarily associated with a single user and is generally configured to allow access for multiple users.
Site mailbox	A mailbox comprised of an Exchange mailbox to store email messages and a SharePoint site to store documents. Users can access both email messages and documents using the same client interface. For more information, see Site Mailboxes.
User mailbox	A mailbox that's assigned to an individual user in your Exchange organization. It typically contains messages, calendar items, contacts, tasks, documents, and other important business data.
Office 365 mailbox	In hybrid deployments, an Office 365 mailbox consists of a mail user that exists in Active Directory on-premises and an associated cloud mailbox that exists in Exchange Online.
Linked user	A linked user is a user whose mailbox resides in a different forest than the forest in which the user resides.