Applies to: Exchange Server 2013
Topic Last Modified: 2013-02-19
In Microsoft Exchange Server 2010, the Mailbox server role hosted both mailbox and public folder databases and also provided email message storage. Now, in Exchange Server 2013, the Mailbox server role also includes the Client Access protocols, Transport service, mailbox databases, and Unified Messaging components.
In Exchange 2013, the Mailbox server role interacts directly with Active Directory, the Client Access server, and Microsoft Outlook clients in the following process:
- The Mailbox server uses LDAP to access recipient, server, and
organization configuration information from Active Directory.
- The Client Access server sends requests from clients to the
Mailbox server and returns data from the Mailbox server to the
clients. The Client Access server also accesses online address book
(OAB) files on the Mailbox server through NetBIOS file sharing. The
Client Access server sends messages, free/busy data, client profile
settings, and OAB data between the client and the Mailbox
- Outlook clients inside your firewall access the Client
Access server to send and retrieve messages. Outlook clients
outside the firewall can access the Client Access server by using
Outlook Anywhere (which uses the RPC over HTTP Proxy
- Public folder mailboxes are accessible via RPC over HTTP,
regardless of whether the client is outside or inside the
- The administrator-only computer retrieves Active Directory
topology information from the Microsoft Exchange Active Directory
Topology service. It also retrieves email address policy
information and address list information.
- The Client Access server uses LDAP or Name Service Provider
Interface (NSPI) to contact the Active Directory server and
retrieve users' Active Directory information.
Mailbox and Client Access server interaction and architecture
For more details, see the “Exchange 2013 architecture” section in What's New in Exchange 2013.
New Mailbox features
The following list briefly describes some new and some improved features in the Mailbox role for Exchange 2013:
- Evolution of the Exchange 2010 database availability group
- Transaction log code has been refactored for fast failover with
deep checkpoint on passive database copies.
- To support enhanced site resiliency, servers can be in
- Transaction log code has been refactored for fast failover with deep checkpoint on passive database copies.
- Exchange 2013 now hosts some Client Access components, the
Transport components, and the Unified Messaging components.
- The Exchange Store has been re-written in managed code to
improve performance in additional I/O reduction and
- Each Exchange 2013 database now runs under its own process.
- Smart Search has replaced the Exchange 2010 multi-mailbox
Securing Mailbox servers
By default, HTTP, Microsoft Exchange ActiveSync, POP3, and IMAP4 communication between the Mailbox servers and other Exchange server roles, domain controllers, and global catalog servers is encrypted. In addition, make sure that your Mailbox servers aren't accessible to the Internet.