- The mailbox server role (formally known as a back-end server in Exchange 2003)
- The client access server role (formally known as a front-end server in Exchange 2003)
- Client Access service
- Front End Transport service
- Provides a unified namespace, authentication, and network security.
- Handles all client requests for Exchange.
- Routes requests to the correct Mailbox server.
- Proxies or redirects client requests for legacy servers, such as Exchange 2007 and Exchange 2010 Client Access.
- Enables the use of layer 4 (TCP affinity) routing... i.e. stupid load balances with no affinity.
- Protocol level filtering Performs connection, recipient, sender, and protocol filtering
- Network protection Centralized, load-balanced egress and ingress point for the organization.
- Mailbox locator Avoids unnecessary hops by determining the best Mailbox server to deliver the message to.
- Load-balances client and application SMTP requests.
- All Outlook Web App, Active Sync and Outlook Anywhere (RPC over HTTP) sessions are processed on the Exchange 2013 mailbox servers
- The message queue and mail routing is performed on the mailbox servers (which the exception of the mailbox locator service on the client access which provides the ability to always deliver inbound mail to the correct mailbox server in the same AD site)
- Provides Unified Messaging services
- And of course it acts as a mailbox server providing companies enhanced Database Availability Groups (DAGs) which are improved over Exchange 2010.
Now why did Microsoft make such significant changes to the Architecture in Exchange 2013? When Exchange 2007 released the concept of a multi-role servers, processing power was significantly less then what it is today. Large scale deployments of Exchange 2003 which extended into the hundreds of thousands of users faced significant resource limitations due to hardware back in the day. Microsoft needed to address this to allow Exchange to extend into larger scale deployments and as a result separate the server roles.
Due to a lot of smart people doing a lot of smart things over the years, today's servers have so much grunt we are virtualising to try and make use of it all. This architecture of multi-role servers no longer makes sense! In fact for large scale deployments of Exchange, as of Ex2010 SP1, Microsoft started recommending building all Exchange 2010 servers as multi-role servers and simply adding an additional server when required as a simple unit of scaling out. The recommendations for multi-role Exchange servers can be found here:
Now the problem here is the Exchange 2010 roles have been designed to run on separate servers and when all installed on the same server they still follow the same processes to communicate with one another through a TCP network call on localhost. This creates inefficiencies as separate roles are all operating on the same server when the roles could be more incorporated to work more as one to provide better performance. In fact this is one of the selling points behind Exchange 2013 from Microsoft:
"been re-written in managed code to improve performance in additional IO reduction and reliability."
First of all what operating systems are supported to install Exchange Server 2013? Easy one:
- Windows Server 2008 R2 Standard, Enterprise and Datacenter Editions or higher. Make sure it is R2 as 2008 is not supported.
- Windows Server 2012
- Exchange 2007
- Exchange 2010
Whilst Exchange 2013 now has greater support for IPv6 such as Unified Messaging now supporting IPv6, a pure IPv6 environment isn't supported. IPv6 is only supported when IPv4 is also used.
Active Directory requirements are that of 2003 Forest Functional Level (FFL) and 2003 Domain Functional Level (DFL) or higher. Schema master must run on Server 2003 SP2 or higher.
At this stage Exchange 2013 only supports the following clients:
- Outlook 2013 Preview
- Outlook 2010 SP1 with April 2012 Cumulative Update
- Outlook 2007 SP3 with July 2012 Cumulative Update
- Entourage 2008 for Mac, Web Services Edition
- Outlook for Mac 2011
Can you install the Exchange 2013 Client Access Role and the Exchange 2013 Mailbox Role on the same server?
The answer is Yes.
Edge Transport Role
Currently there is no Edge Transport role for Exchange 2013. Microsoft are advising customers to use Exchange 2010 SP2 Edge Transport with Exchange 2013 for now. Due to a tight product release time frame the Exchange product team have not had time to develop the Exchange 2013 edge transport role however this role will be released in the future through a service pack.
A New Management Interface
The popular Exchange Management Console (EMC) which was used by for managing Exchange 2007/2010 has been removed from Exchange 2013. Administrators are provided two methods for maintaining an Exchange 2013 environment:
- Exchange Management Shell (EMS) - also available in Exchange 2007/2010
- Exchange Administration Center (EAC) - new in Exchange 2013.