Demystifying the CAS Array Object – Part 1

Since its release in 2009, the interest in Exchange 2010 has been fantastic. While working with customers to educate them and prep them for moving to Exchange 2010, we've uncovered some common misconceptions. One trend has to do with misconceptions around the Client Access Server array object, or CAS array object for short. Technical Writer and frequent blogger Scott Schnoll suggested I put pen to paper… err… keys to keyboard (?) when I was commenting on this trend on an internal Microsoft distribution group, so here we are with this post.

I’m not going to go into all of the technical aspects of a CAS array object in this post. That's already been covered wonderfully by Nagesh Magadev in a prior post: Exploring Exchange 2010 RPC Client Access service.

The following list is a collection of truths many customers are not aware of when it comes to the CAS array object which I'll try to demystify. Part 1 will discuss the first three items and l'll cover the last three items in part 2.

  1. A CAS array object does not load balance your traffic
  2. A CAS array object does not service Autodiscover, OWA, ECP, EWS, IMAP, POP, or SMTP
  3. A CAS array object does not need to be part of your SSL certificate
  4. A CAS array object should not be resolvable via DNS by external clients
  5. A CAS array object should not be configured or changed after creating Exchange 2010 mailbox databases and moving mailboxes into the databases
  6. A CAS array object should be configured even if you only have one CAS or a single multi-role server.

Read out the complete article at

Read my favorites blogs:

Designing a backup less Exchange 2010 Architecture

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Microsoft Exchange 2010 CAS Array – Steps and Recommendations

Appear Offline in Microsoft Office Communicator Server 2007

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